How should I interpret a positive result for serum cryoglobulins?

Cryoglobulins (CGs) are immunoglobulins that precipitate in the blood under cold conditions (<37◦ C) and redissolve upon warming1.  The term “cryoglobulinemia” is commonly used to describe patients with a systemic inflammatory syndrome that is often associated with small-to-medium vessel vasculitis due to cryoglobulin-containing immune complexes. Although some patients with cryoglobulinemia may be asymptomatic, most present with a range of diseases characterized by fatigue, arthralgia, skin rashes or necrosis, purpura, neuropathy, bowel wall ischemia and/or glomerulonephritis and kidney failure.

Wintrobe and Buell are credited for first describing cryglobulinemia in 1933 when assessing a patient who ultimately was found to have multiple myeloma2. Since then the spectrum of diseases associated with CG has expanded to also include seemingly disparate conditions such as hepatitis C, autoimmune disorders and monoclonal gammopathy of undetermined significance (MGUS).  A commonly cited classification scheme for CG is shown (Table)3.   It should be emphasized that some CGs may not fit neatly into this scheme.

In our patient, the positive CG serum test should be interpreted in the clinical context in which it was obtained while searching for risk factors as well as signs and symptoms that may be associated with cryoglobulinemia.

 

Table. Classification of cryoglobulinemia

Category Description Examples
Type I Isolated monoclonal immunoglobulin, either IgM or IgG (less commonly IgA or free immunoglobulin light chains Multiple myeloma, Waldenström’s macroglobulinemia, monoclonal gammopathy of undetermined significance (MGUS)
Type II Mixture of monoclonal IgM and polyclonal IgG Hepatitis C, HIV, other viral infections
Type III Polyclonal mixture IgM and IgG Autoimmune disorders, hepatitis C

References

  1. Takada S, Shimizu T, Hadano Y, et al. Cryoglobulinemia (review). Mol Med Rep 2012;6:3-8
  2. Wintrobe MM, Buell MV. Hyperproteinemia associated with multiple myeloma. Bull Johns Hopkins Hosp 52: 156-165, 1933
  3. Brouet JC, Clauvel JP, Danon F, et al. Biological and clinical significance of cryoglobulins. Am J Med 1974; 57:775-88.

 

Contributed by Kirstin Scott, Medical Student, Harvard Medical School

How should I interpret a positive result for serum cryoglobulins?

What complication of Behçet’s syndrome carries the highest mortality?

Behçet’s syndrome may cause life-threatening hemoptysis due to pulmonary artery aneurysms.1 In a cohort of 387  patients with such syndrome followed for over 20 years, massive hemoptysis was the leading cause of death, found most commonly early in the course of the disease among young men.2 Conversely, the one-year mortality of pulmonary artery aneurysm in Behçet’s may be greater than 50%.1 Behçet’s syndrome is the only vasculitic disease with a proclivity for large pulmonary vessels, while its less frequent pulmonary manifestations, such as fibrosis and thrombosis, overlap with other small vessel vasculitides.3 Beware that the initial presentation of pulmonary aneurysm rupture may be confused with that of pulmonary embolism, with potential for fatal complications from anticoagulation.1 CT angiogram should help in distinguishing the two conditions.

 

References 

  1. Uzun O, Akpolat T, Erkan L. Pulmonary vasculitis in behcet disease: a cumulative analysis. Chest. 2005;127(6):2243-2253.
  2. Kural-Seyahi E, Fresko I, Seyahi N, et al. The long-term mortality and morbidity of Behçet syndrome: a 2-decade outcome survey of 387 patients followed at a dedicated center. Medicine (Baltimore). 2003;82(1):60-76.
  3. Hamuryudan V, Er T, Seyahi E, et al. Pulmonary artery aneurysms in Behçet syndrome. Am J Med. 2004;117(11):867-870.

 

Contributed by Sam Slavin, Harvard Medical Student

What complication of Behçet’s syndrome carries the highest mortality?