ALS Flashcards
What is ALS?
degeneration and scarring of motor neurons in ventro-lateral aspect of SC, BS, and cortex
There is secondary degeneration to ______________ tracts in ALS.
pyramidal
What are the two potential onsets for ALS?
limb onset
bulbar onset
What is cause of ALS?
unknown
some cases are considered familial
What are risk factors for ALS?
age between 40-70
male gender
family hx
disease causing mutations
What is the pathology of ALS?
massive loss of anterior horn cells in SC and CN nuclei in lower BS
degeneration of betz cells in motor cortex
astrocytic gliosis with axonal loss in CST
muscle fibers undergo denervation changes and scarring occurs
Where does the greatest destruction occur (motor neurons)?
lumbar
cervical
internal capsule
In what lamina does ALS begin in?
IX (9)
How does ALS initially present?
both sides distally, but asymmetrical
What neurotransmitter may play a role in contributing to ALS?
glutamate
Why is it thought that glutamate may be a contributing factor in ALS?
people with ALS lack an enzyme that naturally breaks down excess glutamate
Is there a genetic component of ALS?
yes, there appears to be an inherited autosomal trait
What are the earliest clinical signs?
fasciculations (tongue)
muscle cramps
fatigue
weakness
NO sensory changes
What is the main clinical sign?
chronic progressive weakness
Why do flexors tend to be the first to develop weakness?
There is more real estate in central horn donated to flexors
What cranial nerves are affected in a bulbar onset?
trigeminal V
facial VII
glossopharyngeal IX
vagus X
What CN are often spared in ALS?
eye movement - 3,4,6
because they come off BS higher
What tracts are often spared in ALS?
sensory systems and spinocerebellar tracts
What are symptoms of bulbar onset?
dysphagia- swallowing
dysarthria- speaking
difficulty coughing
emotional lability
excessive drooling
Why is respiratory dysfunction associated with ALS?
progressive weakness causes decreased vital capacity
ends up being the cause of death
Is there a definitive test for ALS? How is it diagnosed?
No
elevated creatine phosphokinase
EMG and nerve conduction velocity
muscle and nerve biopsies
neuro-imaging
What are diagnoses to rule out instead of ALS?
cervical or lumbar spondylosis
syringomyelia
MS
What are symptoms that would exclude ALS from a differential?
oculomotor dysfunction
synergy present
sensory changes
autonomic dysfunction
early cognitive changes
What is the only FDA approved drug for ALS?
riluzole
slows disease progression
