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Amyotrophic Lateral Sclerosis (ALS)


  • Progressive weakness, often asymmetric and profound with no sensory loss

  • Combination of LMN and UMN findings

    • LMN findings: weakness, flaccidity, absent/decreased reflexes, fasciculations

    • UMN findings: weakness, spasticity, hyperreflexia, pathologic reflexes (e.g. extensor plantar response), slow movements

  • Pts with bulbar symptoms may complain of difficulty swallowing, changes in their voice, or increased saliva production (they just aren’t swallowing it)

  • Tongue fasciculations are fairly uncommon in other disorders and is a good clue for ALS if present (these can be hard to be certain of – tongue movements that are symmetric are typically not fasciculations)

  • Pseudobulbar affect – inappropriate laughing or crying; relatively common in ALS

  • FVC is an important marker for function


  • EMG/NCS is gold standard; El Escorial Criteria looks for evidence of UMN and LMN findings at cranial, cervical, thoracic and lumbosacral levels to determine if ALS or not

  • Exclude mimicking lesions, which may be treatable (see below)


  • Patients with ALS are ideally treated with a multidisciplinary team of Neurologists, Pulmonologists, Speech therapists, PT, OT and mobility

  • Two medications have been shown to add a few months to survival:

    • Riluzole - PO med; have to track CBC/LFTs. Side effects: GI and general weakness

    • Edaravone (Radicava) – IV, given daily for 2 weeks every month. SE = HA, bruising

Mimics of ALS

  • High cervical spine lesions –UMN changes in upper extremity with LMN pattern in LE

  • Primary Lateral Sclerosis – UMN-only disease, much less common with much slower progression. Many transition to ALS in the first 1-2 years, which then is likely a spectrum of the same disease

  • Multifocal Motor Neuropathy – rare autoimmune disorder that looks like ALS with LMN signs only, responds to IVIG. Can have anti-GM1 Ab in blood. EMG/NCS pattern is different with conduction block

  • Kennedy Disease – X-linked genetic disorder with progressive LMN pattern of weakness and endocrine disorders w/androgen resistance profile (gynecomastia, defective spermatogenesis)

  • Inclusion Body Myositis – can be asymmetric with grip weakness and quadriceps weakness. Biopsy and atrophy pattern usually distinguishes it. CPK 500-800.

  • Polymyositis/dermatomyositis – proximal weakness in arms/legs, CPK > 1000, usually younger onset (30-40s), no UMN signs

Last update: 2022-06-23 17:28:12