Diving-related illnesses

Decompression illness

• Mechanism & Triggers:

  • Rapid ascent or unpressurized flight/altitude exposure <12–24h post-scuba dive.
  • Insoluble nitrogen bubbles form in tissues/blood (Decompression Sickness [DCS]) or alveolar rupture seeds gas into systemic circulation (Arterial Gas Embolism [AGE]).
  • Patent foramen ovale (PFO) is a major predisposing anatomic factor (paradoxical emboli).

• Clinical Presentation:

  • Type I DCS (Mild): “The bends” (dull, periarticular joint pain, especially shoulders/elbows) and cutis marmorata (mottled/marbled skin, pruritus). c
    • Nitrogen is ~5× more soluble in fat than water. Periarticular adipose tissue, joint capsules, and adjacent bone marrow act as large nitrogen reservoirs during hyperbaric exposure.
  • Type II DCS (Severe): Spinal cord ischemia (ascending paraparesis, sensory level, urinary retention), “the chokes” (cough, hemoptysis, dyspnea), and “the staggers” (vertigo, ataxia, nystagmus).
  • AGE: Symptoms occur immediately (<10 min post-surfacing); presents with sudden collapse, seizure, or focal stroke-like neurologic deficits.

• Diagnosis:

  • Purely clinical: Never delay treatment for imaging or lab confirmation.
  • CXR: Done immediately to evaluate for concomitant pneumothorax or pneumomediastinum.
  • Outpatient TTE/TEE with bubble study: Screening for underlying PFO after recovery.

• Management Hierarchy:

  1. Immediate: 100% high-flow O₂ (washes out nitrogen, accelerates bubble resorption) + aggressive IV isotonic crystalloids (treats hemoconcentration; avoid dextrose).
  2. Definitive / Gold Standard: Hyperbaric Oxygen Therapy (HBOT) in a recompression chamber.
  3. Transport precautions: Maintain sea-level cabin pressure or ground transport (cabin altitude must remain <1,000 ft).
  4. Safety imperative: Place chest tube prior to HBOT if pneumothorax is identified (prevents tension pneumothorax during recompression).

• High-Yield Complications:

  • Dysbaric osteonecrosis (avascular necrosis [AVN] of femoral/humeral heads).
  • Permanent spinal cord deficits (paraplegia, neurogenic bladder).