A 50-year-old diabetic is treated with a below-knee cast for a distal tibia fracture. Four days later she reports burning pain and paraesthesia in the sole. Cast is removed and compartment pressures are 45 mmHg with an arterial pressure of 90 mmHg diastolic. The delta pressure (diastolic BP minus compartment pressure) is 45 mmHg. What is the correct next step?

• A Observe for 6 hours and re-measure
• B Elevate limb and administer IV mannitol
• C Immediate fasciotomy ✓
• D Apply a bivalved cast

Explanation

Acute compartment syndrome is confirmed when the delta pressure (ΔP = diastolic BP − compartment pressure) falls to ≤30 mmHg; at ΔP = 45 mmHg here it is borderline, but combined with the clinical picture of burning pain and paraesthesia (early nerve ischaemia), immediate fasciotomy is indicated. Waiting, elevation, or mannitol are inappropriate once nerve symptoms indicate ischaemia is occurring. Bivalved casting partially reduces pressure but is insufficient when compartment syndrome is clinically established.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.