ALS Flashcards
key findings
weakness of the legs > arms
- fasciculations* of several muscles and is
- hyperreflexic* in all 4 extremities
- both upper and lower motor neurons
epi
common cause of anterior horn cell disorder
M>W
pathophys
HALLMARK: SIMULTANEOUS UPPER AND LOWER MOTOR NEURON DISEASE
Loss of lower motor neurons in the anterior horns of spinal cord
Loss of upper motor neurons that project in corticospinal tracts
2 characteristics
Neuronal muscle atrophy (amyotrophy)
Hyperreflexia
ddx
Multifocal motor neuropathy Polio (now “post-polio syndrome”) “Spinal muscular atrophy” West Nile Virus encephalitis Demyelination diseases CVA/TIA Heavy metal poisoning B12 deficiency Syphilis Various Endocrinopathies
early symptoms
Lower extremity weakness Frequent falls Asymmetric weakness of the hands Difficulty with fine motor skills Foot drop Severe muscle cramping Spasticity of arms and legs Dysarthria Dysphagia *Cognitive dysfunction NOT a feature
late symptoms
Fasciculations
Recurrent bouts of pulmonary infection after respiratory muscle involvment
Respiratory failure–>death
signs
Diffuse hyperreflexia and spasticity (upper motor neuron)
Fasciculations, weakness, and atrophy (lower motor neuron)
+Babinski
claw hands
tongue: “can of worms”
rating scale
ALSFRS-R (ALS Functional rating scale-Revised)
lower score is worse
see charts
UMN vs LMS
*limb s/s
axial s/s
lab imaging: MRI
dx of exclusion
Brain and spinal MRI-done to rule out other conditions that can mimic early ALS
MR spectroscopy and CT with myelography can also be used if MRI contraindication
PET
lab imaging: EMG
Fibrillation and fasciculation potentials
Motor units polyphasic with high amplitude and long duration
Examine at 3 levels:
Most involved limb first
Distal muscles
Bulbar muscles
labs to rule out
B12/folate HIV status Lyme serology Thyroid function tests CPK
CSF?
gen not helpful
PFTs?
test in sev. disease
