Definitions
Seizure: clinical manifestations of an abnormal, uncontrolled activity by a group of neurons
Unprovoked (idiopathic)
Provoked (acute symptomatic)
Seizure disorder: condition with recurrent, paroxysmal seizures without evidence of a reversible metabolic cause
Definitions
Tonic – A sustained muscular contraction
Clonic – Intermittent muscular contractions and relaxations
Aura: subjective disturbance of perception representing a focal electrical disturbance
Pathophysiology
A seizure is a temporary involuntary disturbance of brain function that may be manifested as impaired consciousness, abnormal motor activity, sensory disturbances or autonomic dysfunction.
Pathophysiology
Seizures are accompanied by abnormal electrical discharges in the brain that can usually be detected by electroencephalography (EEG).
Caused by an increase in cell excitability of neurons.
Maybe caused by a deficiency in an inhibitory neurotransmitter
eg. GABA
Signs and Symptoms
One or a combination
Motor symptoms
Sensory symptoms
Autonomic symptoms
Signs and Symptoms
Motor cortex: cause movements on contralateral side according to the somatotopic location of the seizure focus.
Somatosensory cortex: cause an epileptic aura in which a sensation is experienced. Also depends on somatotopic representation
Auditory cortex: cause an auditory aura (humming, buzzing, and ringing).
Visual cortex: cause a visual aura (flashes, colours).
Classification
Of all patients with epilepsy, 70% have only one type of seizure disorder whereas the remaining 30% have two or more types.
Staging of Seizures
Aura The first self-experienced symptom
The Attack
Post-Ictal Period Associated with headache, drowsiness, or focal
neurologic abnormalities
May last for hours or days
Classification
Partial seizures
Generalized seizures
Partial Seizures
Focal origin
Types:
Simple partial
Complex partial
Secondarily generalized partial
EEG: Partial Seizures
Generalized Seizures
Virtually simultaneous onset in both hemispheres
Diverse clinical manifestations
Loss of consciousness
Classification
EEG: Generalized Seizures
Generalized Seizures
4 categories:
Absence (petit mal)
Atonic
Myoclonic
Tonic-clonic (grand mal)
Absence Seizures
(Petit mal seizures)
Generalised non-convulsive epileptic events
Eg. Blank stare, motionless, unresponsive
May have assoicated automated movements
eg. Lip smacking, grimacing
Atonic Seizures
(Drop attacks)
Sudden loss of muscle tone leading to slackening of the jaw, drooping of the limbs or falling to the ground
Myoclonic Seizures
Brief involuntary Muscle contractions
Bilateral jerking of muscles (generalised or localised)
Tonic-clonic Seizures
(Grand mal seizures)
Major motor seizure
Tonic-clonic contraction of muscles with loss of consiousness
Cyanosis may occur due to contraction of respiratory muscles
Normally lasts 60 - 90 s
Diagnosis
History
Examination
“Routine laboratory tests”
EEG
Neuroimaging (CT/MRI)
Differential Diagnosis