Compartment Syndrome: What Is It?

Medically Reviewed by Poonam Sachdev on December 17, 2023
6 min read

Compartment syndrome occurs when excessive pressure builds up inside an enclosed muscle space in the body. The condition usually results from bleeding or swelling after an injury. The dangerously high pressure in compartment syndrome slows the flow of blood, oxygen, and nutrients to and from the affected tissues. It can be an emergency, requiring surgery to prevent permanent injury.

Acute compartment syndrome vs. chronic compartment syndrome

Acute compartment syndrome is the most common type of compartment syndrome. About three-quarters of the time, acute compartment syndrome is caused by a broken leg or arm. Acute compartment syndrome develops rapidly over hours or days. It is also the most severe type. If left untreated, it can result in loss of function or amputation of the affected area.

Chronic compartment syndrome develops over days or weeks. Also called exertional compartment syndrome, it may be caused by regular, vigorous exercise such as running, swimming, or biking. Exercise-induced compartment syndrome tends to flare up when you do any exercise that causes swelling, such as running, and then goes down when you are done. This is usually less severe than acute compartment syndrome and may just limit the duration and intensity of the exercise. It usually involves the lower leg, buttock, or thighs.

Groups of organs or muscles are organized into areas called compartments. Webs of connective tissue, called fascia, form the walls of these compartments. Fascia is a strong tissue and, unlike muscles, doesn't stretch a lot.

After an injury, the affected area may swell, and blood or fluid resulting from inflammation or injury can accumulate in the compartment, causing edema. The tough walls of fascia can't easily expand to make room for the swelling or fluid build-up, and compartment pressure rises. When this happens, tissues inside the compartment don't get sufficient blood flow. It also puts pressure on the nerves and muscles in the compartment. This can cause tissues in the area to die leading to damage of the organs or muscles, loss of function, or even death.

The legs, arms, forearms, thighs, feet, gluteal region, hands, and abdomenare most prone to developing compartment syndrome.

Acute compartment syndrome can occur after you have some kind of trauma, such as:

  • Crush injuries
  • Burns
  • An overly tight bandaging
  • Prolonged compression of a limb during a period of unconsciousness
  • Surgery to blood vessels of an arm or leg
  • Blood clot in the blood vessel of an arm or leg
  • Severe muscle sprain or bruise
  • Broken bone (immediately due to pressure from bleeding and edema or later, as a result of treatment like surgery or casting)

Taking anabolic steroids can also contribute to developing compartment syndrome.

Abdominal compartment syndrome almost always develops after a severe injury or surgery, or during critical illness. As the pressure in the abdominal compartment rises, blood flow to and from the abdominal organs is reduced. The liver, bowels, kidneys, and other organs may be injured or permanently damaged. Some conditions associated with abdominal compartment syndrome include:

  • Trauma, especially when it results in shock
  • Abdominal surgery, particularly liver transplant
  • Burns
  • Sepsis (an infection causing inflammation throughout the body)
  • Severe ascites (fluid collecting in the abdomen) or abdominal bleeding
  • Pelvic fracture

Exertional compartment syndrome can happen after:

  • Extremely vigorous exercise, especially eccentric movements (extension under pressure)
  • Vigorous eccentric abdominal exercises (such as sit-ups on a back extension machine in weight rooms)

Acute compartment syndrome usually develops over a few hours after a serious injury to an arm or leg. Some symptoms of acute compartment syndrome include:

  • A new and persistent deep ache in an arm or leg
  • Pain that seems greater than expected for the severity of the injury
  • Numbness, pins and needles, or electricity-like pain in the limb
  • Swelling, tightness, and bruising
  • Weakness or loss of sensation
  • Pain that doesn't go away after treatment such as pain medicine or icing and raising the limb
  • Pale skin in the affected area

Symptoms of chronic compartment syndrome (exertional compartment syndrome) include aching or cramping in the affected muscle (buttock, thigh, or lower leg) that gets worse within 30 minutes after starting exercise. If it's in the leg, it can cause foot drop (difficulty lifting the front of the foot when you walk, which sometimes makes you drag your foot). Symptoms usually go away with rest, and muscle function remains normal. Exertional compartment syndrome can feel like shin splints and be confused with that condition.

Abdominal compartment syndrome usually develops in people who are hospitalized and critically ill on life support. They usually cannot describe their symptoms. Doctors or family may notice the following symptoms:

  • A tense, distended abdomen
  • Wincing when the abdomen is pressed
  • Urine output that slows down or stops
  • Low blood pressure

Acute compartment syndrome is a medical emergency. If you think you have it, go to an emergency room or urgent care clinic. If you think you have exertional compartment syndrome, talk to your doctor.

A doctor may suspect compartment syndrome based on the type of injury, a person's description of symptoms, and a physical exam. Sometimes, the diagnosis of compartment syndrome is clear from these findings.

In many cases, a definite diagnosis of compartment syndrome requires direct measurement of pressures inside the body compartment. To do this, a doctor can insert a needle into the area of suspected compartment syndrome while an attached pressure monitor records the pressure. A plastic catheter can also be inserted to monitor the compartment pressure continuously. With chronic compartment syndrome, your doctor will take a pressure test and repeat it after you have done the exercise that is causing the pain.

In suspected abdominal compartment syndrome, a pressure monitor can be inserted into the bladder through a urinary catheter. High pressures in the bladder, when there are signs of abdominal compartment syndrome, strongly suggest the diagnosis.

Laboratory and imaging tests (such as an X-ray) can support the diagnosis of compartment syndrome. But no single test other than a direct pressure measurement can diagnose abdominal compartment syndrome.

Treatments for compartment syndrome focus on reducing the dangerous pressure in the body compartment. Dressings, casts, or splints that are constricting the affected body part must be removed.

Most people with acute compartment syndrome require immediate surgery to reduce the compartment pressure. A surgeon makes long incisions through the skin and the fascia layer underneath (fasciotomy), releasing excessive pressure.

Other supportive treatments include:

  • Keeping the body part below the level of the heart (to improve blood flow into the compartment)
  • Giving oxygen through the nose or mouth
  • Giving fluids intravenously
  • Taking pain medications

Chronic compartment syndrome may be treated by avoiding the activity that caused it. Your doctor can recommend other options including:

  • Stretching
  • Physical therapy
  • Anti-inflammatory medications
  • Orthotics
  • Switching to lower-impact exercise (such as walking instead of running)
  • Changing the exercise routine temporarily to train other muscles and relieve the ones that are inflamed

Surgery is not as urgent in chronic or exertional compartment syndrome and may not be necessary. If other treatments don't work, it may be required to relieve pressure.

Abdominal compartment syndrome treatments include options such as decompression of the area and drainage through a small tube in the stomach. Your doctor may also try life support measures such as mechanical ventilation, medicines to support blood pressure (vasopressors), and kidney replacement therapies (such as dialysis). Surgery to open the abdomen to reduce the compartment syndrome pressures may be necessary. The best time to perform surgery in people with abdominal compartment syndrome is often not clear. Surgery for abdominal compartment syndrome may be lifesaving but can also cause complications including:

  • More organ damage
  • Infection
  • Fistula, when two body parts come together that aren't supposed to be connected (such as the stomach and skin's surface) 
  • Hernia, when a muscle bulges through surrounding tissue

Compartment syndrome can be a serious condition that is caused by some kind of trauma, such as a car accident or broken bone. If you have symptoms, you need to see your doctor immediately for treatment. There are several treatments used to treat and release the pressure in the affected area including surgery. If acute compartment syndrome is left untreated, it can cause permanent damage to the limb.