Module 14B CNS Flashcards
1
Q
Epilepsy
A
- Neurological disorder
- Brief disturbances in brain electrical activity
- Sudden brief seizure
- Varying intensities
2
Q
Seizure
A
- Alteration of behaviour
- Caused by CNS dysfunction
- Sudden & transient
3
Q
Epileptic Seizure
A
- Caused by primary CNS dysfunction
- Excess depolarization
- Hypersynchronization of neurons
4
Q
Non-Epileptic Seizure
A
- Seizure like episode
- Not caused by abnormal electrical brain activity
5
Q
Status Epilepticus
A
- Unremitting epileptic seizure
- Duration longer than 30 mins
- Frequent seizures without recovery/awareness
6
Q
Focal/Partial Seizures
A
- Occur in 1 area of brain
7
Q
Simple Partial Seizure
A
- No loss of consciousness
- Symptoms dependent on area of seizure activity
8
Q
Complex Partial Seizure
A
- Involves loss of consciousness
- Awake but not aware of surroundings
- Symptoms dependent on area of seizure activity
9
Q
Generalized Seizure
A
- Bilateral diffuse onset, arise from all brain areas
10
Q
Types of Generalized Seizures
A
- Absence
- Tonic/clonic
- Myoclonic
- Tonic
- Atonic
11
Q
Absence Seizures
A
- Loss of consciousness
- Behavioural arrest/staring
- Brief, occur in clusters (multiple per day)
- No association with automatisms
- Common in childhood
12
Q
Tonic/Clonic Seizures
A
- Abrupt loss of consciousness
- Tonic period of 1 min (rigid muscles)
- Clonic period of 2-3 mins (involuntary muscle contraction)
- Incontinent state/tongue biting
- Drowsy/confused/headache post seizure
13
Q
Myoclonic Seizures
A
- Sudden, brief muscle contraction (any muscle group)
- No loss of consciousness
- Associated with later development of tonic/clonic seizure
14
Q
Tonic Seizures
A
- Sudden muscle rigidity
- Consciousness impairment
15
Q
Atonic Seizures
A
- Sudden loss of muscle tone
- Duration 15 secs
- Drop to ground (fall injury risk)
16
Q
Secondary Generalized Seizures
A
- Begins in 1 are of brain and spreads
- Focal phase (primary) referred to as ‘aura’
17
Q
Frontal Lobe
A
- Simple repetitive motor movements (primary motor cortex)
- Tonic posturing (supplemental motor structures)
- Behavioural automatisms with bilateral movement
18
Q
Parietal Lobe
A
- Localized paresthesia (somatosensory cortex)
- Complex/widespread paresthesia (somatosensory association cortex)
- Multisensory hallucinations (high order sensory association areas)
19
Q
Occipital Lobe
A
- Visual hallucinations
- Temporary blindness
- Reflex nystagmus (involuntary eye movement)
- Simple seizures mistaken for migraines (similar symptoms)
20
Q
Temporal Lobe
A
- Emotions & psychic symptoms
- Auditory, olfactory, gustatory hallucinations
- Visual distortions
- Paresthesia (numbness)
21
Q
Epileptogenesis Classes
A
- Symptomatic (identified physical cause)
- Idiopathic (no identified cause)
- Cryptogenic (underlying cause likely but not identified)
22
Q
Seizure Threshold
A
- Balance between excitable/inhibitory forces in brain
- Susceptibility to having a seizure
- Threshold must be reached & AP fired to generate seizure
23
Q
Affecting Factors of Seizure Threshold
A
- Stroke
- Head injury
- Drug/alcohol withdrawal
- Infection
- Tumour
- Severe fever
- Visual stimuli
24
Q
Actions of AntiEpileptic Drugs (AED)
A
- Blocking sodium channels
- Blocking voltage-dependent calcium channels
- Glutamate antagonists
- Potentiating actions of GABA
25
Q
Sodium Channel Blocking
A
- Prolong inactivation state of Na+ channel
- Neurons fire at low frequency
26
Q
Phenytoin
A
- Most common AED
- Blocks sodium channels
- Treatment for all seizure types (excludes absence)
- Non-linear kinetics (limited liver metabolism)
- Narrow therapeutic range (monitoring)
- Teratogenic
27
Q
Adverse Effects of Phenytoin
A
- Sedation
- Gingival hyperplasia
- Skin rash
28
Q
Blocking Voltage-Dependent Calcium Channels
A
- Inhibition of Ca++ channels
- Suppress neurotransmitter release
29
Q
Glutamate Antagonists
A
- Decreases CNS excitation
- Treatment target AED’s
- Binds to NMDA/AMPA receptor acts as block
30
Q
GABA Receptor
A
- Inhibitory CNS neurotransmitter
- Binding to receptor causes Cl- ions into cell
- More difficult to reach threshold
31
Q
Potentiating Actions of GABA
A
- Increase inhibitory stimuli
- Suppress seizure activity