ALS Flashcards
ALS
amyotrophic lateral sclerosis
ALS is also known as
lou gehrigs dz
what is ALS
most common form of adult onset progressive motor neuron dz
may be the most devastating of the neurologic degenerative dz
hallmark of ALS
combo of UMN and LMN signs and symptoms
UMN signs
spasticity
hyperreflexia
pathological reflexes
where do UMN signs stem from
destruction of motor neurons int he brain
causing degeneration of the corticospinal and corticobulbar tracts
LMN signs
muscle wasting
weakness
fasciculations
muscle weakness
amyotrophy
LMN signs stem from
destruction of the anterior horn cells of teh SC and cell bodies of the motor CN nuclei
90% of the CST fibers
decussate at the medulla
descend in the SC as the lateral CST
lateral sclerosis
destruction and scarring of the lateral CST
classification
sporadic
familial
sporadic
the most common form of ALS in the US
90-95% of all cases
familial
occurring more than once in family lineage (autosomal dominant)
accounts for very small number of cases in the US (5-10%)
familial is caused by
genetic mutation in a gene encoding an enzyme called copper-zinc superoxide dismutase
initial S&S
limb onset ALS
bulbar onset ALS
limb onset ALS
75% of cases
limb onset ALS is
difficulty walking or difficulty with the fine motor coordination of UEs
bulbar onset ALS
25% of cases
bulbar onset is
dysphagia
dysarthria
overactive gag reflex
what motor nuclei are involved in bulbar
CN 5,7,9,10,12
weakness and atrophy –> bulbar onset
tongue, pharynx, larynx, soft palate, muscles of the mouth and muscles of mastication
what CN are typically spared –> bulbar onset
3,4,6
pseudobulbar affects
15-45% of bulbar onset
3 stages of diagnosis
clinically possible
clinically probable
clinically definite
clinically possible
UMN and LMN findings in the same region
clinically probable
UMN and LMN findings in 2 regions
clinically definite
UMN and LMN findings in 3 or more regions
regions
bulbar
cervical
thoracic
lumbosacral
dx is supported by
spread of signs and symptoms from one region to another
with a linear increase in severity
dx can be ruled out by
presence of cognitive, oculomotor, B&B or sensory sx
how to dx
exclusion
no definite tests for it
exclusion tests
CSF
CT/MRI
biopsy or ms or nerve
lab tests
other motor neuron dz
spinal muscle atrophy
primary lateral sclerosis
spinal muscle atrophy
autosomal recessive genetic LMN dz of childhood
primary lateral sclerosis
slowly progressive UMN dz
characterized by spasticity and hyperreflexia
onset of primary lateral sclerosis
after 40
is PLS an subset of ALS
unknown
incidence
4-6/100000
incidence gender
men > women by 2:1
except bulbar onset affects females and older people more
90% of ALS occurs
sporadically with an unknown cause
mean age at onset
57
clinical presentation
no lab test to confirm dx
nerve conduction velocity is normal
emg consistent with LMN dz
dz is based on
recognition of clinical pattern or syndrome
one of exclusion
first and earliest symptoms notes in 90% of pt
striated muscle weakness
initially focal but grows to include the entire body
onset is
insidious
with most pts being unaware of changes until they have difficulty with fxnal activity
physical exam
MMT will show greater weakness than the pt reports
what occurs by the time pt c/o weakness
up to 80% of the motor neurons int heir areas of weakness have been lost
