Neurology >
Epilepsy

“Paroxysmal transient disturbances of nervous system function resulting from abnormal electrical activity of the brain”

Aetiology & Risk Factors
  • Children
    • Inherited syndromes
    • Congenital brain malformations
    • Infection
    • Head trauma
    • Lack of oxygen during birth
  • Young Adults
    • Head trauma
  • Middle Age
    • Stroke
    • Tumours
    • Head trauma
  • Old Age
    • Stroke
    • Alzheimer’s
    • Other degenerative diseases
  • Chromosomal syndromes that can cause seizures
    • 22q deletion syndrome
    • Wolf-Hirschhorn syndrome – 4p16.3
    • 1p36 deletion
  • Metabolic Diseases
    • Hypoglycaemia
    • Acidosis
    • Vitamins
    • Peroxisomal biogenesis disorders
    • Glycosylation disorders
    • Neuronal ceroid lipofuscinosis
    • Metal and metal cofactor deficiency
    • Neurotransmitter metabolism
    • Lysosomal storage diseases
  • Mitochondrial Diseases
    • MELAS
    • MERRF
Pathophysiology
  • The sudden imbalance between the excitatory and inhibitory forces within the network of cortical neurons in favour of sudden-onset excitation
Clinical Presentation
  • Focal Seizures
    • Simple/aware (patient is conscious) – focal motor, sensory, autonomic or psychic symptoms, no post-ictal symptoms
    • Complex/impaired awareness (patient loses consciousness) – awareness impaired either at seizure onset or following a simple partial aura; most commonly from the temporal lobe, in which post-ictal confusion is a feature
    • Evolving to bilateral convulsive seizure – in 2/3 patients with partial seizures, the electrical disturbance which starts focally spreads widely to cause a generalised seizure, which is typically convulsive
    • Localising features of focal seizures
      • Temporal lobe – automatisms (lip-smacking, chewing, swallowing, fumbling, fiddling, grabbing), dysphasia, déjà vu, jamais vu, emotional disturbance, hallucinations of smell/taste/sound, delusional behaviour, bizarre associations
      • Frontal lobe – motor features such as posturing or peddling movements of the legs, jacksonian march, motor arrest, subtle behavioural disturbances, dysphasia/speech arrest, Todd’s palsy post ictally
      • Parietal lobe – sensory disturbances (tingling, numbness, pain – rare), motor symptoms (precentral gyrus)
      • Occipital lobe – visual phenomena (spots, lines, flashes)
  • Generalised Seizures
    • Absence seizures (previously known as petit-mal) – brief <10s pauses, e.g. suddenly stop talking mid-sentence, and then carry on where left off; presents in childhood
    • Tonic-clonic seizures (previously known as grand-mal) – loss of consciousness, limbs stiffen (tonic), then jerk (clonic), may also have one without the other, post ictal confusion and drowsiness
    • Myoclonic seizures – sudden jerk of limb, face or trunk, patient may be thrown suddenly to the ground, or have a violently disobedient limb
    • Atonic (akinetic) seizures – sudden loss of muscle tone causing a fall (no LOC)
    • Infantile spasms – commonly associated with tuberous sclerosis
Investigations
  • Look for provoking causes
  • Consider an EEG
  • Emergency EEG if non-convulsive status
  • MRI – structural lesions
  • Drug levels if the patient is on anti-epileptics
  • Drug screen
  • LP if an infection is suspected
Management
  • Counselling about swimming, driving, heights, employment, insurance, conception – must contact DVLA and avoid driving until seizure-free for >1 yr
  • Psychological therapies – relaxation, CBT (adjunct only)
  • Surgical intervention – can be considered if a single epileptogenic focus can be identified, 70% chance of seizure resolution, risk of causing focal defects
  • Vagal nerve stimulation/deep brain stimulation (DBS)
  • Medication:
Seizure TypeFirst Line DrugsSecond Line Drugs
PartialCarbamazepine
Lamotrigine
Oxcarbazepine
Sodium Valproate
Clobazam
Gabapentin
Levetiracetam
Pregabalin
Tiagabine
Topiramate
Zonisamide
Tonic-clonicCarbamazepine
Lamotrigine
Sodium Valproate
Clobazam
Levetiracetam
Oxcarbazepine
Topiramate
MyoclonicSodium ValproateClonazepam
Levetiracetam
Lamotrigine
Topiramate
AbsenceEthosuximide
Sodium Valproate
Clonazepam
Lamotrigine
AtonicSodium Valproate
Lamotrigine
Clonazepam
Clobazam
Ethosuximide
Levetiracetam
Topiramate
Complications
  • SUDEP – more common in uncontrolled epilepsy, or nocturnal seizure-associated apnoea or asystole
  • Medications and pregnancy – many are teratogenic
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