Epilepsy

Introduction:
o A neurological disorder characterised by recurrent seizures.
o International League Against Epilepsy (ILAE) definition:
• At least two unprovoked seizures occurring greater than 24 hours apart.
• One unprovoked seizure and a high probability of further seizures of recurring seizures over 10 years.
• Diagnosis of an epilepsy syndrome.
o Seizures occur due to sudden, excessive and rapid discharges of neurons in the brain.
o Seizures can be classified as focal or generalised, based on whether the lesion is located in a specific or generalised area of one or both hemispheres respectively.
o Epilepsy is caused by a variety of pathologies ranging from infection to alcohol withdrawal
o Estimated to affect 362,000 – 415,000 people in England.
o Incidence is higher in men and peaks in patients under 18 years of age or over 60 years of age.
Presentation:
o The symptoms of epilepsy are dependent on its type. Seizure features strongly suggestive of epilepsy:
o Pre-seizure
• Auras – some forms of epilepsy may present with a ‘warning’ of any sensory modality before the seizure. For example olfactory hallucinations.
o During seizure
• Involuntary movements – associated with generalized tonic-clonic, and myoclonic seizures however can occur in other non-epileptic seizures.
• Presence of automatisms
o Post seizure
• Post-ictal phase – slight confusion after the seizure, the patient may have been disorientated in time and place.
• Temporary aphasia.
• Post-ictal paralysis or weakness.
• Time to recovery – immediate recovery is indicative of a cardiac syncope rather than epilepsy.
History:
o Previous seizure events or suspected seizure events?
o Premature birth?
o Previous or current history of CNS infection?
• Meningitis
• Encephalitis
• Neurocysticerosis
o Previous history of head trauma?
o Family history of epilepsy?
o History of complex febrile seizures in childhood?
o History of cerebral palsy?
o Previous strokes?
o Previous history of intracranial arteriovenous malformations?
o History of alzheimers dementia?
o Symptoms suggestive of brain tumour?
o Previous history of mental health illness or recent stressors?
Examination:
o Neurological examination findings in epilepsy are dependent on the type of epilepsy, presence of underlying pathology or specific syndromes, however they can be normal.
• Stigmata of neurocutaneous syndromes
• Focal neurology
• Investigations should only be performed if the clinical presentation is not definitively suggestive of epilepsy and/or to rule out serious causes of seizures.
Laboratory investigations:
o Bloods
• Full blood count – may be raised indicating CNS infection.
• Glucose – extreme hypo/hyperglycaemia can cause seizures.
• Urea and Electrolytes – electrolyte imbalance can lead to seizures.
• Calcium – high or low levels can lead to seizures.
• Serum creatine kinase – raised in generalized tonic clonic seizures (GTCS).
Radiological investigations:
o Neuroimaging
• Used to identify structural abnormalities of the brain that may cause certain epilepsies.
• CT should be used in an acute setting to detect any lesion causing the seizures.
• MRI is the imaging investigation of choice if available in a non-acute situation.
Other investigations:
o Electroencephalogram (EEG) – helps aide diagnosis, may show:
• GTCS - Generalised epileptiform activity or focal, localising abnormality.
• Focal seizures - spikes or sharp waves in one temporal lobe.
o 12 lead Electrocardiogram (ECG) – cardiac causes of syncope/seizure like activity.
Management:
o Conservative
• Lifestyle advice – stop driving and inform the DVLA; avoid precipitants; avoid swimming pools and baths; avoid working at heights
• They should also be under the care of an epilepsy specialist nurse.
o Medical
• The mainstay of treatment is by anti-epileptic medication (AED). The type of AED prescribed is dependent on the type of epilepsy syndrome, if that cannot be determined then it is based on the presenting seizure type. Where possible a patient should be limited on one AED (monotherapy).
• Avoid using sodium valproate in pregnant and potentially pregnant patients due to risks of malformation and neurodevelopmental impairments in an unborn child.
• First line AED treatment for newly diagnosed patient seizures are summarized below:
• Doses are dependent on the age of the patient, whether the patient is pregnant and severity of disease. Seek specialist advice.
• Focal seizures – Carbamazepine or lamotrigine or Levetiracetam (not cost effective)
• Generalised Tonic-Clonic – Sodium Valproate or Lamotrigine
• Absence seizures – Ethosuximide or sodium valproate
• Myoclonic seizures – Sodium valproate, levetiracetam or topiramate. AVOID LAMOTRIGINE
• Tonic or atonic seizures – Sodium valproate
• Infantile spasms – Steroid (prednisolone or tetracosactide) or vigabatrin (infantile spasms due to tuberous sclerosis)
• Juvenile myoclonic epilepsy – Sodium valproate
• Vagus nerve stimulation can be used in conjunction with AED therapy in refractory cases
o Resective Surgery
• Used for severe refractory cases of epilepsy
Complications:
o Head trauma
o Bone fractures
o Memory loss
o Status epilepticus
o Medication related problems
o Sudden, unexpected death in epilepsy (SUDEP)

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