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Assessing Coma and Management

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If genuinely uncertain as to cause (CT negative) consider giving Cefotaxime, Aciclovir, Pabrinex (B1) and Naloxone until more information is available

Coma management
ABC, O₂, Recovery position and Anaesthetic review if GCS < 9. Early CT head and exclude Neck fracture. Surgical cause - SDH, EDH, ICH, Tumour refer neurosurgery Consider medical causes especially if CT scan normal Opiate toxicity: Small pupils. Low GCS. IV Naloxone 400 mcg (0.4 mg) IV/ IM which can be repeated up to 2 mg Hypoglycaemia: IM Glucagon 1 mg and/or 200ml 20% or 50 ml 50% Dextrose IV or equivalent Cefotaxime IV for suspected Meningitis Aciclovir 10 mg/kg IV 8-hrly if suspect HSV encephalitis Aspirin if Artery of Percheron stroke with low GCS Steroids if endocrine/pituitary disease consider Hydrocortisone 100 mg stat Sepsis: Tazocin/Gentamicin Thyroid replacement IV T3/T4 if Myxoedema coma (Low temp and bradycardia) Seizure: Are they post ictal then supportive care. Could they have non convulsive status. Look at eyes. Are eyes fixed to the same side as cortical damage? Usually eyes look away. Consider Lorazepam/Keppra IV. take advice Large MCA stroke: Mechanical Thrombectomy Malignant MCA stroke: Decompressive Hemicraniectomy Cerebellar Stroke: Decompressive surgery or shunting for hydrocephalus Quinine IV: for cerebral malaria send blood films Raised ICP for whatever cause Intubation and ventilation to lower pCO₂ to 28-32 mmHg Mannitol IV Boluses Definitive surgery e.g. Evacuate haematoma, Hemicraniectomy or EVD for Hydrocephalus

Coma management

ABC, O₂, Recovery position and Anaesthetic review if GCS < 9. Early CT head and exclude Neck fracture.
Surgical cause - SDH, EDH, ICH, Tumour refer neurosurgery
Consider medical causes especially if CT scan normal
- Opiate toxicity: Small pupils. Low GCS. IV Naloxone 400 mcg (0.4 mg) IV/ IM which can be repeated up to 2 mg
- Hypoglycaemia: IM Glucagon 1 mg and/or 200ml 20% or 50 ml 50% Dextrose IV or equivalent
- Cefotaxime IV for suspected Meningitis
- Aciclovir 10 mg/kg IV 8-hrly if suspect HSV encephalitis
- Aspirin if Artery of Percheron stroke with low GCS
- Steroids if endocrine/pituitary disease consider Hydrocortisone 100 mg stat
- Sepsis: Tazocin/Gentamicin
- Thyroid replacement IV T3/T4 if Myxoedema coma (Low temp and bradycardia)
- Seizure: Are they post ictal then supportive care. Could they have non convulsive status. Look at eyes. Are eyes fixed to the same side as cortical damage? Usually eyes look away. Consider Lorazepam/Keppra IV. take advice
- Large MCA stroke: Mechanical Thrombectomy
- Malignant MCA stroke: Decompressive Hemicraniectomy
- Cerebellar Stroke: Decompressive surgery or shunting for hydrocephalus
- Quinine IV: for cerebral malaria send blood films
Raised ICP for whatever cause
- Intubation and ventilation to lower pCO₂ to 28-32 mmHg
- Mannitol IV Boluses
- Definitive surgery e.g. Evacuate haematoma, Hemicraniectomy or EVD for Hydrocephalus

Recovery position

Assessment of Coma: use Glasgow Coma Scale and examine pupils

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Pathophysiology ascending reticular activating system (ARAS)

Consciousness is arousal and awareness of environment and self, achieved through the action of the ARAS on the brain stem and cerebral cortex
ARAS is composed of several neuronal circuits connecting the brainstem to the cortex.
ARAS is composed of structures such as the brainstem nuclei (locus coeruleus, dorsal raphe, median raphe, pedunculopontine nucleus, parabrachial nucleus), and non-specific thalamic nuclei, hypothalamus, and the basal forebrain.
These structures may come under pressure with subsequent vascular compromise as ICP rises or when bilateral structures are involved such as with bilateral thalamic infarction.
Compression on the brainstem will also lead to damage to the third nerve and dilated pupils with bilateral mydriasis and absence of pupillary light reflex
Pontine damage however may show small pinpoint pupils.

Differential: CT head and CBG are the high yield tests

Cause	Comments
Hypoglycaemia	Test CBG and Give IV Glucose
Opiates	Small pupils. Give Naloxone. Remove opiate patches. Stop oral or IV opiates.
Stroke	Will be large infarct with oedema or large bleed or thalamic infarcts. Get CT head. Protect airways. Recovery position. Stroke care depending on CT
Post Seizure	Protect, ABC and recovery position. Further seizures treat as Status
Encephalitis/Meningitis	Protect, ABC and recovery position. Consider CT/MRI and Aciclovir and Cefotaxime
Carbon Monoxide	Protect, ABC and recovery position. Measure COHb. 100% Oxygen and See topics
Head Injury	Protect neck, ABC and recovery position. Protect spine. Get CT head and C spine.
Low Na	Usually < 115 mmol/L. Consider hypertonic saline if seizure. Otherwise, fluid restrict if SIADH suspected
Sepsis	IV Broad spectrum antibiotics
Brain Tumour	Consider IV Dexamethasone and Mannitol
Non convulsive status	Fluttering eyelids, gaze, twitching. Try Lorazepam
SDH/ EDH	Consider IV Mannitol and Neurosurgical input
Cerebral malaria	Flu like illness and recent travel

General Measures

ED/First responder should check CBG > 4.0 mmol/L. If unsure give glucose.
Get IV access and Bloods.
Check COHb levels on ABG.
ABC, Recovery position, high flow O₂. IV fluids.
Assessment top to toe. Front and back.
Check for Opiate/fentanyl patches and remove them.
Get CT Head +/- Neck. Are there any injuries. Is neck stiff.
Look at pupils.
- Single large suggest ipsilateral coning should be seen on CT.
- Both small: opiates. Both large: cocaine +/- resultant ICH/SAH.
- Rewarm if hypothermia.
Little harm and much good in giving Naloxone and Glucose if unsure.
If no alternative diagnosis on CT consider IV Cefotaxime and IV Aciclovir. Consider LP. Treat Cerebral malaria if travel and blood films suggest.
EEG if non convulsive status.
IF GCS < 9 then needs intubation to protect airway. If no ceiling of care discuss HDU/ITU. If Sepsis then broad-spectrum antibiotics
Differential depends on Context

Raised ICP Causes

Complete MCA occlusion in young person with small CSF spaces + Malignant MCA
Acute Carotid T occlusion + Malignant MCA type syndrome
Extensive ICH or SAH
Space occupying lesion, Subdural haematoma, Extradural haematoma
All of the Above +/- Hydrocephalus

Non-Stroke Causes

Bilateral Thalamic Strokes [link]
Post Ictal Generalised seizure
Non convulsive status
Hypoglycaemia
Hyponatraemia
Drugs - opiates etc.

CT Normal

Hypoglycaemia, Opiate toxicity
Benzodiazepine toxicity
Post ictal/non-convulsive status
Alcohol excess, Baclofen excess, Ketamine
Carbon Monoxide poisoning
Cerebral malaria: Travel history
Bilateral thalamic infarct : may only be seen MRI DWI
Encephalitis/Meningitis: Ceftriaxone, Aciclovir
Toxic-metabolic- Myxoedema coma needs T3/T4/Steroids
Severe Hyponatraemia - hypertonic saline
Hyperammonaemia: Valproate/Liver failure
Thiamine deficiency give Pabrinex first before glucose

CT Abnormal

Intracranial Bleeds: ICH/SAH/SDH/EDH
Malignant MCA +/- ACA/PCA infarct
Dense Basilar artery and posterior circulation stroke
Pituitary bleed: apoplexy, Subarachnoid bleed
Bilateral thalamic infarct seen after 6 hours or on MRI
Inflammatory and Anoxic-ischaemic post arrest
Unrecognised Traumatic Brain Injury
Large SOL: coning: tumour , abscess, bleed, oedema
Cerebral venous sinus thrombosis
Coma with neck stiffness
SAH/Encephalitis/Meningitis

If normal CT and medical cause are suspected then try Naloxone, Glucose, Cefotaxime, Aciclovir and Pabrinex and stop when the diagnosis is apparent.

References

PLEASE NOTE LEGAL ADVICE: The contents are under continuing development and improvements and may contain errors of omission or fact. Feedback vital and always welcome at drokane at gmail.com. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice. It is only for educational purposes. Please adhere to your local protocols. If you are unwell please seek healthcare advice from your doctor. This does not replace senior or specialist advice. If you do not accept this then please do not use the website. If you need medical advice, please consult a doctor or other appropriate medical professional. If you are a medical professional and you need advice then speak to your senior or colleagues.

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