Epilepsy

Question 1

Define

Answer 1

a tendency to recurrent unprovoked seizures

You need to have had > 2 seizures for epilepsy to be diagnosed

Definition of Seizure: paroxysmal synchronised cortical electrical discharges

Types of Seizure

• Focal Seizure: seizure localised to specific cortical regions (e.g. temporal lobe seizure). These can be further divided into:
  
  1. COMPLEX partial seizure: consciousness is affected
  2. SIMPLE partial seizure: consciousness is NOT affected
• Generalised Seizure: seizures that affect the whole of the brain. It also affects consciousness. There are different types of generalised seizure:
  
  • Tonic-clonic
  • Absence
  • Myoclonic
  • Atonic
  • Tonic

Question 2

Causes

Answer 2

Most cases are IDIOPATHIC

Primary epilepsy syndromes (e.g. idiopathic generalised epilepsy)

Secondary Seizures

• Tumour
• Infection (e.g. meningitis)
• Inflammation (e.g. vasculitis)
• Toxic/Metabolic (e.g. sodium imbalance)
• Drugs (e.g. alcohol withdrawal)
• Vascular (e.g. haemorrhage)
• Congenital abnormalities (e.g. cortical dysplasia)
• Neurodegenerative disease (e.g. Alzheimer’s disease)
• Malignant hypertension or eclampsia
• Trauma

Common things that look like seizures

• Syncope
• Migraine
• Non-epileptiform seizure disorder (e.g. dissociative disorder)

Pathophysiology of Seizures

• Result from an imbalance in the inhibitory and excitatory currents or neurotransmission in the brain
• Precipitants include anything that promotes excitation of the cerebral cortex
• Often it is unclear why the precipitants cause seizures

Question 3

Epidemiology

Answer 3

COMMON

1% of the general population

Typical age of onset: CHILDREN and ELDERLY

Question 4

Symptoms

Answer 4

Frontal Lobe Focal Motor Seizure

• Motor convulsions
• May show a Jacksonian march (when the muscular spasm caused by the simple partial seizure spreads from affecting the distal part of the limb towards the ipsilateral face)
• May show post-ictal flaccid weakness (Todd’s paralysis)

Temporal Lobe Seizures

• Aura (visceral or psychic symptoms)
• Hallucinations (usually olfactory or affecting taste)
• Frontal Lobe Complex Partial Seizure
• Loss of consciousness
• Involuntary actions/disinhibition
• Rapid recovery

Generalised Seizures

Tonic-Clonic (Grand Mal)

• Vague symptoms before attack (e.g. irritability)
• Tonic phase (generalised muscle spasm)
• Clonic phase (repetitive synchronous jerks)
• Faecal/urinary incontinence
• Tongue biting
• Post-ictal phase: impaired consciousness, lethargy, confusion, headache, back pain, stiffness

Absence (Petit Mal)

• Onset in CHILDHOOD
• Loss of consciousness but MAINTAINTED POSTURE
• The patient will appear to stop talking and stare into space for a few seconds
• NO post-ictal phase

Non-Convulsive Status Epilepticus

• Acute confusional state
• Often fluctuating
• Difficult to distinguish from dementia

TONIC→

stiffening of the body

MYOCLONIC→ sudden, isolated, rapid muscle jerking

ATONIC-Loss of muscle tone →‘Drop attacks’

Question 5

Signs

Answer 5

epends on aetiology

Patients tend to be normal in between seizures

Question 6

Investigations

Answer 6

Bloods

• FBC
• U&E
• LFTs
• Glucose
• Calcium
• Magnesium
• ABG
• Toxicology screen
• Prolactin - shows a transient increase shortly after seizures

EEG

• Helps to confirm diagnosis
• Helps classify the epilepsy
• Ictal EEGs are particularly useful (i.e. during a seizure)

CT/MRI

• Shows structural, space-occupying or vascular lesions
• Other investigations
• If it is suspected to be a secondary seizure (e.g. due to infection)

Question 7

Management

Answer 7

Treatment of STATUS EPILEPTICUS

• DEFINITION of Status Epilepticus: a seizure lasting > 30 mins or repeated seizure without recovery and regain of consciousness in between
• Although the definition states that the seizure must last > 30 mins, treatment is usually initiated early (after around 5-10 mins)

ABC approach

• Check GLUCOSE (give glucose if hypoglycaemic)
• IV lorazepam OR IV/PR diazepam - REPEAT again after 10 mins if seizure does not terminate
• If seizures recur following the next dose of lorazepam or diazepam, consider IV phenytoin - an ECG monitor is required

NOTE: other agents include phenobarbitone, levetiracetam and sodium valproate

• If this also fails, consider general anaesthesia (e.g. thiopentone) - intubation and mechanical ventilation required
• Treat the CAUSE (e.g. hypoglycaemia or hyponatraemia)
• Check plasma levels of anticonvulsants (because status epilepticus is often caused by lack of compliance with anti-epileptic medications)

Treatment of newly diagnosed epilepsy

• Only start anti-convulsant treatment after > 2 unprovoked seizures
• FOCAL Seizure 1st Line: lamotrigine or carbamazepine
• GENERALISED Seizure 1st Line: sodium valproate
• Start treatment with only ONE anti-epileptic drug
• Other anti-convulsants: phenytoin, levetiracetam, clobazam, topiramate, gabapentin, vigabatrin

Patient Education

• Avoid triggers
• Use seizure diaries
• Particular consideration for women of child-bearing age because the anti-epileptic drugs can have teratogenic effects
• Be careful of drug interactions (e.g. AEDs can reduce the effectiveness of the oral contraceptive pill)
• Surgery may be considered for refractory epilepsy

Question 8

Complications

Answer 8

Fractures from tonic-clonic seizures

Behavioural problems

Sudden death in epilepsy (SUDEP)

Complications of anti-epileptic drugs:

Gingival hypertrophy (phenytoin)

Neutropaenia and osteoporosis (carbamazepine)

Stevens-Johnson syndrome (lamotrigine)

Question 9

Prognosis