Epilepsy

Definition/diagnostic criteria Epilepsy is a neurological condition characterised by recurrent unprovoked seizures. According to the International League Against Epilepsy (ILAE), a diagnosis can be made after two unprovoked seizures occurring more than 24 hours apart, a single unprovoked seizure with a high recurrence risk, or diagnosis of an epilepsy syndrome.

Epidemiology In the UK, epilepsy affects around 600,000 individuals, or about 1% of the population, making it one of the most common neurological conditions. The condition can begin at any age, though onset is most common in childhood and in people over 60 years of age, reflecting a bimodal distribution.

Diagnosis

Clinical features: Epilepsy manifests through seizures, which vary widely in presentation. Seizures are classified into focal, generalized, or unknown onset, with further subdivisions based on awareness and motor symptoms. Clinical history and witness accounts are paramount for diagnosis, focusing on seizure onset, progression, duration, frequency, and postictal symptoms.

Investigations: Investigations aim to confirm the diagnosis, classify the seizure type, and identify the underlying cause. The mainstay is electroencephalography (EEG), which may show typical abnormalities such as focal or generalized epileptiform discharges or specific epilepsy syndromes patterns. Neuroimaging, particularly MRI, is recommended to identify structural causes. Less commonly, blood tests, lumbar puncture, or genetic testing are utilized based on clinical suspicion. Further tests may be required to rule out other diagnostic possibilities (eg cardiac event monitoring if the differential includes a cardiac cause).

Treatment Treatment is primarily pharmacological, with antiepileptic drugs (AEDs) chosen based on seizure type, epilepsy syndrome, potential side effects, and patient factors such as age, sex, comorbidities, and concurrent medications.

Sodium valproate used to be a common first line treatment for generalised seizures, but UK guidance has been tightened because of the risk of adverse events and states that no one under the age of 55 should be initiated on valproate unless two specialists independently consider and document that there is no other effective or tolerated treatment.

Carbamazepine or lamotrigine are often used for focal seizures.

Treatment initiation and monitoring would be the remit of a specialist with the emphasis on seizure control and minimizing adverse effects. Refractory epilepsy may require consideration of surgical treatment, dietary therapies (e.g. ketogenic diet), or vagus nerve stimulation.

Prognosis The prognosis of epilepsy is variable. Approximately 70% of individuals achieve seizure freedom with appropriate AED treatment. However, the prognosis depends on the underlying cause, seizure type, and presence of comorbidities. Early diagnosis and effective management can improve quality of life and reduce mortality risk. Sudden unexpected death in epilepsy (SUDEP) remains a significant concern, with risk factors including uncontrolled seizures, generalized tonic-clonic seizures, and nocturnal seizures.