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Last reviewed: 4 Nov 2023
Last updated: 14 Aug 2020



History and exam

Key diagnostic factors

  • musculoskeletal pain
  • numbness
  • tingling
  • paresthesia
  • nonspecific constitutional symptoms
  • muscular weakness
  • paralysis
  • rash
More key diagnostic factors

Other diagnostic factors

  • headache
  • ear or sinus pain
  • dizziness or vertigo
  • nausea
  • vomiting
  • shortness of breath
  • tachypnea
  • difficulty in walking
  • reduced hearing
  • middle ear bleeding or tympanic membrane perforation
  • pruritus
  • reduced level of consciousness
  • crackles
  • wheezing
  • reduced breath sounds
  • subcutaneous emphysema
Other diagnostic factors

Risk factors

  • diving or other activity involving increased atmospheric pressure (decompression illness)
  • increasing depth and duration of dives (decompression illness)
  • strenuous exercise during diving (decompression illness)
  • rapid ascents (decompression illness)
  • multiple ascents (decompression illness)
  • missed safety stops (decompression illness)
  • repetitive diving (decompression illness)
  • altitude exposure (decompression illness)
  • right-to-left shunt (decompression illness)
  • dehydration (decompression illness)
  • cold temperature (decompression illness)
  • hot temperature (decompression illness)
  • high body fat content (decompression illness)
  • increasing age (decompression illness)
  • menstruation (decompression illness)
  • poor physical fitness (decompression illness)
  • recent physical injury (decompression illness)
  • carbon dioxide retention (decompression illness)
  • failure to equilibrate pressure (barotrauma)
  • breath-holding during ascent (barotrauma)
  • lung disease (barotrauma)
  • eustachian tube dysfunction (barotrauma)
  • sinus ostia blockage (barotrauma)
  • incorrect autoinflation (barotrauma)
  • trapped gas in or near teeth (barotrauma)
  • Fallopian canal dehiscence (barotrauma)
  • deep diving (nitrogen narcosis)
More risk factors

Diagnostic investigations

1st investigations to order

  • chest x-ray
  • pure-tone audiometry
More 1st investigations to order

Investigations to consider

  • tympanometry
  • electronystagmography
  • facial x-rays
  • ECG
  • echocardiography
  • CBC
  • blood glucose
  • carboxyhemoglobin
  • creatine kinase
  • D-dimer
  • CT of the head or spine
  • CT of the sinuses
  • CT of the chest
  • MRI
  • subclavian Doppler ultrasound
More investigations to consider

Treatment algorithm


decompression illness


nitrogen narcosis



Oliver M. Firth, MBBs, BSc, MRCGP

Diving Physician & Director

Hyperdive, Ltd.




OMF declares that he has no competing interests.


Dr Oliver M. Firth would like to gratefully acknowledge Dr John D. King, the previous contributor to this topic. JDK declares that he has no competing interests.

Peer reviewers

Avi Shupak, MD

Head Otoneurology Unit

Carmel and Lin Medical Centers




AS declares that he has no competing interests.

John R. Fitz-Clarke, MD, PhD

Staff Hyperbaric Physician

Queen Elizabeth II Health Sciences Centre


Nova Scotia



JRFC declares that he has no competing interests.

  • Dysbarism images
  • Differentials

    • Gas toxicity (decompression illness)
    • Hypercapnia
    • Hyperventilation
    More Differentials
  • Guidelines

    • US Navy diving manual, revision 7 with change A entered. Chapter 17: diagnosis and treatment of decompression sickness and arterial gas embolism
    • Pre-hospital management of decompression illness: expert review of key principles and controversies
    More Guidelines
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