Wk 6/7 - Epilepsy intro

What is epilepsy?

A group of neurological disorders characterised by recurrent seizures

What is a seizure?

Unregulated and synchronous neuronal activity in the brain – bursts of high frequency action potentials

What disturbances can seizures cause?

Consciousness, behaviour, motor function, sensation, emotion, autonomic function

How many people worldwide have epilepsy?

70 million

What percentage of active epilepsy is in low-middle income countries?

80% (due to lack of treatment)

What is the UK prevalence of epilepsy?

5-10 cases per 1000 people

What shape is the age incidence curve for epilepsy?

U-shaped – high incidence in children and elderly

What is the mortality rate compared to normal?

2-3x normal

What is SUDEP?

Sudden Unexpected Death in Epilepsy – occurs in ~1 in 1000 epilepsy patients

What does "idiopathic" mean in epilepsy?

No known cause (most cases)

What is the genetic concordance in identical twins for epilepsy?

50-60%

What is the genetic concordance in non-identical twins for epilepsy?

15%

What are secondary causes of epilepsy?

Brain damage at birth, malformations, head trauma, tumour, stroke, neurodegeneration, infection (meningitis), drug/alcohol withdrawal

What percentage of epilepsy patients have photosensitive seizures (triggered by flashing lights)?

6%

What are the two main classifications of seizures?

Focal and generalised

What is a focal seizure?

Occurs in a small part of the brain, stays in that area

What is a generalised seizure?

Involves all of the brain (both hemispheres) – loss of consciousness from onset

What are the types of generalised seizures?

Absence, tonic-clonic, myoclonic, atonic, tonic, clonic

Describe an absence seizure.

Childhood onset, very frequent, short duration (3-30 sec), vacant staring, lack of awareness, rapid recovery with no after-effects

Describe a tonic-clonic seizure.

Loss of consciousness, tonic phase (rigidity ~1 min), clonic phase (jerking 2-4 min), postictal confusion

What happens in the tonic phase of a tonic-clonic seizure?

Muscle rigidity, respiration stops (cyanosis), involuntary cry, loss of bladder/bowel control – lasts ~1 minute

What happens in the clonic phase of a tonic-clonic seizure?

Contraction and relaxation of muscles (jerky movements), tongue biting – lasts 2-4 minutes

What happens in the postictal phase?

Confusion, drowsiness, nausea, headache

What is a myoclonic seizure?

Quick, jerky muscle movements

What is an atonic seizure?

Sudden loss of muscle tone ("drop attacks")

What is an aura in epilepsy?

A specific sensation that precedes a seizure (warning)

What is status epilepticus?

Prolonged seizure (>5 minutes) or continuous, uninterrupted seizures – medical emergency

What investigations are used in epilepsy?

MRI/PET (to find lesion), EEG (to determine seizure type)

What percentage of epilepsy patients become seizure-free with medication?

70-80%

What percentage can successfully withdraw medication?

50%