Decompression Sickness Clinical Presentation

Updated: Mar 05, 2019
  • Author: Stephen A Pulley, DO, MS, FACOEP; Chief Editor: Joe Alcock, MD, MS  more...
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When taking the history remember that symptoms or signs that appear during or following a dive are pressure-related until proven otherwise based on a diagnostic or therapeutic recompression via hyperbaric oxygen (HBO). Therefore, having the forethought to ask about pressure exposure aids in the diagnosis. Having a familiarity with diving aids the healthcare provider in raising concern for pressure-related injuries. However, some patients have symptoms temporally linked to diving that ultimately are determined to be nondiving-related issues. The take-home point is to consider decompression sickness (DCS) as a possibility but not to exclude others, especially if symptoms are atypical and the dive profile would not normally be expected to cause a problem.

The examiner needs to elicit the following specifics about the dive(s):

  • Location of the dive (eg, ocean, lake, river, quarry, or cave)
  • Timing of events during the dive and over the prior 72 hours (eg, time dives occurred, length of dives, surface intervals, safety stops, flying, and method of timing used [eg, watch with tables, dive computer])
  • Maximum dive depth and the rate of ascent
  • Approximate times spent at specific depths
  • Work of the patient during the dive (ie, consider currents, distance swam, water temperature, and primary activity [eg, wreck diving, artifact recovery, or commercial work])
  • Gases and equipment used (ie, compressed air, rebreathing equipment, mixed gases, or none as in a free dive)
  • Problems encountered (eg, violation of no–decompression-limit dive tables, equipment, entanglement, dizziness, or marine bites or stings)
  • Patient's physical condition before, during, and after the dive (eg, fatigue, hydration, drug or alcohol intake, fever, vertigo, nausea, overexertion, or pulled muscles)
  • First aid delivered (ie, oxygen, positioning, medications, and fluids)

Ask the patient about the following symptoms:

  • General symptoms of profound fatigue or heaviness, weakness, sweating, malaise, or anorexia
  • Musculoskeletal symptoms of joint pain, tendonitis, crepitus, back pain, or heaviness of extremities
  • Mental-status symptoms of confusion, unconsciousness, changes in personality
  • Eye and ear symptoms of scotomata (negative then positive), diplopia, tunnel vision, blurring, extraocular motor paresis, tinnitus, or partial hearing loss
  • Skin symptoms of pruritus or mottling
  • Pulmonary symptoms of dyspnea, nonproductive cough, or hemoptysis
  • Cardiac symptoms of inspiratory, substernal, or sharp or burning chest pain
  • Gastrointestinal symptoms of girdle abdominal pain, fecal incontinence, nausea, or vomiting
  • Genitourinary symptoms of urinary incontinence or urinary retention
  • Neurologic symptoms of paresthesia (general or over a joint), paresis, paralysis, migrainous headache, vertigo, dysarthria, or ataxia
  • Lymphatic symptoms of edema

Physical Examination

Physical signs and examination findings in decompression sickness (DCS) may include the following:

  • General - Fatigue, shock
  • Mental status - Disorientation, mental dullness
  • Eyes - Visual-field deficit, pupillary changes, air bubbles in the retinal vessels, or nystagmus
  • Mouth - Liebermeister sign (a sharply defined area of pallor in the tongue)
  • Pulmonary - Tachypnea, respiratory failure, respiratory distress, or hemoptysis
  • Cardiac - Tachycardia, hypotension, dysrhythmia, or Hamman sign (crackling sound heard over the heart during systole)
  • Gastrointestinal - Vomiting
  • Genitourinary - Urinary bladder distention, decreased urinary output
  • Neurologic - Hyperesthesia, hypoesthesia, paresis, anal sphincter weakness, loss of bulbocavernosus reflex, spotty motor or sensory deficits, focal seizure, generalized seizure, or ataxia
  • Musculoskeletal - Subjective joint pain without objective findings, or decreased range of motion because of muscle splinting of involved joint or tendon
  • Lymphatic - Lymphedema
  • Skin - Pruritus, mottling/marbling, hyperemia, violaceous color, cyanosis, or pallor

Diagnostic maneuvers

Pain, frequently musculoskeletal, occurs in 50-60% of DCS cases. Two specific maneuvers can aid the practitioner in diagnosing DCS.

Place a large blood pressure (BP) cuff over the area of pain and inflate it to 150-250 mm Hg. In patients with nitrogen bubbling in the joint or tendons, this increase can force some of the nitrogen back into solution, resulting in a temporary decrease in pain.

Milking the muscle toward the affected joint may increase pain by pushing more nitrogen bubbles toward the joint.

Differentiating between arterial gas embolization (AGE) and DCS

For AGE, (1) any type of dive can cause AGE, (2) the onset is immediate (< 10-120 min), and (3) neurologic deficits manifest in only the brain.

For DCS, (1) the dive must be of sufficient duration to saturate tissues, (2) the onset is latent (0-36 h), and (3) neurologic deficits manifest in spinal cord and brain.

Differentiating carbon monoxide poisoning

The symptoms of carbon monoxide poisoning (eg, dyspnea, headache, fatigue, dizziness, visual changes, and unconsciousness) can mimic DCS or AGE. Sources for this carbon monoxide can include improper filling of tanks or boat engine exhausts, among others. Failure to recognize carbon monoxide poisoning is not a serious omission as long as the patient is recognized as having a diving injury. The hyperbaric treatment of DCS and AGE is also the treatment of choice for carbon monoxide poisoning. Also see Carbon Monoxide Toxicity and Carbon Monoxide Screening.



Residual paralysis, myocardial necrosis, and other ischemic injuries may occur without immediate recompression. These may occur even in adequately treated patients.