A client with a long leg cast reports severe pain. What symptom indicates possible compartment syndrome?

The presence of pallor in the exposed portion of the limb is a key symptom that indicates possible compartment syndrome. Compartment syndrome occurs when there is increased pressure within a muscle compartment that can lead to insufficient blood supply and subsequent tissue damage. Pallor suggests that blood flow is compromised, leading to a lack of oxygen and nutrients reaching the tissues.

In the context of compartment syndrome, pallor indicates that the affected limb is being deprived of adequate circulation, which can lead to serious complications if not addressed promptly. Other signs and symptoms of compartment syndrome may include extreme pain, paresthesia, and weakness in the affected area.

The other symptoms listed, such as swelling above the cast, inability to move the foot, and coolness of the skin, can also be associated with complications but do not specifically indicate the diminished blood flow and urgency of compartment syndrome in the same way pallor does.