Epilepsy

Definiton: Paroxysmal abnormal discharges of neurons in the CNS.
Attacks are typically stereotyped and unpredictable. Epilepsy is a symptom not a disease, although the cause is often idiopathic.

Epidemilogy

5% of people will have at least one seizure in their life.
0.5% of people have recurrent seizures.

Differential diagnoses

Other causes of syncope; hysteria.

Diagnosis

Usually Hx only. EEG may be helpful.

Treatment

Refer to neurologist.
Use only one drug. Raise dose until maximum before switching to another drug. At 20y: 50% fit free, off treatment; 20% fit free, on treatment; 30% fits despite treatment. Consider weaning off treatment after 3y.
Type 1st line 2nd line 3rd line
Partial/2° GTCS Carbamazepine Lamotrigine
Valproate
Topiramate
Bagapentin
Clobazam
Phenytoin
Primidone
Phenobarbitone
Vigabatrin
1° GTCS Valproate Carbamazepine
Lamotrigine
Topiramate
Phenytoin
Gabapentin
Primidone
Phenobarbitone
Absence Ethosuximide Valproate Lamotrigine
Clonazepam
Myoclonic Valproate Clonazepam Phenobarbitone

Monitoring therapy

Many antiepileptic drugs (AEDs) are toxic. Monitoring drug levels may be useful in:

Difficult to control epilepsy

  1. Review diagnosis (exclude structural lesion)
  2. Check compliance
  3. Drug interactions?
  4. Consider surgery (temporal lobectomy for hippocampal sclerosis)

Drug interactions

Withdrawing treatment

MRC withdrawal study 1991

41% relapse within 2 years vs. 22% of those still on AEDs.

Risk of relapse:
  1. long history of seizures before remission
  2. multiple seizure types
  3. structural lesion
  4. abnormal neurological signs
  5. learning disability

Status epilepticus

Causes
  1. Pseudoseizures
  2. Withdrawal of AEDs
  3. Structural lesions
  4. Metabolic disturbance (esp. ↓Na+ or ↓glucose)
  5. Eclampsia
Investigations
  1. drug levels
  2. EEG (exclude pseudoseizures)
  3. imaging (exclude structural lesion)
Treatment
  1. IV diazepam 10mg (once only)/IV lorazepam (max twice only)
  2. (PR paraldehyde 5 ml in equal volume of arachis oil)
  3. IM fosphenytoin/IV infusion phenytoin/phenobarbitone
  4. Admit to ITU, ventilate, IV infusion thiopentone

Pregnancy

Risk of teratogenesis vs. risk of epilepsy on pregnancy Remember physiological changes of pregnancy: ↑vol of distr., Δ protein binding.

Driving

Single seizure: 1 year ban.
Withdrawing treatment: while withdrawing + 6/12 after.
HGV licence: 10 year ban.