Epilepsy and Neurophysiology Flashcards
What is epilepsy?
Chronic CNS disorders characterized by recurrent seizures
What is a seizure?
Sudden, transitory, and uncontrolled episodes of brain dysfunction resulting from abnormal discharge of neuronal cells with associated motor, sensory, and behavioral changes
What is the type of diet used for a child who has a multiple seizure type?
Ketogenic: high fat, low glucose
What are the side effects to a ketogenic diet?
Kidney stones, weight loss, acidosis, dyslipidemia
What classifies epileptic seizures?
Idiopathic and symptomatic
What are the different types of channelopathies?
Modification of channel function, activation of second-messenger system that affect channel function , modulation of gene expresion
What are the inherited types of mutations?
Voltage or ligand gated ion channels, if simple gene mutations
What are the acquired types of mutations?
Auto-immune, changes after seizures
What genes will you see a mutated gene for sodium channels?
SCN1A, SCN1B, SCN2A1
What genes will you see a mutated gene for chloride channels?
CLCN2A
What types of seizures are associated with chloride channel mutations?
Juvenile absence epilepsy, juvenile myoclonic epilepsy, epilepsy with grand mal upon awakening
What is kindling?
Minor, rapid fire electrical signals happening in succession
Alone they don’t cause a seizure but together they do
Where is a very likely location of a partial seizure?
Amygdala and hippocampus (70%)
What are the two main types of stem cell niches in the brain?
Subventricular zone and subgranular zone of hippocampus
What is the implication of having less stem cell niches in the brain?
Decrease is due to seizures
What area of the hippocampus is susceptible to hypoxia?
Cell bodies of CA1
Describe partial seizures.
Affects limited areas of the brain, most common type, simple and complex, can spread causing a secondary generalized seizure
What is the defining feature of a simple partial seizure?
No cognitive effects
What is the defining feature of a complex partial seizure?
Loss of awareness
What type of partial seizure will you see from the frontal region?
Motor, bizarre, brief, nocturnal
What type of partial seizure will you see from the temporal region?
Fear, amnesia, automatism
What type of partial seizure will you see from the parietal region?
Somato-sensory, dizziness
What type of partial seizure will you see from the occipital region?
Visual, often propagate with false localization
Where is a seizure likely to spread through from one hemisphere to another ?
Anterior commisure
What are the characteristics of a simple partial seizure (Jacksonian)?
Involves one side of brain at onset, focal, motor, sensory, speech disturbances, single limb/muscle group, no alteration of consciousness
What type of EEG will you see with simple partials?
Excessive synchronized discharge - contralateral discharge
What are the characteristics of a complex partial seizure?
Produces confusion and inappropriate or dazed behavior, no-reflexive actions, automatism, consciousness impaired/lost
What type of EEG will you see with complex partials?
Bizarre generalized, anterior temporal lobe focal abnormalities, bilateral
What are the generalized seizures?
Absence, myoclonic, atonic, tonic, tonic-clonic
What are the general characteristics for generalized seizures?
Affects both hemispheres, more common in children
What occurs in the tonic phase of a tonic-clonic seizure?
Contraction of all muscles which arrests ventilation
What does the EEG look like in the tonic phase of tonic-clonic?
High rhythmic frequency, high voltage discharge, sustained depolarization
What occurs in the clonic phase of a tonic-clonic?
Alternating contraction and realization, causing reciprocating movement which could be bilaterally symmetrical or running movements
What does the EEG look like in the clonic phase of tonic-clonic?
Groups of spikes on the EEG and periodic neuronal depolarization with clusters of action potentials
What are absence seizures?
Brief and abrupt loss of consciousness, sometimes motor symptoms, symmetric clonic motor activity, short duration but can happen may times a day
When to absence seizures usually start?
Childhood
What is found to be the expect cause of absence seizures?
A low threshold Ca2+ current has been found to govern oscillatory response in thalamic neurons
What does the EEG look like for an absence seizure?
Bilaterally synchronous, high voltage, spike phase with short duration
What is a tonic seizures?
Motor contractions, loss of consciousness, marked autonomic functions
What is an atonic seizure?
Loss of postural tone, sagging of the head or falling, may loose consciousness
What is a clonic seizures?
Rhythmic clonic contractions of all muscles, loss of consciousness and marked autonomic manifestations
What is a myoclonic seizure?
Isolated clonic jerks associated with brief bursts of multiple spikes in EEG
What is an infantile spasm?
Fragmented attacks that are usually bilateral, brief recurrent myoclonic jerks of the body w/ sudden flexion/extension of body and limbs
Which type of seizure are you likely to see in early childhood?
Primary generalized
