Lecture 36: Seizure and Epilepsy in adults

73% at four years

after two unprovoked non-febrile seizures, the chance of having another is

seizure

a transient occurrence of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain

epilepsy

•a chronic disease of the brain characterized by an enduring predisposition to generate epileptic seizures, and by the neurobiological, cognitive, psychological, and social consequences of this condition

•the occurrence of two unprovoked seizures occurring at least 24 hours apart .

-at least two unprovoked seizures more than 24 hours apart

-one unprovoked seizures and a probability of further seizures

-at least two seizures in a setting of reflex epilepsy

What criteria is required to define epilepsy?

-individuals who had an age dependent epilepsy syndrome but are now past the applicable age

-seizure free for at least 10 years off seizure medications

epilepsy is considered to be no longer present for...

generalized onset seizures

what type of seizure

-originating at some point within rapidly engaging bilaterally distributed networks

focal onset seizure

what type of seizure?

defined as originating within networks limited to one hemisphere. May originate in subcortical structures

yes! but they still have to rapidly engage in bilaterally distributed networks

can generalized seizures be asymmetric?

absence seizures

all nonmotor seizures are considered

level of awareness

focal seizures are classified by

absence seizures

•Childhood or teenage onset

•Sudden onset, without aura, prompt offset

•Momentary loss of consciousness

•Eyelid flutter/minor automatisms

•3-15 seconds duration

•Family History

3 Hz spike-wave/HV sensitive

EEG of absence seizures:

tonic seizures

-sudden stiffening

-extension maximal in arms

-a few seconds in duration

-associated with falls and injury

-refractory the therapy

tonic seizures

what type of seizure is extra-temporal in origin and refractory to therapy

flattening/high frequency discharge

EEG of tonic seizures:

atonic seizure

-abrupt onset

-sudden loss in tone

-head drop/falls/injuries

-a second or two in duration

-poor response to AEDs

-poor overall prognosis

slow spike-wave/flattening

EEG of atonic seizure

myoclonic seizures

-sudden jerks

-usually bilateral, maximal in arms

-one second in duration

-often multiple

-may be photic or sensory triggered

-often maximal on awakening

generalized polyspike-wave burst

EEG of myoclonic seizure:

tonic-clonic seizures

•Loss of Consciousness

•May have a focal or generalized onset

•Tonic Extension of limbs (about 20-40 sec)

•Evolves to rhythmic clonic jerking of extremities (about 30-50 secs)

•Cessation of breathing, tongue biting, incontinence

•Post-ictal sleep

variable, often obscured

EEG of tonic-clonic seizure

•occurs abruptly and includes limb extension bilaterally

-Air ejected forcefully against tightened vocal cords is responsible

for the "epileptic cry" associated with a tonic-clonic seizures.

describe the tonic phase of a TCS:

epileptic cry

-occurrs during tonic phase of TCS

-air ejected forcefully against tightened vocal cords

synchronous muscle contraction

describe the clonic phase of TCS:

simple partial seizures

focal seizures without impairment of consciousness are aka

focal seizures without impairment of consciousness

what type of seizure:

•Motor, sensory, psychic or autonomic signs or symptoms

•Preservation of consciousness & awareness

•May progress to dyscognitive seizures or tonic-clonic seizures

interictal-focal sharp or slow; ictal-rhythmic discharge or often normal

EEG of simple partial seizures

complex partial seizures

focal discognitive seizures are aka

complex partial seizures

what kind of seizure?

•Altered consciousness/awareness

•Duration 30 secs to 3 min

• Purposeless automatisms – Arms– Oral

•Amnesia

•Semiology varies with site of origin

interictal-sharp waves or spikes; ictal-focal or bilateral rhythmic sharp

EEG of focal dyscognitive seizures

Jacksonian March

The wave-like movement of a seizure from a point of focus to other areas of the brain.

-focal seizure in adults

-has a large cortical representation

symptom

syndrome

seizure is a _____ and epilepsy is a _________

-too much excitation by NT glutamate, aspartate; too much sodium or calcium influx

AND/OR

-too little inhibition by NT GABA; inward chloride or outward potassium currents

cellular mechanisms of seizure generation:

10/20 placement

electrode placement for evaluating seizure/epilepsy in adults:

-precipitants

-metabolic and electrolyte imbalance

-intoxication

-withdrawal

-sleep deprivation

-hormonal variations

-stress

-fever

-concussion

questions to consider when evaluating seizure:

-family hx, hx of febrile seizures, hx of head trauma, hx of meningitis, hx of stroke or other structural lesions

main risk factors for seizure:

CBC, electrolytes, glucose, calcium, magnesium, phosphate, hepatic and reenal function

blood tests to order for evaluation of a first seizure

•Lumbar puncture only if meningitis or encephalitis suspected and potential for brain herniation is ruled out

why would you order an LP for evaluation of a first seizure?

sodium inactivation

Phineas' Lamborghini Car Tops Vals

what mechanism do these AED drugs use?

Phenytoin, Carbamazepine, Lamotrigine, Topiramate, Valproic acid,

GABA activation

Gabby Tops Phineas and Val Via her Tiny Benz

what mechanism do these AED drugs use?

Gabapentin, Topiramate, Phenobarbital, Valproic acid, Benzodiazepine, Tiagabine, Vigabatrin.

blocks T-type calcium channel

MOA of ethosuximide

barbituates, phenytoin, carbamazepine

-has significant drug interaction

what AEDs are P-450 inducers?

depakote

What AED is a weak P-450 inhibitor?

Hepatotoxicity, neutropenia, thrombocytopenia, teratogenicity( neural tube defects in the fetus)

adverse effects of Valproate

Hepatotoxicity, aplastic anemia, agranulocytosis, diplopia.

adverse effects of carbamazapine

Gingival hyperplasia, hirsutism, teratogenicity, ataxia, neuropathy.

adverse effects of phenytoin

Steven-Johnson syndrome ( a bullous form of erythema multiforme that involves mucous membranes and large areas of the body)

adverse effects of ethosuximide and lamotrigine

status epilepticus

defined as a seizure that persists for a sufficient length of time or is repeated frequently enough that recovery of consciousness between attacks does not occur .

-an episode of more than 30 minutes of continuous seizure activity or,

-two or more sequential seizures spanning this period without full recovery between seizures

criteria to define status epilepticus

5-20 minutes

minimum time-frame of a status-epilepticus event:

Lorazepam

-immediately follow with phenytoin or fosphenytoin

in the first 2 min of a status epilepticus event, treat with

addtional phenytoin or fosphenytoin

if a status epilepticus event lasts more than 20 min, treat with

phenobarbital

if a status epilepticus event lasts more than 30 min, treat with

additional phenobarbital

if a status epilepticus event lasts more than 50 min, treat with

anesthesia with midazolam or propofol

if a status epilepticus event lasts more than 60 min, treat with

long duration and those who have severe physiologic disturbance

•The outcome is usually worse in patients with status epilepticus of .

Paroxysmal Disorders

cerebral function characterized by spontaneous electric discharges from the cerebral cortex

•Transient ischemic attacks (TIAs)

•Panic attacks

•Convulsive Syncope

•Complicated Migraines

•Pseudo seizures

DDx of paroxysmal disorders

•distinct visual phenomena including simple or complex visual hallucinations, visual distortions, hemianopsia and amaurosis.

manifestation of occipital epilepsy

migraines

seizures in adults are often misdiagnosed as

pseudo seizures

seizure-like activity such as twitching or loss of consciousness without electrical disruptions in the brain

-common symptom of conversion or somatization disorder

-post-ictal confusion often absent; loss of motor control is rare

aura

common pre-seizure symptom distinct from psedo seizure

tonic, clonic feature, epileptic cry, injury( tongue bitten), incontinence etc

during seizure symptoms (distinct from pseudo seizure)

disorientation, confusion, weakness (todd's paralysis)

post-seizure symptoms distinct from pseudo seizure

•Lumbar puncture only if meningitis or encephalitis suspected and potential for brain herniation is ruled out

why would you order an LP for evaluation of a first seizure?