Opened database successfully add two inverted commas for every one Medicine for Medical Students, Doctors, Physicians, Surgeons, Allied Healthcare Professionals

ABC Medical Notes.com
Free Open Access Medical Information











@About this App@Contributers@DeveloperACTH (Adrenocorticotropic hormone)AFP (Alpha-fetoprotein) TestingAIDS Dementia Complex (HIV)AIDS HIV InfectionAPGAR Scoring (Children)APTT and CoagulationAbacavirAbataceptAbbreviated Mental Test Score (AMTS)AbciximabAbdominal Aortic AneurysmAbdominal paracentesis for ascitesAbducent NerveAbetalipoproteinaemiaAbnormal Vaginal bleedingAcamprosateAcanthocytosisAcanthosis NigricansAcarboseAccelerated Idioventricular RhythmAcetazolamideAcetylcholine Receptor AntibodiesAcetylcholinesterase inhibitorsAchalasiaAchilles Tendon ruptureAchondroplasia (Children)AciclovirAcid maltase deficiency (Pompe disease)Acne RosaceaAcne VulgarisAcoustic Neuroma (Schwannoma)Acrodermatitis enteropathica (Children)Acromegaly and GiantismAcromio-clavicular jointActinomyces israeliAction PotentialActivated CharcoalActrapid (Insulin)Acute Abdominal Pain - Acute PeritonitisAcute Acalculous CholecystitisAcute Anaphylactoid ReactionsAcute AnaphylaxisAcute Angle Closure GlaucomaAcute AppendicitisAcute Bacterial MeningitisAcute BronchitisAcute CholangitisAcute CholecystitisAcute Colonic Pseudo-obstructionAcute Coronary Syndrome (ACS) GeneralAcute Coronary Syndrome (ACS) NSTEMI USAAcute Coronary Syndrome (ACS) STEMIAcute Coronary Syndrome (Cardiac Troponins)Acute Coronary Syndrome Grace scoreAcute DeliriumAcute Disc lesionsAcute Disseminated EncephalomyelitisAcute Diverticulitis - Diverticular diseaseAcute Dystonic ReactionAcute EncephalitisAcute Eosinophilic PneumoniaAcute EpiglottitisAcute Exacerbation of COPDAcute HepatitisAcute HydrocephalusAcute HypotensionAcute InflammationAcute Intermittent Porphyria (AIP)Acute Interstitial nephritisAcute Kidney Injury (AKI)Acute Limb IschaemiaAcute Liver FailureAcute Lymphoblastic Leukaemia (ALL)Acute MastoiditisAcute MonoarthritisAcute Myeloid Leukaemia (AML)Acute MyocarditisAcute PancreatitisAcute Pelvic Inflammatory DiseaseAcute PericarditisAcute Phase reactantsAcute PorphyriasAcute Promyelocytic LeukaemiaAcute Respiratory Distress Syndrome (Adults)Acute Retroviral Syndrome (HIV)Acute RhabdomyolysisAcute Rheumatic feverAcute Rotator cuff tearAcute Severe AsthmaAcute Severe ColitisAcute SinusitisAcute Stroke Assessment (ROSIER&NIHSS)Acute TonsilitisAcute Urinary RetentionAcute and Chronic GoutAcute and Chronic Heart FailureAcute on Chronic Liver Disease DecompensationAcutely Ill PatientAdalimumabAddenbrooke's Cognitive Examination-Revised (ACER)Addison Disease (Adrenal Insufficiency)AdefovirAdenosineAdenosine deaminase deficiencyAdhesive Capsulitis (Frozen Shoulder)Adjustment - Anxiety disordersAdrenal AntibodiesAdrenal PhysiologyAdrenaline (Epinephrine)AdrenoleukodystrophyAdrenomyeloneuropathyAdult Onset Still's DiseaseAfrican Trypanosomiasis (Sleeping sickness)Age related macular degenerationAicardi syndromeAir EmbolismAlbuminAlbumin-Protein Creatinine Ratio (PCR)Alcohol AbuseAlcohol Withdrawal (Delirium Tremens)Alcoholic (Steato)HepatitisAlcoholic KetoacidosisAldosterone PhysiologyAlendronate (Alendronic acid)AlfacalcidolAlkaline phosphatase (ALP)Alkalinisation of urineAlkaptonuriaAllergic Bronchopulmonary AspergillosisAllogeneic stem cell transplantationAllopurinolAlogliptin (Vipidia)AlopeciaAlpha FetoproteinAlpha ThalassaemiaAlpha subunit (ASU) of TSHAlpha-1 Antitrypsin (AAT) deficiencyAlport's SyndromeAlteplaseAltitude sicknessAluminium and Magnesium AntacidsAlveolar Gas EquationAlzheimer disease (Dementia)AmantadineAmenorrhoeaAmerican Trypanosomiasis (Chagas Disease)AmilorideAmino acidsAminoglycosidesAminophyllineAminosalicylatesAmiodaroneAmiodarone and Thyroid diseaseAmitriptylineAmlodipineAmmonia EncephalopathyAmnestic syndromesAmoebiasis (Entamoeba histolytica)AmoxicillinAmphetamine toxicityAmphotericin BAmpicillinAnaemia of Chronic DiseaseAnagrelideAnakinraAnal CancerAndexanet alfaAndrogen insensitivity syndromeAneurysmsAngina bullosa haemorrhagicaAngiodysplasiaAngiomyolipomaAngioneurotic OedemaAngiotensin Converting Enzyme InhibitorsAngiotensin Converting enzyme (ACE)Angular Stomatitis - CheilitisAnion GapAnkle and Foot fractures and InjuriesAnkle-Brachial pressure Index (ABPI)Ankylosing spondylitisAnorexia NervosaAntacid medicationAntepartum haemorrhageAnterior Horn Cell diseasesAnterior circulationAnti Dementia DrugsAnti-Cyclic Citrullinated Peptide (CCP) AntibodyAnti-D immunoglobulinAnti-Hu antibodiesAnti-OKT3 antibodiesAnti-RNP AntibodyAnti-Yo antibodiesAnti-neutrophilic cytoplasmic antibodies (ANCA)Antibiotics for Abdominal InfectionsAnticholinergic BurdenAnticholinergic syndromeAnticipationAnticoagulation and AntithromboticsAntidiuretic hormone (Vasopressin)Antigen presenting cellsAntimicrobial ChoicesAntimuscarinic drugsAntiphospholipid syndromeAntithrombin III deficiency (AT3)Aorta anatomyAortic DissectionAortic Regurgitation (Incompetence)Aortic SclerosisAortic StenosisAortoenteric fistulaApathetic thyrotoxicosisApixabanAplastic anaemiaApomorphineAppendix Cancer TumoursApproach to Assessing Sick ChildApproach to child with Acute GastroenteritisApproach to child with respiratory DistressArnold Chiari malformationArrhythmogenic Right ventricular CardiomyopathyArtemisininsArterial Blood gas analysisArterial Pulse assessmentArterial blood gas samplingArterial vs Venous vs Other Leg UlcersArteriovenous malformationsArtery of Percheron strokeArtery-to-artery embolic strokeArtesunateAsbestos Related Lung diseaseAscites Assessment and ManagementAspergillomaAspergillus fumigatusAspirinAspirin Salicylates toxicityAssessing Abdominal PainAssessing BreathlessnessAssessing Chest PainAssessing FallsAsteatotic eczemaAsthmaAstigmatismAstrocytomasAsystoleAtaxia TelangiectasiaAtazanavirAtenololAtherosclerosisAtopic Eczema or Atopic DermatitisAtorvastatinAtracuriumAtrial Ectopic beatsAtrial Fibrillation (Chemical cardioversion)Atrial Natriuretic Peptide (ANP)Atrial fibrillation (AF)Atrial flutterAtrial myxomaAtrial septal defect (ASD)Atrioventricular nodal reentrant tachycardiaAtropine SulfateAutoantibodiesAutoimmune Haemolytic anaemia (AIHA)Autoimmune HepatitisAutonomic neuropathyAutosomal DominantAutosomal Dominant Polycystic kidney diseaseAutosomal RecessiveAzathioprineAzithromycinB lymphocytesBRCA genes (Familial Breast Cancer)Bacillus anthracisBacillus cereus poisoningBackpain / BackacheBaclofenBacteriaBacteroides fragilisBalanitis (Adults)Balanitis (Children)Balkan endemic nephropathy (BEN)Balsalazide (Aminosalicylate)Barrett's oesophagusBartonellaBartters syndromeBasal Cell Carcinoma (BCC)Basic Fracture managementBasilar artery thrombosisBecker Muscular dystrophyBeclometasoneBeer PotomaniaBehavioural and Psychological Symptoms of DementiaBehcet's syndromeBell's palsyBendroflumethiazide (Bendrofluazide)Benign Paroxysmal Positional Vertigo (BPPV)Benign Prostatic HyperplasiaBenign recurrent intrahepatic cholestasisBenzodiazepine ToxicityBenzodiazepinesBenzylpenicillin Sodium (Penicillin G)Berg Balance ScaleBeriplexBerylliosisBeta AgonistsBeta Blocker toxicityBeta ThalassaemiaBeta-2 MicroglobulinBeta-lactamasesBetahistine (Serc)BezafibrateBiceps ruptureBilateral adrenalectomyBiliary atresiaBilirubinBiochemical Lab valuesBisacodylBisoprololBisphosphonatesBladder CancerBladder StonesBleedingBleeding disordersBleeding due to DrugsBleomycinBlindness - global causesBlood products - Packed cells blood transfusionBlood Products - CryoprecipitateBlood Products - Fresh Frozen PlasmaBlood Products - PlateletsBlood film interpretationBlood gas valuesBloody DiarrhoeaBlotting Techniques: Gel ElectrophoresisBone Marrow TransplantationBone disease Lab resultsBone metabolism RANK RANKL OPG pathwayBone scintigraphy (Bone scan)Bordetella pertussis - Whooping coughBorrelia burgdorferiBorrelia recurrentisBotulismBrachial neuritis (neuralgic amyotrophy)Brachial plexus anatomyBrachial plexus and associated injuryBrain AbscessBrain Anatomy and functionBrain MRIBrain Natriuretic Peptide (BNP)Brain PhysiologyBrain Tumours (Cancer)Brainstem anatomyBranchial cleft cystBreast CancerBreast FibroadenomaBretyliumBroad complex TachycardiaBromocriptineBronchial adenomaBronchiectasisBronchiolitisBronchoscopyBrown-Sequard syndromeBrucellaBrugada syndromeBudd-Chiari syndromeBudesonideBuerger disease (Thromboangiitis obliterans )Bulbar vs Pseudobulbar palsyBulimia NervosaBullous PemphigoidBumetanideBunionsBuprenorphineBupropionBurkholderia cepaciaBurkitt's lymphomaBurnsBusulphan (Busulfan)ByssinosisC reactive protein (CRP)CADASILCARASILCHADS2 - CHA2DS2-VASc scoreCMV retinitisCNS fungal InfectionsCNS infectionsCSF RhinorrhoeaCT Head Basics (Stroke)CT Pulmonary angiogram (CTPA)CT imaging basics for StrokeCURB 65 scoreCabergolineCaecal VolvulusCaisson Disease - Decompression sicknessCalcitoninCalcitriol (1,25 Dihydroxycholecalciferol)Calcium Chloride or GluconateCalcium PhysiologyCalcium Pyrophosphate Deposition (Pseudogout)Calcium ResoniumCalcium channel blockers toxicityCalot's triangleCampylobacterCancer of Unknown PrimarCandesartanCandidiasisCannabis toxicityCapecitabineCapnocytophaga canimorsusCapnographyCapreomycinCaptopriCarbamazepineCarbapenemase-producing EnterobacteriaceaeCarbimazoleCarbon monoxide poisoningCarcinoembryonic antigen (CEA)Carcinoid Heart DiseaseCarcinoid Tumour SyndromeCarcinoma of the Bile DuctCarcinoma of the GallbladderCardiac Amyloid heart diseaseCardiac Anatomy and PhysiologyCardiac Catheter ablationCardiac InfectionsCardiac MRICardiac Resynchronisation Therapy (CRT) PacemakerCardiac Valve replacementCardioembolic strokeCardiogenic Pulmonary OedemaCardiogenic shockCardiology - History TakingCardiology Exam ListCardiology ExaminationCardiology Valves SummaryCardiopulmonary bypassCarmustineCarotid Artery anatomyCarotid Body TumourCarotid EndarterectomyCarotid Sinus SyncopeCarotid StentingCarotid artery DissectionCarotid sinus massageCarpal tunnel syndromeCarvedilolCase 01 Sudden weaknessCase 02 Loss of speechCase 03 Adult male weak legsCase 04 High calciumCase 05 High Potassium and heart failureCase 06 High calcium and weight lossCase 07 Weak eyesCase 08 Weak faceCase 09 A cause of DeliriumCase 10 Older patient presenting post strokeCase 11 Young patient with acute headacheCase 20 Young patient with acute headacheCase 21 HypoglycaemiaCase 22Case 23 Old man with tremorCase 24 Cancer and weakCase 99 (Acute breathlessness)Case TemplateCat Scratch DiseaseCataractCatheter Related Urinary Tract infection UTICatheter related Blood stream infectionCatheter related UTICauda equina syndromeCaudate NucleusCauses of Airway ObstructionCauses of Avascular Necrosis of Femoral headCauses of Sore throatCauses of WeaknessCavernous angiomas (Cavernomas)Cavernous sinusCavernous sinus thrombosisCefaclorCefalexinCefotaximeCeftazidimeCeftriaxoneCefuroximeCelecoxibCell Response to InjuryCellular Anatomy and PhysiologyCellulitisCentral Cord SyndromeCentral Retinal Vein Occlusion (CRVO)Central Retinal artery Occlusion (CRAO)Central Venous line InsertionCentral pontine myelinolysisCephalosporinsCerebellar Anatomy Physiology Signs DiseaseCerebellar HaemorrhageCerebellar StrokeCerebral Amyloid angiopathy (CAA)Cerebral AneurysmsCerebral AngiitisCerebral Atrophy vs HydrocephalusCerebral CortexCerebral MetastasesCerebral PalsyCerebral PerfusionCerebral Salt WastingCerebral Venous Sinus thrombosisCerebral arteritisCerebral microbleedsCervical Cancer screeningCervical Spine injuryCervical cancerCervical spondylosisCetirizineChancroidCharcot Foot Syndrome (CFS)Charcot Marie Tooth (CMT) diseaseChediak Higashi syndromeChest Abdomen anatomyChest X Ray #1Chest X Ray InterpretationChest drain InsertionChlamydia - Chlamydophila pneumoniaeChlamydia psittaciChlamydia trachomatisChlorambucilChloramphenicolChlordiazepoxideChloroquineChlorphenamine(Chlorpheniramine)ChlorpromazineCholangiocarcinomaCholera (Vibrio cholera)Cholestatic JaundiceCholesteatomaCholesterol - LipidsCholinergic crisis-syndromeChondrocalcinosisChorea - BallismusChoreoacanthocytosisChromosome instability syndromesChronic BronchitisChronic HepatitisChronic InflammationChronic Inflammatory Demyelinating polyneuropathyChronic Interstitial NephritisChronic Kidney Disease (CKD)Chronic Lymphocytic leukaemia (CLL)Chronic Myeloid Leukaemia (CML)Chronic Obstructive Pulmonary Disease (COPD)Chronic PancreatitisChronic PeritonitisChronic Radiation EnteritisChronic Urinary RetentionChronic Vision Uni-Bilateral loss (Blindness)Chronic and recurrent MeningitisChronic liver diseaseChronic mucocutaneous candidiasisChronic stable anginaChylomicronsCiclosporinCimetidineCinacalcetCiprofloxacinCirrhosisCisplatinCitalopramCladribineClarithromycinCleft lip or palateClindamycinClopidogrelClostridium botulinumClostridium difficileClostridium perfringensClostridium tetani - TetanusClotrimazole creamClotting pathwaysClozapineCo Careldopa (Sinemet)Co-Amoxiclav (Augmentin)Co-Beneldopa (Madopar)Co-codamolCo-trimoxazoleCoagulopathyCoal Worker's PneumoconiosisCoarctation of the Aorta (CoA aortopathy)Cocaine abuseCocaine induced chest painCocaine toxicityCoccidioidomycosisCodeineCoeliac diseaseCogan SyndromeColchicineCold Agglutinin Disease (CAD/AIHA)CollagenColloid cyst in the third ventricleColloidsColonic (Large bowel) ObstructionColonoscopyColorectal cancerColorectal polypsColposcopyComa managementCombined Oral contraceptive pill (COCP)Common Peroneal Nerve (CPN)Common variable immunodeficiencyComparing Rheumatoid and OsteoarthritisComplementComprehensive Geriatric Assessment (CGA)Confirming DeathCongenital Acyanotic Heart Disease (Children)Congenital Adrenal hyperplasiaCongenital Complete Heart BlockCongenital Cyanotic Heart Disease (Children)Congenital HypothyroidismCongenital Talipes Equinovarus - ClubfootConstipationConstrictive PericarditisContact allergic dermatitisContinuous Positive Airways Pressure (CPAP)Continuous ambulatory peritoneal dialysisContraceptionConus Medullaris syndromeCor PulmonaleCoronary artery bypass graft surgeryCoronavirus SARS-CoV-2 COVID 19Corticobasal degeneration (Dementia)Corticosteroid-related psychosisCorticosteroidsCorynebacterium diphtheriaeCotard delusionCoxiella BurnetiiCranial nerves and examinationCraniopharyngiomaCreatinine ClearanceCremation forms (UK)Creutzfeldt Jakob disease (Dementia)Crimean-Congo haemorrhagic feverCritical illness neuromuscular weaknessCrohn's diseaseCroupCryptococcus neoformans infectionsCryptogenic Fibrosing AlveolitisCryptogenic Organising Pneumonia (COP-BOOP)CryptosporidiosisCrysal arthritisCrystalloidsCushing diseaseCushing syndromeCutaneous LeishmaniasisCyanide toxicityCyanosis - Central and PeripheralCyclizineCyclo-oxygenase (COX) enzymesCyclophosphamideCycloserineCys leukotriene receptor antagonistsCystic FibrosisCystinosisCystinuriaCytokinesCytomegalovirus infectionsD DimerDNA and RNA short notesDNA replicationDabigatranDalteparinDandy Walker syndromeDantroleneDapagliflozinDarier's DiseaseDarunavirDeQuervain's thyroiditisDeath Certificates (UK)Deep brain stimulationDeep vein thrombosis (DVT)Dehydration PhysiologyDelayed Puberty CriteriaDemeclocyclineDementia with Lewy bodiesDementiasDemyelinating DiseasesDengue FeverDenosumab (Prolia)Dental AnatomyDentatorubral pallidoluysian atrophyDepressionDermatitis HerpetiformisDermatology termsDermatomesDermatomyositisDermoid cystsDesferrioxamineDesmopressin (DDAVP)Desogestrel (Progestogen Only Pill)Developmental Dislocation (Dysplasia) of the HipDevelopmental MilestonesDexamethasoneDiGeorge syndrome (thymic aplasia)Diabetes Insipidus (Cranial and Nephrogenic)Diabetes Mellitus Type 1Diabetes Mellitus Type 1 and DKA (children)Diabetes Mellitus Type 2Diabetes Mellitus in pregnancyDiabetes on the wardDiabetic Autonomic Neuropathy (DAN)Diabetic Ketoacidosis (DKA) AdultsDiabetic Ketoacidosis (DKA) with SGLT2 InhibitorsDiabetic NephropathyDiabetic RetinopathyDiabetic amyotrophyDiabetic footDiamond-Blackfan anaemiaDiamorphineDiaphragmatic disordersDiarrhoeaDiazepamDidanosine (ddI)DiethylstilbestrolDifferentials causes of Foot DropDifferentials of ABCDifferentials of Generalised lymphadenopathyDifferentials of Painful thighDifferentials of XXXDiffuse Oesophageal spasmDiffuse large B-cell lymphomaDiffusion CapacityDigoxinDigoxin ToxicityDihydrocodeineDilated cardiomyopathyDiltiazemDiphtheriaDipyridamoleDischarges against adviceDiscoid lupus erythematosus (DLE)Disease templateDiseases with associated cancersDislocation Sternoclaivcular jointDisopyramideDisseminated Intravascular Coagulation (DIC)Distributive ShockDisulfiram (Antabuse)DobutamineDog BitesDog Bites HandDominant R wave in V1DomperidoneDonepezil (Aricept)DonovanosisDopamine HydrochlorideDopamine agonistsDown's syndrome (Trisomy 21)DoxapramDoxazosin (Cardura)DoxepinDoxorubicin (Adriamycin)DoxycyclineDrivingDrowningDrug Induced Parkinson diseaseDrug Reaction Eosinophilia Systemic Symptoms DRESSDrug TemplateDrug Toxicity - clinical assessmentDrug Toxicity with Specific AntidotesDrug induced Lupus ErythematosusDrug induced liver diseaseDrugsDrugs ListDrugs to Avoid in Acute Renal failureDrugs to avoid ElderlyDrugs to avoid in Liver failureDry and Wet GangreneDual X-ray absorptiometry (DEXA)Duchenne muscular dystrophyDulaglutide GLP-1 agonistDuloxetineDuodenal Atresia (Children)Dupuytrens contractureDysenteryDysphagiaECG - Acute Coronary SyndromeECG - Acute ST Elevation Myocardial InfarctionECG - Atrial fibrillationECG - Atrial flutterECG - BasicsECG - Broad complex tachycardia (possible VT)ECG - Brugada syndromeECG - Causes of a Dominant R wave in V1ECG - Early Repolarisation vs STEMIECG - First degree AV BlockECG - Heart BlockECG - HyperkalaemiaECG - InterpretationECG - Ischaemic Heart DiseaseECG - Left Axis DeviationECG - Left Bundle Branch Block LBBBECG - Left Ventricular HypertrophyECG - Low Voltage ComplexesECG - Narrow complex tachycardiaECG - Normal appearanceECG - Pathological Q wavesECG - QT intervalECG - Right Axis DeviationECG - Right Bundle Branch Block RBBBECG - ST-T T waves changesECG - Supraventricular tachycardia ECG - The QRS complexECG - Tutorial from Queens UniversityECG - Ventricular fibrillationECG - Ventricular tachycardiaECG - Wolff Parkinson White syndrome (WPW)ECG - short PR intervalECG - sinus pauseECG - tall R wave V1ENT Exam - Assessing hearingENT infectionsEbola Virus DiseaseEbstein anomalyEchinocytesEchocardiogramEcstasy toxicityEctopia lentis (subluxation of the lens)Ectopic PregnancyEctropionEculizumabEdoxaban (Lixiana)Edward syndrome (trisomy 18 syndrome)Efavirenz (Sustiva) EFVEhlers-Danlos syndromesEhrlichiosisEikenella corrodensEisenmenger's syndrome (Children)Elbow fractures and InjuriesElectrical injuryEloquent brainEmergency DrugsEmphysemaEmpty sella syndromeEmtricitabine (Emtriva) FTCEnalaprilEnd of Life Care PrescribingEndocarditis and StrokeEndocrinology Lab valuesEndometrial (Uterine) CancerEndometriosisEndoscopic Retrograde Cholangiopancreatography XEndothelinsEnfuvirtideEnoxaparin Sodium (Clexane-Lovenox)EnoximoneEntacaponeEnterococciEnteropathic SpondyloarthritisEnzyme inducers and inhibitorsEosinophilic granulomatosis (Churg Strauss)EpendymomaEpidural HaematomaEpidural abscessEpilepsy - General ManagementEpilepsy - Idiopathic Generalised EpilepsyEpilepsy - Mesial temporal lobe epilepsyEpilepsy - Post TraumaticEpilepsy in PregnancyEpiscleritisEpistaxisEplerenoneEponymous brainstem strokesEpstein-Barr Virus infectionEquivalent doses of OpiatesErb PalsyErgocalciferol (Calciferol)Erlotinib (Tarceva)Erysipelothrix rhusiopathiaeErythema MultiformeErythema NodosumErythrocyte Sedimentation rate (ESR)ErythrocytesErythrodermic PsoriasisErythromycinEscherichia coliEscitalopramEsomeprazoleEssential Thrombocythaemia (ET)Essential TremorEtanerceptEthambutolEthanolEthanol toxicityEthylene glycol toxicityEtomidateEtravirine (intelence) ETREwing sarcomaExenatide (Byetta) GLP1 agonistExercise stress testExploding head syndromeExtradural haematomaExtrapyramidal symptomsExtrinsic Allergic alveolitis (Hypersensitivity)Eye infectionsEzetimibeFabry diseaseFacial NerveFacioscapulohumeral muscular dystrophyFactor V Leiden DeficiencyFaecal CalprotectinFahr syndromeFailure to thrive or Faltering growthFamilial Adenomatous polyposis (FAP)Familial AmyloidosisFamilial HypercholesterolaemiaFamilial Mediterranean Fever (FMF)Familial hypocalciuric hypercalcaemia (FHH)Family Tree (Pedigree)FamotidineFanconi AnaemiaFanconi SyndromeFat embolismFatigue - CausesFatty acidsFebrile seizuresFelodipine (Dihydropyridine)Femoral HerniaFemoral triangleFemur fractures and InuriesFentanyl - FentanilFerritinFerrous Fumarate - Gluconate - SulphateFetal Alcohol SyndromeFetal circulationFever - Pyrexia of unknown origin (FUO PUO)Fever in a travellerFibratesFibrinogenFibromuscular dysplasiaFibromyalgiaFidaxomicinFinasteride (5 alpha-reductase inhibitor)First SeizureFitz-Hugh Curtis SyndromeFlail ChestFlecainide AcetateFlexor sheath infection (flexor tenosynovitis)FlucloxacillinFluconazoleFlucytosineFludrocortisoneFluid balances statusFlumazenil (Annexate - Romazicon)FluoxetineFocal Segmental Glomerulosclerosis (FSGS)Foix-Alajouanine syndromeFolate (Folic) acidFolate deficiencyFolinic acid (Leucovorin)FomepizoleFondaparinuxFood borne diseaseFoscarnet SodiumFosfomycinFosphenytoinFoster Kennedy SyndromeFournier's gangreneFracture TemplateFractured ClavicleFractured Neck of FemurFractured Pubic RamusFractured ScapulaFractured Shaft FemurFractured Tibia and FibulaFractures Shaft HumerusFractures in ChildrenFractures of Upper humerusFragile X syndromeFrailtyFraser guidelines and Gillick CompetenceFree RadicalsFriedreich's AtaxiaFrontotemporal dementiaFull or Complete Blood Count (FBC CBC)FungiFurosemide (Frusemide)Fusidic acidFusobacteria - Tropical ulcerFusobacteriumG protein-coupled receptorsGP Emergency Drugs CarriedGabapentinGalactorrhoeaGalantamineGamete intra-fallopian tube transfer (GIFT)Gamma Glutamyl Transferase (GGT)Gamma hydroxy butyrate (GHB) toxicityGanciclovir - ValganciclovirGardner syndromeGardnerella vaginalisGas GangreneGastric (MALT) LymphomaGastric CancerGastric Outlet obstruction (pyloric stenosis)GastrinomaGastro Intestinal Stromal Tumours (GIST)Gastro-Oesophageal Reflux (Adult GORD)Gastro-Oesophgeal Reflux (Paediatrics GORD)GastroenteritisGastroenterology Exam ListsGastroenterology ExaminationGastroenterology HistoryGastroenterology assessment - JaundiceGastrointestinal anatomy and physiologyGastrointestinal perforationGastrostomy (PEG) tubesGaucher's diseaseGene componentsGenetic DiseasesGentamicinGiardiasisGilbert's syndromeGingival (Gum) hyperplasia-hypertrophyGitelman's syndromeGlasgow Blatchford ScoreGlasgow Coma scaleGlatiramer acetate (Copaxone)GlibenclamideGliclazideGlimepirideGlipizideGlobus PallidusGlomerulonephritisGlossitisGlucagonGlucagonomaGlucose 6 phosphate dehydrogenase deficiencyGlucose Tolerance TestGlutamateGlycated HaemoglobinGlyceryl Trinitrate (GTN)Glycogen storage diseasesGlycolysis_Krebs_Electron_Transport_ChainGlycopyrronium BromideGoitreGolfer's ElbowGolimumab (Simponi)Goodpasture's syndrome (Anti GBM disease)Goserelin (Zoladex)Gradenigo's syndromeGrades of RecommendationGram StainGranuloma annulareGranulomatosis with Polyangitis GPA (Wegener)Graves DiseaseGriseofulvinGrowth Hormone DeficiencyGuillain Barre SyndromeGum hypertrophyGuthrie test New Born blood spotGynaecological History TakingGynaecomastiaHAS-BLED scoreHIV and Post-Exposure Prophylaxis (PEP)HIV and Pre-exposure prophylaxisHIV associated nephropathy (HIVAN)HIV disease AssessmentHTLV-1 Associated myelopathyHaematemesisHaematology Examination - SplenomegalyHaematology Lab valuesHaematuria Mild to SevereHaemodialysisHaemoglobinsHaemolysisHaemolytic AnaemiaHaemolytic Uraemic syndromeHaemolytic disease of the newbornHaemophilia AHaemophilia BHaemophilus aegyptiusHaemophilus ducreyiHaemophilus influenzaeHaemophilus parainfluenzaeHaemopoiesisHaemorrhagic TransformationHaemorrhagic strokeHaemorrhoids (Piles)Hairy Cell LeukaemiaHairy LeukoplakiaHallervorden-Spatz disease (PKAN)HaloperidolHamman-Rich syndromeHand foot and mouth diseaseHand fractures and InjuriesHantavirus infectionsHartmann's solution (Ringer's lactate)Hartnup disease*Hashimoto's (Steroid responsive) EncephalopathyHashimoto's thyroiditisHbA1cHead (Brain) InjuryHead and Neck CancersHeadache - Analgesic overuseHeadache - Assessing Acute and SevereHeadache - Basilar MigraineHeadache - ClusterHeadache - Low CSF pressureHeadache - MigraineHeadache - TensionHeadaches - GeneralHearing aidsHeat StrokeHelicobacter pyloriHelvetica Spotted feverHemicraniectomyHenoch-Schonlein purpuraHeparin - GeneralHeparin - Low Molecular Weight HeparinHeparin - Unfractionated HeparinHeparin-induced thrombocytopenia (HIT)Hepatic EncephalopathyHepatitis AHepatitis BHepatitis CHepatitis DHepatitis EHepatocellular CarcinomaHepatorenal syndromesHereditary ElliptocytosisHereditary HaemochromatosisHereditary Haemorrhagic TelangiectasiaHereditary Spastic ParaparesisHereditary SpherocytosisHereditary angio-oedemaHereditary neuropathy with pressure palsiesHereditary non polyposis coli (Lynch syndrome)Herpes GestationisHerpes SimplexHerpes Simplex Encephalitis (HSV)Herpes VirusesHerpes Zoster Ophthalmicus (HZO) ShinglesHerpes simplex keratitis (HSK)Heyde syndromeHiatus herniaHiccups (Singultus)High Dose Dexamethasone Suppression TestHip pain in childrenHirschsprung disease (congenital megacolon)Hirsuitism XXXHistonesHistoplasmosisHodgkin LymphomaHolt-Oram syndromeHolter monitor (tape) 24-72 hHomocystinuriaHookwormHorner's syndromeHospital acquired Pneumonia (NICE 139)Human albumin solution (HAS)Human prion diseasesHumeral fractures and injuriesHunter's syndrome (MPS-2)Huntington ChoreaHurler's syndrome (MPS-1)Hydatid disease (Echinococcus)Hydatidiform moleHydralazineHydrocortisoneHydrogen BondsHydrops fetalisHydroxocobalaminHydroxocobalamin - Cyanocobalamin (B12)HydroxychloroquineHydroxyurea-HydroxycarbamideHyoscine (Buscopan)Hyper IgM syndromeHyperbaric Oxygen therapyHypercalcaemiaHyperglycaemic Hyperosmolar State (HHS)Hyperinsulinaemic-euglycemic therapy (HIET)HyperkalaemiaHyperkalaemic and Hypokalaemic Periodic ParalysisHypermagnesaemiaHypernatraemiaHyperphosphataemia (High phosphate)HyperprolactinaemiaHypersensitivity reactionsHypertensionHypertension in PregnancyHypertriglyceridaemia (HTG)Hypertrophic cardiomyopathy (HCM - HOCM)Hyperventilation SyndromeHyperviscosity syndromeHypocalcaemiaHypoglycaemiaHypogonadism (Female)Hypogonadism (male)HypokalaemiaHypokalaemic Periodic ParalysisHypomagnesaemiaHyponatraemiaHypoparathyroidismHypophosphataemia (Low phosphate)Hypopituitarism (Pituitary Failure)HypospadiasHypothermiaHypothyroidismHypovolaemic or Haemorrhagic ShockIL-12 receptor deficiencyIV ImmunoglobulinIbandronic acid (Bisphosphonate)IbuprofenIcatibantIdiopathic Intracranial hypertensionIdiopathic Parkinson diseaseIdiopathic Pulmonary FibrosisIgA Nephropathy (Berger's disease)Images - Spot diagosesImatinib mesylateImipenem (Primaxin) with CilastinImmune Reconstitution SyndromeImmune(Idiopathic) Thrombocytopenic Purpura (ITP)Immunoglobulin G4-related disease (IgG4-RD)ImpetigoImplantable cardioverter defibrillator (ICD)Impulse control disordersInclusion Body MyositisIncubation periodsIndapamideIndinavir (IND)Infection screening in Septic patientInfections and their Microbial causeInfectious MononucleosisInfective ConjunctivitisInfective EndocarditisInfertilityInfliximabInfluenzaInguinal HerniaInitial Trauma AssessmentInjury Severity Score (ISS)Insomnia - sleep issuesInsulinInsulinomaInterferon BetaIntermittent ClaudicationInternal CapsuleInternuclear OphthalmoplegiaInterpreting HaematinicsInterstitial KeratitisIntestinal obstruction (Children)Intra Aortic Balloon PumpIntraabdominal abscessIntracerebral Haemorrhage (ICH) ScoreIntracranial HypertensionXIntravenous Iron Replacement (Ferrous)Intraventricular haemorrhage (neonates)Intubation and Mechanical VentilationIntussusception (Adults)Intussusception (Children)Iodine deficiency GoitreIpratropium Bromide (Atrovent)IrbesartanIron SaltsIron deficiency AnaemiaIron toxicityIrritable bowel syndromeIschaemic ColitisIschaemic StrokeIschaemic heart diseaseIsoniazidIsoprenalineIsosorbide DinitrateIsosorbide mononitrateIsotretinoin (Accutane)Ispaghula Husk (Fybogel)IvabradineJansen DiseaseJanus kinase 2Jervell and Lange-Nielsen syndromeJob Syndrome (Hyper IgE syndrome)Jugular Venous Pressure (JVP)Junctional TachycardiaJuvenile DermatomyositisJuvenile Idiopathic arthritis (Stills Disease)Juvenile Myoclonic epilepsy (JME)Kallmann's syndromeKaposi sarcoma (KS)Karnofsky performance status scaleKawasaki diseaseKennedy SyndromeKeratoconusKernicterusKetamineKetoconazoleKlebsiella pneumoniaKlinefelter Syndrome (Children)Klumpke palsyKnee fractures and InjuriesKoebner phenomenonKugelberg Welander syndromeKwashiorkorL-Thyroxine (T4)Labetalol (Trandate)Labyrinthitis - Vestibular NeuronitisLactateLactate dehydrogenase (LDH)Lactic acidosisLactobacillus acidophilusLactose IntoleranceLactuloseLady Windermere syndromeLambert-Eaton syndrome (LEMS)Lamivudine (3TC)LamotrigineLangerhans Cell Histiocytosis XLansoprazoleLanthanumLateral Medullary SyndromeLaxativesLe Fort FracturesLead toxicityLeber hereditary optic neuropathy (LHON)LeflunomideLegal definition of BlindnessLegionella pneumophilaLeishmaniasis (Cutaenous and Visceral)Lemierre's syndromeLenalidomide (Revlimid)Length Dependent PolyneuropathyLennox-Gastaut syndromeLenticulostriate branch occlusionLeprosyLeptinLeptospira interrogansLeptospirosis (Weil's Disease) (Notifiable)Leriche syndrome (aortoiliac occlusive disease)Lesch-Nyhan syndrome (Children)LeukaemiaLeukaemias in GeneralLeukoariosisLeukocytoclastic vasculitisLeukotrienesLevetiracetam (Keppra)LevodopaLevomepromazineLevosimendanLi Fraumeni syndromeLichen PlanusLiddle's syndromeLidocaine(Lignocaine)Lightning strikeLimb girdle dystrophyLimbic EncephalitisLinagliptin (Trajenta)LinezolidLinkageLiothyronine Sodium L-Triodothyronine (T3)Lipid emulsion therapy - IntralipidLipid management [NICE 2014]LipoatrophyLipoprotein lipase deficiencyLiraglutide (Victoza)LisinoprilListerial MeningitisListeriosisLithiumLithium toxicityLivedo ReticularisLiver Anatomy PhysiologyLiver BiopsyLiver Function TestsLiver TransplantationLiver abscessLiver disease in PregnancyLocalisation of cortical functionLofepramineLong QT syndrome (LQTS) AcquiredLong QT syndrome (LQTS) CongenitalLong term Oxygen therapy (LTOT)Loop diureticsLooser's zonesLoperamideLopinavirLoratadineLorazepamLosartanLow Dose Dexamethasone Suppression TestLower Gastrointestinal BleedingLugol iodineLumbar puncture and CSF interpretationLumbrosacral radiculopathyLung AbscessLung CancerLung ComplianceLung EmpyemaLung TransplantLupus NephritisLupus VulgarisLyme diseaseLymphocytic HypophysitisLymphogranuloma Venereum (LGV)LyonizationLysosomal storage diseasesMCune Albright syndromeMELASMacrocytic anaemiaMacroglossiaMagnesium PhysiologyMagnesium Sulphate - SulfateMagnetic resonance cholangiopancreatographyMagnetic resonance imagingMajor Histocompatibility complexMalabsorption - small intestineMalaria (non falciparum)Malaria FalciparumMale InfertilityMale Urethral CatheterisationMale erectile dysfunctionMalignant AscitesMalignant Hyperpyrexia (Malignant Hyperthermia)Malignant HypertensionMalignant MelanomaMalignant pleural mesotheliomaMallet FingerMallory-Weiss TearMalnutrition Universal Screening ToolManiaMannitolMantle cell lymphomaMarantic EndocarditisMarasmusMaraviroc (Celsentri)Marfan syndromeMarginal Zone LymphomaMassive HaemoptysisMaturity Onset Diabetes of the Young (MODY)McArdles disease (type V)Measles (notifiable)MebeverineMeckel's diverticulumMeconiumMedian NerveMedical Mnemonics Basic SciencesMedical Mnemonics CardiologyMedical Mnemonics EndocrineMedical Mnemonics Mental HealthMedical Mnemonics MiscellaneousMedical Mnemonics NeurologyMedical ProceduresMedical TeethMedullary Sponge kidneyMedulloblastomaMefenamic acidMefloquine (Larium)Megaloblastic anaemiaMelatoninMelioidosisMemantine HydrochlorideMembranous GlomerulonephritisMenetrier diseaseMeniere diseaseMeningiomaMeningitis in the ImmunocompromisedMenopauseMenstrual cycleMental Capacity Act 2005Mental Health Act 1983Mental State ExaminationMercaptopurineMeropenemMesalazine (Aminosalicylate)Mesangiocapillary GlomerulonephritisMesenteric infarctionMetabolic Syndrome XMetabolic acidosisMetabolic alkalosisMetachromic leucodystrophyMetastatic AdenocarcinomaMetastatic bone diseaseMetforminMethaemoglobinaemiaMethanol ToxicityMethodoneMethods to reduce toxin absorptionMethotrexateMethylcelluloseMethylprednisoloneMetoclopramideMetolazoneMetoprololMetronidazole (Flagyl)Metyrapone (Metopirone)MiconazoleMicroangiopathic Haemolytic anaemiaMicrocytic anaemiaMicroscopic PolyangiitisMicroscopic colitisMicrostomiaMidazolamMiddle East Resp Syndrome (MERS) CoronavirusMidodrineMigraine Disability Assessment (MIDAS)Miller-Fisher syndromeMilwaukee shoulder syndromeMini Mental State Examination (MMSE)Minimal Change Disease GlomerulonephritisMinocyclineMinoxidilMirabegronMirizzi syndromeMirtazapineMiscarriageMisoprostolMitochondrial diseasesMitral Regurgitation (Incompetence)Mitral StenosisMitral Stenosis vs Regurgitation - DominanceMitral Valve prolapseMittleschmerzMixed Connective Tissue Disease (MCTD)Mobility aidsModified Duke Criteria for EndocarditisModified Oxford Handicap Scale (MOHS)Modified Rankin ScoreMolluscum contagiosumMonoclonal gammopathy of undetermined significanceMonocular loss of visionMonocytesMonosodium glutamate (MSG) syndromeMontelukastMontreal Cognitive Assessment (MOCA)Moraxella catarrhalisMorphine SulphateMosquito borne diseasesMotor Neuron Disease (MND-ALS)Moyamoya diseaseMucormycosisMultifocal Atrial TachycardiaMultifocal Motor Neuropathy with Conduction blockMultiple Antithrombotics AnticoagulantsMultiple Endocrine Neoplasia type 1 (MEN1)Multiple Endocrine Neoplasia type II (MEN2)Multiple MyelomaMultiple PregnancyMultiple Sclerosis (MS) DemyelinationMultiple System Atrophy (MSA)Mumps (Notifiable)Muscles of the Abdominal RegionMuscles of the BackMuscles of the Head and NeckMuscles of the Lower LimbMuscles of the Pelvis and PerineumMuscles of the Thoracic RegionMuscles of the Upper limbMyasthenia GravisMycobacterium TuberculosisMycophenolate mofetilMycoplasma pneumoniaeMycoplasmasMycosis Fungoides (Sezary Syndrome)Myelodysplastic syndrome (Myelodysplasia)MyelofibrosisMyelofibrosis vs CMLMyelopathyMyeloproliferative disordersMyobacterium avium Complex InfectionMyocardial perfusionMyoclonusMyotonic dystrophy - Dystropica myotonicaMyxoedema comaN-Acetylcysteine (Parvolex)NEWS Reacting to Low Oxygen SaturationsNICE Guidelines LinksNICE Trauma Guidance Summary 2016NSAID toxicityNaloxone (Narcan) Opiate antagonistNaproxenNarcolepsyNasal polypsNasogastric tube insertionNatalizumab (Tysabri)National Early Warning Score NEWS 2 ScoreNeck PainNeck swellings and lumpsNecrotising Enterocolitis (Infants)Necrotising fasciitisNeedlestick injuryNefopamNeisseria gonorrhoeaeNeisseria meningitidisNelson SyndromeNeomycinNeonatal Abstinence Syndrome NASNeonatal JaundiceNeonatal Lupus ErythematosusNeonatal meningitisNeostigmineNephritic syndromeNephroblastoma (Wilm's tumour)Nephrotic syndromeNephrotoxic drugsNerve conduction studiesNerve fibresNeuroanatomy 101Neuroanatomy imagesNeuroblastomaNeurocysticercosisNeuroferrinopathyNeurofibromatosis Type 1Neurofibromatosis Type 2Neuroleptic Malignant SyndromeNeurological - Relative Afferent pupillary defectNeurological - Vision and Eye movementsNeurological Examination - CognitionNeurological Examination - Cortical FunctionsNeurological Examination - MotorNeurological Examination - SensoryNeurological Examination - Speech&LanguageNeurological ListsNeurological assessment - PtosisNeurological examination - EyesNeurological or ENT Examination - NystagmusNeurology - History takingNeurology Exam - Reflex findingsNeuromyelitis optica*Neuropathic Pain ManagementNeurotransmittersNeutropeniaNeutropenic SepsisNeutrophil Alkaline PhosphataseNeutrophilsNevirapine (Viramune) NEV-NVPNiacin deficiency (Pellagra Vitamin B6)Nicardipine (Cardene)NicorandilNiemann-Pick diseaseNifedipineNimodipine (Nimotop)Nitric OxideNitrofurantoinNitrous oxideNizatidineNocardiaNoise induced hearing lossNon Alcoholic Fatty Liver Disease NAFLDNon Convulsive Status EpilepticusNon Hodgkin LymphomaNon alcoholic steatohepatitis (NASH)Non gonococcal urethritisNon invasive ventilation (NIV)Non steroidal anti inflammatory drugs (NSAIDs)Non sustained Ventricular tachycardiaNoonan syndromeNoradrenalineNormal DistributionNormal Pressure HydrocephalusNormal Saline 0.9%Normocytic anaemiaNortriptylineNosocomial infectionsNotifiable disease and organisms UKNutrition in Infants BreatsfeedingNystatinOSCE - Administer IV InjectionOSCE - Blood cultureOSCE - VenepunctureOSCE - Venous Cannula InsertionObsessive-Compulsive disorderObstetric definitionsObstructive ShockObstructive Sleep ApnoeaOctreotideOculomotor Nerve (IIIrd Cranial Nerve)OedemaOesophageal CarcinomaOesophageal Perforation - RuptureOesophageal Variceal BleedingOesophagogastroduodenoscopyOlanzapineOlfactory Nerve (I)OligodendrogliomaOlmersartanOlsalazine (Aminosalicylate)OmalizumabOmeprazoleOnchocerciasisOncogenic virusesOncological emergenciesOndansetronOne Table TemplateOphthalmology Exam ListsOpiate ToxicityOpiatesOpicaponeOpioid toxicityOptic Neuritis-NeuropathyOptic atrophyOptic tract anatomyOral Aphthous UlcersOral CandidiasisOral LeukoplakiaOrbital vs Preorbital CellulitisOrganism and sensitivitiesOrganophosphate (OP) PoisoningOrphenadrineOrthopaedic infectionsOrthostatic - Postural hypotensionOscillopsiaOseltamivir - TamifluOsteoarthritisOsteogenesis ImperfectaOsteogenic sarcoma (Osteosarcoma)Osteomalacia-Rickets-Vitamin DOsteomyelitisOsteonecrosis of the jawOsteopetrosisOsteoporosisOtitis Externa (Malignant)Otitis MediaOtosclerosisOttawa rules for ankle and foot x-rayOvarian CancerOvarian CystOvaryOxford community stroke project (Bamford)Oxybutynin (Ditropan)Oxycodone (Oxycontin-Oxynorm)Oxygen delivery devicesOxytetracyclinePEDIS Score for Diabetic Foot UlcersPOEMS syndromePabrinexPacemaker DDDPacemaker VVIPacemaker syndromePacemakersPacing - Indications for temporary pacingPaediatric emergenciesPaediatricsPaget's (Bone) diseasePain ManagementPainful Shoulder syndromesPalliatiion - Nausea Dyspnoea Secretions PainPalliation prescribingPalpitationsPamidronate (Bisphosphonate)Pancoast tumour (Cancer)Pancreatic CancerPanton-Valentine leucocidin toxinPantoprazolePapilloedemaParacetamol (Acetaminophen)Paracetamol toxicityParadoxical embolisationParaneoplastic Encephalitis with NMDA antibodiesParaneoplastic Limbic Encephalitis (Dementia)Paraneoplastic cerebellar degenerationParaphimosisParaquat toxicityParkinson Plus syndromesParkinsonismParonychiaParoxetineParoxysmal Nocturnal HaemoglobinuriaParvovirus (Erythrovirus 19) B19 infectionPasteurella multocidaPatau syndrome (trisomy 13)Patent Ductus arteriosus (PDA) (Children)Patent Foramen Ovale (PFO)Pathogen - pattern recognition receptorsPathological bone fracturePegvisomantPelvic fracturesPemphigus VulgarisPenetrating Abdominal TraumaPenetrating Thoracic TraumaPenicillaminePenicillinsPenile CancerPeptic ulcer diseasePercutaenous Coronary Intervention (PCI ACS)PergolidePericardial Effusion_TamponadePerimesencephalic Subarachnoid haemorrhagePerindoprilPerinephric abscessPerioperative AnticoagulationPeripartum cardiomyopathyPeripheral Arterial Disease (PAD)Peripheral Cannula InsertionPeripheral Nerve Palsies*Peripheral neuropathyPeripherally inserted central cathetersPernicious anaemiaPerthes disease (Osteochondritis of the Hip)PethidinePeutz-Jeghers syndromePhaeochromocytomaPhagocytesPharmacokinetic notesPharmacokineticsPharyngeal arch derivativesPhenobarbital sodiumPhenoxymethylpenicillin (Penicillin V)PhentolaminePhenylketonuria (PKU)Phenytoin (Dilantin)Philadelphia chromosomePhimosisPhobic disordersPhocomelia and ThalidomidePhosphorusPhysiology of visionPicolax - CitrafleetPilonidal Abscess (sinus)Pioglitazone (Thiazolidinediones)Pituitary AdenomaPituitary Anatomy and PhysiologyPituitary ApoplexyPityriasis or Tinea versicolor infectionsPityriasis roseaPivmecillinam (a penicillin antibiotic)Placenta praeviaPlacental abruptionPlantar fasciitisPlasmacytomaPlasmapharesisPlasmidsPleural effusionPleural tap (thoracentesis)Pneumococcal meningititisPneumoconiosisPneumocystis jirovecii pneumoniaPneumoniaPneumothoraxPoisons eliminated Haemodialysis - perfusionPoliomyelitisPolyarteritis nodosa (PAN)Polyarticular arthritisPolycystic Ovary syndromePolycythaemia Vera (primary polycythaemia)Polymerase chain reactionPolymorphic light eruptionPolymyalgia RheumaticaPolymyositisPolypharmacy Start CriteriaPolypharmacy Stop CriteriaPolyuriaPontine-Midbrain haemorrhagePorphyria Cutanea Tarda (PCT)Porphyria TestingPortal HypertensionPositron Emission TomographyPost Menopausal BleedingPost Operative ManagementPost Partum ThyroiditisPost Polio SyndromePost SplenectomyPost Streptococcal/Infectious GlomerulonephritisPost Stroke Epilepsy (PSE)Post traumatic stress disorderPost-exposure prophylaxis with ImmunoglobulinsPosterior Reversible Encephalopathy Syndrome (PRESPosterior circulationPostpartum haemorrhagePotassium PhysiologyPralidoximePramipexole (Mirapexin)PrasugrelPravastatinPraxbind - IdarucizumabPraziquantelPrazosinPre-Operative AssessmentPreEclampsia, Eclapsmia and HELLPPrednisolonePrednisonePregabalinPremature LabourPremature MenopausePresbyacusisPrescribing InformationPrescribing in PregnancyPressure soresPrevotella (Bacteroides) melaninogenicaPriapismPrimaquinePrimary (Chronic simple) Open angle GlaucomaPrimary Biliary CirrhosisPrimary CNS LymphomaPrimary HyperparathyroidismPrimary Sclerosing CholangitisPrimary ciliary dyskinesiaPrimary hyperaldosteronism (Conn's syndrome)Primary progressive aphasia (Dementia)ProbenicidProchlorperazine (Stemetil)ProcyclidineProgressive Multifocal Leukoencephalopathy (PML)Progressive Supranuclear Palsy (PSP)ProlactinomaPropafenonePropanthelinePropionibacteriumPropofolPropranololPropylthiouracilProstate cancerProsthetic ValvesProtamine SulfateProtein C DeficiencyProtein S DeficiencyProtein losing enteropathyProtein p53Protein synthesisProteusProthrombin 20210A mutationProthrombin Complex Concentrates (PCC)Prothrombin time and CoagulationProthrombotic disordersProton Pump InhibitorsProximal myopathyPrucalopridePsammoma bodiesPseudohypoparathyroidismPseudomonas infection (Pseudomonas aeruginosa)Psoas AbscessPsoriasisPsoriatic arthritisPsychogenic PolydipsiaPubic Lice (Pediculosis Pubis)Pulmonary Alveolar ProteinosisPulmonary Arteriovenous malformationPulmonary EmbolismPulmonary Eosinophilia and CXR changesPulmonary HypertensionPulmonary Hypertension - PrimaryPulmonary RegurgitationPulmonary StenosisPulmonary hypertension - SecondaryPulse oximetryPutamenPutaminal HaemorrhagePyloric stenosis (Children)Pyoderma gangrenosumPyonephrosisPyrazinamidePyridostigminePyruvate Kinase deficiencyQuetiapineQuinineQuinine toxicityRabiesRadial PulseRadial nerveRadiation exposureRadioactive iodine (I 131)Radiofrequency Catheter AblationRadius and Ulna fractures and InjuriesRaloxifeneRaltegravirRamiprilRamsay Hunt syndromeRanitidineRanolazineRapid sequence intubation (RSI)Rapidly Progressive GlomerulonephritisRasagilineRasburicaseRaynaud's PhenomenonReactive arthritisRectal ProlapseRed cell aplasiaRed eyeRefeeding syndromeReferring to Level 2 or 3 care (ITU ICU HDU)Refractive ErrorsRefsum's diseaseRelapsing polychondritisRemdesvir (Veklury)Renal Artery StenosisRenal Papillary NecrosisRenal Physiology IRenal Stones (Nephrolithiasis)Renal TransplantationRenal Tubular AcidosisRenal Vein ThrombosisRenal cell carcinomaRenal physiologyRenin and Aldosterone Renin ratio (ARR)Renin-angiotensin systemRespiratory (Chest) infections and pneumoniaRespiratory - History TakingRespiratory AcidosisRespiratory AlkalosisRespiratory Anatomy and PhysiologyRespiratory Disease InvestigationsRespiratory Distress Syndrome (Neonates)Respiratory ExaminationRespiratory Examination - Finger ClubbingRespiratory Failure (hypoxia-hypercarbia)Resting membrane potentialRestless legs syndromeRestriction enzymesRestrictive CardiomyopathyResuscitation - Adult Bradycardia AlgorithmResuscitation - Adult Tachycardia AlgorithmResuscitation - Advanced Life SupportResuscitation - Basic Life Support ABCDEResuscitation - Choking AlgorithmResuscitation - Post Resuscitation AlgorithmReteplaseReticulocytesRetinal detachmentRetinitis pigmentosaRetinoblastomaRetinoidsRetroperitoneal fibrosisRett SyndromeReversible cerebral vasoconstriction syndromeReye syndromeRhesus haemolytic diseaseRheumatoid arthritisRheumatology AutoantibodiesRheumatology Lab valuesRhodococcus equiRibavirinRicin ToxicityRickettsia (General Principles)Rickettsia africae (Tick Bite Fever)Rickettsia akariRickettsia conorii (Tick Bite Fever)Rickettsia prowazekiiRickettsia rickettsiiRickettsia tsutsugamushiRickettsia typhiRifampicin (Rifabutin Rifampin)RifaximinRilipivirine (Edurant) RVPRiluzole (Rilutek)Risedronate (Bisphosphonate)RisperidoneRitonavir (Norvir) RTVRituximab (Mabthera)Rivaroxaban (Xarelto)Rivastigmine (Exelon)Rocky Mountain Spotted FeverRocuroniumRotigotineRubella (German Measles) NotifiableSCL70 AntibodySMASH U Intracerebral Haemorrhage ClassificationSOCRATES mnemonicST segment changesSacubitril with ValsartanSalivary Gland DiseaseSalivary glandsSalmonella entericaSalmonella typhiSaquinivir (Invirase) SQVSarcoidosisSaxagliptin (Onglyza)ScabiesScarlet Fever (Scarlatina)SchistosomiasisSchizophreniaSchmidt's syndromeSciaticaSeborrheic DermatitisSecondary Brain TumoursSecondary MessengersSecondary dysmenorrhoeaSecondary hyperparathyroidismSedation and Analgesia on ITUSelective IgA deficiencySelective Serotonin reuptake Inhibitor toxicitySelective serotonin reuptake inhibitors (SSRI)SelegilineSelenium deficiencySennaSeptic Shock and Sepsis 3Septic arthritisSepticaemiaSeronegative SpondyloarthropathiesSerotonin syndromeSerratiaSevelamerSevere combined immunodeficiency disordersSex Linked RecessiveSheehan's syndromeShigella characteristicsShigellosis (Bacillary Dysentery)Shock (General Assessment)Short Synacthen test (SST)Short and Tall stature Growth in ChildrenShoulder dislocationsSick Euthyroid SyndromeSickle Cell DiseaseSideroblastic AnaemiaSigmoid VolvulusSildenafil (Viagra)SilicosisSilver Trauma - Age over 65SimvastatinSinus BradycardiaSinus Node diseaseSinus TachycardiaSitagliptinSitosterolemiaSjogren's syndromeSkin and soft tissue infectionsSkull AnatomySleep physiologySlipped Upper Femoral Epiphysis (SUFE)Small Bowel IschaemiaSmall Bowel ObstructionSmall vessel diseaseSmallpoxSmokingSnake BitesSneddon SyndromeSodium BicarbonateSodium NitroprussideSodium PhysiologySodium PicosulfateSodium Thiopental - Sodium ThiopentoneSodium Valproate (Epilim Depakote)Sodium Zirconium Cyclosilicate (Lokelma)Soft tissue injuries (sprains, strains)SolifenacinSolitary Pulmonary NoduleSotalol HydrochlorideSpetzler-Martin Grading of AVMSpina BifidaSpinal Cord AnatomySpinal Cord Arteriovenous MalformationsSpinal Cord CompressionSpinal Cord HaematomaSpinal Cord InfarctionSpinal StenosisSpirometrySpironolactoneSpleenSplenic RuptureSpondylolisthesisSpontaneous Bacterial PeritonitisSpontaneous intracranial hypotensionSquamous Cell CarcinomaSt John's WortStaphylococcal InfectionsStaphylococcus aureusStaphylococcus epidermidisStaphylococcus saprophyticusStatinStatus Epilepticus (Epilepsy)Stavudine (Zerit) d4TStevens-Johnson SyndromeStiff Person SyndromeStrabismus (Lazy Eye)Streptobacillus moniliformisStreptococci - anaerobesStreptococcusStreptococcus agalactiaeStreptococcus milleriStreptococcus pneumoniae (Pneumococcus)Streptococcus pyogenesStreptococcus viridansStreptokinaseStreptomycinStridorStroke - Arterial Occlusion and clinical correlateStroke - Epidemiology and risk factorsStroke - General ManagementStroke - ImagingStroke ASPECTS scoringStroke CollateralsStroke Risk FactorsStroke ThrombolysisStrongyloides stercoralis (threadworm)StrontiumSubacute Sclerosing PanencephalitisSubacute ThyroiditisSubarachnoid HaemorrhageSubclavian Steal SyndromeSubclavian vein thrombosisSubdural haematomaSucralfateSudden Cardiac Death (SCD)Sudden Infant Death Syndrome (SIDS)Sudden sensorineural hearing loss (SNHL)SuicideSulfasalazine - SulphasalazineSulphonamide (Sulphamethoxazole)SumatriptanSuperior Mesenteric Artery (SMA) SyndromeSuperior Sagittal Sinus ThrombosisSuperior vena caval obstruction syndromeSupracondylar Femur FracturesSupracondylar Humerus FracturesSupraspinatus tendonitisSupraventricular TachycardiaSurgical CricothyroidotomySurgical prophylaxisSurgical site infectionSusac syndromeSuxamethoniumSydenham's choreaSynchronised DC CardioversionSyncopeSyndrome X (Cardiology)Syndrome of Inappropriate ADH (SIADH) secretionSyndromes with Severe Cognitive IssuesSyphilisSyringobulbiaSyringomyeliaSystemic AmyloidosisSystemic Lupus Erythematosus (SLE)Systemic MastocytosisSystemic SclerosisT cellsTIMI scoreTMN Staging tumoursTNF receptor-associated periodic syndromeTORCH infectionsTURP Hyponatraemia syndromeTabes dorsalisTacrolimusTafamidisTakayasu arteritis (pulseless disease)Takotsubo CardiomyopathyTamoxifenTamsulosin (Flomax)Tanner Stages of Pubertal DevelopmentTardive DyskinesiasTay-Sachs diseaseTazocin (Tazobactam - Piperacillin)TeicoplaninTelomeresTemazepamTemozolomide (Temodal)Template XTemplate two columns listTemporal (Giant Cell GCA) ArteritisTenecteplaseTennis ElbowTensilon testTension PneumothoraxTerbutalineTeriparatideTerlipressinTertiary hyperparathyroidismTesticular CancerTesticular torsionTestingTetrabenazineTetracosactide (Synacthen)TetracyclinesTetralogy of Fallot (Children)Thalamic HaemorrhageThalamic Pain SyndromeThalamic Stroke SyndromeThalidomideTheophyllineTheophylline toxicityThiamineThird Degree (complete) Heart BlockThoracic TraumaThoracic anatomyThoracic outlet syndromeThrombocytosisThrombolysisThrombophilia testingThrombotic Thrombocytopenic purpura (TTP)Thyroglossal Cyst (Children)Thyroid CancerThyroid Function Tests and antbodiesThyroid GlandThyroid Storm - Thyrotoxic crisisThyroid Surgery (Thyroidectomy)Thyroid noduleThyrotoxicosis and HyperthyroidismTiagabineTibia and Fibula fractures and InjuriesTicagrelorTick ParalysisTimololTinea capitisTinidazoleTinzaparin (Innohep)Tiotropium (Spiriva)Titre - TiterTocilizumabTolbutamideTolcaponeTolosa Hunt SyndromeTolterodineTolvaptanTongue tie - ankyloglossia (Children)Topiramate (Topamax)Torsades de pointes (Polymorphic VT)Total Anomalous Pulmonary Venous DrainageToxic Epidermal Necrolysis (TEN)Toxic MegacolonToxic Shock SyndromeToxoplasmosisTramadolTranexamic AcidTranscatheter aortic valve implantation (TAVI)Transfer factor (TLCO)Transfusion ten commandmentsTransient Global Amnesia (TGA)Transient Ischaemic Attack (TIA)Transient Monocular Blindness (TMB)Transoesophageal Echocardiography (TOE-TEE)Transplant and organ rejectionTransposition of the great arteries (Children)Transverse myelitisTrastuzumab (Herceptin)Traumatic Spinal InjuryTravellers DiarrhoeaTrazodoneTreponemaTriangles of the neckTrichinellosisTricuspid Atresia (Children)Tricuspid RegurgitationTricuspid StenosisTricyclic Antidepressant ToxicityTricyclic antidepressantsTrigeminal NerveTrigeminal neuralgiaTrihexyphenidyl (benzhexol)TrimethoprimTrinucleotide (triplet) repeatsTrochlear NerveTropheryma whipplei (Whipple disease)Tropical SprueTruncus Arteriosus (Children)TuberculosisTuberculous MeningitisTuberous sclerosisTularaemiaTumour Lysis SyndromeTumour markersTurcot's syndrome (Brain tumor polyposis syndrome)Turner's syndrome (Children)Two list Table templateTyphoid - Paratyphoid fever (Enteric Fever)Tyrosine Kinase receptorsUS vs UK Drug namesUbiquitinUlcerative ColitisUlnar nerveUltrasound - Echo basicsUndifferentiated Inflammatory Arthritis (Children)Unexplained symptomsUpper Gastrointestinal Bleed (GI Bleed)Upper-Lower Motor Neurone signsUrea and ElectrolytesUrethral syndomeUrinary CatheterisationUrinary Incontinence (Stress and Urge)Urinary Tract Infection (UTI Children)Urinary Tract InfectionsUrinary Tract ObstructionUrinary UTI Antibiotic guidanceUrine AnalysisUrothelial tumoursUrticariaUterusVIPomasVTE DVT PE in PregnancyVaginal CarcinomaValaciclovirValsartanVancomycinVariable rate intravenous insulin infusion VRIIIVariant (Prinzmetal) AnginaVaricella-Zoster (Chickenpox Shingles) InfectionVariegate PorphyriaVascular DementiaVasculitis - General Issues and ClassificationVasopressin (AVP) Antidiuretic hormoneVasovagal syncopeVaughan-Williams ClassificationVecuroniumVedolizumab (Entyvio)VenlafaxineVenous Insufficiency and Leg UlcersVenous access Venflons and Central linesVentilator associated pneumonia (VAP)Ventricular FibrillationVentricular Septal defect (VSD) (Children)Ventricular TachycardiaVentricular ectopic beatsVerapamilVertebral artery dissectionVertigoVesicoureteric reflux (VUR) (Children)Vibrio parahaemolyticusVibrio vulnificusVibrio vulnificus Vigabatrin (Sabril)VinblastineVincristineViral MeningitisViral associated cancersVirusesVisual acuityVitamin A deficiency (Children)Vitamin B1 Thiamine deficiencyVitamin B12 deficiencyVitamin B12 excessVitamin C deficiency (Scurvy)Vitamin D (1,25 OH2)Vitamin D (25 OH D)Vitamin D deficiencyVitamin D resistant rickets (Children)Vitamin K (Phytomenadione)Vitamin K deficiencyVitiligoVoltarol (Diclofenac)Von Gierke Disease (Children)Von Hippel LindauVon Willebrand DiseaseWaardenburg's syndrome (Children)Wagner Classification Diabetic foot ulcersWaldenstrom Macroglobulinaemia (WM)Wallerian DegenerationWarfarinWarfarin and BleedingWater PhysiologyWatershed InfarctsWerdnig Hoffman Disease (Children)Wernicke Korsakoff SyndromeWhite Blood Cells - LeukocytesWilliams Syndrome (Children)Wilson diseaseWiskott-Aldrich syndrome (Children)Wolff-Parkinson White syndrome (WPW)Wolfram syndrome (DIDMOAD)Wound healingX linked Agammaglobulinaemia (Bruton)X linked Hypophosphataemic ricketsX-linked IchthyosisX-linked lymphoproliferative disease (Children)Xeroderma pigmentosumYellow FeverYellow Nail SyndromeYersinia enterocoliticaYersinia pestis - Bubonic PlagueYersinia pseudotuberculosisZZAAAZZ_Abnormal charZabramski Classification of CavernomasZidovudine (Retrovir) AZT - ZDVZieve's syndromeZika virusZinc deficiencyZoledronic acidZollinger Ellison syndromeZolpidemZopicloneeGFR

MEDICAL DISCLAIMER:The contents are under continuing development and improvements and despite all efforts may contain errors of omission or fact. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice by healthcare workers or laypeople. It is for educational purposes only. Please adhere to your local protocols. Use the BNF for drug information. If you are unwell please seek urgent healthcare advice. If you do not accept this then please do not use the website. Makindo Ltd

CT Basics for Stroke



Introduction
  • Stroke medicine did not really develop into a proper speciality until the arrival of the CT scanner and the increasing access to early imaging that could tell us if there was a stroke and if that stroke was likely to be ischaemic or haemorrhagic. A simple non-contrast CT head can be done on anyone (unlike MRI) if they are claustrophobic (most scanners are fairly open), if they are unwell (they take less than a minute and they can be monitored throughout), if they have metal fragments (there is no magnet). CT is much faster than MRI with shorter image acquisition times. The only catch is that changes on CT for an early ischaemic stroke can be subtle or it can appear normal so initially the rationale for CT is that a clinical stroke syndrome with no haemorrhage is assumed to be an ischaemic event if within the first 6 hours and this is good enough for thrombolysis.
  • CT imaging forms the basis of stroke care as it can rapidly differentiate between Ischaemic and Haemorrhagic stroke and some stroke mimics. All clinicians need to develop competencies in reading CT scans and identifying what is normal and what is not. The best way to learn is to look at all the scans which you request, to attend a weekly neuroradiology meeting and to spend time learning the cross-sectional anatomy and vascular supply. Looking at scans is part of good stroke practice and the correlation and sometimes lack of correlation between clinical findings and imaging can be vitally important. Looking at imaging isn't just for medical staff but something that should be of interest to all involved in stroke care. In some centres specialist nurses and therapists attend the neuroradiology meetings and this helps to educate all.
  • It wasn't always this way. I inherited a copy of Brain's clinical neurology from the 1970s and there isn't a single cross-sectional image in the whole book as it didn't exist. Prior to CT there was no reliable way to diagnosing haemorrhage versus ischaemia other than at post mortem. Various clinical scoring systems were developed but were unreliable. A calcified pineal good give some idea of where the midline was and tell if it had shifted but it is hard to think that was very useful and I suspect craniectomies were done for suspected haemorrhage which never were. It was really a forlorn attempt at gathering information. No wonder the feeling of diagnostic futility led to a very negative view of stroke. How times change. It's still a surprise that even with the amazing advances in imaging that we still have to deal with diagnostic uncertainties and the answers are not always clear.
History of CT Imaging
  • The first CT scanner was developed in 1972 by Sir Godfrey Hounsfield who was a researcher at EMI. It's a fascinating fact that it was the wealth derived by record sales from the Beatles who were signed to EMI that funded early CT research. Hounsfield went on to win a Nobel prize. It was Hounsfield who came up with the idea that one could determine what was inside a box by taking X-ray readings at all angles around the object. He then built a computer that could take input from X-rays at various angles to create an image of the object in "slices".
  • Applied medically this became computed tomography. Hounsfield built a prototype head scanner and tested it first on a preserved human brain, then on a fresh cow brain from a butcher shop, and later on himself. On 1st October 1971, CT scanning was introduced into medical practice with a successful scan on a cerebral cyst patient at Atkinson Morley Hospital in Wimbledon, London, United Kingdom.
  • It wasn't until the mid to late 80's that CT was available initially in teaching hospitals for assessing stroke patients. Prior to this, there was no way to discern ischaemic and haemorrhagic strokes ante-mortem. The CT scanner consists of an X-ray tube and on the opposite side of the cylinder where the patient lies is a set of x-ray detectors. Through a process of data acquisition, the X-ray tube and detectors rotate 360 degrees around the patient in the x and y plane and acquire a vast amount of imaging information which then undergoes image reconstruction. The tube also moves in the z-axis so building up a 3 d image.
  • Spiral CT was developed in the early 1990s and improves scan speed and flexibility. The x-ray tube and detectors rotate continuously about the patient while the scan table advances the patient continuously through the gantry. Between the x-ray tube and the detectors, there is a loss of attenuation as it travels through structures and this is known as the attenuation coefficient which reflects the degree to which the x-ray intensity is reduced by the material. These values are scaled to give values known as Hounsfield units seen in the table below. The overall appearance can be altered by varying Window level and window width. Different windows can be used to look at different structures as shown below. Helical scans mean that there is a continuous movement of the patient through the gantry whilst imaging. Multislice scanners mean that anything from 16-64 slices may be acquired at one time. For CT head slice thickness, is typically 5 mm for a standard head CT and between 0.625-1.25 mm for CTA. Although there is a wide number of Hounsfield numbers the human eye can only differentiate less than 100 different levels of grey.

Different Hounsfield units

MediumHounsfield UnitsAppearance
Air-1000Black
Fat-80 to -100Black
Water0Black
CSF +5Black
White matter +30Dark Grey
Grey matter +40Light Grey
Acute haemorrhage +70White
Bone+400 to +3000Bright White

Radiation Exposure
  • CT involves exposure to ionising radiation and so care must always be taken in its use. In the UK access to scanning is guided by IRMER guidelines and only trained professionals can request scans which includes appropriately trained doctors, specialist nurses and radiographers and radiologists.
  • In many trusts have protocols (See indications for urgent CT scan)and agreements that allow specialist stroke nurses to arrange urgent Head CT scans without medical input. This is a vital time-saving step in those who need acute therapies and experience tend to show that this works well. CT scans should only be done when there is a clear clinical need and the result will help to direct therapies or provide useful information that can alter management.
  • A typical head CT involves exposure to 2.1 milli-Sieverts (mSv) but can often be more. For comparison, 10 millisieverts (mSv) of radiation is the rough equivalent of 200 chest X-rays. An increased risk of cancer has been identified among long-term survivors of the Hiroshima and Nagasaki atomic bombs who received exposures of 10-100 milliSieverts so care must be taken. Obviously denser structures need greater doses of radiation. Risk can be measured here.
ScanDose
Natural Background3.1 mSv/year
Domestic pilots2.2 mSv/year
Average US Exposure6.2 mSv/year
CXR (AL and lateral)0.10 mSv/year
Chest CT7.0 mSv/year
Chest Abdomen Pelvis CT21.0 mSv/year
Brain CT (standard)2.0 mSv/year
CTA/CTP Head16.4 mSv/year
Contraindications

Clinically there are no real contraindications for CT if clinically indicated. There are no concerns about pacemakers or defibrillators or metal clips or recent surgery. It is probably unwise if the patient is moribund and too unwell for any intervention and better served by palliation but that's a specialist call. Scans are incredibly quick nowadays and patients can be closely monitored. The only real difficulty is with agitated or confused patients in whom scan quality will be degraded with movement artefact. A doctor can be at the side of the patient during a CT with an appropriate lead apron or behind a screen for protection if needed. CT does not prevent monitoring equipment of infusions or drips. It may be occasionally necessary to intubated and ventilate a patient prior to scanning.

Non contrast CT scan in Ischaemic stroke

Non-contrast CT scan is the standard imaging modality for hyperacute stroke care. It is fast, cheap, accessible, and very sensitive for haemorrhage and there is no problem with pacemakers or monitoring equipment. Claustrophobic or monitored patients can be scanned relatively easy. Done early many scans will be normal despite significant clinical findings. Stroke is primarily a clinical diagnosis and not a radiological diagnosis.

Indications for urgent CT scan
Clinical Indications for urgent CT i.e. within 1 hour of arrival at hospital
  • Acute stroke suspected eligible for acute therapies needs done immediately
  • Acute neurology on Anticoagulant treatment or known bleeding tendency needs done immediately
  • Depressed level of consciousness
  • Unexplained progressive or fluctuating Symptoms
  • Papilloedema
  • Neck stiffness or fever
  • Severe headache at onset
CT and Windowing

This involves a mechanism by which one can select for different Hounsfield numbers. Used well it can help increase the contrast between various structures. For example, a window of 2000 will show most CT numbers. A wide window (W) 400-2000 HU is useful for showing low and higher density tissues. A narrow window 50-350 HU is better at showing soft tissue. Window Level (L) is the midpoint of the CT range. The brain is W80:L40, Stroke is W8:L32 or W40:L40.

IndicationParameters
Brain window to best show white/grey matter differentiationW=80 L=40
Bone windows for bone pathologyW=3500 L=700
Subdural windows for small or isodense subdurals W=250 L=70

What may be missed on a CT Scan

CT is incredibly useful but not infallible and its limitations should be respected. A normal CT scan is entirely compatible with a large ischaemic stroke when within 6 hours of onset. There may be some subtle early changes. CT is also very poor at picking up changes in tissue density in bony spaces such as temporal bones and posterior fossa due to what is called beam hardening as the x-ray beam is distorted by the dense bone traversed. Metallic objects such as aneurysm clips or piercings that weren't removed can cause a radiating streak pattern. Partial volume artefacts can cause streaks or bands of alternating dark and light stripes and beam hardening also affect the posterior fossa. CT scanning cannot differentiate between hypodensity due to infarction or haemorrhage after 1-2 weeks and MRI with GRE or T2* must be used. Subacute ischaemic stroke after several days can show haemorrhage and irregular patterns of density and haemorrhagic changes which can resemble tumours. Follow up interval scanning will be needed.
Caution : What may be missed on a CT scan
  • Isodense Subdural haematoma
  • Brainstem or Posterior fossa pathology though more recent scanners are much improved
  • Low attenuation lesions near skull missed 'beam hardening'
  • Suspected Haemorrhage over 2 weeks ago (get GRE MRI)
  • Multiple sclerosis plaques

Make sure you understand the terms axial, sagittal and coronal. Axial is simple horizontal slices from above down. Sagittal is in the same plane as cutting the brain in the midline or parallel to this (parasagittal). The falx cerebri that separates the brain hemispheres lies in the sagittal plane. Coronal is like a tiara or 'corona'. It is vital to have a good inner representation of the cerebral vessels as they enter the skull and join the circle of Willis and the circle of Willis as well and the position of the vessels. A few simple points will help greatly. The circle of Willis (COW) is at the level of the midbrain. Find the midbrain and then look for the vessels. This is a good place to start looking for the hyperdense MCA as the MCA leaves the COW laterally within the Sylvian fissure.
AxialCoronalSagittal

Looking at Imaging

Starting with imaging. It is important to take your time and go through each slice from top to bottom in every case. Don't be distracted by the most obvious "big" finding and make sure you take time to ensure that you don't miss things. This is even more important in thrombolysis cases where the main concern is "is there any blood" and great care must be taken in what is a time-pressured environment. In that situation, I look at the scan whilst it is being done in the CT and then as soon as the patient is out and before we give open the Alteplase I will go off to a monitor away from the team and distractions and quickly go through all the slices without interruption at least twice. As I have become more experienced and seen more and more cases I think this level of care is important. It's one of the reasons why I don't rush to give Alteplase in the CT scanner as the control room is not the best place to look at a scan with diagnostic quality. I feel that several minutes quickly reviewing the scan in a controlled way is important especially in patients where things may just not seem clinically right. In most cases, we do not get a radiology review before lysis. I will actively look for any suggestion of a thin layer of subdural blood or any hyperdensity that might reflect acute bleeding. Sometimes it is difficult if there is asymmetrical basal ganglia calcification that can mimic blood or it may actually be blood. I will take particular care to look for any subarachnoid blood within the ventricles and cisterns as well as convexity blood in the sulci. I have seen excellent colleagues caught out with very subtle basal ganglia blood that looked very much like calcification even when shared with the neuroradiologist and also subtle sulcal convexity blood probably due to cerebral amyloid. One possible clue is that often the NIHSS if the neurology is due to very subtle haemorrhage is usually in that low threshold to treatment range. The rest of the time scans can be looked at with time. It is very important whatever stage you are at the look at every scan. It may not mean much at the start but you are building up your own visual memory bank of imaging with which to compare every new scan and it quickly trains your visual skills.

Normal Cross sectional CT anatomy

Top down Axial Imaging

Image below:The top image two slices here are useful for just ensuring that there is no subdural blood or any other abnormality. It is on the top few slices that we may see a subtle anterior cerebral artery infarct that can have caused contralateral leg weakness and these slices must be looked at very carefully. It is important to recognise calcification of the choroid plexus which is within the ventricles and produces CSF. It is possible to get a focal haemorrhage up at this level. Each slice needs careful review.

Image below:A good view to look for any evidence of parenchymal abnormality in the cerebral hemispheres. Here we have brain supplied by ACA, MCA and PCA. Look for any asymmetry and look closely for any space between the parenchyma and the inner skull that could be subdural. Appreciate the contrast between the outer grey matter and the more central darker white matter.

Image below:A good view to look for any evidence of parenchymal abnormality in the cerebral hemispheres. You can also see the frontal and temporal horns of the lateral ventricle and the slit-like third ventricle. Any enlargement of these particularly the temporal horns can suggest hydrocephalus.

Image below:This is the level going through the Midbrain. Identify the V shape of the midbrain. This is formed by the cerebral peduncle which carries the descending motor fibres in the front of the "V". This is a good position or a slice above or below to see the branches of the circle of Willis and this is often the level at which one can see clot "the hyperdense artery sign" within the MCA or even PCA. You can also see the frontal and temporal horns of the lateral ventricle and the slit-like third ventricle. Any enlargement of these particularly the temporal horns can suggest hydrocephalus.

Image below:This is the level going through the Upper Pons. As you can see the pons is a slightly rounded structure with the cerebellum attached posteriorly separated by the fourth ventricle. This a common area to contain blood in those who have had bleeding into the ventricular system.

This is the level going through the lower Pons

This is the level going through the medulla

Basal Ganglia calcification

Some degree of basal ganglia calcification is normally seen and the main issue is to differentiate it from blood. There are extreme variants and the so-called Fahr syndrome. Normal calcification is seen in middle age and beyond. Unless extreme it is rarely associated with any problems.

Introduction

It is important to develop your ability to study imaging and correlate it with brain structure and function. There is a standard anatomical vocabulary with terms such as axial, sagittal and coronal which are commonly used in both CT and MR to describe different cross-sectional images. Modern-day imaging actually allows the brain to be imaged and reconstructed in any plane but these are the standard and familiar views.

Look at as much brain imaging as possible, the ones that you request and more. The key is to see a wide variety of normality and to build up some pattern matching skills and experience in identifying important structures and lesions. You will have an advantage over the radiologist who has only the clinical details on the card whereas you have the patient.

CT Interpretation

Definitive distinctive changes may not occur until 6-8 hours. In the meantime, more subtle signs are seen. At about 6 hours and sometimes earlier there may be loss of grey-white matter differentiation - seen at the cortical surface due to localised changes such as cytotoxic oedema within the grey matter which has a higher metabolic requirement and so becomes oedematous quicker. These signs are subtle and can be missed by even the most experienced

Left MCA hyperdense artery

This can be the earliest sign of a large vessel stroke is accompanied by a corresponding Left MCA stroke syndrome. There are no obvious tissue changes and the patient is within the window and NIHSS is raised and no contraindications should be considered for thrombolysis/thrombectomy if safe. Occasionally due to good collaterals, there may be minimal symptoms and in others, they can be profound. A dense artery may just be calcium in the vessel wall and scans must be interpreted within the clinical context.

Dense Basilar Artery

The patient was comatose and sustained massive damage to the posterior circulation. This is an important sign in a deteriorating and comatose and quadriplegic patient needing consideration for thrombectomy. There are no parenchymal changes seen yet.

Early signs: less than 6 hrs of Acute Ischaemic Stroke

  • May be entirely normal initially
  • Cortical Sulcal effacement - suggests some increased oedema
  • Loss of Grey/White differentiation in the basal ganglia
  • Loss of insular ribbon sign is similar to the loss of grey-white differentiation with localised cytotoxic oedema. Vascular supply here is more vulnerable due to poor collateralisation and so this may show first.
  • Obscuration of the Sylvian fissure: Similar to insular ribbon sign
  • Hypoattenuation seen on CT is highly specific for irreversible ischaemic brain damage and infarction if it is detected within the first 6 hours.
  • Hyperdense MCA sign or more distal MCA "dot sign" it may be normal is a sign of clot (thrombotic or embolic) (not a contraindication to lysis) but shows the extent of possible infarct which depends also on collateral flow.
  • Obscuration of the lentiform nucleus (loss of the normal attenuation difference of the globus pallidus and/or putamen with respect to contiguous white matter structures
Developed Anterior Cerebral Artery Infarct

This shows an evolved subacute infarct as the edges are still indistinct and so there is ongoing liquefactive necrosis. This is about Day 2-4 or beyond. There is some mild midline shift due to some localised oedema.

Bilateral PCA infarcts due to Basilar occlusion seen above

Infarction involves both occipital lobes. The patient who survived is blind.

Large left Subdural Haematoma

There is no bright white fresh blood so this is a subacute bleed and it can be surprising how well these are tolerated. The midline is shifted. This is not stroke. It needs urgent discussion with neurosurgeons. Any anticoagulants or antithrombotic therapy must be stopped. The decision on whether to operate will depend as well on the clinical state of the patient.

Later signs (6-24 hrs) of Acute Ischaemic Stroke
  • Watershed infarcts between vascular territories often bilateral strokes between ACA and MCA territory and MCA and PCA may suggest carotid disease
  • Clearly delineated wedge shaped hypodense region involving cortex and adjacent white matter related to the occluded artery anatomy and collaterals at 12 hours.
  • May be some haemorrhagic transformation. Estimated incidence of haemorrhagic transformation is up to 40% in the subacute period even when not thrombolysed.
  • Lacunar infarcts may be seen deep within white matter and within the basal ganglia.
  • Occasionally due to collateralisation or perhaps reperfusion of the MCA the cortex remains unaffected but subcortical areas infarct and become hypodense and this is seen with a subcortical striato-capsular type of stroke.
  • Late changes over days and weeks is most marked Hypodensity due to cytotoxic oedema initially and Vasogenic oedema secondarily and best seen days 3-10.

Late signs ( > 24 hrs) of Acute Ischaemic Stroke
  • Fogging - density of ischaemic tissue reaches same intensity as normal brain tissue and so evidence of infarction not seen
  • Late changes over weeks and months shows continue as the infarcted zone has density of CSF and there is loss of volume.
  • A hypodense caudate suggests MCA occlusion proximally taking out lenticulostriate arteries.
  • Depends on leptomeningeal anastomoses of ACA and PCA
  • Haemorrhagic transformation may occur

Non-contrast CT false negatives (there is a stroke) usually in infarcts when done early or in those who present 7-10 days after stroke and there is a visible hypodensity but no blood and so aetiology of perhaps a small bleed may be missed. In these cases, a gradient echo will show haemosiderin deposition around the margins suggesting haemorrhage as he cause.

NCCT false positives are seen particular in older hypertensive patients where Lacunar infarcts are common and most often asymptomatic but appear on scans done for a myriad of reasons so unless there is corresponding new neurology do not diagnose acute stroke but do treat for "stroke disease".

ASPECTS

The Alberta Stroke Program Early (non-contrast) CT score (ASPECT) is a scoring system used to assess the extent of early ischaemic changes in the middle cerebral artery territory on non-contrast computed tomography. The clinician/radiologist studies the appearance at two different axial slices corresponding with two different anatomical levels and subtracts 1 from the total maximum of 10 for each area affected. A score of 0 suggests extensive MCA infarction and correlates inversely with NIHSS. A score of 10 is normal. An ASPECTS score less than or equal to 7 predicts a worse functional outcome at 3 months as well as symptomatic haemorrhage. Online training and more information is available from link

Basically the higher the ASPECTs score the better the prognosis. High scores such as 10 are normal and low scores < 5 suggests evolved ischaemic changes.

A normal CT scan has an ASPECTS of 10 points. One point is subtracted for ischaemic changes in each region of the MCA territory.
Lentiform nucleus level / Subcortical Structures
M1 Anterior MCA cortex (Frontal operculum) -1
M2 MCA cortex lateral to the insular ribbon (Anterior temporal lobe) -1
M3 Posterior MCA cortex (Posterior temporal lobe) -1
Lentiform (L) -1
Caudate nucleus (C) -1
Internal capsule any part (IC) -1
Insular ribbon/cortex (I)-1
Centrum semiovale level
M4 (Anterior)superior to M1 -1
M5 (Lateral)superior to M2 -1
M6 (Posterior) superior to M3 -1
Total ASPECTS Score. ?/10

Assessing

The ASPECTS score has some clinical correlation. A normal brain has a score of 10 and as more areas are affected the score falls. A full MCA territory infarct with CT changes would have a score of 0. A sharp increase independence and death occurs with an ASPECTS of 7 or less. A common misunderstanding of ASPECTS scoring is to assess only two standardised cuts, i.e. one ganglionic cut through the thalamus and one supraganglionic cut above this. Be sure to include the assessment of all axial cuts of the brain NCCT scan. The ASPECT score is not needed prior to thrombolysis but it does give an element of quantitative rigor to assessing the CT analysis and may be mentioned in any discussion with a stroke physician so useful to have heard of it. The aspects does not incorporate ACA and PCA territories but adjacent infarcts may well have clinical implications.

Uses

The ASPECTs scoring system has been utilised in many ways. It has been used to prognosticate for example the score is a strong predictor of functional outcome. It has also been used to direct therapies. The effectiveness of intra-arterial thrombolysis in patients with middle cerebral artery occlusion shows effect modification by the Alberta Stroke Program Early CT Score. Those with a low ASPECTS score suggesting large MCA infarction can be excluded from futile intra-arterial treatments which are unlikely to result in patient functional independence and increases the risk of haemorrhage.

Acute stroke imaging concepts: one suggested system is the 4 P's
  • Parenchyma - look for blood and early signs of infarction
  • Pipes - look at head and neck vessels if possible and intracerebral vessels for thrombosis or dissection depending on the modality
  • Perfusion - depending on modality assess cerebral blood volume and flow and mean transit time
  • Penumbra - assess for potentially salvageable tissue
Non contrast CT scan
  • Within 24 hours is standard and useful and will reliably exclude primary intracerebral haemorrhage
  • An urgent CT is indicated: Anticoagulant treatment, a known bleeding tendency, Depressed level of consciousness
  • Unexplained progressive or fluctuating Symptoms
  • Papilloedema, Neck stiffness or fever
  • Severe headache at onset
  • Indications for thrombolysis or early anticoagulation
Changes: Definitive distinctive changes may not occur until 6-8 hrs. In the meantime more subtle signs are seen
  • loss of grey-white matter differentiation - seen at the cortical surface due to localised changes such as cytotoxic oedema within the grey matter which has a higher metabolic requirement and so becomes oedematous quicker
  • sulcal effacement - suggests some increased oedema
  • loss of insular ribbon - similar to loss of grey white differentiation with localised cytotoxic oedema. Vascular supply here is more vulnerable due to poor collateralization and so this may show first
  • low density area/hypoattenuation - Hypoattenuation on CT is highly specific for irreversible ischaemic brain damage if it is detected within the first 6 hours
  • hyperdense MCA sign or "dot sign" it may be normal is a sign of clot (thrombotic or embolic) (not a contraindication to lysis) but shows the extent of possible infarct which depends also on collateral flow.
  • obscuration" of the lentiform nucleus (loss of the normal attenuation difference of the globus pallidus and/or putamen with respect to contiguous white matter structures
  • CSF space compression
Changes After 12 hours
  • Clearly delineated wedge-shaped hypodense region involving cortex and the adjacent white matter related to the occluded artery anatomy and collaterals. May be some haemorrhagic transformation.
  • Estimated HT is up to 40% in the subacute period. Lacunar infarcts were seen deep within white matter and within the basal ganglia
Other findings
  • Hypodensity is the main finding and is due to Cytotoxic oedema initially and Vasogenic oedema secondarily and is best seen days 3-10
  • Fogging when the density of ischaemic tissue reaches same intensity as normal brain tissue and so evidence of infarction not seen. The late infarcted zone has a density of CSF
Middle cerebral artery
  • Hypodense caudate suggests MCA occlusion proximally taking out lenticulostriate arteries
  • Depends on leptomeningeal anastomoses of ACA and PCA
  • NCCT false negatives: Infarcts when done early or Late haemorrhage after 7-10 days
  • NCCT false positives: Lacunar infarcts are common and most often asymptomatic but appear on scans are done for a myriad of reasons so unless there is corresponding new neurology do not diagnose acute stroke but do treat for "stroke disease".
CT angiography
  • Allows visualisation of the pipes from the aortic arch to the circle of Willis and so includes head and neck vessels and COW and its branches
  • Added value is the identification of vessel occlusion from carotid to COW branches. The extent of collaterals.
  • Can help to direct mechanical or systemic or intraarterial thrombolytic therapies
CT Perfusion
  • Assess perfusion in a CT slice following an injection of IV contrast an measuring the first pass as the contrast perfuses the brain. Modern scanners can take 10 and more images per second. Multislice scanners allow different slices to be taken simultaneously. A time density curve for each pixel can be generated.
  • Can calculate relative cerebral blood flow, relative cerebral blood volume, time to peak and mean transit time which can be displayed in a colour map
  • Volume of blood per unit of brain 4-5 ml/100 g
  • Flow to grey matter is 50-60 ml/100 g/min
  • Transit time is from arterial inflow to venous outflow.
  • Time to peak enhancement - beginning of contrast injection to the maximum contrast in the area under study
Magnetic resonance imaging
  • Acute ischaemia: T2WI and FLAIR show increased signal which peaks at 7 days and may persist for a month. Diffusion-weighted imaging : This the most sensitive sequence for acute ischaemia as it shows the restriction of diffusion (Brownian motion) of extracellular water due to imbalance caused by cytotoxic oedema within minutes. It can remain bright for up to 3 weeks. Some of the bright area maybe viable. ADC map is initially low signal and then increases in signal later on
  • Chronic infarction : DWI shows decreased signal intensity and ADC shows increased ADC values
Magnetic resonance angiography
  • Investigation of Haemorrhage e.g. AV Malformations, Aneurysms, AV fistulae, Vasculitis.
  • Uses time of flight to image vessels or can use Contrast-enhanced MRA (CEMRA) for improved imaging mainly used for extracranial vessels
Magnetic resonance venography
  • Used in the Investigation of CVT
Magnetic resonance perfusion
  • Multislice imaging without radiation
  • Perfusion weighted T2* images taken following a bolus of Gadolinium every 1-2 seconds for 1-2 minutes
  • Calculates time to peak, mean transit time, relative cerebral blood flow, relative cerebral blood volume
CT based studies Penumbra assessment
  • Penumbra assumed to have an increased mean transit time with decreased cerebral blood flow (> 60%) and normal or increased cerebral blood volume (80-100%)
  • increased mean transit time with a marked reduction in CBF (> 30%) and moderately reduced CBV (> 60%)
  • Infarction - severely decreased CBF < 30% and CBV volume < 40% with an increased mean transit time
  • CBF = CBV divided by mean transit time
  • Penumbra = Map of Cerebral blood volume - Map of Cerebral blood flow
  • Measurements are made after the passage of contrast is given through the cerebral circulation
ASPECTS scan
  • Assesses MCA infarction at two different axial slices and subtracts -1 from total of 10 for each area affected
  • Lentiform nucleus level- M1, M2, M3, Lentiform, Caudate nucleus, Internal capsule, Insular cortex
  • Centrum semiovale level - M4, M5, M6
  • A score of 0 suggests extensive MCA infarction and correlates inversely with NIHSS
Ultrasound Doppler
  • Carotid/Vertebral duplex: Identify stenosis - useful for those with the symptomatic disease for consideration of endarterectomy or stenting. Shows occlusion - due to atheroma/embolism or dissection
  • Transcranial: Identifies MCA flow through a temporal bone window. Takes 30-60 minutes. Useful to identify reduced MCA flow with vasospasm post-SAH, Emboli and microemboli seen following agitated saline in those with Right to left shunt. Bilateral TCD can help show emboli origin. Both sides show emboli if cardiac, one side if carotid
CT Interpretation

Definitive distinctive changes may not occur until 6-8 hours. In the meantime, more subtle signs are seen. At about 6 hours and sometimes earlier there may be loss of grey-white matter differentiation - seen at the cortical surface due to localised changes such as cytotoxic oedema within the grey matter which has a higher metabolic requirement and so becomes oedematous quicker. These signs are subtle and can be missed by even the most experienced

FindingsExplanation
Hyperdense Artery or more distal MCA "dot sign"This may be a sign of large vessel occlusion but does not replace a CTA if needed. The hyperdense vessel sign is most specific but has low sensitivity. Always look at it in context. Some arteries are simply calcified. It may support the diagnosis of large vessel infarct in the clinical context. It is not just seen with the MCA but can also be seen with PCA and basilar arteries.
Loss of Grey white differentiationThis is a very important and early sign of ischaemic stroke. The outer cortical surface of the brain has a different appearance to the subcortical grey matter usually. When ischaemic one of the early signs is that this difference begins to be lost. It is often accompanied by oedema
Loss of insular ribbon or Obscuration of the Sylvian fissure or Lentiform nucleus Both signs suggest a sign similar to loss of grey-white differentiation with localised cytotoxic oedema. Vascular supply here is more vulnerable due to poor collateralisation and so this may show first. loss of the normal attenuation difference of the globus pallidus and/or putamen with respect to contiguous white matter structures
Hypoattenuation Hypoattenuation seen on CT is highly specific for irreversible ischaemic brain damage and infarction if it is detected within first 6 hours. It suggests that the patient may not benefit from reperfusion therapies.
Wedge shaped infarctsClearly delineated wedge shaped hypodense region involving cortex and adjacent white matter related to the occluded artery anatomy and collaterals at 12 hours. Can suggest large artery disease. Often embolic.
LacunesSmall round infacts often in basal ganglia and pons. Usually < 1.5 cm in diameter. Seen with age, diabetes and HTN.
Haemorrhagic transformationBleeding into brain parenchyma. Many large strokes show some of this in the first fortnight. May be some haemorrhagic transformation. Estimated incidence of haemorrhagic transformation is up to 40% in the subacute period even when not thrombolysed.
Watershed infarctsThese occur between vascular territories often bilateral strokes between ACA and MCA territory and MCA and PCA may suggest carotid disease or a systemic drop in BP
FoggingFogging - density of ischaemic tissue reaches same intensity as normal brain tissue and so evidence of infarction not seen
EncephalomalaciaLate changes over weeks and months shows continue as the infarcted zone has density of CSF and there is loss of volume.

Non contrast CT false negatives (there is a stroke) usually in infarcts when done early or in those who present 7-10 days after stroke and there is a visible hypodensity but no blood and so aetiology of perhaps a small bleed may be missed. In these cases a gradient echo will show haemosiderin deposition around the margins suggesting haemorrhage as he cause.

NCCT false positives are seen particular in older hypertensive patients where Lacunar infarcts are common and most often asymptomatic but appear on scans done for a myriad of reasons so unless there is corresponding new neurology do not diagnose acute stroke but do treat for "stroke disease".

References and reading

free web counter Hits