NEURO 3: CNS DISORDERS Flashcards
Explain the development of a seizure disorder
Alteration in membrane potential in a small area (epileptogenic focus)
Neurons become hyperactive & hypersensitive
What are 2 classifications of seizure disorders based on brain involvement?
- Generalized onset: both hemispheres affected
- Focal onset: only one hemisphere affected
What are 2 kinds of generalized onset seizures?
- Motor seizures
- Nonmotor (absence) seizures
What are 4 types of motor seizures based on symptoms?
- Tonic: Loss of consciousness, muscle rigidity (stop breathing)
- Clonic: Involuntary rhythmic muscle contractions
- Myoclonic: Muscle twitching
- Atonic: Loss of muscle tone
What are 2 kinds of nonmotor absence seizures based on symptoms?
- Typical: staring spells in children
- Atypical: similar to typical but with some muscle involvement
What are 2 kinds of focal onset seizures based on LOC?
- Aware: no change in LOC (just a funny feeling)
- Unaware: altered LOC, automatisms
What is the term for the 5-30 minutes period after a seizure where the person may feel drowsy, confused, or weak?
Postictal state
What is the term for a prolonged seizure episode or continuing series of seizures without a period of recovery between episodes?
Status epilepticus
What are 3 priorities during a seizure episode?
- Maintain airway
- Protect from injury
- Document
What are 3 types of medications that can help control epilepsy?
- Sodium channel blockers
- GABA stimulation
- Glutamate receptor antagonists
What is the purpose of GABA?
Opens chloride channels, making cell membrane more negative and less likely to depolarize
What is the pathogenesis of cerebral palsy?
Damage in upper motor neurons that control voluntary and involuntary muscle movement
What is the term for brain damage due to accumulation of bilirubin in a baby’s blood?
Kernicterus
What determines the types of symptoms a person with cerebral palsy will experience?
Symptoms depend on function of damaged upper motor neuron
If neuron had inhibitory function, muscle relaxation becomes more difficult > rigidity
If neuron had excitatory function, muscle contraction becomes more difficult > ataxia
What is the term for rigidity due to continuous muscle contractions?
Spasticity
What is the term for uncoordinated movements and instability associated with cerebral palsy?
Ataxia
What is the term for abnormal involuntary movements associated with cerebral palsy?
Dyskinesia
What are 3 steps in the pathogenesis of multiple sclerosis?
- T and B cells damage myelin and oligodendrocytes (the cells that make myelin)
- Slowing or halting of nerve conduction
- Damage to underlying axons
What does it mean when they say that diagnosis of MS requires the disease to be “disseminated in space and time?”
Lesions must be present in at least 2 separate regions of the brain
Patient must experience at least 2 separate episodes of clinical symptoms
Around what age does the onset of MS occur, and how long do patients survive after diagnosis?
Onset: 30 yrs
Survival: 20-30 years
What happens in amyotrophic lateral sclerosis?
Diffusely affects upper and lower motor neurons of cerebral cortex, brainstem, spinal cord
In patients with ALS, what are 3 potential causes of death?
- Aspiration pneumonia
- Malnutrition
- Respiratory failure
Which 2 medications are used in patients with ALS, and what are their functions?
- Riluzole: inhibits glutamate release
- Edaravone: free-radical scavenger
Around what age does the onset of ALS occur, and how long do patients survive after diagnosis?
Onset: 60-75 yrs
Survival: 3-5 yrs
What causes Huntington’s disease?
Autosomal dominant mutation in gene for huntingtin protein
Name 4 steps in the pathogenesis of Huntington’s disease
- Accumulation of mutant huntingtin protein in neurons
- Damage to GABA inhibitory causes decreased ACH activity in corpus striatum
- Striatal atrophy
- Excessive dopamine activity in corpus striatum
What are 2 types of motor hyperkinesis seen in Huntington’s disease?
- Chorea: jerky involuntary movements
- Athetosis: slow writhing movements of hands and feet
What is the term for impairment of willpower seen in Huntington’s disease?
Abulia
What type of medication inhibits dopamine release to treat Huntington’s disease?
VMAT2 inhibitors
Around what age does the onset of Huntington’s occur, and how long do patients survive after diagnosis?
Onset: 40-50 years
Survival: About 15 years
What happens in Parkinson’s disease?
Loss of dopamine-releasing neurons in the substantia nigra (area of midbrain that modulates motor movement)
What is the result of dopamine depletion in Parkinson’s disease?
Causes imbalance between direct & indirect motor pathways, which results in difficulty initiating/controlling movements
What is the surgical treatment used to treat Parkinson’s?
Deep brain stimulation
What is the purpose of levodopa in treating Parkinson’s?
Penetrates blood-brain barrier and then converted into dopamine
Why is carbidopa combined with levodopa in treating Parkinson’s?
Prevents conversion of levodopa until after it crosses the BBB
Other than levodopa-carbidopa, what are 2 other types of medications used in treating Parkinson’s?
- Dopamine receptor agonists
- MAO inhibitors
What forms the intracellular neurofibrillary tangles in Alzheimer’s disease?
Hyperphosphorylated tau protein
What forms the plaques in Alzheimer’s disease?
Amyloid beta protein
What are 3 kinds of medications used to treat Alzheimer’s disease?
- Acetylcholinesterase inhibitors (donepezil, rivastigmine, galantamine)
- NMDA receptor antagonists (memantine)
- Monoclonal antibody against amyloid beta protein (aducanumab)
What do MAO inhibitors do?
Inhibit breakdown of serotonin, norepinephrine, dopamine
What do tricyclic antidepressants do?
Inhibit reuptake of serotonin, norepinephrine, dopamine
What is the term for the theory that neurotransmitter imbalance is the cause of depression?
Monoamine hypothesis
Which hormone imbalance may lead to depression?
Increased cortisol causing neuronal atrophy
What is the difference between mania and hypomania?
Mania lasts at least one week
Hypomania lasts at least 4 days
What does lithium do in treating bipolar disorder?
Increases serotonin activity
Decreases norepinephrine and dopamine activity
Inhibits adrenergic and cholinergic receptor signaling
What does valproic acid do in treating bipolar disorder?
Increases activity of GABA
What is the term for rigidity due to continuous muscle contractions associated with cerebral palsy?
Spasticity
What is the term for abnormal involuntary movements associated with cerebral palsy?
Dyskinesia
Which 2 medications are used in patients with ALS, and what are their functions?
- Riluzole: inhibits glutamate release
- Edaravone: free-radical scavenger
What is the action of carbamazepine?
Sodium channel blocker
What is the term for uncoordinated movements and instability associated with cerebral palsy?
Ataxia
