Week 6 - Neuromuscular Disorders Flashcards
Neuromuscular Junction Disorders
- drug/toxin induced
- Myasthenia Gravis
What is Myasthenia Gravis?
- NMJ disorder
- autoimmune
- attack on the Nicotinic Acetylcholine Receptors
What is Spinal Muscular Atrophy?
- Lower motor neuron disorders
- genetic, degenerative neuropathy
- selectively affects the alpha motor neurons in the anterior horn of the spinal cord and cranial nerve motor neurons
- variability in severity depending on the type
- muscle atrophy and weakness (anywhere from hypotonia to eventual death from aspirations or respiratory failure)
What is Guillain-Barre Syndrome?
- Lower Motor Neuron Disorders
- acute autoimmune-mediated reaction (most commonly following a virus or bacterial infection)
- demyelination of neurons of the peripheral NS
- Motor &/or sensory symptoms
What are the motor/sensory symptoms of Guillain-Barre Syndrome?
- paresthesia, weakness, absence of reflexes
- rapidly progressive ascending symmetrical symptoms
What is Amyotrophic Lateral Sclerosis (Lou Gehrig)?
- NM disorder of upper MN
- genetic/unknown etiology
- rapidly progressive degenerative disease
- degeneration of motor neurons
- affects upper AND lower motor neurons
End Stage of Amyotrophic Later Sclerosis (Lou Gehrig)
- paralysis, respiratory failure
Lou Gehrig degeneration of motor neuron physiology
- Protein misfolding -> neuronal death -> retrograde neuronal degeneration
- Gliosis: clumps of glial cells replace neurons that have died (forms “glial scar”)
What is Multiple Sclerosis
- inflammatory autoimmune disease that affects the conduction of neural impulses
- chronic degenerative disease
- demyelination of neurons within the CNS
Multiple Sclerosis cause
- unknown
- links to genetics, environmental, virus
Multiple Sclerosis symptoms
- exacerbations and remissions
- degeneration can be progressive in late stages
- myelin can be repaired (repairing becomes less effective with repeated attacks)
- variable severity
- loss of balance; ataxia (cerebellum)
- diplopia, loss of vision (cranial nerve)
- weakness, paralysis (motor nerve tracts)
- paresthesia (damage to sensory nerve tracts)
What determines the symptom type in Multiple Sclerosis?
location of demyelination
What determines the symptom severity in Multiple Sclerosis?
extent of demyelination
Multiple Sclerosis Pathophyisiology
- unknown trigger
- activated T cells cross the blood brain barrier
- secrete cytokines
- more immune cells recruited
- attack oligodendrocytes
- myelin damaged and breaks down
- plaque formation
- scar tissue formation and axonal destruction
Multiple Sclerosis diagnosis
- no definitive test
- MRI provides useful info
- based on history of exacerbations & remissions
- usually need multiple symptoms
- often ‘diagnosis of exclusion’
Multiple Sclerosis Treatment
- disease modifying drugs (slow progression)
- pharmaceuticals to treat complications
- physio and exercise to maintain strength and mobility
- OT to support ADL, adaptive equiptment
Multiple Sclerosis exercise considerations
- improve muscle weakness, bladder and bowel function, fatigue, QOL
- consider supportive equipment
- prescribe within limitations
- importance of stretching
- resist heat stress
- avoid exercise during an exacerbation
What is Cerebellar Ataxia?
can be a side effect of many neurodegenerative disorders if the cerebellum is involved
What is Cerebral Palsy?
- non-progressive brain condition causing paralysis
- neurodevelopment condition (pre- or Post- natal)
- muscle affected depends on what part of brain is affected
- either spastic (upper MN damage), dyskinetic (basal ganglia damage, or ataxic (cerebellum damage)
- physical and OT useful for treatment
What is Parkinson’s disease
- synaptic transmission disease
- dopamine release is reduced, specifically via destruction of neurons on nigrostriatal pathway
- progressive and degenerative
What is the average age of diagnosis for MS
15-50 years
What is the average age of diagnosis for Parkinson’s?
56 years old
Parkinson’s Disease Progression
Postural instability -> Dementia (sometimes) -> death
Parkinson’s disease etiology
- unknown
- thought to be combination of environmental and genetic factors
Parkinson’s disease pathophysiology
- unknown trigger
- degeneration of neurons in substantia nigra that produce/release dopamine
- less dopamine release onto neurons of striatum
- imbalance of excitatory and inhibitory NT’s released in striatum
- result: not enough voluntary initiation of movement and too much involuntary movement
Parkinson’s disease main symptoms
-resting tremors
- muscle rigidity (spastic movement)
- bradykinesia (slow movement)
- postural instability (later feature)
What are the dopaminergic neurons of the substantia nigra responsible for?
- allowing signals to be sent to the cerebral cortex for movement initiation
- fine tuning movements
Parkinson’s diagnosis
- based on symptoms
Parkinson’s disease treatment
Pharmaceuticals:
- dopamine replacement therapy (L-dopa, converted to dopamine in brain)
- drugs that inhibit dopamine breakdown in drain (produced dopamine lasts longer)
Exercise, OT, PT:
- maintain general mobility to delay
- exercise to maintain strength, balance, flexibility
- safe use of adaptive devices
