Epilepsy Flashcards
How is epilepsy diagnosed?
Detailed history- eyewitness
Physical exam
ECG
Blood tests
Imaging techniques: CT scan or MRI
Neuropsychological assessment
EEG
How are seizures classified?
Seizures are divided into groups depending on:
(1) where they start in the brain (onset)
(2) whether or not a person’s awareness isaffected
(3) whether or not seizures involve othersymptoms, such as movement
Depending on where they start, seizures aredescribed as being focal onset, generalisedonset or unknown onset.
What is epilepsy?
Epilepsy is the term used to describe when seizures recur
What is an epileptic seizure?
An epileptic seizure is a transient episode of uncontrolled discharge of cerebral neurons causing a variety of symptoms usually associated with a disturbance of consciousness.
Why do seizures occur and what symptoms occur?
Their behavious is caused by disordered, rhythmic and synchronous firing of populations of neurons.
Can be preceded by an aura: numbness, tingling or hallucinations.
Followed by seizures (convulsions), loss of consciousness and involuntary skeletal muscle contractions.
Afterwards period of tiredness, drowsiness, headache, confusion, followed by sleep
How many different types of epilepsy are there?
40 different types - high chance of misdiagnosis
What are some reasons why people may develop epilepsy?
Head trauma, Poisoning, Infection, Maternal injury, brain tumour, cardiovascular 30%. 70% are all unknown cause
What is EEG?
measure of CNS electrical activity
Not routinely carried out but can help, 15% of patients who do not have epilepsy have abnormal epilepsy. 20-40% of people with epilepsy have normal EEG
What are the two types of seizures?
Focal (partial) - Affects only a part of the brain may be simple or complex
Generalized- Affects both hemispheres
What are focal aware seizures?
AFFECTS A SMALL PART OF BRAIN
Person is conscious
Range of symptoms - tingling, twitching, flashing lights to joy and fear, (strange)
Depends on which part of brain is affected
What are impaired focal awareness seizures
Affect larger part of one hemisphere
Person may be confused
Automatism: strange repetitive movements
What are generalised seizures?
Affects BOTH hemispheres
Absence - ): blank, unresponsive, briefly unconscious
blank, unconscious, muscles become stiff (tonic), then shake and jerk (clonic)
Afterwards person often feel tired, sleepy and have headaches
Tonic - muscles relax
Myoclonic - muscles jerk (consciousness)
Status epilepticus - continuous or repeated seizures longer than 30 mins
Which seizure requires urgent treatment with emergency medication? What is the medication and treatment?
Tonic clonic (convulsive) seizure
Treatment
Two emergency medications used to prevent status in the community (outside of the hospital setting) are midazolam and diazepam:
*Buccal midazolam – is given into the buccal cavity (the side of the mouth between the cheek and the gum).
*Rectal diazepam – is given rectally (into the bottom).
What is the patho-physiology of seizures?
Increases in excitatory inputs via Ach or glutamate
Reduction in inhibitory drive via GABA
Change in Na channel function or activity to reduce threshold and/or increase rate of APs
Rise in extracellular K ion concentration
Change in K+ channel function or activity to increase rate of APs
What are the three reasons for increased excitability?
Increased excitability may be due to:
(i) Membrane depolarization
alteration in Na or K channel function and/or
extracellular potassium buildup
(ii) Increased excitation
release of excitatory amino acids (EAA)
Glutamate is the most common EAA
(iii) Decreased inhibition
reduced inhibitory transmission
GABA is the main inhibitory transmitter
