Epilepsy (Final Exam) Flashcards
this is a group of disorders characterized by excessive excitability of neutrons within the CNS. usually a chronic condition. alterations in inhibitors mechanisms or enhancement of local excitatory circuits
epilepsy
this is a general term applied to all types of epileptic events
seizure
this is an abnormal motor phenomena (i.e. jerking movements)
convulsions
true or false: all convulsions can be seizures
true
true or false: all seizures can be convulsions
false
this is a class of seizures; can be further described as having an intact or impaired awareness, motor or non motor onset, or evolve from focal to bilateral tonic clonic
focal onset
this is a class of seizures;
motor
- tonic-clonic
- other motor (atonic, myoclonic)
nonmotor (absence)
generalized onset
this is a class of seizures; motor, nonmotor or unclassified
unknown onset
what is the basic pathophysiology of seizures
recurrent seizures initiated by synchronous high frequency discharges from a group of hyper-excitable cortisol neurone (focus). autonomous in nature. spreads to neighbouring and distal neurons which is known as recruitment
what are some inhibitory mechanisms, that if interrupted, can cause seizures
- GABA
- Adenosine
- reorganization of neural networks (favouring excitatory circuits - usually a Brian injury does this)
*domoic acid and penicillin can cause seizures
how does recruitment occur?
high frequency of discharges leads to:
- increase in extracellular K+
- accumulation of Ca++ in presynaptic terminals
- depolarization-induced activation of NMDA
- changes in tissue osmolarity & cell swelling
- enhanced neurotransmitter release at excitatory synapses (post tetanic potentiation)
- desensitization of GABA receptors
- recruitment of nearby neurone (through cortisol connections)
- recruitment of distal areas (corpus collosum)
what are some triggers of seizures
- fever
- stress, fear, anger and worry
- poor nutrition (alcohol)
- allergies
- flickering lights
- lack of sleep
what are the two main classes of seizures
focal and generalized
this is one of the two main classes of seizures; activity begins focally in cerebral cortex (focal brain disease/tramua). spreads minimally to cortical areas. signs/symptoms depend on area affected
focal
this is one of the two main classes of seizures; focal seizure activity is conducted widely throughout both hemispheres. leads to loss of consciousness
generalized
this type of seizures arise from discrete or broadly distributed neuronal networks within a cerebral hemisphere
- can have intact or impaired awareness
- the onset can be motor or nonmotor
- can evolve into a generalized seizure
- may need surgically implanted electrode (medial temporal lobe or inferior frontal lobe)
focal onset seizures
this type of focal seizures has discrete symptoms that depend on the area of the brain affected
- no LOC
- twitching, numbness, visual hallucinations, salivations, incontinenece, feelings of unreality
- lasts 20-60 secs
- Jacksonian march (tingling/twitching begins in a small region then “marches” to a larger area of the body)
- Todd’s paresis (weakness or paralysis of part or all of the body as soon as the ictal discharge (seizure) has ended)
- could last hours to days (epilepsia partialis continua)
focal seizure - with intact awareness
what are some signs/symptoms of frontal seizures with intact awareness
primary motor cortex
- involuntary movements of the contralateral hand
temporal or frontal cortex
- unusual, intense odors
- strange sounds
- epigastric sensation to the head
- fear, a sense of impending change, detachment, depersonalization
- illusions of microplasia/macroplasia (objects seem bigger/smaller than their actual size)
this type of focal seizure, person is unable to maintain contact with the environment during the ictal event
- unable to respond during the ictal episode
- impaired recollection of the event
- the ictal phase often begins with a motionless stare
- automatism and confusion following the ictal phase (chewing, lip smacking, swallowing, picking movements of the hands
focal seizure with impaired awareness
* think of Dale!!
true or false: focal seizure can spread to a generalized seizure
true: can spread to both hemispheres
- usually tonic-clonic type (involve both tonic (stiffening) and clonic (twitching/jerking) phases of muscle activity
- commonly frontal lobe involved
this type of seizures arises at some point in the brain but immediately and rapidly spreads to both cerebral hemispheres
generalized seizures
what are the four categories of generalized seizures
- typical and atypical absence
- tonic-clonic
- atonic
- myoclonic
this type of generalized seizure has
- sudden, brief lapses of consciousness without loss of postural control (10 to 30 sec)
- no post seizure confusion
- blinking of the eyelids, chewing movements, clonic movements of the hands
- genetic predisposition onset ages 4-10
- main type of seizures in children
- can occur hundreds of times a day
- child unaware or able to convey its existence
- often missed, first clue is daydreaming and decline in school performance
- attention deficit disorder
generalized seizure - typical absence seizure
this type of generalized seizure differs from typical absence seizures by:
LOC
- less abrupt in onset andcessaiton
- longer duration
Seizure
- more obvious motor signs
- usually associated with multifocal structural brain abnormalities, mental retardation
- less responsive to anticonvulsants
generalized seizures - atypical absence seizures
