Neurology Neurology · Emergency

Seizure Causes

Seizures result from abnormal hypersynchronous neuronal activity. First seizure in an adult requires investigation to exclude a structural, metabolic, or toxic cause.

✦ The Mnemonic

"VITAMINS Causes Seizures"

Vascular · Infection · Trauma · Autoimmune · Metabolic · Idiopathic/Inherited · Neoplasm · Substance

V Vascular Stroke, haemorrhage, hypertensive encephalopathy, cortical vein thrombosis

I Infection Meningitis, encephalitis (HSV most important — treatable), brain abscess, HIV, neurocysticercosis

T Trauma Post-traumatic epilepsy; early (<7 days) vs late (>7 days) seizures

A Autoimmune / Inflammatory Anti-NMDA receptor encephalitis (young women, ovarian teratoma), Hashimoto's encephalopathy

M Metabolic Hyponatraemia, hypoglycaemia, hypocalcaemia, uraemia, hepatic encephalopathy

I Idiopathic / Inherited Epilepsy syndromes (JME, CAE, Dravet); genetic channelopathies

N Neoplasm Primary brain tumour, metastasis, paraneoplastic

S Substance withdrawal Alcohol, benzodiazepines, barbiturates — GABA withdrawal; cocaine/amphetamine intoxication

📚 Clinical Breakdown

First seizure investigation: urgent blood glucose (exclude hypoglycaemia), U&E, Ca2+, Mg2+, FBC, LFTs, toxicology screen. Brain imaging — CT head urgently if focal signs, immunocompromised, age >60, fever, or recent head trauma. MRI brain for all first seizures once stable. LP if meningitis/encephalitis suspected.

Status epilepticus: seizure lasting >5 minutes or two seizures without recovery between. Time-critical: IV lorazepam → IV levetiracetam or phenytoin → general anaesthesia. Every minute of status increases neuronal injury and mortality. Treat hypoglycaemia and give IV thiamine before glucose in alcoholics.

Anti-NMDA receptor encephalitis: classic in young women — psychiatric prodrome (psychosis, agitation), then seizures, movement disorders, autonomic instability, and decreased consciousness. Check serum/CSF anti-NMDA receptor antibodies. Screen for ovarian teratoma. Treat with immunotherapy and remove teratoma.

Most important treatable cause HSV encephalitis — give IV aciclovir empirically

Status epilepticus — first drug IV lorazepam 4 mg

Alcohol withdrawal seizures Risk at 24–48 hours — give IV chlordiazepoxide or lorazepam

Anti-NMDA encephalitis — screen for Ovarian teratoma

⭐ Clinical Pearl

Febrile convulsions: occur in 2–4% of children aged 6 months–6 years. Simple FC: <15 minutes, generalised, no recurrence within 24 hours. Complex FC: >15 minutes, focal, or recurs within 24 hours. Simple FC do not increase risk of epilepsy significantly. Parents should receive first aid education and rectal diazepam for prolonged seizures.

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