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EPILEPSY. Definition. Epilepsy: A group of recurrent disorders of cerebral function characterized by both seizures and convulsions. Convulsion: Sudden attack of involuntary muscular contractions and relaxations. Seizure: Abnormal central nervous system electrical activity.
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Definition • Epilepsy: A group of recurrent disorders of cerebral function characterized by both seizures and convulsions. • Convulsion: Sudden attack of involuntary muscular contractions and relaxations. • Seizure: Abnormal central nervous system electrical activity. • Sezures are generated by abnormal synchronous electrical brain activity
Etiology • Idiopathic – genetic conditions • Acquired: • Trauma • Brain tumors • Stroke • Infections • Degenerative diseases
Ion channels • Proteins that are organised into small pores in the cell membrane • They allow selective passage of ions (Na, Ca, K, Cl), with an important contribution in maintaining the membrane potential and in forming the trans membranare electric flow. • Intercelular signals, transmembrane transport, pH and cell volume
Na channel Natrium channel
Classification • Generalized • Tonic • Atonic • Clonic • Tonic-clonic • Mioclonic • Absence • unclassifiable Partial (focal) • Simple • Motor • Sensitive • Vegetative • Psichical • Complex • Secondary generalized International Classification of Seizures (ILAE, Epilepsia 1981)
Epileptogenesis • The abnormal discharge originates usually in a definite area
Investigatii • Electroencefalogrphy – spectral analysis • Cerebral Computed Tomography (CT) • MRI • Functional imagistics techniques: • PET • fMRI • SPECT • Magnetoencephalography • video – EEG monitoring
10-second EEGs: Seizure Evolution Normal Pre-Seizure Post-Seizure Seizure
- Complexe virf-unda
Generalized Seizures • Grand Mal • Absence • Tonic seizures • Atonic seizures • Mioclonic seizures
Generalized Seizures Excessive electrical activity in both cerebral hemispheres. Usually originates in the thalamus or brainstem. Affects the whole body. Loss of consciousness is common.
Generalized Seizures Myoclonic: Brief shock-like muscle jerks generalized or restricted to part of one extremity. Atonic: Sudden loss of muscle tone. Tonic Seizures: sudden stiffening of the body, arms, or legs Clonic Seizures: rhythmic jerking movements of the arms and legs without a tonic component Tonic-clonic (grand mal): Tonic phase followed by clonic phase http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/19076.jpg
Generalized Seizures Absence (petit mal): Person appears to “blank out” - “Daydreaming” Simple Absence (primarily effects consciousness only) Complex Absence Atypical Absence (Includes physical symptoms like eye blinking or lip movements) Status Epilepticus: A seizure lasting longer than 30 min, or 3 seizures without a normal period in between May be fatal Emergency intervention required
Partial (focal) Seizures Excessive electrical activity in one cerebral hemisphere. -Affects only part of the body. Simple Partial: Person may experience a range of strange or unusual sensations. Motor Sensory Autonomic Key feature: preservation of consciousness.
Partial (focal) Seizures Complex Partial: Loss of awareness at seizure onset. Person seems dazed or confused and exhibits meaningless behaviors. Typically originate in frontal or temporal lobes (e.g. Temporal lobe epilepsy)
Motor partial seizures • Motor (Jacksonian) seizures • Oculo-cefalogiric seizures • Adversive seizures • Supplementary motor area seizures • Tonic seizures
Sensory partial seizures • Jacksonian sensory seizures • Visual • Auditive • Vestibulary • Olfactive & gustative • Vegetative
Partial complex seizures Association areas are involved: • Partial loss of awareness • Dream state, • Déjà vu, • Jamais vu • Anger, fear, joy crisis
Drugs • Cetogenic diet • Surgery • Vagal stimulation
Treatment principles • Monotherapy • Politherapy • Titration • Treatment cessation
Absence seizures • Etosuximide • Oxazolidindione
Drugs that work in seizures other than absence • Phenobarbital • Phenitoin • Carbamazepine • Primidone
Drugs efficient in all types of seizures • Sodium valproate • Clonazepam
Status epilepticus • Prolonged seizure or seizures without remission periods between • Parenteral treatment: • Clonazepam • Diazepam • Phenitoin
Large range of efficacy Narrow range Antiepileptics: efficacy range • Phenytoin • Carbamazepine • Ethosuximide • Gabapentin • Oxcarbazepine • Tiagabine • Pregabalin • Sodium valproate • Levetiracetam • Phenobarbital • Benzodiazepines • Topiramate • Lamotrigine • Zonisamide* * Based on preliminary evidence
Topiramate Vigabatrin Oxcarbazepine Lamotrigine Clobazam Gabapentin Pregabalin Tiagabine Levetiracetam Zonisamide Modern Antiepileptics