What is Decompression Sickness?
Decompression sickness, or DCS, is a serious risk that can occur when gases like nitrogen in your bloodstream and tissues turn into bubbles. This condition is typically seen in people who are exposed to rapid changes in pressure. For example, scuba divers, individuals who fly at high altitudes, and those who work in environments where pressure is controlled.
When you’re under pressure, like during a deep-sea dive, gases balance in a dissolved state in tissues. If the pressure around you decreases quickly, these dissolved gases can turn into bubbles in your body. These bubbles might block blood vessels, cause inflammation, and injure tissues, which can lead to the problems associated with DCS.
DCS can mostly be avoided by following safe practices when diving. This includes ascending at a proper speed, sticking to decompression schedules, making safety stops, and planning your dive with safety first in mind. To treat DCS, high levels of oxygen are typically given, and in more serious situations, hyperbaric oxygen therapy (HBOT) may be used. Recognizing the early signs of DCS, intervening promptly, and working well with healthcare professionals can improve the patient’s outcome.
What Causes Decompression Sickness?
Decompression sickness (DCS) happens when there’s a rapid reduction in the surrounding pressure, which can cause gases like nitrogen present in the tissues to form bubbles in the bloodstream. Nitrogen is mainly found in the air we breathe and is also commonly inhaled by divers. Though normally harmless, when there’s too much in the blood vessels, it can cause blocks and inflammation.
This occurs because the amount of nitrogen in the body changes with the pressure of the surrounding environment. For instance, when a diver stays deep underwater for a long time, the body absorbs more nitrogen due to the high pressure. If the diver ascends slowly, the nitrogen is safely released from the body. But surfacing quickly can cause the nitrogen to form bubbles rapidly in the body, leading to DCS. Similarly, it can also happen to pilots who climb quickly to great heights in an aircraft that isn’t pressurized, and to astronauts working outside their spacecraft in space.
There are several individual factors that could make a person more likely to get DCS, such as dehydration, having a heart condition called patent foramen ovale, a previous injury, being exposed to cold temperatures, a high percentage of body fat, and having recently consumed alcohol. The most common form of DCS, or Type I, also known as the bends, comes with skin, lymphatic, or musculoskeletal symptoms. Meanwhile, Type II affects the nervous system and generally happens when the bubbles in the vein move from the right to the left side of the heart.
Risk Factors and Frequency for Decompression Sickness
Decompression sickness (DCS) has become rare thanks to advancements in technology and safety procedures for diving. It is estimated to occur in about 3 out of every 10,000 recreational diving activities. However, it’s more common among commercial divers, with the incidence rate being anywhere from 1.5 to 10 cases per 10,000 dives. Factors such as the length and depth of the dive can increase the likelihood of developing DCS. Furthermore, men are 2.5 times more likely than women to get DCS.
- Decompression sickness is now rare due to technological advancements and diving safety procedures.
- In recreational diving, the estimated incidence is 3 cases per 10,000 dives.
- For commercial divers, the rates are higher, ranging from 1.5 to 10 cases per 10,000 dives.
- The risk of getting decompression sickness increases with the duration and depth of the dive.
- Men are 2.5 times more likely than women to develop decompression sickness.
Signs and Symptoms of Decompression Sickness
Decompression sickness (DCS) primarily affects individuals exposed to rapid changes in pressure. People diagnosed with DCS exhibit symptoms within the first hour of exposure in about 75% of cases. Immediate response and treatment are critical. Providers often give high-flow oxygen to help the body eliminate nitrogen gas pockets, which can form even when the patient’s oxygen saturation is normal.
Symptoms usually begin after rapid decompression and may include changes to the skin, muscles, bones, and joints. Symptoms can also involve the inner ear, brain, spine and, although rare, the lungs. A person’s shoulder is the most common joint affected, skin patterns known as ‘Cutis marmorata’ can appear, and lymph nodes may become swollen and painful.
The second type of DCS may show signs such as headaches, visual and hearing issues, nausea, tinnitus (buzzing, humming, or ringing sounds in the ear), and poor coordination. Some patients may also experience an altered state of consciousness.
In rare cases, DCS can lead to abdominal pain, chest pain, and breathing difficulties, indicating potential problems with the abdomen, mediastinum, or lungs. Pulmonary DCS requires prompt treatment since it can be life-threatening, mimicking conditions like pulmonary embolism, asthma, or heart attack.
During a physical examination, initial findings may seem normal with calm vital signs. However, upon further inspection, skin lesions, visual problems such as scotoma, signs of ear damage, heart murmurs, joint or muscle tenderness, and issues with balance can be observed. In severe cases, patients might be unconscious. Pulmonary DCS may cause unusual lung sounds due to fluid accumulation, wheezing in patients with asthma, or an absence of breath sounds due to a collapsed lung.
Recognizing DCS is based on observing clinical symptoms. Immediate recompression can alleviate symptoms quickly and also confirm the diagnosis. Once initial treatment is in progress, further details such as precise diving information and other potential injuries are assessed.
Testing for Decompression Sickness
Decompression Sickness (DCS) is diagnosed based on the patient’s symptoms. Running a full battery of tests isn’t always necessary and might even be harmful as this condition can progress very quickly. However, if a patient with possible DCS is struggling to breathe, a chest x-ray should be taken straight away. It’s important to note that untreated air leaks in the chest (pneumothoraces) mean a patient can’t have hyperbaric oxygen therapy, a common treatment for DCS.
When it comes to imaging and lab tests, the results are often not specific. While most individuals with DCS have normal chest x-rays, some may show fluid accumulation or a collapsed lung. A bone x-ray might reveal tiny gas bubbles in the joints. Also, those exposed to repeated pressure changes like divers or certain workers could show signs of long-term decay in bones and joints. CT or MRI scans may detect air pockets in different structures within the chest and abdomen. Brain and spine scans using CT or MRI can also reveal swelling, blocked blood vessels, brain bleeds, or pockets of gas in the spaces around the spinal cord. An echocardiogram is a type of ultrasound for the heart, which could help identify holes between the heart’s chambers.
Lab tests could indicate damage to the kidneys, liver, and pancreas if these organs are affected. Elevated levels of C-reactive protein and white blood cells, which are involved in the body’s response to inflammation, might also be found.
Treatment Options for Decompression Sickness
If a patient loses consciousness and has no heartbeat or breathing, they must be given cardioresuscitation, no matter the cause. If the patient is suspected of decompression sickness (DCS), they should be given pure oxygen until hyperbaric oxygen therapy (HBOT) can be applied. Medical professionals should start giving the patient fluids via an intravenous drip and monitor their heart rate continuously. A chest X-ray should be performed as soon as possible to check for a collapsed lung and prepare the patient for HBOT. Recompression via HBOT should be commenced right away, often using U.S. Navy protocols.
If the patient needs to be moved quickly to a specialized treatment center, it is recommended to use a pressurized aircraft. If an unpressurized aircraft, like a helicopter, has to be used, it should not fly higher than 300 meters or 1000 feet.
Patients who are awake can be given fluids and electrolytes orally, unless there is a possibility they may need immediate abdominal or chest surgery. Even patients showing delayed symptoms related to their nervous system, lungs, or skin may still gain benefits from using HBOT. To prevent blood clots in the person’s deep veins or lungs, especially if they are not able to move around, a low-molecular-weight heparin could be used. However, other blood thinners, anti-inflammatory medication, and steroids are not recommended in treating DCS. Aspirin should also not be used as it might hide pain and other symptoms.
If the patient starts to vomit, they should be positioned upright or their head should be raised to prevent them from inhaling the vomit. It’s no longer recommended to put patients in the Trendelenburg or left lateral decubitus positions for a long time because these positions can increase the risk of brain swelling.
What else can Decompression Sickness be?
Patients showing symptoms like muscle pain, skin rashes, and swollen lymph nodes might be misdiagnosed with Type I Decompression Sickness (DCS) when they might actually have:
- A viral disease affecting various parts of the body
- Systemic lupus erythematosus, a long-term autoimmune disease
- Acute leukemia, a type of blood and bone marrow cancer
- Bacterial infections like gonorrhea or syphilis
- Lymphoma, a group of blood cancers
- Lyme disease, a tick-borne infection
- Simple dehydration
Similarly, Type II DCS can sometimes be mistaken for other conditions like:
- Ear damage because of changes in air or water pressure (barotrauma)
- Stroke
- Near-drowning experiences
- Thermal stress, or the body’s reaction to extreme heat or cold
- The effect of nitrogen on a person’s behavior and body function under high pressure (nitrogen narcosis)
- Illnesses caused by the bacterium Neisseria meningitidis (Meningococcemia)
- Growth within the brain or spinal cord
- Multiple sclerosis, a long-term disease that impacts the brain and spinal cord
- Abnormally low blood sugar (hypoglycemia)
- Heart-related problems (acute coronary syndrome)
- Exposure to toxins from different marine life
- High levels of oxygen in body tissues (oxygen toxicity)
For a healthcare provider, it is crucial to quickly and accurately differentiate between these conditions to ensure the correct treatment is provided promptly.
What to expect with Decompression Sickness
The outcome for DCS, or decompression sickness, can change based on a variety of factors. These include the range and seriousness of symptoms, the speed and effectiveness of treatment, and a person’s overall health. In general, if someone has mild symptoms, gets fast and proper treatment, and was in great health before their dive, they usually have a good outcome. Symptoms might even disappear within a few days of receiving high-flow oxygen and resting.
Things that can lead to a worse outcome include having severe symptoms, delayed treatment, and poor health to begin with. In these cases, permanent nerve damage and even death could occur if recompression treatment – or treatment to correct the pressure inside the body – isn’t administered swiftly or adequately.
Possible Complications When Diagnosed with Decompression Sickness
Decompression sickness (DCS) can affect any part of the body. Skin issues like cutis marmorata and ulcers may heal without causing lasting issues. However, other complications can occur in other parts of the body, such as:
- Osteonecrosis, which can lead to bone fractures and long-term arthritis, often affecting the femur, humerus, and tibia.
- Persistent symptoms similar to a stroke, such as muscle weakness, bladder control problems, and even coma due to severe nerve damage.
- People who survive lung-related decompression sickness may develop lung fibrosis, a condition where parts of the lungs become scarred and thickened.
- If the abdomen is affected, it may result in pancreatic, liver, and kidney damage. Problems with the digestive system can lead to obstructions.
Administering high-flow oxygen and hyperbaric oxygen therapy (HBOT) early on can help reduce the impact of these complications.
Recovery from Decompression Sickness
Recovery after Decompression Sickness (DCS) depends on multiple factors such as the severity of symptoms, the person’s overall health, and how well they respond to treatment. Around 85% of DCS cases are considered Type I, where most people recover without any issues. Regular health check-ups, education about how to prevent DCS, and continued monitoring can be beneficial for these individuals. Emotional support may also be provided if needed or if requested by the patient.
For those with more severe or widespread symptoms, a combination of physical therapy, neurorehabilitation, occupational therapy and nutritional guidance could be necessary, alongside the normal post-treatment recovery measures. Physical therapy aims to improve joint movement, strength, and flexibility. Neurorehabilitation assists in restoring motor skills, coordination, and sensory functions. Occupational therapy works on boosting a person’s ability to carry out daily tasks independently, helping them to return to their normal activities. Nutritional advice will be personally designed based on a person’s current health condition and the progress of their physical recovery. Counseling can also be beneficial to help individuals recover from the emotional trauma and deal with any complications.
Preventing Decompression Sickness
Preventing decompression sickness (DCS), a risk for divers and pilots, requires combined efforts from different individuals. Firstly, people who dive or fly should follow safety guidelines. This includes ascending slowly and planning their flights or dives appropriately. They should only tackle complex tasks if they have a highly experienced instructor with them. Divers and pilots can also reduce their risk of DCS by staying hydrated, keeping fit, resting well, avoiding alcohol, and maintaining their equipment properly.
Healthcare providers need to emphasize and discuss these measures with at-risk individuals. It’s also essential for medical professionals to remind their patients to act quickly if they notice strange symptoms after a dive or high-altitude exposure. On top of educating the patients, doctors can prevent DCS by closely examining patients before they dive or fly. Individuals with certain conditions like a hole in their heart (known as a patent foramen ovale), lung disease, or poor physical fitness are more likely to experience severe DCS.
Owners of diving centers can also contribute to DCS prevention by ensuring their equipment and computers are always in good condition. They should consider asking for medical clearance from each diver and have a medical team available at all times. It’s also important to have a plan in place to quickly transport patients with suspected DCS to the nearest emergency medical facility.
Lastly, the wider community can help prevent DCS. This can be done by sharing information, offering logistical and medical help, and promoting safe diving and flying habits.
