Which sign of compartment syndrome is a late and unreliable indicator?

• A. Severe pain out of proportion to exam
• B. Paresthesias
• C. Pallor
• D. Pulselessness

Answer: (D)

Pulselessness is a late and unreliable indicator because arterial flow can remain intact while the pressure inside a muscle compartment climbs high enough to compromise perfusion. Early signs reflect evolving tissue ischemia: the most telling early clue is severe pain that’s out of proportion to exam and worsens with passive stretching, signaling muscle and nerve distress. Nerve involvement can produce paresthesias as compression progresses, often before any loss of pulses. Pallor can occur later, but pulses may still be present despite significant pressure, so relying on a diminished or absent pulse can miss evolving compartment syndrome. When suspicion is high, measuring the compartment pressures and treating promptly is essential, rather than waiting for a pulse change to guide action.