Epilepsy Lecture Note PPT
Transcript of Epilepsy Lecture Note PPT
![Page 1: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/1.jpg)
![Page 2: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/2.jpg)
What are Epilepsies?
• Groupf of disorders of the CNS characterized by paroxysmal cerebral dysrhythmia, manifesting as brief episodes (seizure) of loss of consciousness, with or without characteristic body movements (convulsions), sensory or psychiatric phenomena
![Page 3: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/3.jpg)
What are seizures?
• A seizure is a transient alteration of behaviour due to the disordered, synchronous, and rythmic firing of populations of brain neurones.
• Seizure can be non-epileptic and can be evoked in normal brain.
• A seizure is a paroxysmal behavioral spell generally caused by an excessive disorderly discharge of cortical nerve cells.
![Page 4: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/4.jpg)
Clinical Presentation of Epilepsies
• Epilepsy is a syndrome of two or more unprovoked or recurrent seizures on more than one occasion.
• Epileptic seizures range from clinically undetectable(electrographic seizures) to convulsions
![Page 5: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/5.jpg)
Types
1) Generalized A) Generalized tonic-clonic seizuresB) Absence seizuresC) Atonic seizure D) Myoclonic seizuresE) Infantile spasms
![Page 6: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/6.jpg)
Types
• 2) Partial (focal) SeizuresA. Simple partial seizuresB. Complex partial seizures
![Page 7: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/7.jpg)
Causes of Epilepsy
• Acute • Congenital
![Page 8: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/8.jpg)
Causes of epilepsy
• Acute epilepsy– Cortical damage– Trauma– Stroke– Neoplasm– Autoimmune effects
![Page 9: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/9.jpg)
Classification of antiepileptic drugs
• Hydantoins: Phenytoin. Phosphenytoin• Barbiturates: Phenobarbitone• Iminostilbenes: carbamazepine, oxcarbazepine• Succinimides: Ethosuximide• Aliphatic carboxylic acid: Valproic• Benzodiazepines: Clonazepam, diazepam,
lorazepam• New agents: Gabapentin, lemotrigine, tiagabine,
topiramate
![Page 10: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/10.jpg)
Mechanisms of seizure and antiseizure drugs
• Common ones• Modification of ion conductance– Prolongation of Na+ channels inactivation– Inhibition of ‘T’ type Ca++ current
• Increase inhibitory (GABAergic) transmission• Glutamate receptor antagonism (NMDA,
AMPA, or Kainic acid)• Genetic Mechanisms
![Page 11: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/11.jpg)
Anticonvulsant Mechanism
• The sodium Channel:• A) RESTING STATE• B) Arrival of action potential causes
depolarization and channel opens allowing sodium to flow in.
• C) Refractory State, Inactivation – reduce the rate of recovery.
![Page 12: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/12.jpg)
Sodium channel
• Drugs acting via this channel:– Phenytoin, sodium valproate,– Carbamazepine, lamotrigine,– Topiramide and zonisamide
![Page 13: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/13.jpg)
Anticonvulsant mechanism
• T type Ca++ current inhibition:• T type current is responsible for 3 Hz spike and
wave• Throughout the thalamus T current has large
amplitudes• Burst of action potential is by action of T current• In absence seizure• Drugs – ethosuximide, valproate and
trimethadione
![Page 14: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/14.jpg)
Anticonvulsant mechanism
• The GABA mediated Cl channel opening• Drugs: barbiturates, benzodiazepines,• Vigabatrin, gabapentin and valproate
![Page 15: Epilepsy Lecture Note PPT](https://reader036.fdocuments.in/reader036/viewer/2022081715/544eae1cb1af9fad108b47f4/html5/thumbnails/15.jpg)
Phenobarbitone
• Mechanism of action