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Essentials of Diagnosis
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Symptoms temporally related to recent altitude or pressure changes (eg, scuba diving and flying)
Early recognition and prompt treatment are extremely important
Patient must also be assessed for hypothermia, hypoglycemia, concurrent injuries, and medical conditions
Consultation with a specialist in diving medicine or in hyperbaric oxygen therapy is indicated
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General Considerations
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Dysbarism and decompression illness result from altitude changes and the environmental pressure effects on gases in the body during underwater descent and ascent, particularly when scuba diving is followed closely by travel to high altitudes (ie, air travel or mountain hiking)
Dysbarism results from barotrauma when gas compression or expansion occurs in parts of the body that are noncompressible or have limited compliance
Pulmonary overinflation syndrome
One of the most serious and potentially fatal results of barotrauma
Due to an inappropriately rapid ascent causing alveoli rupture and air bubbles extravasation into tissue planes or even the cerebral circulation
Lung barotrauma can result in
Overpressurization of the bowels may occur, resulting in
Less serious conditions include
Mask squeeze
Ear squeeze
Sinus squeeze
Headache
Tooth squeeze
Decompression illness occurs when pressure change is too rapid from higher pressure to lower pressure
Symptoms depend on the size and number of gas bubbles released (notably nitrogen)
Location (eg, coronary, pulmonary, spinal or cerebral blood vessels, joints, soft tissue) of released gas bubbles also determines symptoms
The appearance of symptoms depends on
Dive details (depth, duration, number of dives, and interval surface time between dives, water conditions)
Degree of physical exertion
Age, weight, and physical condition of the diver
Rate of ascent
The length of time between the low altitude (scuba dive) and high altitude (air travel or ground ascent)
Predisposing factors for decompression illness
Obesity
Injury
Hypoxia
Lung or cardiac disease, especially right to left cardiac shunt (ie, patent foramen ovale)
Dehydration
Panic attacks
Other comorbidities
Alcohol and medication effects
Decompression illness also occurs in persons who take hot showers after cold dives
Delayed decompression illness
May be caused by the cavitation effects of gas trapped in the body, which is described as "vacuum phenomenon" in radiological studies
Clinical cases have been reported following post-dive exercise
Possible contraindications to diving
Asthma
Pneumothorax
Reduced pulmonary function
Lung cysts
Thoracic trauma
Cardiovascular disease
History of bowel obstruction
Recent brain or eye surgery
Seizures
Diabetes mellitus and hypoglycemic episodes
Definite contraindications to diving
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Symptom onset may be immediate, within minutes or hours (in the majority), or up to 36 hours later
Symptoms are highly variable