Bilateral forefoot ischemia as a premonitory symptom of mixed cryoglobulinemia.

Cryoglobulins are composed of cold-sensitive immunoglobulins that precipitate upon cooling. As the cutaneous vasculature of the extremities is commonly exposed to colder temperatures than the body core, this precipitation often occurs in cutaneous, or even digital vessels. Hyperviscosity from the precipitated proteins can incite local thrombosis in otherwise normal vessels, which is manifested clinically as ischemic ulceration. In previously injured vessels, as seen with atherosclerotic occlusive disease, cryoglobulin precipitation can lead to thrombosis of larger vessels, with the consequence being more severe ischemic necrosis. A case of bilateral forefoot ischemia is presented where the precipitating cause of the gangrenous changes appears to be the development of a mixed cryoglobulinemia and a B-cell lymphoma. Tibial angioplasty, plasmaphoresis, and chemotherapy directed at the B-cell lymphoma allowed limb salvage with bilateral transmetatarsal amputations.