Term
|
Definition
| an uncontrolled paroxysmal neuronal discharge in any part of the brain. this may cause physical or mental symptoms and may be convulsive/non-convulsive. |
|
|
Term
|
Definition
| 2+ unprovoked recurrent seizures. 75% of which occur secondary to some other pathology, the other 25% is idiopathic. |
|
|
Term
|
Definition
| a muscular contraction/relaxation which is rapid/repeated which results in uncontrollable shaking of the body. |
|
|
Term
| what characterizes the incidence of epilepsy? |
|
Definition
| epilepsy is the 3rd most common neurological problem after a stroke/alzheimer's. there is a slight male predominance b/c of trauma. |
|
|
Term
| when are the peak occurrences of epilepsy? |
|
Definition
| infancy, teens, 30's, and then a progressive increase past 75 y/o |
|
|
Term
| what is an action potential? |
|
Definition
| the cell is normally internally negative/externally positive. when the neuron is stimulated, Na+ channels open, and Na+ ions rush into the cell = depolarization (cell positive internally/negative externally). quickly, K+ channels open, ions then leave the cell = repolarization (internally negative/externally positive). Na+ ions still within the cell move down the neuron, opening up new Na+ channels and continuing the depolarization/repolarization process of signal transduction. a Na+/Ka+ pump works (via ATP) to keep the overall levels of K+ inside the cell and Na+ outside the cell. |
|
|
Term
| what is a paroxysmal depolarizing shift (PDS)? |
|
Definition
| an abnormally rapid depolarization of neurons |
|
|
Term
|
Definition
| on the EEG (on which negative is up/positive is down) a 70-200 msec wave occurs when more neurons fire simultaneously than normal |
|
|
Term
|
Definition
| an EEG wave which takes place between 20-70 msec (more rapid than a sharp wave) |
|
|
Term
| what is a spike and slow wave? |
|
Definition
| an EEG wave complex where the a rapid depolarization occurs followed by a slow polarization |
|
|
Term
| what characterizes cerebral metabolism during a seizure? |
|
Definition
| there is an increase in blood flow, O2 consumption, and lactic acid production |
|
|
Term
| what characterizes systemic metabolism during a seizure? |
|
Definition
| lactic acidemia (faster muscle contraction), hypoxemia (unorganized respiratory effort), cardiac rhythm changes (including asystole), and hypotension (cardiac problems/change in sympathetic control). |
|
|
Term
|
Definition
| sudden unexplained death in epilepsy pt: death during sleep observed in epilepsy pts, likely related to cardiac arrhythmia. |
|
|
Term
|
Definition
| the phenomenon where a small number of cells start to experience PDS, which then recruit more, etc. (may take months to develop seizure after trauma) |
|
|
Term
|
Definition
| if there is an epileptic focus on the R temporal lobe, the same may develop in the L brain in the same place |
|
|
Term
| what is status epilepticus? |
|
Definition
| a potentially fatal condition involving ongoing seizures defined as a continuous seizure for more than 20 min or 3+ seizures in 30 min w/o regaining consciousness. |
|
|
Term
| how is status epilepticus treated? |
|
Definition
| ABCs (airways, breathing, circulation assessment), IV access, acute anticonvulsants (lorazepam [shorter acting respiratory depressant/longer acting anticonvulsant effect], diazepam [short anticonvulsant effect, strong respiratory depressant], and midazolam [short acting, will stop any convulsion]), antiepileptics (phenytoin, fosphenytoin), if that doesn't work then 2nd line antiepileptics (phenobarbital, valproate, levetiracetam, lacosamide), if that doesn't work then continous diprovan/midalozam and/or EEG monitoring. |
|
|
Term
| what is a simple seizure? |
|
Definition
| one which does not affect consciousness |
|
|
Term
| what is a complex seizure? |
|
Definition
| seizure w/a change in consciousness (however does not mean pt loses consciousness) |
|
|
Term
| what is a partial seizure? what are the different kinds of this type? |
|
Definition
| one which has a focal location in the cortex (60% of seizures). partial seizures may be motor or sensory. |
|
|
Term
| what are the different types of simple partial motor seizures? |
|
Definition
| focal twitch (ex: thumb/index movements, may not spread, but dangerous if it does), **jacksonian march (seizures which move from the hand up to the face - marching along the homunculus, either sensory/motor or both), and **epilepsia partialis continua (permanent focal motor seizure, sometimes due to a small tumor on the motor strip - hard to tx) |
|
|
Term
| what are the different types of simple partial sensory seizures? |
|
Definition
| paresthesias (tingling) and formication (feeling of bugs crawling on the skin) |
|
|
Term
| what characterizes partial complex seizures? |
|
Definition
| frequently these will start in the temporal lobe (but can start in frontal, parietal, occipital lobe). they last 1-3 min and are the **most common seizure type (60-80%)**. these are usually focal seizures which *generalize secondarily (rapidly). the phases: *aura (warning), *cry (pt lets out noise), *fall, *fit [tonus, clonus, P&S (excretory phenomenon)]. |
|
|
Term
| how do epileptic phenomena appear on an EEG? |
|
Definition
| as a focal spike which are electronegative (above the base). when two lines are pointing at each other, that means the electrical stimulus has occurred between the scalp electrodes. |
|
|
Term
|
Definition
| behavior which may include lip smacking, chewing, swallowing, picking at imaginary lint, undressing - which pts exhibit when experiencing a partial complex seizure. |
|
|
Term
| what is a generalized seizure? what are the different kinds of this type? |
|
Definition
| one which affects the entire cortex (40% of seizures). generalized seizures may be absence, myoclonic (jerks inbetween seizures), tonic/clonic, clonic/tonic/clonic and atonic (infantile). |
|
|
Term
| what is the architecture of a seizure? |
|
Definition
| start: aura (focal warning). middle: ictus (event). end: post-ictal paralysis (physical/mental exhaustion - todd's post-ictal paralysis: neuronal exhaustion). |
|
|
Term
| what are the different kinds of psychic aura? |
|
Definition
| *deja vu: feel like you know what is going to happen next. *jamais vu: you are in familiar situation and you have no idea what is going on. *autoscopy: visualizing yourself outside yourself when you recall the past (common w/temporal lobe auras). fear: strong/disturbing/overwhelming/sudden/intense/doom/depression sensation (also seen in MI pts). |
|
|
Term
| what are the different kinds of sensory aura? |
|
Definition
| visual (palinopsia): "trailing" effect behind moving objects or distortion of size/space (alice in wonderland). auditory: sounds may seem more loud, echoing. vestibular: sense of spinning, off balance. GI: tremendous sense of thirst, other abdominal sensations (esp w/insular cortex), need to evacuate bowel/bladder. taste: awful taste - burnt/metal/fecal. smell: generally unpleasant - rotten/burning/fecal (common w/seizures starting in the *uncus). paresthesia: jacksonian march up arm. pain: rare. |
|
|
Term
| where is the generator thought to exist for generalized seizures? |
|
Definition
| somewhere deep in the brain (brainstem, thalamus, mid brain– the location is not very clear) |
|
|
Term
| do auras occur w/generalized seizures? |
|
Definition
| no auras only occur w/partial seizures - but automatisms can occur in either partial or generalized seizures. |
|
|
Term
| what characterizes the generalized absence (petit mal) seizure? how can they be precipitated? |
|
Definition
| 3-15 sec duration, 3 Hz spike and wave, and blinking/staring automatisms. these can be precipitated by hyperventilation (blowing CO2 down) or photic stimulation (blinking lights). |
|
|
Term
| what characterizes the generalized myoclonic seizure? when are they seen? |
|
Definition
| this consists of irregular, unsustained jerks which may occur during the seizure or inter-ictally. myoclonic seizures may be hypnopompic or associated w/syndromes, metabolic, or post-hypoxic (seen in cardiac arrest pts). |
|
|
Term
| what characterizes the generalized tonic-clonic seizure? |
|
Definition
| these last 3-5 min, consist of aversive head/eye movements, *lateral tongue biting, incontinence, and frothing/foaming (increased parasympathetic state) |
|
|
Term
| what can the epilepsy evaluation consist of? |
|
Definition
| r/o preciptants, classify seizure type, check glucose/Na+/Ca++/Mg++ levels, EEG (routine 20 min study, ambulatory or monitored), cortical arrays (electrodes on dura), depth electrodes (inside brain), magnetoencephalography (better method of assessing electrical disturbances, uses dipoles), neuroimaging (MRI, PET - then coregistration), metabolic/toxic, and CSF |
|
|
Term
| what are some seizure etiologies? |
|
Definition
| infectious (meningitis, encephalitis, bacterial abscess), tumor, stroke, metabolic, trauma, syndromes, and idiopathic (40%+). |
|
|
Term
| what does surgical tx for epilepsy consist of? (usually done when pts have reached the toxic levels for 1-2 drug classes) |
|
Definition
| intensive monitoring, focus resection (find focus via wada test, remove it), callosotomy (cut 1st 2/3 of corpus callosum to reduce generalizing to other hemisphere), vagal nerve stimulator (reduces frequency of seizures - may work for refractive depression), neuropace (implanted defibrillator for brain - not yet FDA approved) |
|
|
Term
| what does traditional pharmacologic tx (1900-1978) for epilepsy consist of? |
|
Definition
| *phenobarbital (works well, but bad ADRs: sedation, mental clouding, paradoxical effect in children [revs them up], but cheap/broad spectrum), *phenytoin (modified phenobarbital, IV, lasts 22 hrs, broad spectrum, but zero order kinetics = high toxicity if pt cannot metabolize immediately [narrow therapeutic range], ADRs: gingival hypertrophy, roughened facial features, hirsutism, atrophy of cerebellum/peripheral neuropathy, osteoporosis due to modified Ca++ metabolism), *primidone (better tolerated than phenobarbitol - which happens to be a metabolite of primidone, IV, cheap, broad spectrum), *carbamazepine (PO, broad spectrum, ADRs: *aplastic anemia/hypernatremia [SIADH], if titrated too high initially = accumulation of 10-11 hypoxide: n/v. contraindicated for primary generalized epilepsy), and *valproic acid (very good for primary generalized and focal epilepsy, but ADRs: thrombocytopenia, wt gain, and harmful to GI unless protein-coated [depakote]) |
|
|
Term
| what needs to be checked for all antiepileptic meds? |
|
Definition
|
|
Term
| what are the 2 drugs contraindicated for primary generalized epilepsy? |
|
Definition
| carbamazepine (tegretol) and oxcarbazepine |
|
|
Term
| what does newer pharmacologic tx (1990-1999) for epilepsy consist of? |
|
Definition
| *gabapentin (good for pain, not as good for epilepsy [need higher dose]), *lamotrigine (if titrated too fast = exfoliation of skin [steven-johnson syndrome], very well tolerated and effective, "safest" in pregnancy), *topiramate (good for migraine prevention, usually well tolerated, makes pts "stupid" [can't talk], carbonic anhydrase activity = tingling/numbness, can produce acute angle glaucoma, interfere w/production of Cl- ion [inhibits sweating], promotes wt loss), and tiagabine (not popular, an "ok" agent) |
|
|
Term
| what do the newest pharmacologic tx (2000-) for epilepsy consist of? |
|
Definition
| *oxcarbazepine (variation of carbamazepine, less severe ADRs), *zonisamide (similar to topiramate, 1x/day, good drug, carbonic anydrate effects early on), *levetiracetam (well tolerated, not hepatically metabolized but can unmask psychiatric disorders), and *lacosamide (2 y/o, titrated up) |
|
|
Term
| what is the special indication for ethosuximide? |
|
Definition
|
|
Term
| what is the special indication for ACTH/acthar? |
|
Definition
|
|
Term
| what is the special indication for acetazolamide? |
|
Definition
| seizures worse during menstrual cycle |
|
|
Term
| what is the special indication for the benzodiazepines: clonazepam/clorazepate? |
|
Definition
|
|
Term
| what is the special indication for the benzodiazepines: diazepam/lorazepam/midazolam? |
|
Definition
|
|
Term
| what characterizes anti-epileptic toxicity? |
|
Definition
| ataxia, visual blurring, n/v, and nystagmus |
|
|
Term
| what may provoke seizures? |
|
Definition
| alcohol withdrawal (depletes GABA in brain), benzo withdrawal, stimulants (cocaine, PCP), severe sleep deprivation, immediately after head trauma, acutely w/CNS infection/neoplasm, uremia, eclampsia, high fever, hypoxemia, hyper/hypoglycemia, electrolyte disorders, and psychogenic (conversion disorder, somatization, factitious disorder, malingering) |
|
|
Term
| what are some syndromes which involve epilepsy? |
|
Definition
| benign rolandic syndrome, juvenile myoclonic, landau-kleffner (aphasic), lennox-gastaut (abnormal neurology, slow EEGs), and unverricht-lungborg (baltic myoclonus) |
|
|
