Epilepsy Viva

Long Case Viva Defence

Candidate's opening statement (model answer)

"Mr Kovac is a 34-year-old electrician with a 16-year history of focal impaired awareness seizures arising from the left temporal lobe. He experiences 4 to 6 seizures per month despite adherence to lamotrigine 400 mg daily and levetiracetam 2000 mg daily. Two of his seizures in the past year progressed to bilateral tonic-clonic seizures. He had prolonged febrile convulsions at age 2 years. ^[1]

His seizures begin with a rising epigastric sensation that lasts 20 to 30 seconds, followed by impaired awareness with lip-smacking and fumbling hand automatisms lasting 1 to 2 minutes, and postictal confusion lasting a further 15 minutes. There is no postictal paralysis. ^[1]

His MRI brain shows left hippocampal sclerosis — hippocampal atrophy with T2/FLAIR hyperintensity and loss of internal architecture. Video-EEG monitoring captured three habitual seizures, all with left temporal ictal onset. Neuropsychology reveals impaired verbal memory localising to the left temporal lobe. ^[1]

His main problems are:

1. Drug-resistant focal epilepsy from left mesial temporal sclerosis — concordant presurgical data
2. Seizures causing driving and occupational restriction and a high SUDEP risk
3. The question of surgical referral
4. Psychosocial comorbidity — anxiety and depression related to long-standing uncontrolled epilepsy
5. Long-term prognosis and the need for integrated care." ^[1]

Examiner probing questions and model answers

Q1: "Define drug-resistant epilepsy and explain why it matters." ^[1]

"Drug-resistant epilepsy is defined by the ILAE as the failure of two appropriately chosen and tolerated antiepileptic drugs, whether as monotherapy or in combination, to achieve seizure freedom. This patient meets that definition — he has failed lamotrigine and levetiracetam at appropriate doses for adequate durations. Drug resistance matters for three reasons. First, the chance of achieving seizure freedom with each subsequent drug trial is low — under 10 per cent once two drugs have failed. Second, ongoing seizures carry cumulative risks: injury, drowning, status epilepticus, sudden unexpected death in epilepsy (SUDEP), and cognitive and psychosocial decline. Third, and most importantly for this patient, the average delay from onset of drug-resistant focal epilepsy to surgical referral in clinical practice is over 20 years — a major failure of care — during which time the patient's life is restricted and the natural history of the epilepsy continues. Once the diagnosis of drug-resistant focal epilepsy is made, the patient should be referred to a specialist epilepsy centre for surgical evaluation without further delay." ^[1]

Q2: "Why is this patient a good surgical candidate?" ^[1]

"Because the presurgical data are concordant — they all point to the same epileptogenic zone. The ILAE 2017 classification requires a syndrome-based approach ^[1], and mesial temporal lobe epilepsy with hippocampal sclerosis is the best-characterised surgically remediable syndrome. In this patient: the structural lesion on MRI is left hippocampal sclerosis; the electrical data on video-EEG shows ictal onset from the left temporal region; the neuropsychological data shows impaired verbal memory localising to the left temporal lobe (the dominant hemisphere); and the clinical semiology — epigastric aura followed by impaired awareness with orofacial automatisms — is characteristic of mesial temporal onset. Because all four data streams agree, no invasive EEG monitoring is required and the patient can proceed directly to anterior temporal lobectomy with amygdalohippocampectomy. If the data were discordant — for example, right temporal MRI lesion with left temporal EEG onset — invasive EEG with subdural grids or stereo-EEG would be needed to clarify the epileptogenic zone before resection."

Q3: "What is the evidence for surgery in this situation?" ^[1]

"The Wiebe randomised controlled trial, published in the New England Journal of Medicine in 2001, randomised 80 patients with temporal lobe epilepsy to surgery versus continued medical therapy ^[2]. At 1 year, 58 per cent of the surgical group were seizure-free compared with 8 per cent of the medical group — a number-needed-to-treat for seizure freedom of approximately 2. This is the most effective intervention in all of neurology. Longer-term follow-up studies report that approximately 50 to 70 per cent of well-selected patients remain seizure-free at 5 years after anterior temporal lobectomy. The benefit is not only in seizure freedom — quality of life improves, employment increases, and SUDEP risk falls. The risks of surgery include a small risk of stroke (under 2 per cent), a visual field defect (quadrantanopia) in up to a quarter of patients, and a decline in verbal memory in some patients with dominant temporal lobe resection — though this is weighed against the natural memory decline of ongoing seizures. Mortality is under 0.5 per cent. Given the patient's disabling and drug-resistant seizures, the risk-benefit balance strongly favours surgery."

Q4: "What are the alternatives if he declines surgery?" ^[1]

"If Mr Kovac declines surgery or is found to have discordant presurgical data, the alternatives are: first, a trial of a third or fourth antiepileptic drug — lacosamide or carbamazepine as a third agent, accepting that the chance of seizure freedom is under 10 per cent. Second, neuromodulation. Vagus nerve stimulation is a palliative option that achieves at least 50 per cent seizure reduction in about half of patients but rarely produces seizure freedom. Responsive neurostimulation — a closed-loop device implanted at the seizure focus that detects abnormal electrical activity and delivers responsive stimulation — achieves a median 75 per cent seizure reduction at 9 years with about 15 per cent becoming seizure-free. Deep brain stimulation of the anterior nucleus of the thalamus achieves about 69 per cent seizure reduction at 5 years. None of these approaches match the curative potential of resective surgery. The third alternative is to accept continued seizures with appropriate counselling on SUDEP, driving restrictions, and lifestyle — but this carries substantial cumulative morbidity." ^[1]

Q5: "What is his SUDEP risk and how would you counsel him?" ^[1]

"SUDEP is sudden unexpected death in epilepsy — sudden, non-traumatic, non-drowning death in a patient with epilepsy, often unwitnessed and presumed to follow a seizure. The dominant risk factor is generalised tonic-clonic seizures, especially nocturnal ones. Mr Kovac has had two bilateral tonic-clonic seizures in the past year, so his annual SUDEP risk is approximately 1 in 200 — significantly elevated above the baseline population risk. The best way to reduce SUDEP risk is seizure freedom — surgery is therefore itself the most effective SUDEP prevention strategy. Other measures include medication adherence, nocturnal supervision, and consideration of a nocturnal movement or audio monitor. I would counsel him directly, using plain language: 'In rare cases, epilepsy can cause sudden death, usually after a major seizure during sleep. The best way to reduce your risk is to achieve seizure freedom — which is why I'm recommending surgery. In the meantime, take your medication reliably, do not sleep alone if possible, and consider a night monitor.' The conversation should be documented." ^[1]