Epilepsy and its treatment Flashcards
Epilepsy?
Group of CNS disorders in which recurrent seizures
Occurs due to chronic underyling processes
Affecting motor, sensory and autonomic outputs.
Seziures are paroxysmal?
Sudeen recurrent events
Due ot abnormal, excessive, synchronous discharges from a population of CNS neurones.
Different types of seizures?
Lots of types
Generalised seizures: involves many brain regions.
Mapping of the origin of a seizure?
Mapped electrophysiologically to a focus of origin within the brain
Types of epilepsy?
Lots of types
Primary or secondary
Primary or idiopathic epilepsy?
Cannot be ascribed to a particular cause or incidient.
Secondary or symptomatic epilepsy?
Associated with trauma, neoplasm, infectio, development abnromailites or cerebrovascular disease
Epilepsies are broadly classified into two major categories?
based on the locus
Based on the locus of epileptiform activity in the brain.
- Generalised epilepsy
- Focal epilepsy eg. partical seizures. Originate at a specific brain region.
Epilepsies are broadly classified into two groups based on their aetiology (cause)?
- Idiopathic
- Symptomatic: Environmental factors such as trauma, infection etc
Electroencephalogram?
Records brain waves throuhg scalp, skull etc
Detects rhythms, spikes.
Useful for diagnosing the type of epilepsy
Partial seziures:
3 types?
Focal/local seizures.
- Simple partial seizures: no impairment of consciousness. Can be confined to a single limb or muscle group.
- Complex partial seizures: Confusion, stumbling and falling. Unconscious movement that resemble a tics.
- Parital seizures secondarily generalised: Partial seizure immediately preceding a GTC seizure.
ECG of a partial seizure?
Generalised seizure:
5 types?
No evidence of locus.
- Generalised tonic-clonic: can go on for a long time. Tonic rigidity followed by a tremor.
- Absence: small duration but can have many a day/ Concsciousness altered.
- Myoclonic: Isolated clonic jerks associated with multiple spikes in the EEG.
- Atonic: sudden loss of posture leading to collapse.
- Infantile spasms: Brief recurrent myoclonic jerks. 90% causes before 1yo.
Status epilepticus?
Continous or repetitive seizures lasting 30mins or more.
Inadequate treatment can result in brain damage or death.
Can be caused by drug withdrawal.
Epilepsy sufferers that are infected with fever.
Sedatives as treatment
Initiation of a seizures involves 2 things?
- High frequency bursts of action potentials
- Hypersynchronisation
3 Mechanisms for recruitment of surrounding neurones?
- Increase in extracellular potassium- depolarises neighboring neurones.
- Accumulation of calcium in presynaptic terminals resulting in enhanced transmitter release.
- Depolarisation induced activation of glutamate (NMDA) receptors resulting in calcium influx.
Experimental models of epilepsy
Name the 3 main ones?
- Maximal electric shock test
- PTZ-induced clonic seizures
- Lethargic