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Soft‐tissue gangrene secondary to mixed cryoglobulinemia

Copyright © 2008 Society of Hospital Medicine

A 61‐year‐old Hispanic male with chronic hepatitis C presented with a 4‐week history of a nonpruritic skin rash involving his lower extremities, hands, arms, and right ear. He also reported purple discoloration of his right foot, along with pain in the extremity that worsened with ambulation. Physical examination revealed diffuse purpura of both arms and legs (Figure 1). The right foot was cold to the touch and purple to black in color (Figure 2). There were multiple skin ulcers of various sizes covering the anterior aspect of his legs bilaterally. Pedal pulses were 2/4. Laboratory evaluation revealed positive cryoglobulins with low C4 and CH50 concentrations of 3 mg/dL (10‐40) and 2 units/mL (60‐144), respectively. Other immunological studies were negative. Lower extremity arterial Doppler studies were normal.

Figure 1

Left‐foot purpura.

Figure 2

Right‐foot gangrene.

His clinical and laboratory findings were attributed to mixed cryoglobulinemia, and treatment, consisting of daily intravenous methylprednisolone, a single dose of intravenous cyclophosphamide, and plasmapheresis, was initiated. Despite these interventions, 5 days later, he developed severe burning pain in the right extremity with worsening discoloration and a line of demarcation at the level of his proximal midfoot. Eventually, right below the knee, amputation was performed, and histopathological examination showed soft‐tissue gangrene with avascular necrosis of the bone (Figure 3). The patient subsequently had an uneventful course. Plasmapheresis and oral prednisone were continued.

Figure 3

Avascular necrosis of the bone.

Cryoglobulinemia is a small‐ to medium‐vessel vasculitis due to cryoglobulin‐containing immune complexes. There are 3 types, with the classification based on an immunological analysis of the cryoglobulin composition. Hepatitis C virus infection is closely associated with type II mixed cryoglobulinemia. Cutaneous manifestations are the most common, consisting of palpable purpura, urticaria, postinflammatory hyperpigmentation, acrocyanosis, and skin ulcers. A serum cryoglobulin elevation is diagnostic and is usually accompanied by hypocomplementemia.

Treatment of the underlying disease is essential. However, aggressive therapy with plasmapheresis and immunosuppressive medications is warranted in severe cases involving limb‐ or organ‐threatening vasculitis.

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