Seizures and Epilepsy Flashcards
In what type of seizure will there not be a loss or alteration of awareness?
The hypersynchronous activity is limited to a very focal area
What is the new definition of epilepsy?
One epileptic seizure with an enduring predisposition to further epileptic seizures, based on clinical risk factors / additional tests
What are the cognitive, psychological, and social consequences of epilepsy?
Cognitive: memory loss and poor executive function
Psychological: anxiety and depression
Social: Loss of ability to work, drive to work, and stigmatization
What are the two broad types of epilepsy? What characterized them?
- Primary generalized epilepsy - bilateral synchronous activity, seizures generated reciprocally between cortex + thalamus and spread rapidly thru corpus callosum
- Focal epilepsy - seizures begin at one area of the brain and spread to adjacent cortices
What happens in focal epilepsy which makes it appear like primary generalized?
“Secondary generation” spread of seizure from focal point to contralateral hemisphere via the corpus callosum
Why do auras typically precede seizures?
Because they represent focal seizures without loss of awareness, and are sensory in nature only.
The electrical activity can spread to motor areas of the brain and thus lead to other seizure manifestations
What specific areas of the brain are affecting in auras?
Depending on the aura type, whatever brain part is associated with it
i.e. somatosensory tingling = poscentral gyrus, areas 5,7, and the insula (visceral - as in abdominal discomfort)
What can lead to macropsia or micropsia?
This is having objects appear to increase or decrease in size, like Alice in Wonderland
Caused by basal temporal cortex seizure (optic radiations), or visual association cortices
What can lead to psychic auras?
Temporal lobe seizures
i.e. fear, euphoria, distortion of familiarity, deja vu, due to involvement of amygdala
- it Jimbo!
What are the most common types of motor seizures?
- Focal seizures without loss of awareness - simple partial seizures
- Focal seizures with loss of awareness - complex motor seizures
What is a tonic seizure?
Sustained contraction of a muscle or group of muscles
What is a clonic seizure?
Repetitive and rapid contraction + relaxation of muscle
What is a myoclonic seizure?
A clonic seizure but it only happens once -> single contraction. Looks like a tic
What is a versive seizure? What part of the brain is affected?
Forced head deviation to one side or the other
Frontal eye field (area 8) is affected
What is an atonic seizure?
Loss of postural tone leading to abrupt fall
What is the most violent type of seizure? How does it progress?
Generalized tonic-clonic, usually occurs with diffuse tonic contraction followed by clonic seizures
“grand mal” = bilateral, occurs in diffuse / generalized epilepsy
What is an automatism / automotor seizure? What part of the brain is more affected?
Seizure characterized by loss of awareness + lip smacking / chewing behaviors, very involuntary
Temporal lobe > frontal lobe affected
What is a hypermotor seizure? What part of brain is more affected?
Involuntary automatic motor behaviors, involving proximal muscles. I.e bicycling movements at night / arm flailinng
Frontal lobe > temporal lobe
What is a gelastic seizure?
gelan = to laugh
Brief periods of laughter or grimaces
What causes an aphasic seizure?
Focal seizure in frontal or temporal lobe in dominant hemisphere (affects Wernicke / Broca’s areas)
What are the two primary types of non-motor seizures with unawareness? What age groups do they affect?
- Complex partial seizure (CPS) - any age
2. Absence - exclusively childhood
What are the motor features and relative lengths of CPS vs absence seizures?
CPS - hand / oral automatism - 1-2 minutes
Absence - eye fluttering <20 seconds
Is postictal confusion present or absent for CPS / absence seizures? What characterizes the EEG?
CPS - present - left temp spikes and seizures
Absence - absent - 3 Hz spike-and-wave
What is Todd’s paralysis and what is the etiology of most post-ictal signs?
Contralateral postictal paresis - due to depletion of excitatory neurotransmitter
What are some other postictal symptoms?
Confusion, disorientation
Retrograde / anterograde amnesia - hard to remember back or forward
Language dysfunction
Psychosis
What is an example of a prodromal symptom you screen for when taking a seizure history?
The aura, includes lightheadness, sweats, deja vu, smells and tastes
prodrome = an early symptom indicating the onset of a disease or illness.
What is the most important thing for making history taking of seizures easy?
Find a witness!
Why is situation important for seizure diagnosis?
Syncope / vasovagal syncope is on the differential diagnosis. Stress / prolonged standing could indicate syncope, vs sleep deprivation could point to seizures
What is the biggest clue that you are dealing with epilepsy vs syncope?
Response to antiepileptic drugs
What are some examples of epileptiform discharges that can be seen on EEG during interictal periods?
Spikes, polyspikes, sharp-waves, and sharp-and-slow wave complexes
What is defined as the seizure threshold? How do drugs treat this?
Level of stimulation at which the brain will have a seizure, this is lower in epileptic patients.
Drugs raise the seizure threshold, but do not lower the brain activity
What can an MRI detect for diagnosing epilepsy?
The lesion associated with seizures in focal epilepsy
What are a few proprosed mechanisms of seizure generation?
Enhanced glutamate / excitatory transmission, with impaired inhibition -> higher basal activities to bring patients near seizure threshold in epilepsy
Lesions like scar tissues interrupting the macroenvironment
