Seizures Flashcards
What is a seizure?
- sudden, brief attacks
- altered motor, sensory, psychological, consciousness
- abnormal hyper synchronous (simultaneous) or hyper excitable discharge of cortical neurones
What is the epidemiology of seizures?
- recurrent affect 0.5-1%
- <5% has had 1 seizure
- first seizure happens before age 20
- > 20yrs, seizure is due to structural change, trauma, tumour, stroke
What is the aetiology of seizures?
- manifestation of underlying CNS dysfunction
- from any serious illness
- brain: trauma, infection, tumours, drug abuse, vascular lesions, congenital deformities, brain injury
What are the classifications of seizures?
Provoked (secondary or acute symptomatic):
• includes febrile children
Unprovoked (primary or idiopathic):
• multiple episodes of unprovoked seizures = epilepsy
What may cause a seizure?
• alterations in cell membrane permeability or distribution of ions across neuronal cells membranes
• decreased inhibition of cortical or thalamic neuron activity or structural changes (ex. glial scarring) that alter the excitability of neurons
• neurotransmitter imbalances (ex. ACh or deficiency of GABA)
• brain damage at birth
• metabolic imbalance
• infections, meds
• vascular disturbances
• trauma, tumour, abscesses
What happens during a seizure episode?
- 250% increase in ATP
- cerebral oxygen consumption increase by 60%
- cerebral blood flow increase by 250%
- depletes glucose and oxygen
If severe: lactate accumulates ingrain, secondary hypoxia, acidosis
• brain injury and destruction
What is a partial focal seizure?
- begins in specific area of ONE cerebral hemisphere (cortical origin)
- most common type > 10yrs
What is a simple partial seizure?
- consciousness not impaired
- local motor, sensory, psychic features
- features depends area affected
What is a Jacksonian march seizure?
- if motor area is involved in a simple partial seizure
* motor movement may spread to other cortical areas with involvement of body parts in a characteristic “march”
What is a complex partial seizure?
- impairment of consciousness
- arise in temporal lobe
- rapidly progress to both hemisphere
- automatisms
- consciousness feels remote
- deja vu, jamais vu
- hallucinations of smell, taste, hearing sight
- fear, uncontrolled forced thinking, flood of ideas, feelings of detachment
What is a temporal lobe seizure?
old name for complex partial seizure
What are automatisms?
repetitive, non purposeful activity (lip smaking, grimacing, patting, continual rubbing)
What are generalized seizures?
- simultaneous onset in both hemispheres
- most common in young kids
- unconsciousness
- subcortical origin
What are absence seizures?
- petit mal
- blank stare, motionless, unresponsive
- few seconds
- Atypical type - greater alterations in tone, less abrupt onset and cessation compared to Typical type
What are atonic akinetic seizures?
- sudden split second loss of muscle tone
- slack jaw, drooping limb, fall to ground
- drop attacks
