What symptom is associated with severe ischemia in the lower extremity?

The symptom associated with severe ischemia in the lower extremity is observed when there is reduced blood flow to the tissues. In such cases, pallor when the limb is raised indicates that the blood supply is not adequate. This phenomenon occurs because when a person elevates a limb, gravity exacerbates the inability of the already compromised vasculature to adequately perfuse the area, resulting in a pale appearance of the skin. This is particularly indicative of severe ischemia, as it reflects a significant reduction in arterial blood flow.

In contrast, muscle cramps typically occur with intermittent claudication due to less severe ischemic symptoms rather than profound ischemia. Cold extremities can result from various conditions and may not specifically indicate severe ischemia. Bright red skin color, often seen in cases of reactive hyperemia or inflammation, may also be misleading in the context of ischemia and does not typically correlate with severe blood supply compromise.