Epilepsy

Ravinder Phagura, a final year medical student gives a complete overview of the diagnosis, investigation and management of epilepsy including all the drugs you need to know for both maintenance and status. This is one not to be missed!

 

Video Duration: 30 minutes

  • Epilepsy
    Created by Christian Flynn
    General
    Epidemiology

    Sudden event in which changes of behaviour, sensation or cognitive processes are caused by excessive, hypersynchronous discharges in the brain

    Pathology

    Epilepsy mechanism unknown - brain goes into seizure activity; excessive synchronisation. Resistance of excitatory neurone firing is decreased (ion channel changes/dysfunctioning inhibitory neurons).

    Area where seizure develops is called 'seizure focus' (is needed for any surgical options - only 3% eligible). Another mechanism; possibly upregulation of excitatory circuits/downregulation of inhibitory circuits post-injury to brain. NB - BBB failure = toxin accumulations --> may cause epilepsy. Scarring from any infections, trauma, inflammation or surgery may cause epilepsy as well.

    Top three causes

    Febrile seizures, genetic factors, Infections/trauma

    Clinical Features
    Symptoms

    SEIZURES - 60% convulsive. 30-120 second duration. Positive ictal symptoms - movements, noise, tastes. Post-ictal symptoms - memory loss, temporary paralysis/unconsciousness. May occure from sleep (seperates from Non-epileptic seizures). May be associated with other brain pathologies - eg scarring.

    Typical seizure phenomenon - lateral tongue biting, deja vu, jamais vu (opposite).

    Can be primary or secondary. Focal point in brain determines type of seizure and symptoms seen.

    Stereotypical seizures (patient knows usual pattern of events).

    Focal - from specific part of the brain, may spread --> secondary globalised seizure.

    Focal - preceded by isolated disturbance of cerebral function (aura - smell, taste, emotion).

    eg - Left frontal seizure - with secondary generalisation = jerking of the foot, leg, trunk, arm , head.

    Generalised - distorts activity of whole brain/ symmetrically.

    Unclassifiable, provoked and acute.

    Signs

    Tongue biting, hypertonic, clonic (movement). Unconsciousness, memory loss, myotonic, atonic. Emotion (if limbic system affected). On examination - look for underlying cause as there may be one (eg - brain tumour), ask detailed history - previous injury.

    Investigations
    Cultures

    EEG (interictal/ictal). Video EEG. MRI/CT.

    Neuropsychological testing.

    SPECT (radioactive tracer for bloodflow detection in the brain).

    PET - which sites take up glucose, where is metabolically active.

    Invasive EEG recording (grid electrode - on exposed brain).

    Wada test - barbiturate is introduced into each of the internal carotid arteries in turn in order to evaluate the other hemisphere; language and memory tests. (Prior to ablation for epilepsy surgery).

    Bloods

    General for underlying cause

    Imaging

    See investigations - MRI/CT/PET.

    Scopic/Biopsy

    None

    Functional

    EEG

    Treatment
    Conservative

    Education, epilepsy nurse, supportive, counselling - for employment, driving licence loss, etc.

    Medical

    Anti - epileptic drugs ; carbamazipine, sodium valproate, lamotrigine (warning - major side effect profile - caution in pregnant women/women of child bearing age as AEDs are usually teratogenic - cause harm to unborn fetus).

    Specific drug regimen for different type of epilepsy/seizures. Monotherapy, maybe dual therapy. Try different drugs - titre up to lowest effective dose.

    Surgical

    3% eligible - often curative, last resort.

  • Epilepsy
    Created by Ziad Aldabbagh
    General
    Epidemiology

    Recurrent unprovoked seizures, which are abnormal excess activation of neuronal activity causing neurological dysfunction

    Pathology

    Inc connectivity between neurons

    Inc excitatory transmission

    Dec inhibition (GABA)

    Top three causes

    50% no known cause

    Neoplasia eg brain tumours

    Syncopal episode

    Remember VINDICATE

    Clinical Features
    Symptoms

    Focal - simple, complex or 2e generalised

    Complex - tonic clonic, tonic, myoclonic, absence, atonic

    Signs

    Hypertension

    Tachycardia

    Extensor plantar response

    Hypoxia

    Investigations
    Cultures

    Check for infections

    Bloods

    dec pO2, dec pH (checking for hypoxia induced seizure)

    Imaging

    MRI/CT to exclude structural mass

    Scopic/Biopsy

    None

    Functional

    ECG to exclude arrhythmia

    EEG to confirm

    Treatment
    Conservative

    None

    Medical

    Carbamazepine - focal and 2e generalised

    Lamotrigine - broad spectrum

    Sodium Valproate - broad spectrum

    Phenytoin - tonic clonic and status epilepticus

    Surgical

    Tumour excision if necessary