Decompression Illness: Causes, Symptoms, and Treatment

Have you ever heard of the “bends” or seen it depicted in movies? The medical term is decompression illness. This, in fact, is a rare occurrence.

It’s estimated that in sports diving, only about 3 cases happen for every 10,000 dives. Among commercial divers, the incidence is higher. An estimated 1.5 to 10 divers experience decompression sickness per 10,000 dives.

If you plan on diving, it’s important to understand decompression illness. Continue reading to learn about the causes, symptoms, and treatment for this sickness.

What is Decompression Illness?

Nitrogen and oxygen are the main components in the air. When you breathe under high pressure, such as deep in the water, your body takes in more molecules. The body uses oxygen on an ongoing basis.

When you’re exposed to high pressure, your body uses the extra oxygen, so they don’t build up. Nitrogen molecules, however, build up in the blood and tissues.

When a diver is ascending from deep in the water or if you leave an area with compressed air, you’re at risk for ACS. If you can’t exhale the nitrogen fast enough, nitrogen bubbles form in the blood and tissues.

If the nitrogen bubbles grow, they injure tissue and even block blood vessels in your organs. This can cause small blood clots. The nitrogen bubbles also cause swelling, pain, and loss of function.

Risk Factors for Decompression Illness

Several factors increase a person’s risk for developing DCS including:

  • Heart defects including a patent foramen ovale or atrial septal defect
  • Cold water
  • Dehydration
  • Traveling in an airplane after diving
  • Exercise
  • Exhaustion
  • Level of pressure exposure
  • Length of time exposed to a pressurized environment
  • Obesity
  • Older age
  • Rapid return from a pressurized environment

The excess nitrogen stays in the body tissues for at least 12 hours after each exposure to increased pressure. Thus, if you’re diving multiple times in one day, you’re at increased risk for DCS. If this is a vacation and you fly within 12 to 24 hours of diving, this adds to your risk.

Symptoms of Decompression Sickness

The severity of DCS varies depending on the exposure and risk factors. Only about 50% of people show symptoms of DCS in the first hour after returning to normal pressure. By the sixth hour, 90% of people with DCS develop symptoms.

The symptoms develop slowly. You may first notice a headache, loss of appetite, fatigue, and a slight feeling of illness. DCS is categorized into two types.

Type I DCS

This type, called the “bends”, includes pain in the arm and leg joints. The person also has pain in the back and/or muscles. The pain often is mild at first and becomes more severe and increases with movement.

Other less common symptoms include itching, mottled skin, swollen lymph nodes, rash, and extreme exhaustion.


This type often causes neurologic problems from mild numbness to paralysis and death. The spinal cord is more vulnerable to the effects of DCS. Damage to this area causes numbness, tingling, and/or weakness in the arms, legs, or both.

With spinal cord involvement, the symptoms increase over hours leading to permanent paralysis. The person loses control over urination and/or defecation. Abdominal and back pain are common symptoms.

With brain involvement, the person experiences headache, confusion, difficulty speaking, and double vision. Most people don’t lose consciousness.

When the nerves of the inner ear become affected, this leads to additional symptoms. These include dizziness, ringing in the ears, and hearing loss.

As gas bubbles move through the veins, they can enter the lungs. This can cause a cough, chest pain, increasing trouble breathing and choking. In rare, severe cases, this can lead to shock and death.

Dysbaric osteonecrosis or avascular bone necrosis describes a late effect of DCS. This can also occur in people without DCS. This condition results in bone tissue destruction, most often seen in the shoulders and hips. The person may experience ongoing pain and severe disability.

These injuries occur more often among people who work as professional divers or in a compressed-air environment.

How Is This Illness Treated?

Treatment depends on the severity of the symptoms. If the patient only experiences itching, mottled skin, and fatigue, 100% oxygen therapy may resolve symptoms.

Severe cases of DCS need recompression in a hyperbaric facility or chamber.  This treatment reestablishes normal oxygen levels and blood flow to tissues.

Recompression therapy is helpful for up to 24 hours after the event. Thus, even people with mild or intermittent symptoms should get treatment. This may require travel to reach a qualified facility.

During transport, the patient should receive oxygen by mask and fluid by mouth or an IV. Delaying treatment can lead to permanent injury or death.

During treatment, the pressure is decreased incrementally. The treatment includes pauses to let the excess gas leave the body. The speed of recompression depends on the condition of the patient.

Quick recompression may provide immediate symptom relief. For patients with pain, neurologic problems, or other symptoms, recompression may occur slower.

Most people experience a complete recovery from DCS. Yet, some patients may need further treatment if symptoms recur. These treatments are often shorter.

Are You Considering Buying a Hyperbaric Chamber?

Some individuals may wish to buy a hyperbaric chamber for personal use. The following are some tips to help you may the right choice.

  • Make sure you have a prescription from your healthcare provider
  • Check and see if you qualify for any discounts
  • Take measurements of the room where you want to keep the chamber
  • For home use, it’s recommended to choose a 26/27” chamber for women and 33/34” for men
  • For professional use, you may wish to buy a 60 Vertical, 60” Grand Dive Pro Plus, or 42” Class 4
  • Know what your budget is when you begin shopping

If you only need the chamber for a short time, you may wish to explore options for borrowing one.

Do You Take an Active Role in Staying Healthy?

If your activities involve pressurized environments, it’s important to understand decompression illness. Work to decrease your risk factors and get treatment if you experience any symptoms.

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