Amyotrophic lateral sclerosis

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

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

Neuromuscular weakness
- Upper motor neuron:
  - CVA
  - Hemorrhagic stroke
  - Multiple sclerosis
  - Amyotrophic Lateral Sclerosis (ALS) (upper and lower motor neuron)
- Lower motor neuron:
  - Spinal and bulbar muscular atrophy (Kennedy's syndrome)
- Spinal cord disease:
  - Infection (Epidural abscess)
  - Infarction/ischemia
  - Trauma (Spinal Cord Syndromes)
  - Inflammation (Transverse Myelitis)
    - Acute flaccid myelitis
  - Degenerative (Spinal muscular atrophy)
  - Tumor
- Peripheral nerve disease:
  - Guillain-Barre syndrome
  - Toxins (Ciguatera)
  - Tick paralysis
  - Diabetic peripheral neuropathy
- Neuromuscular junction 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
  - Aortic disease - occlusion, stenosis, dissection
- 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

Authors: