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Compartment syndrome — limb and abdomen
Compartment syndrome is a rise in pressure within a closed compartment until tissue perfusion stops; the diagnosis is clinical — pain out of proportion to the injury and pain on passive stretch — and the treatment is urgent fasciotomy, because a normal pulse does not exclude it.
Why it matters in the exam
The classic case is a patient with a tibial fracture (the most common cause), a crush injury, a tight cast, a circumferential burn or a limb after revascularisation, who complains of steadily worsening pain that does not respond to opioids, with severe pain when the muscles are gently stretched — the most important early sign. Paraesthesia, weakness and an absent pulse are late signs, and when they appear damage to muscle and nerve has already occurred. In a sedated or unconscious patient compartment pressure is measured.
Candidates are also asked about pressure thresholds: a compartment pressure above 30 mmHg, or a difference of less than 30 between the diastolic blood pressure and the compartment pressure, supports fasciotomy. The first step is to remove a tight cast and dressings and to keep the limb at heart level (not above it); if there is no immediate improvement — fasciotomy of all compartments, in the leg with two incisions for four compartments. After fasciotomy rhabdomyolysis (high CK, myoglobinuria, renal failure) and hyperkalaemia are expected. In the abdomen, an intra-abdominal pressure of more than 20 mmHg together with new organ dysfunction is abdominal compartment syndrome, measured through the bladder and treated by decompressive laparotomy.
Key points
- The early signs: disproportionate pain and pain on passive stretching.
- A normal pulse does not exclude it; the diagnosis is clinical.
- Pressure above 30 or diastolic difference below 30 — fasciotomy.
- First remove cast and dressings, limb at heart level; then fasciotomy.
- Abdomen: pressure above 20 with organ failure — decompressive laparotomy.
Summary table
| Topic | Finding | Action |
|---|---|---|
| Limb causes | Tibial fracture, crush, tight cast, circumferential burn, revascularisation | Tibial fracture — the most common cause |
| Early signs | Pain greater than the injury explains, pain when the muscles are passively stretched | Clinical diagnosis |
| Late signs | Paraesthesia, weakness, absent pulse | A normal pulse does not exclude it |
| Pressure measurement | Above 30 mmHg, or diastolic difference below 30 | In a sedated or unconscious patient |
| Treatment | Remove cast and dressings, limb at heart level; fasciotomy of all compartments | In the leg — two incisions for four compartments |
| Abdominal compartment syndrome | Intra-abdominal pressure of more than 20 mmHg together with new organ dysfunction | Measured through the bladder; decompressive laparotomy |
Example question from the licensing exam (IMLE)
A 30-year-old male is injured in his abdomen during a fight. On admission to the ER he complains of upper abdominal pain. Blood pressure is 110/72, pulse 90/min, room air saturation 96%. Abdominal CT demonstrates a 3 cm laceration at the right liver lobe with mild amount of free fluid (blood). Which of the following is the most appropriate treatment?
- A. Laparotomy with packing below and above the liver
- B. Angiography with right liver embolization
- C. Laparoscopy with right hepatic artery ablation
- D. Observation in the ICU
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Sources
- British Orthopaedic Association Standard for Trauma (BOAST): Diagnosis and management of compartment syndrome of the limbs, 2016 — Diagnosis, pressure thresholds and fasciotomy
- WSACS — The Abdominal Compartment Society consensus definitions and clinical practice guidelines, 2013 — Intra-abdominal hypertension and abdominal compartment syndrome
- Sabiston Textbook of Surgery, 21st edition (2022) — Management of Acute Trauma
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.