ABSTRACT
A 47-year-old man has hepatitis C, joint pains, weakness, polyneuropathy, and the skin lesions shown here. What is the most likely cause?
a. Churg-Strauss vasculitis b. Buerger’s disease c. Porphyria cutanea tarda d. Mixed cryoglobulinemic vasculitis e. Polyarteritis nodosa
• Cryoglobulins are immunoglobulins that reversibly precipitate in cold temperatures and are classified by their immunoelectrophoresis and immunofixation patterns into types I, II, and III, depending on monoclonal and polyclonal distributions
• More than 70% of patients have one or more of the following: palpable purpura, arthralgia or arthritis, and weakness. The combination of all three major symptoms, known as Meltzer’s triad, is found in less than 40% of patients
• Acral ulcerations and necrosis may occur where peripheral temperature is less than core temperature
• Polyneuropathy occurs in 40% to 70% of patients
• The vast majority of cases previously known as “essential mixed cryoglobulinemia” are now thought to be due to hepatitis C virus (HCV). Anti-HCV antibodies and HCV RNA are present in 85% to 90% of patients
• Mixed cryoglobulinemia may be present in more than 50% of HCV-infected patients. However, cryoglobulinemic
vasculitis develops in only a minority of these patients
• If HCV antibodies or HCV RNA is absent, look for other associated disorders, such as infective endocarditis, lymphoma, myeloproliferative disorders, autoimmune diseases, and connective tissue disorders
• For non-HCV-related cases, treat the underlying disorder
• Sample collection is important. Venous blood must be kept at 37°C for 2 hours before serum is removed and placed at 4°C for up to 4 days to allow cryoproteins to precipitate
