Compartment syndrome: a case-based approach

The presentation

Imagine someone who has broken a bone in the lower leg or forearm, or suffered a crush or a tight plaster cast. Over the next hours the limb becomes intensely painful — far more than the injury seems to warrant — and the pain does not settle with rest or the usual painkillers. A classic clue is severe pain when the fingers or toes are gently stretched. The limb may feel tight, tense and swollen, and later can become numb, tingly or weak, and pale or cold. Compartment syndrome most often follows fractures, crush injuries, tight bandages or casts, but it can also follow surgery or reperfusion after a blocked artery is reopened. Escalating pain out of proportion to the injury should always be taken seriously.

Why the pressure is dangerous

Muscles are wrapped in tough sheets of tissue that divide the limb into sealed compartments with little room to expand. When bleeding or swelling raises the pressure inside a compartment, that space cannot stretch, so the pressure climbs. Once it rises high enough, it squeezes the small blood vessels and chokes off the blood flow feeding the muscles and nerves inside. Starved of oxygen, muscle and nerve tissue begin to die within hours, and this damage can be permanent even though the main pulses in the limb may still be present. Dying muscle can also release harmful substances into the blood that damage the kidneys. This is why compartment syndrome is a race against time rather than something to watch and wait on.

When to seek urgent help

Acute compartment syndrome is a surgical emergency — call 999 or go straight to the emergency department if you suspect it. Warning signs after an injury, cast or operation include pain that is severe and getting worse rather than better, pain far greater than expected, pain on gently stretching the fingers or toes, and a limb that feels tight, tense or swollen. Later signs include numbness, tingling, weakness, or a pale, cold limb — but do not wait for these, as by then damage may already be done. If you are in a plaster cast and the limb becomes agonising, do not simply take more painkillers; seek urgent help, as the cast may need splitting. Waiting hours to see if it settles can cost the limb, so raise the alarm early.

What happens in hospital

The team assess the limb urgently and remove anything that could be adding pressure, such as splitting or loosening a tight cast or bandage and lying the limb level with the heart. They give strong pain relief and fluids and check for kidney strain. If compartment syndrome is confirmed or strongly suspected, the treatment is an emergency operation called a fasciotomy, in which a surgeon cuts open the tight tissue sheets to release the pressure and let the swollen muscle expand, restoring blood flow. The wounds are usually left open at first and closed later, sometimes needing a skin graft. Doctors may measure the pressure inside the compartment to help decide, but in a clear-cut case surgery is not delayed for tests. Speed is everything in protecting the muscle and nerves.

Recovery and the safe pathway

Recovery depends heavily on how quickly the pressure was released. Treated early, many people regain good function, though the wounds and any muscle damage take time to heal and physiotherapy is often needed. If treatment is delayed, there can be lasting weakness, stiffness, altered sensation or, in severe cases, permanent damage. Because the condition can develop after an injury has been treated, people sent home in a cast are usually warned about the danger signs and told to return at once if pain becomes severe or the limb goes numb. The practical message is simple: pain out of all proportion to an injury, especially in a plastered or recently injured limb, is an emergency — call 999 or go to A&E without delay.