Differential diagnosis of epileptic seizures

1. Big picture

The main exam question is not only “Was this epilepsy?”, but more precisely:

Was this a true epileptic seizure, a provoked acute symptomatic seizure, or a non-epileptic paroxysmal event?

Many conditions can look like epilepsy because they cause sudden, short-lasting attacks with loss of consciousness, abnormal movements, staring, falls, confusion, or amnesia. The most important mimics are:

• Syncope, especially convulsive syncope

• Psychogenic non-epileptic seizures

• Metabolic/toxic events, for example hypoglycemia, electrolyte disorders, intoxication

• Transient ischemic attack, migraine aura, movement disorders

• Sleep disorders, for example narcolepsy/cataplexy, parasomnias

• Tetany, especially due to hypocalcemia

• Eclampsia in pregnancy

The examiner usually wants you to know the bedside clues: trigger, prodrome, body position, type of movements, tongue biting, incontinence, duration of unconsciousness, recovery, and postictal confusion.