Compartment syndrome: symptoms, causes and emergency treatment

The NHS describes compartment syndrome as an increase in pressure inside a muscle, which restricts blood flow and causes pain. The muscles of the limbs sit in closed compartments, so when pressure rises inside one there is nowhere for it to go.

The British Orthopaedic Association (BOA) explains that acute compartment syndrome of a limb causes local tissue ischaemia, a lack of blood supply, due to raised pressure within a myo-fascial compartment, and that early diagnosis and treatment is vital to avoid harm.

There are two types, which the NHS describes: acute compartment syndrome, when it starts suddenly, and chronic compartment syndrome, when symptoms come on gradually after exercise and go away when you rest. The BOA guidance covers the acute form and excludes chronic (exertional) compartment syndrome.

The NHS says you can get compartment syndrome in any muscle, but it most often affects the muscles in the lower legs. The symptoms are:

• Severe pain in a muscle, which may be worse when stretching it.

• Swelling.

• Numbness, weakness or pins and needles.

• Tightness or difficulty moving the affected body part.

The NHS says symptoms can start suddenly, such as after an injury or if a bandage or plaster cast is too tight. The NHS says to call 999 or go to A&E if you have sudden, severe pain in any part of your body, because if compartment syndrome is causing the pain you will need surgery as soon as possible.

It says not to drive yourself to A&E. Ask someone to drive you or call 999 and ask for an ambulance, and bring any medicines you take with you.

In hospital, the BOA says a key clinical finding is pain out of proportion to the associated injury and pain on passive movement of the muscles of the involved compartments. Patients with symptoms or signs should have circumferential dressings released to expose the skin and the limb elevated, with re-evaluation within 30 minutes.

The NHS says treatment depends on whether it happens suddenly or gradually.

The BOA standards say hospitals receiving musculoskeletal trauma should be able to perform intracompartmental pressure monitoring. For patients at risk, it says assessment should be hourly and documented, and inconclusive cases should be considered for pressure measurement and senior review.

The BOA says immediate surgical decompression should follow a diagnosis, involving open decompression of all involved compartments and removal of non-viable muscle. It recommends that patients who have had a fasciotomy are discussed with a plastic surgeon within 24 hours and re-explored within 72 hours or earlier if needed. Patients with delayed presentation or diagnosis have a high risk of complications with surgery.

For the gradual type, the NHS says a GP may refer you to a specialist for tests if they think you may have compartment syndrome. Tests you may have include:

• An X-ray to check whether you have broken a bone.

• MRI scans.

• Compartment pressure measurement, where a needle connected to a pressure monitoring device is inserted into the muscle before and after exercise.

The NHS says acute compartment syndrome can follow an injury or a bandage or plaster cast that is too tight. The BOA says assessment for it should be part of routine evaluation of anyone presenting with limb injuries, after extremity surgery, or after any prolonged surgical procedure that may cause reduced blood flow. The BOA guidance on supracondylar fractures of the humerus in children also lists compartment syndrome among the possible complications.

Chronic compartment syndrome comes on gradually after exercising and goes away with rest, according to the NHS. See a GP if you keep getting pain, numbness, swelling or difficulty moving a part of your body when you exercise, as a GP can help find out if the pain is caused by compartment syndrome or another condition.

Acute compartment syndrome is an emergency treated through 999, A&E and orthopaedic or trauma surgical teams on the NHS. This is not something to arrange as an appointment; sudden severe pain needs emergency care.

The gradual form is assessed by your GP and then a specialist, often sports and exercise medicine or orthopaedics, who arrange pressure testing and imaging. Private specialists can offer the same assessment and tests. Ask what the pressure measurement showed and what the options are if avoiding the activity does not help.