Epilepsy

Definitions SeizureSeizure –A convulsion or other transient event caused by paroxysmal discharge of cerebral neurons EpilepsyEpilepsy –the tendency to have recurrent seizures

Mechanisms repetitive,unrestricted, hyper-synchronous activation of large groups of neurons failure of synaptic inhibition between neurons

Classification generalized seizure –absence seizures –generalized tonic- clonic seizures –myoclonic seizures partial seizures –simple partial seizures –complex partial seizures –partial seizures evolving into tonic-clonic seizures

partial seizure –epileptic activity confined to one area of cortex with a recognizable clinical pattern generalized seizure –abnormal electrical discharges originate from the diencephalic activating system and spread simultaneously to all areas of the cortex.

Absence seizures ( petit mal) developmental abnormality begins in childhood activity ceases patient stares for a few seconds,eyelids twitch after an attack normal activity resumes EEG- 3 hertz spike and wave activity

Generalized clonic seizures tonic phase –body becomes rigid, patient utters a cry and falls –biting of tongue –bowel-bladder incontinence clonic phase –generalized convulsions –frothing at the mouth –bilateral rythymic jerking –lasts seconds to minutes self limiting followed by drowsiness, confusion or coma

Other generalised seizures myoclonic seizures –isolated muscle jerking tonic seizures –intense stiffining of the body

Partial seizures simple partial seizures –without impaired consciousness complex partial seizures –with impaired consciousness

Causes Partial seizures –Genetic (Tuberous sclerosis) –Cerebrovascular disorders Intracranial bleeding cerebral infarction –Tumours –Trauma (including neurosurgery) –Infection Cerebral abscess Encephalitis

Causes Generalized seizures –Genetic –Cerebral hypoxia –Drugs Penicillin Lignocaine Antipsychotics –Alcohol withdrawal –Toxin (Organophosphorus) –Metabolic –Infective Meningitis, encephalitis

Clinical features - Generalized Tonic Clonic Aura (partial seizure) Rigidity (tonic) Unconscious (falls) Respiratory arrest & central cyanosis Clonic jerks Flaccid/coma state Regains consciousness Disoriented/confused

Clinical features - Complex partial Preceded by alteration of mood/memory/perception Jamais vu, deja vu complex hallucinations Altered consciousness Patient does not collapse Blank stare Repetitive blinking, lipsmacking, picking at clothes

clinical features - absence Like complex partial shorter duration < 30 sec more frequent no post ictal confusion no loss of posture

Investigations EEG (to determine site of origin) Metabolic cause? –Urea, electrolytes, LFT, Glucose, S. calcium & magnesium Inflammation or infective cause? –CBC, ESR, CRP, serology (HIV), CSF exam

Treatment First aid during seizure –Move patient away from danger –Cushion head to prevent injury –After convulsions, turn patient to recovery position (semi-prone) –Do not leave unattended until fully conscious

Medication Prolonged treatment with Anticonvulsants –Primary GTCs - Sodium valproate –Partial & secondary GTCs - Carbamazepine –Absence - Ethosuximide –Myoclonic - Sodium valproate