The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
Background
- Progressive muscle atrophy/weakness due to degeneration of upper and lower motor neurons
- Patients will rarely present to the ED undiagnosed
- Likely related to mutated superoxide dismutase (SOD1) gene
- Involvement of the anterior horn cells
Clinical Features
A man with ALS using a head-mounted laser pointer to comunicate. Note asymetic motor weakness.
- Acute respiratory failure
- Predicted by forced VC <25 mL/kg or 50% decrease from normal
- Aspiration pneumonia
- Trauma related to extremity weakness
- Asymmetric weakness without sensory findings with mixed upper and lower motor nerve findings
Differential Diagnosis
- Neuromuscular weakness
- Upper motor neuron:
- Lower motor neuron:
- Spinal and bulbar muscular atrophy (Kennedy's syndrome)
- Spinal cord disease:
- Peripheral nerve disease:
- Neuromuscular junction disease:
- Muscle disease:
- Non-neuromuscular weakness
- Can't miss diagnoses:
- Emergent Diagnoses:
- Other causes of weakness and paralysis
Evaluation
MRI (axial FLAIR) demonstrates increased T2 signal within the posterior part of the internal capsule, consistent with the diagnosis of ALS.
Management
Disposition
See Also
External Links
References
- Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e (2010), Chapter 167. Chronic Neurologic Disorders