Which symptom is most characteristic of compartment syndrome?

• A. Pain out of proportion to exam and worsened by passive stretch
• B. Numbness alone without pain
• C. Fever and leukocytosis
• D. Muscle wasting without pain

Answer: (A)

Compartment syndrome involves a rise in pressure within a closed muscle compartment that reduces blood flow and causes tissue ischemia. The most characteristic early sign is severe pain that is out of proportion to what the exam suggests, and this pain typically gets worse with passive stretching of the involved muscles. Stretching the muscle increases intracompartmental pressure and worsens ischemia, so the pain response to passive movement is a key clue.

Numbness or tingling can occur, but it usually appears later as nerves suffer from ischemia and is not as reliably specific. Fever and leukocytosis point more toward infection or systemic inflammation rather than acute compartment syndrome. Muscle wasting without pain would be a late and nonspecific finding, not the hallmark of the acute process.

Because the symptom described signals acute ischemia from elevated compartment pressure, recognizing it quickly is critical, as urgent relief of pressure (often with fasciotomy) is needed to prevent irreversible damage.