19th February, 20212 min read

What is decompression sickness?

Medical reviewer:
Dr Ann Nainan
Dr Ann Nainan
Dr Lauretta Ihonor
Dr Lauretta Ihonor
Last reviewed: 07/02/2021
Medically reviewed

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Decompression sickness is a condition that happens when gas (nitrogen) bubbles form inside some of your blood vessels and block normal blood flow through them.

It’s caused by quickly moving from high to low pressure, which is why it most commonly affects deep sea divers when they come back up to the surface too quickly or people going up in the air in an unpressurised or poorly pressurised plane (this isn’t common in commercial planes).

Symptoms of decompression sickness

There are 2 types of decompression sickness.

Type I is mild and involves the joints, skin and lymph glands.

If you have type I decompression sickness, you may notice symptoms, including;

  • joint and muscle pain that gradually gets worse
  • swollen lymph glands
  • skin mottling (blotchy patches), itching and rash

Type II decompression sickness is more serious than type I and can be life threatening. It typically involves the brain, heart and lungs.

If you have type II decompression sickness, you may develop symptoms that include:

  • muscle weakness, numbness and tingling
  • trouble peeing
  • peeing or pooing when you don't mean to
  • headache, tiredness and lightheadedness
  • dizziness, ringing ears and hearing loss

In the most serious cases, you may develop fits, loss of vision, confusion, slurred speech and fall into a coma.

It’s also possible to die from type II decompression sickness, so go to an emergency department or call an ambulance immediately if you have or think you may have decompression sickness.

How is decompression sickness diagnosed and treated?

A doctor will usually diagnose decompression sickness based on your symptoms and if you’ve been diving or doing other activities that put you at risk of developing the condition.

They may also do an MRI or CT scan to rule out other causes of your symptoms.

If you have decompression sickness, you'll need to be treated in hospital with oxygen and fluids. You may also be put into a closed chamber with 100% oxygen. This is known as oxygen recompression therapy.

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