Transient Loss of Consciousness (TLOC)

Related Subjects: |Transient Loss of Consciousness |Vasovagal Syncope |Syncope |Aortic Stenosis |First Seizure |Carotid Sinus Syncope

Any sudden loss of consciousness without warning must be assumed to be a cardiac arrhythmia or a until proved otherwise. It has implications for those who wish to drive. Patient must be warned not to drive again until the diagnosis is established. They should inform DVLA.

About

• Commonly seen in the ED especially in the elderly
• May be discussed as blackouts

Assessment

• The history is key and must be extracted in minute detail so you can imagine what happened
• Witness evidence is key and must be obtained even if you need to phone family or friend with the patient's consent
• What doing - standing, sitting, lying down.
• What happened during episode - responsive, like a dead person
• What happened after the event - how long to return to normal

Differentials

• Vasovagal Syncope: comes on when standing. Often situational - church or out for a meal. Can happen sitting down at a meal and almost always standing. Exacerbated if alcohol is taken. Some recall of vision dimming, distance, then passes out. Recovers quickly. Incontinence uncommon, patients may jerk for a second or so. Look at any causes of low BP or arrhythmia. Check L/S BP. Check BP and ECG. Consider 24 hr tape and overnight monitoring if concerned. Can be made worse by BP medication and diuretics and medications for the prostate.
• Silent MI and hypotension or arrhythmia: Troponin levels. look at ECG, new murmrs, needs echo and monitoring
• Pulmonary Embolism: can often have syncope and then recovers. It Maybe a sign of a large embolus that passes. Check dimer, CTPA.
• Subarachnoid haemorrhage; usually thunderclap headache then syncope and then may wake up. CT usually diagnostic if done early
• Seizure: No warning., Often no memory of onset. Old seizures or new brain injury. Can bite the side of the tongue or be incontinent. Wakes up drowsy and headache. Often not right for a few hours. Consider CT head and EEG and refer to the first fit clinic.
• Cardiac syncope: Maybe severe bradycardia or even tachyarrhythmia. Depending on severity may have no warning. Consider echo to exclude Aortic stenosis or HOCM and cardiology consult. May need implantable loop recorder or 24-7 day tape. Syncope may be an indication for a pacemaker. There are two forms that can be diagnosed after tilt table tests
  • The cardio-inhibitory variant is diagnosed by >3-s asystole on massage.
  • The vasopressor variant is diagnosed by a 50-mmHg drop in BP or systolic BP drop to <90 mmHg.
  • Many have an element of both
• Carotid sinus syncope: Tight collars and looking up can stimulate the receptor and cause a Heart rate and BP drop. I am reluctant to rub the carotid of older patients and will get a doppler and only do so if convinced.
• Hypoglycaemia: Usually diabetic over treated. Consider Addison's and Insulinoma in rare cases
• Orthostatic hypotension: This is defined as a >20-mmHg drop in systolic BP on standing or during head-up tilt. Very common in the elderly. Due to decreased baroreceptor sensitivity, diuretics, CCB, alpha-blockers, dehydration, beta-blockers, vasodilators, anti-parkinsonian drugs, sedatives, neuroleptics.

Investigations

• FBC, U&E, TFT, Bone
• Troponin, Dimer, consider. ECG
• EEG but often difficult to get and not critical
• 24-7 day tape or implantable loop recorder.
• CT/MRI as needed
• Short Synacthen test + cortisol

Management

• Reduce and rationalise BP meds and set new target in frail patient. Stop CCB and furosemide and alpha-blockers.
• Warn patient not to drive - see DVLA site. Each case needs to be judged on merits.
• Some patients may merit a pacemaker. Other trials of Fludrocortisone and Midodrine
• Consider anticonvulsant if that is the most likely diagnosis and there have been prior episodes. Again inform patient to tell the DVLA