Amyotrophic Lateral Sclerosis (ALS)

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

Acute respiratory failure
- Predicted by forced VC <25 mL/kg or 50% decrease from normal
Aspiration pneumonia
Trauma related to extremity weakness

Neuromuscular weakness
- UMN:
  - CVA
  - Hemorrhagic stroke
  - Multiple sclerosis
  - Amyotrophic Lateral Sclerosis (ALS) (UMN & LMN)
- Spinal cord disease:
  - Infection (Epidural abscess)
  - Infarction/ischemia
  - Trauma (Spinal Cord Syndromes)
  - Inflammation (Transverse Myelitis)
  - Degenerative (Spinal muscular atrophy)
  - Tumor
- Peripheral nerve disease:
  - Guillain-Barre syndrome
  - Toxins (Ciguatera)
  - Tick paralysis
  - DM neuropathy (non-emergent)
- NMJ disease:
- Muscle disease:
  - Rhabdomyolysis
  - Dermatomyositis
  - Polymyositis
  - Alcoholic myopathy
Non-neuromuscular weakness
- Can't miss diagnoses:
  - ACS
  - Arrhythmia/Syncope
  - severe infection/Sepsis
  - Hypoglycemia
  - Periodic paralysis (electrolyte disturbance, K, Mg, Ca)
    - Hypokalemic periodic paralysis
    - Thyrotoxic periodic paralysis
  - Respiratory failure
- Emergent Diagnoses:
  - Symptomatic Anemia
  - Severe dehydration
  - Hypothyroidism
  - Polypharmacy
  - Malignancy
- Other causes of weakness and paralysis
  - Acute intermittent porphyria (ascending weakness)

Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e (2010), Chapter 167. Chronic Neurologic Disorders