Decompression syndrome occurs when a rapid reduction in pressure allows respiratory gases, previously dissolved in the blood or tissues, to form bubbles. This phenomenon is typically seen in divers who rise too quickly to the surface. However, decompression syndrome can also occur when pressure drops suddenly after hyperbaric chamber therapy or when an aviator quickly reaches very high altitudes.
Free gas bubbles can cause local symptoms or reach distant organs, thanks to the blood flow. In some cases, they mechanically obstruct blood vessels, resulting in air embolism. Other times, they rupture or compress the tissues, activating the cascades of coagulation and inflammation. Furthermore, given that nitrogen dissolves easily in adipose tissue, structures with a high lipid content are particularly vulnerable (e.g. spinal cord, white matter of the central nervous system, myelin sheath of nerves, etc.).
Risk factors predisposing to the development of decompression syndrome include low temperature, repeated or deep diving.
Symptoms of decompression syndrome usually occur within 1-6 hours of surfacing; they rarely occur after a few minutes or a few days (24-48 hours). Nitrogen bubbles are mainly localized in the joints and central nervous system, causing mild symptoms, such as pain when mobilizing the joints, or more severe, such as paralysis.
Symptoms of decompression syndrome typically include joint and muscle pain (especially in the elbows, shoulders and back), headache, loss of appetite, fatigue and malaise. Later, wheezing, chest pain, cough, cyanosis, altered pulse, itching, blue skin rash (cutis marmorata), and urticaria-like rash may occur.
Neurological symptoms include pins and needles, paraesthesia, dysuria, clumsy speech, impaired hearing or vision, faecal or bladder incontinence, seizures, and loss of consciousness. Gas embolization of the pulmonary vascular tree can cause heart failure and cardiogenic shock. Very severe cases can lead to coma and death.
Proper diving techniques are essential for the prevention of decompression syndrome;
by gradually rising to the surface, thus allowing the nitrogen bubbles to gradually escape from the solution, divers can avoid the onset of symptoms. Dives made less than 24 hours away (repeated) require special technical measures.
Treatment of decompression syndrome involves recompression therapy in a hyperbaric chamber, so that the bubbles can return to solution. Then, the pressure is gradually decreased to the value of atmospheric pressure, allowing the excess nitrogen to slowly escape from the solution and be eliminated from the body by normal breathing.
Most common symptoms and signs *
- Anorexia
- Arrhythmia
- Asthenia
- Cianosi
- Coma
- Seizures
- Language difficulties
- Dyspnoea
- Dysuria
- Chest pain
- Bone pain
- Articolar pains
- Muscular pains
- Emiparesi
- Tingling in the Head
- Faecal incontinence
- Ipoacusis
- Hypoaesthesia
- Swollen lymph nodes
- Lipotimia
- Livedo Reticularis
- Backache
- Headache
- Nausea
- Urticaria
- Pallor
- Paraesthesia
- Loss of coordination of movements
- Loss of balance
- Pneumomediastinum
- Presincope
- itch
- Reduced vision
- Joint stiffness
- Confusional state
- Fainting
- Tachypnea
- Tetraplegia
- Cough
- Dizziness
- Threw up
* Symptoms highlighted in bold are typical, but not unique, of Decompression Syndrome disorder
