Amyotrophic Lateral Sclerosis (ALS)

Nicholas Mallett

Background 

  • Progressive weakness, often asymmetric and profound, with no sensory loss
  • Combination of LMN and UMN findings
    • LMN findings: weakness, flaccidity, hyporeflexia, fasciculations
    • UMN findings: weakness, spasticity, hyperreflexia, pathologic reflexes
  • Bulbar symptoms: dysphagia, increased saliva production (secondary to dysphagia), speech changes
  • Tongue fasciculations are best assessed while tongue rests in mouth and observed for ~30 seconds but can be hard to be certain of (symmetric movements are typically not fasciculations). A light can be helpful and atrophy, if present, can help differentiate from normal movements
  • Pseudobulbar affect (inappropriate laughing or crying) is relatively common in ALS and other neurodegenerative disorders.
  • FVC is an important respiratory marker for function.

Evaluation 

  • EMG/NCS is gold standard using the El Escorial or Awaji Criteria for diagnosis
  • Exclude mimicking lesions, which may be treatable (see below)

Management 

  • Pts with ALS are ideally treated with a multidisciplinary team of neurologists, pulmonologists, PT, OT, and SLP
  • Given the extensive specialized care requirements, the Office of Outpt Referral Assistance can assist in getting uninsured pt established with specialists
  • Few medications have been shown to add to survival on the order of months:
    • Riluzole: PO, requires CBC/LFT monitoring, AE: GI distress and general weakness
    • Edaravone: IV, QD x2weeks every month, AE: headache, bruising
    • Sodium Phenylbutyrate: PO, recently approved by FDA (9/2022), shown to delay ventilator-dependence by ~7 months, AE: GI distress
  • Otherwise, symptomatic management

Mimics of ALS 

  • Primary lateral sclerosis: UMN-only disease, less common than ALS with slower progression. Suspected to be on spectrum with ALS.
  • Cervical spine lesions: UMN changes in UE with LMN pattern in LE. MRI can reveal lesion
  • Multifocal motor neuropathy: rare autoimmune disorder with LMN-only signs. Responds to IVIG. Can be anti-GM1 Ab positive.
  • Kennedy Disease: X-linked genetic disorder with progressive LMN pattern, endocrine disorders, and androgen-resistance symptoms (gynecomastia, defective spermatogenesis)
  • Inclusion body myositis: Can be asymmetric with grip weakness and quadriceps weakness. Biopsy and atrophy pattern usually distinguishes it. CPK typically runs 500-800.
  • Polymyositis/dermatomyositis: proximal weakness in BUE/BLE, CPK typically runs >1000, usually younger onset (30-40s), no UMN signs.
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