A 68-Year-Old Man with a First Seizure and a Normal CT Head
A 68-year-old man is brought to the emergency department after a witnessed generalised tonic-clonic seizure lasting about 2 minutes. He has no prior history of seizures. He has hypertension and type 2 diabetes, and takes amlodipine and metformin. On arrival he is drowsy but rousable, GCS 14. BP 168/94 mmHg, HR 88, temperature 37.2°C, capillary glucose 5.8 mmol/L. He has a mild left-sided facial droop that resolves over 20 minutes. Non-contrast CT head in the emergency department is reported as normal. He has no focal neurology at the time of review.
1. How would you approach the first seizure in this patient, and what does the normal CT head mean?
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Approach: a first seizure in a patient over 60 requires a structured search for a provoked (secondary) cause before labelling it as epilepsy.
Immediate priorities:
- Airway/breathing/circulation, glucose (5.8 - normal), and check for ongoing seizure activity.
- Exclude reversible causes: electrolytes (sodium, calcium, magnesium), renal and liver function, infection screen (lumbar puncture if fever/meningism and safe), toxicology, and ECG (QT, arrhythmia).
- History: collateral history for aura, focal onset, duration, incontinence, tongue biting, post-ictal confusion; review medications for pro-convulsant drugs (e.g. tramadol, quinolones, bupropion).
The normal CT head: a non-contrast CT excludes large haemorrhage and mass effect but does not exclude:
- Ischaemic stroke (especially early - CT may be normal for hours)
- Cortical or small lesions (tumour, metastasis, abscess)
- Posterior fossa or temporal lobe pathology
- Vascular malformation
Given the transient left facial droop and hypertension, a TIA/stroke must be considered. The normal CT does not exclude a stroke or a structural cause, so MRI brain with diffusion-weighted imaging is the next step, plus vascular imaging (carotid Doppler/CTA) and ECG/telemetry for AF.
2. What is the risk of recurrence, and when would you start an antiepileptic drug?
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Recurrence risk after a first unprovoked seizure is approximately 30-50% over 2 years, higher if there are risk factors:
- Structural lesion on imaging
- Abnormal EEG (especially epileptiform discharges)
- Nocturnal seizure or seizure with focal features
- Family history of epilepsy
- Prior brain insult (stroke, tumour, trauma)
When to start an antiepileptic drug (AED):
- Immediately if there is status epilepticus, recurrent seizures within 24 hours, or a clearly identified high-risk structural lesion.
- After a first unprovoked seizure, AEDs are usually not started routinely - the decision is individualised. If the patient has a high recurrence risk (e.g. abnormal EEG plus structural lesion) and the consequences of recurrence are serious (driving, employment, safety), treatment is reasonable.
- Provoked seizures (e.g. due to hypoglycaemia, hyponatraemia, alcohol withdrawal) are treated by correcting the cause, not with long-term AEDs.
- Driving regulations must be discussed - in most jurisdictions a first unprovoked seizure requires a period of abstinence from driving (often 6-12 months), and this has major practical implications.
Choice of AED: in older adults, levetiracetam or lamotrigine are preferred (fewer drug interactions, better tolerability); avoid carbamazepine and phenytoin (interactions, osteoporosis, hyponatraemia). Start low, go slow.
3. The MRI shows a small acute left frontal infarct with a subtle cortical lesion. How does this change your management?
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The MRI confirms an acute ischaemic stroke with a cortical lesion - the seizure was a provoked (secondary) seizure due to stroke, not epilepsy. This changes management substantially:
Stroke work-up becomes the priority:
- Aetiology: ECG and prolonged cardiac monitoring for AF; carotid imaging; echocardiography (including TOE if embolic source suspected); thrombophilia screen only if young/unusual; HbA1c and lipids.
- Secondary prevention: antiplatelet therapy (aspirin plus clopidogrel short-term for minor stroke, or anticoagulation if AF is found), high-intensity statin, BP control, diabetes optimisation, smoking cessation.
- Thrombolysis/thrombectomy are not applicable now (outside window, minor deficit).
Seizure management:
- AEDs are generally not indicated for a single provoked seizure after stroke; treat only if seizures recur. If a second seizure occurs, start an AED (levetiracetam or lamotrigine).
- Driving advice still applies and must be documented.
Anticoagulation considerations: if AF is found, anticoagulation reduces stroke risk but may interact with seizure risk (falls). Balance with DOACs preferred over warfarin in most patients.
Rehabilitation and follow-up: stroke unit referral, physiotherapy, occupational therapy, and neurology/stroke follow-up. Address vascular risk factors aggressively - this is the key to preventing further events.