Epilepsy
- Other notes

Causes of secondary seizures

• Intracranial hemorrhage (subdural, epidural, subarachnoid, intraparenchymal)
• Structural abnormalities
  * Vascular lesions (aneurysm, AV malformation)
  * Mass lesions
  * Degenerative diseases
  * Congenital abnormalities
• Trauma
• Infection (meningitis, encephalitis, abscess)
• Metabolic disturbances
  * Hypo/hyperglycaemia
  * Hypo/hypernatremia
  * Hyperosmolar state
  * Uremia
  * Hepatic failure
  * Hypocalcemia
  * Hypomagnesaemia
• Toxins and drugs
  * Cocaine, lidocaine
  * Antidepressants
  * Theophylline
  * Alcohol withdrawal
  * Drug withdrawal
• Eclampsia (may occur up to 8 weeks postpartum)
• Hypertensive encephalopathy
• Anoxic-ischaemic injury (cardiac arrest, severe hypoxemia)

Differential diagnosis

Syncope

• Usually has premonitory symptoms such as dizziness, diaphoresis, nausea, and tunnel vision (unless cardiac syncope, which can occur suddenly without any warning)
• Some patients may have brief tonic-clonic activity, but recovery is quick and with very little post-ictal symptoms.
• Injury or incontinence may occur

Pseudoseizure

• Psychiatric rather than neurogenic
• No postictal confusion
• Characteristic movements include side-to-side head thrashing, rhythmic pelvic thrusting, clonic extremity motions that are alternating rather than symmetrical
• Incontinence and injury are uncommon

Hyperventilation syndrome

• Gradual onset, with dyspnoea, anxiety, perioral numbness (perioral numbness also occurs in hypocalcaemia)
• Reproducible by hyperventilation

Migraine

• May be preceded by an aura similar to that seen in partial seizures
• Most common aura in migraine is scintillating scotoma
• May also have focal neurologic symptoms such as homonymous hemianopia, and hemiparesis

Movement disorders

• Dystonia, chorea, myoclonic jerks, tremours, or tics
• Consciousness always preserved
• The movement, though involuntary, can be temporarily suppressed by the patient

Narcolepsy/cataplexy

• Brief attacks of uncontrollable daytime sleepiness