What is the most reliable sign of compartment syndrome?

• A. Pallor
• B. Pain out of proportion
• C. Paresthesias
• D. Pulselessness

Answer: (B)

Pain out of proportion to exam, especially pain that increases with passive stretch, is the most reliable sign of compartment syndrome. This reflects ongoing ischemia within the muscle compartment; the tissue becomes exquisitely sensitive, so even normal-appearing findings can be outweighed by intense, deep pain that worsens when you passively stretch the involved muscles. Pulses can remain present despite elevated pressure, and are therefore not a dependable indicator. Paresthesias and pallor can occur but are later or less sensitive signs. If there’s any doubt, measure the intracompartmental pressure or treat urgently based on the high clinical suspicion to prevent irreversible nerve and muscle damage.