Blackouts

Question 1

HISTORY AND EXAMINATION;

Answer 1

1. Collateral History
2. What was the patient doing? Precipitating factor? Time course of blackout? Prodromal symptoms? Features of blackout, post-ictal effects.
3. Cardiovascular and neurological examination.

Question 2

CAUSES OF EPISODES WITH COLLAPSE:

Answer 2

1. Tonic-clonic seizure
   - Usually with brief warning aura eg smell/taste/strange feeling
   - seizure last for 2-3 mins
   - Post-ictally: patient is muddled. Slow recovery >5 mins
   - Frequently tonge is bit and urinary incontinence
2. Syncope
   - Preceded by feeling of light-headedness, dizziness, dimming of vision, sweaty and feeling distant.
   - Lies still during blackout which last for usually <30s. Possibly small twitching movements
   - rapid recovery <1min. Frequently urinary incontinence.
   - Can progress to tonic-clonic seizure as in reflex-anoxic seizure
   - vasovagal syncope: preceded by prolonged standing, hot place, some distress
   - cardiac syncope: preceded by palpitations/occur on exertion.
   - postural hypotension, physiologically induced via hyperventilation/valsalva manoeuvre

• Rarer causes:
  3. Subarachnoid haemorrhage
• sudden severe headache before collapse.
  4. Intermittent hydrocephalus
• No prior warning
• Colloid cyst in 3rd ventricle
  5. Drop attack
• may be form of seizure, cardiac arrhythmia/structural brain disease. usually older women
  6. Sleep disorders
• Narcolepsy, obstructive sleep apnoea.
• People with narcolepsy may also have cataplexy during intense emotions.
  7. Hypoglycaemia
• Preceded by light-headedness, sweating, dizziness, feeling of fear.
• Alcohol can be a cause
  8. Psychogenic non-epileptic attacks(pseudoseizures)
• seizures more variable, longer-lasting and fluctuating during attacks. Purposeful/semi-purposeful movements
• often resisting/thrasing needing people to hold them down

Question 3

EPISODES WITHOUT COLLAPSE;

Answer 3

1. Absences
   - Typically in children
   - Brief(lasts minutes) but frequent
   - EEG: 3 Hz spike and wave discharges
   - may have fluttering eyelids and mouth movements
2. Partial seizures
   - can be simple/complex
   - may go on to secondary generalised seizure so aura may resemble that of generalised seizure
   - usually brief(seconds-minutes)
   - temporal lobe onset: smell/taste associated with unpleasant feeling; feeling of deja vu
   - Parietal lobe onset: Numbness or tingling
   - Occipital lobe onset: flash of light
   - Frontal lobe onset: Jerking or occasionally more stereotyped movements ie cycling
3. TIA
   - rarely causes loss of consciousness
4. Transient global amnesia
   - common in >40y
   - almost total failure to acquire new information and appears confused for 2-6h. Still able to do complex tasks ie driving
   - recurrence rate 10%
   - associated with migraine but not cerebrovascular disease/epilepsy
5. Migraine
   - focal neurological symptoms with 15-30 mins gradual onset
   - typically visual symptoms or numbness, tingling, speech disturbance

Question 4

INVESTIGATIONS:

Answer 4

1. ECG for all
   - may detect abnormalities ie long QT
2. If syncope suspected,
   - 24h ECG
   - fasting glucose
   - echocardiogram
   - tilt table test
3. If seizure,
   - Head MRI/CT
   - EEG, 24h EEG
   - Calcium

Question 5

EFFECTS ON DRIVING:

1. Single seizure/blackout with seizure markers
2. Single provoked seizure
3. Recurrent seizures
4. Seizures in sleep only
5. TIA
6. Transient global amnesia
7. Simple faint

Answer 5

1. License revoked for 6 months if ECG and scan normal
2. Individual basis but must inform
3. License revoked until seizure-free ≥1y
4. Can drive provided all seizures in sleep for ≥3y
5. Can drive 1 month after single episode
   6 and 7. No effect