Cryoglobulinemia
Cryoglobulinemia is a medical term used to describe a disease related to chronic hepatitis C virus (HCV) infection. In this disease process, immune globulins (antibody-type proteins) are produced and directed against the hepatitis C virus. There are two specific types of antibodies--IgG and IgM--that directly interact with one another and bind with HCV, forming an unstable complex that falls out into the bloodstream. This special type of protein precipitate is most commonly detected as a positive rheumatoid factor; however, it is important to note that hepatitis C does not cause rheumatoid arthritis.
Cryoglobulins can be found in up to 40% of patients with hepatitis C and may explain symptoms of muscle and joint aches and pains. About 2% of patients actually develop tissue damage that can be found on physical examination or laboratory analysis. A red or purple raised rash, called leukocytoclastic vasculitis or palpable purpura, indicates tissue damage that may result in damage to the kidneys, eyes, brain and heart.
Patients with cryoglobulinemia may also develop intestinal disturbances, sinus stuffiness and a feeling that they are unable to think clearly. Some patients have reported painful feelings in their extremities and cryoglobulinemia has been associated with a neuropathy (a disease of the peripheral nerves causing nerve damage accompanied by numbness and/or pain). In very rare cases, after a prolonged period of cryoglobulinemia, some patients have developed a special type of lymph node tumor called B-cell non-Hodgkins lymphoma.
Because cryoglobulinemia may cause kidney insufficiency, protein loss and eventually kidney failure and dialysis, kidney transplantation may be required. Patients who have hepatitis C should undergo assessment of their creatinine (a blood test for kidney function) and a urinalysis to see if they are leaking protein into their urine. If a red/purple rash of the lower extremities is seen, a kidney assessment should take place.
The standard treatment for cryoglobulinemia is interferon therapy, a treatment that may be required for long periods of time at intermittent or daily dosing. Patients with hepatitis C cryoglobulinemia appear to have a similar cure rate from interferon as those without cryoglobulinemia. Prednisone and cyclophosimide, medications that have historically been used for cryoglobulinemia should be discontinued as soon as possible, since they typically cause a marked increase in the level of virus circulating in the bloodstream.
If the patient has serious disease, he or she may also need to undergo plasmapheresis, a filtering process in which a catheter is placed into a central vein and protein precipitate is removed from the blood by a machine. Plasmapharesis is only necessary in more severe forms of cryoglobulinemia disease.