Compartment syndrome is a painful and potentially serious condition caused by bleeding or swelling within an enclosed bundle of muscles (a muscle 'compartment').
Each group of muscles in the arms and legs, together with the nearby blood vessels and nerves, is contained in an enclosed space surrounded by layers of tissue called fascia.
The tough fascia keep the tissues in place and do not easily stretch or expand, so the pressure inside the compartment can easily increase if bleeding or swelling occurs.
The symptoms depend on whether you have acute compartment syndrome – which happens suddenly, after injury – or chronic compartment syndrome, which comes on gradually.
Acute compartment syndrome causes intense pain, especially when the affected muscle is stretched.
You may also have a tingling or burning feeling in the skin, and the muscle may feel tight.
It usually happens after a fracture or a crush injury. It is a medical emergency because the high pressure inside the compartment can potentially cause permanent muscle and nerve damage.
Compartment syndrome can also happen after a broken arm has been put into a plaster cast while the swelling is still happening, and the cast becomes the 'compartment'.
Acute compartment syndrome will be diagnosed and treated by hospital doctors, usually when you are in the hospital emergency department after an accident.
Chronic compartment syndrome causes cramping pain during exercise, mostly in the leg, that eases when the activity is stopped.
You may also have difficulty moving the foot and visible muscle bulging.
It is much less serious than acute compartment syndrome. It comes on gradually, usually after a long period of repetitive-motion exercise, such as running or cycling.
Chronic compartment syndrome will probably be diagnosed by your doctor – a diagnosis is made when other causes of muscle pain, such as tendonitis, have been ruled out.
The above symptoms happen because the swelling or bleeding increases the pressure inside the compartment.
When this pressure exceeds the pressure inside the veins, blood cannot flow properly. Oxygen and nutrients cannot get to the muscles and nerves, leading to tissue damage.
If you go on to develop numbness or paralysis, it usually means there is permanent tissue damage.
Compartment syndrome usually occurs in the legs, feet, arms or hands, but it can occur wherever there is an enclosed compartment inside the body. The abdomen (tummy) and buttocks are less commonly affected.
When the abdomen is affected, this may cause kidney failure or heart problems. If it happens in the buttocks it can result in damage to the sciatic nerve (which runs down your lower back and legs) and disability.
Acute compartment syndrome must be treated in hospital using a surgical procedure called an emergency fasciotoimy.
The doctor will make an incision to cut open your skin and fascia surrounding the muscles, to immediately relieve the pressure inside the muscle compartment and prevent permanent tissue damage. The wound will be closed 48-72 hours later.
Chronic compartment syndrome is usually not dangerous and can sometimes just be relieved by stopping the exercise and choosing low-impact activities instead.
Physiotherapy, shoe inserts and anti-inflammatory medicines may help – speak to your doctor about this.
Surgery (see above) will only be considered if your symptoms persist despite the above measures – in which case you will go on a waiting list, as chronic compartment syndrome is not a medical emergency.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.