Epilepsy symposium Flashcards
What is Epilepsy
A recurring, unprovoked spontaneous seizure.
What are 6 causes of epilepsy in order of most common to least common
- Idiopathic
- CVD
- Other
- Alcohol
- Tumour
- Post traumatic
What are the two seizure types
Focal/partial and Generalised
What is a generalised seizure and what is the first line of treatment?
Electrical discharges appear to start all over the whole brain at the same time. No warning/ dangerous for the patient
Sodium Valproate
Who can not be prescribed sodium valproate and why
pregnant women bc it is teratogenic
What is a partial/focal onset seizure
electric discharge appears to start in one cortical region and then may remain localised or spread over the whole brain (secondary generalised)
Name three main types of Primary generalised seizures
Tonic clonic seizure (grand mal)
Absencs (petit mal)
Myoclonic seizures
Juveline myoclonic seizures
most common Juvenile onset, probably lifelong Early morning myoclonic jerks Photosensitive sleep deprivation triggers plus or minus absences
Tonic-clonic seizures (Grand mal)
Occurs without warning
Tonic phase–> continuous muscle spasm, fall, cyanosis, tongue biting, incontinence
Clonic phase–> rhythmic jerking slows and gets larger in amplitude as attack ends
Post seizure phase–> coma, drowsiness, confusion, muscle aching, headaches
Absences (petit mal)
abrupt
short (5-20 seconds)
Multiple times a day and can lead to learning difficulties
Unresponsive amnesia for the gap, rapid recovery
Tone preserved or mildly reduced
eyelid flickering
absences only, tend to remit in adulthood
Types of focal seizure
Simple partial seizure- aura warning. patient aware
Complex partial seizure- aura warning. reduced awareness
Temporal
Frontal
Parietal/occipital
Temporal love epilepsy
epigastric rising sensation pallor/flushing deju vu speech arrest fear depression
Frontal lobe seizures
brief
rapid recovery
predominantly nocturnal
falling onto one side (jacksonian march)
Parietal/occipital lobe epilepsy
parietal- positive sensory symptoms, tingling pain
occipital- simple visual hallucinations, blackout or whiteout at onset
Epileptogenesis
the process by which parts of a normal brain are converted to a hyperexcitable brain
why is the brain prone to seizure activity
inherently unstable (pos feedback)
intrinsic excitability
thus a network of excitatory neurons connected together in convergent and divergent poathways is potentially explosive
to avoid this explosion the brain requires at least as much inhibition as excitation bymeans of inhibitory synapses
epilepsy represents a failure of inhibitory regulation either focally or generally
Channelopathies (in regions can be focal or generalised)
- Na channel inactivation too slow. (AP repolarisation impaired)
- Reduction in the number of functional K+ channels (AP repolarisation impaired)
How drugs work to prevent spread of epileptic discharges
Sodium channel blockers
Controlling glutamate release (usually excitatory)
block glutamate receptor
Blocking calcium channels in the thalamus (for absence seizures)
GABA enhancers
Examples of sodium channel blockers
Carbamazepine and Phenytoin
Carbamazepine
inhibits voltage gated sodium channels by binding to it in its inactive state, prolonging the period between successive firings
Sodium valproate
facilitates GABAergic transmission
Ideal antiepileptic drug
good efficacy
no interactions
no side effects
cost effective
some drugs exarcebate generalised seizures such as myoclonus and absences
phenytoin
carbamazepine
gabapentin/pregabalin
consider this if patients are worse on treatment
