癫痫发作和癫痫.pptVIP

Seizures Epilepsy MBBS IV Group C Tutor: Prof. V. Wong 16th Feb 2004 Outline Definitions Pathophysiology Aetiology Classification Video demonstration Diagnostic approach Treatment Quiz Definition Seizure (Convulsion) Clinical manifestation of synchronised electrical discharges of neurons Epilepsy Present when 2 or more unprovoked seizures occur at an interval greater than 24 hours apart Definition Provoked seizures Seizures induced by somatic disorders originating outside the brain E.g. fever, infection, syncope, head trauma, hypoxia, toxins, cardiac arrhythmias Definition Status epilepticus (SE) Continuous convulsion lasting longer than 30 minutes OR occurrence of serial convulsions between which there is no return of consciousness Idiopathic SE Seizure develops in the absence of an underlying CNS lesion/insult Symptomatic SE Seizure occurs as a result of an underlying neurological disorder or a metabolic abnormality Aetiology of seizures Epileptic Idiopathic (70-80%) Cerebral tumor Neurodegenerative disorders Neurocutaneous syndromes Secondary to Cerebral damage: e.g. congenital infections, HIE, intraventricular hemorrhage Cerebral dysgenesis/malformation: e.g. hydrocephalus Aetiology of seizures Non-epileptic Febrile convulsions Metabolic Hypoglycemia HypoCa, HypoMg, HyperNa, HypoNa Head trauma Meningitis Encephalitis Poisons/toxins Aetiology of Status Epilepticus Prolonged febrile seizure Most common cause Idiopathic status epilepticus Non-compliance to anti-convulsants Sudden withdrawal of anticonvulsants Sleep deprivation Intercurrent infection Symptomatic status epilepticus Anoxic encephalopathy Encephalitis, meningitis Congenital malformations of the brain Electrolyte disturbances, drug/lead intoxication, extreme hyperpyrexia, brain tumor Pathophysiology Still unknown Some proposals: Excitatory glutamatergic synapses Excitatory amino acid neurotransmitter (glutamate, aspartate) Abnormal tissues — tumor, AVM, dead area Genetic factors Role of substanti