Epilepsy

Epilepsy = a tendency to recurrent seizures — the diagnosis needs ≥2 seizures. Most common first occurrence in childhood/adolescence — think about secondary causes if the first seizure occurs in someone over 25. Common: ~1 in 50 people; 50% will have only a single seizure in their lifetime.

History

Patient’s memory of the seizure; past medical/family history of seizures/epilepsy, toxin exposure, accidents, febrile convulsions, eclampsia; a witness account of the seizure; post-ictal phase.

Generalised seizures may be primary (no focus) or secondary (starts focally, spreads — often reflects acquired cerebral pathology).

Clinical seizure syndromes

• Generalised: tonic-clonic; tonic (stiffness only); clonic (jerks only); atonic (loss of tone, collapse); absence (loss of consciousness without loss of postural tone, no post-ictal period); myoclonic (bilateral, discrete severe muscle jerks).
• Partial (focal): simple partial (consciousness retained); complex partial (consciousness clouded, patient can’t recall the whole seizure); may secondarily generalise into a tonic-clonic seizure.

Examination

General and neurological examination.

Investigations

EEG (usually with sleep deprivation); MRI for underlying brain disease; bloods — CMP, UEC, fasting glucose, syphilis serology.

Secondary causes of seizures

(Organic lesions become more common with a first seizure in someone >25.)

• Vascular — cerebrovascular disease, arteritis, hypertension, eclampsia.
• Infectious — intracerebral infection (meningitis, cysticercosis in refugee populations).
• Neoplastic.
• Degenerative disease.
• Iatrogenic/intoxication/idiopathic — post cerebral surgery; alcohol/amphetamines (including withdrawal); sleep deprivation; antidepressants (SSRIs, TCAs, venlafaxine, mirtazapine); antibiotics (norfloxacin, ganciclovir, isoniazid); antipsychotics.
• Congenital — e.g. MELAS syndrome (mitochondrial myopathy, encephalitis, lactic acidosis, stroke-like episodes).
• Autoimmune — autoimmune encephalitis (see meningitis/encephalitis).
• Traumatic — head injury, hypoxia.
• Endocrine/metabolic — calcium/sodium disturbance, hypoglycaemia, uraemia, hepatic failure.

Management

Refer to neurology — accurate seizure-type diagnosis is important for optimal treatment. Advise alcohol abstinence.

Pharmacotherapy is offered after ≥2 seizures within 6–12 months (i.e. usually commenced after the second seizure). Consider starting after the first seizure if seizures are more likely to recur — focal (partial) seizures, epileptiform EEG abnormalities, an abnormal neurological examination, or a lesion on neuroimaging.

• Most epilepsy is controlled with a single drug — start one agent, titrate to control or until side effects occur; therapeutic drug concentrations don’t necessarily need to be reached.
• If the first drug fails, switch to an alternative agent with a different mechanism rather than adding a second.
• Sodium valproate — 600mg/day in 2 doses initially, increasing by 200mg every 3 days according to response. Avoid in females of childbearing potential where possible (teratogenic) — since 2019 a mandatory TGA Pregnancy Prevention Programme requires a signed risk acknowledgment form and annual specialist review. Side effects: teratogenicity, nausea, vomiting, increased appetite/weight gain, tremor, hair thinning/loss, hyperandrogenism.
• Carbamazepine — 100mg BD initially, increasing by 100–200mg every 2–4 weeks. Side effects: increased neural tube defect risk in pregnancy, drowsiness, ataxia, dizziness, blurred vision, headache, Stevens-Johnson syndrome.

Lifestyle advice

Cease alcohol (intoxication is very harmful); ensure adequate sleep (sleep deprivation is harmful); avoid fatigue/physical exhaustion; shower rather than bathe; avoid prolonged flashing lights if photosensitive; avoid work near heavy machinery, at heights, near deep water, or in other dangerous settings if liable to seizures.

Driving

Scenario	Private	Commercial
Default (established epilepsy)	Conditional licence if seizure-free ≥12 months and adherent to medical advice	Conditional licence if seizure-free ≥10 years, EEG in the last 6 months shows no epileptiform activity, and no EEG in the last 12 months has shown epileptiform activity
Benign childhood seizure/epilepsy syndrome	No restriction (as long as seizure-free after age 11)	No restriction (as long as seizure-free after age 11)
First seizure	Conditional licence if seizure-free ≥6 months	No seizure for ≥5 years, plus the EEG criteria above
Epilepsy, newly treated	Conditional licence after ≥6 months’ treatment with no seizures in the preceding 6 months (any seizures after starting treatment must have occurred only in the first 6 months)	Standard default applies (no reduction)

Withdrawing drug therapy

May be considered after ≥2 years seizure-free. Withdraw over 6 weeks (6 months if a barbiturate/benzodiazepine) — no driving during the dose reduction and for 3 months after.

Monitoring drug levels

Correlation between serum concentration and efficacy is poor — judge efficacy by clinical response, not drug level. Measure levels to confirm concordance, help diagnose toxicity, guide phenytoin dosing, or adjust lamotrigine dosing in pregnancy.

Contraception

• Reduce hormonal contraceptive efficacy (enzyme induction): carbamazepine, phenytoin, topiramate (and oxcarbazepine, perampanel, phenobarbitone, primidone).
• Do not reduce efficacy: valproate, lamotrigine, levetiracetam, lacosamide (and gabapentin, tiagabine, zonisamide).
• Effective options: Mirena, DMPA, copper IUD. COCP can be used with ≥50mcg ethinylestradiol daily using extended/tricycling regimens with a 4-day withdrawal — consider adding barrier contraception given ongoing failure risk.

Pregnancy

Refer to an expert to balance seizure risk against teratogenicity. Use folic acid 5mg for 3 months before planned conception.

Acute seizure management / status epilepticus

Acute seizure management:

• Supportive care — most seizures are brief and don’t need drug treatment.
• Position on the left side, protect the airway, maintain oxygenation.
• If available: commence monitoring, check BGL, obtain IV access, collect bloods (UEC, CMP, FBC, VBG).

Status epilepticus — start drug treatment:

• After 5 minutes of continuous seizure activity, OR
• With repeated seizures without full recovery of consciousness between attacks.

With IV access: midazolam 10mg (child 0.15–0.2mg/kg, up to 10mg) IV over at least 2 minutes.

Without IV access: midazolam — adult >40kg 10mg, adult <40kg 5mg (child 0.15–0.2mg/kg up to 10mg) IM; or 5–10mg (child 0.2–0.3mg/kg up to 10mg) buccally/intranasally.

If the acute cause is reversible, no further treatment may be needed. Otherwise, start an antiepileptic drug in all other patients — seek expert advice if the patient already takes an antiepileptic for known epilepsy.

• Phenytoin sodium 20mg/kg IV, no faster than 50mg/minute — monitor BP and ECG.
• Sodium valproate 40mg/kg (up to 3000mg) IV over 5–10 minutes.