Epilepsy Flashcards
what is the most important excitatory neurotransmitter and receptor, and why?
glutamate via NMDA receptor - cation channel lets in Na, Ca, and lets K out. Depolarises membrane, more likely AP
what is the most important inhibitory NT and receptor, and why?
GABA via GABAa receptor - Cl channel, hyper polarises membrane, less likely to fire action potential
what is a seizure?
excess excitation and synchronisation of neurones, via loss of inhibitory neurones or too strong excitatory signals.
what are some causes of seizures?
genetic differences in brain chemistry/receptor structure, by exogenous activation of receptors (drugs), by acquired brain chemistry changes (drug withdrawal/metabolic changes), or damage to these networks (strokes/tumours)
what are signs of a generalised seizure?
LOC often with changes in muscle tone, tongue biting, loss of bladder and bowel control
what are signs of a tonic clonic seizure?
initial hypertonic phase followed by rapid clonus (shaking, jerking)
what is the post ictal period?
after a seizure, decreased consciousness which can last mins to hours
what is the diagnosis criteria for epilepsy?
1) at least 2 unprovoked seizures occurring >24 hrs apart
2) one unprovoked seizure and a probability of further seizures
what are different types of reflex seizures?
photogenic, musicogenic, thinking, eating, hot water immersion, reading, orgasm, movement
what are the 3 types of classification?
focal onset, generalised onset, unknown onset
where do generalised seizures originate?
at some point within and rapidly engage bilaterally distributed networks, can include cortical and subcortical structures but not necessarily the entire cortex
where do focal seizures originate?
within networks limited to one hemisphere, may be discretely localised or more widely distributed
what can cause a provoked seizure?
as a result of another medical condition - drug use/withdrawal, head trauma, alcohol withdrawal, metabolic disturbances e.g. hyponatraemia, CNS infections, uncontrolled hypertension
what is the initial management of a seizure?
airway - is it patent
breathing - sats reading +/- O2
circulation - expect a high HR, wary of BP
disability - may have reduced consciousness depending on type
e - may want to get them in recovery position, look at clock, get help, majority resolve in 5 mins
what is status epilepticus?
a seizure lasting more than 5 mins, or multiple seizures without complete recovery in between, is a medical emergency
