Three subtypes of cryoglobulins are characterized, according to immunoglobulin type:
- Type I cryoglobulins (10%-15% of cases) are monoclonal cryoglobulins typically made of IgM and sometimes IgA or IgG. Type I cryoglobulinemia is associated with B-cell lymphoproliferative disorders (most commonly multiple myeloma and Waldenström macroglobulinemia). The monoclonal cryoglobulins precipitate at lower temperatures, leading to vascular occlusion and ischemic damage of tissues. Typically, acral areas are affected.
- Type II (50%-60% of cases) and type III (30%-40% of cases) cryoglobulins are mixed cryoglobulins that consist of a rheumatoid factor (IgM) complexed with either a monoclonal IgG (type II) or a polyclonal IgG or non-immunoglobulin serum component (type III). Mixed cryoglobulinemias are caused by chronic B-cell activation that leads to immune complex formation (IgM / IgG) and deposition in small and medium vessels, resulting in vasculitis. The majority of cases (80%-90%) are associated with chronic hepatitis C virus (HCV) infection. Other infections (hepatitis B virus, HIV, Epstein-Barr virus, cytomegalovirus, leprosy, and, more rarely, other viral, bacterial, and parasitic infections) and rheumatological conditions (systemic lupus erythematosus, rheumatoid arthritis, and Sjögren syndrome) have also been associated. Due to chronic B-cell stimulation, cryoglobulinemia is associated with the development of malignant B-cell lymphoproliferative disease, in particular non-Hodgkin lymphoma (35 times higher risk than the general population). When no underlying cause is identified, it is designated as essential mixed cryoglobulinemia.
D89.1 – Cryoglobulinemia
30911005 – Cryoglobulinemia
- Cryofibrinogenemia – Cold precipitable proteins are found in plasma but not in serum.
- Cholesterol emboli – Associated with a recent history of vascular intervention or thrombolytic therapy. Most often affects toes and feet.
- Disseminated intravascular coagulation (DIC) – Presents as diffuse cyanotic lesions, palpable purpura, bullae, or petechiae often associated with bacterial sepsis. Also associated with thrombosis and bleeding.
- Coumadin (warfarin) necrosis – Typically occurs 3-5 days after warfarin initiation.
- Purpura fulminans – Associated with DIC and bacterial sepsis.
- Cocaine levamisole toxicity – Look for purpura on the helix of the ear.
- Raynaud disease – Presents as reversible white or blue discoloration of distal digits triggered by cold exposure or stress.
- Waldenström macroglobulinemia – Associated with cryoglobulinemia. May also cause amyloidosis and cutaneous macroglobulinosis (skin-colored to red papules).
- Livedoid vasculopathy – Presents as ulcers on the lower extremities that resolve as stellate scars. Associated with autoimmune connective tissue disease and coagulopathy.
- Chilblains (perniosis) – Look for symmetric, erythematous papules in an acral distribution 12-24 hours after cold exposure. Most common in children and middle-aged women.
- Heparin-induced thrombocytopenia – Typically occurs 5-14 days after starting heparin. Thrombocytopenia is indicative.
- Thrombotic thrombocytopenic purpura / hemolytic uremic syndrome – Presents with microangiopathic anemia and thrombocytopenia. Schistocytes may be seen on peripheral blood smear.
- Homocysteinemia – Look for developmental delay, ectopia lentis, and marfanoid body habitus.
- Thrombophilia (protein C and protein S deficiencies, antithrombin III deficiency, prothrombin G202120A mutation, factor V Leiden deficiency) – Characterized by recurrent venous thromboembolism.
- Sickle cell disease – Look for anemia on CBC. Hemoglobin electrophoresis and sickling test are diagnostic.