Systemic Immune Presentations of Coxiella burnetii Infection (Q Fever)

Objectives: Q fever is a worldwide zoonosis caused by Coxiella burnetii. Its presentation can be atypical, delaying and complicating the diagnosis. We report 7 cases of Q fever mimicking vasculitis, systemic inflammatory disease, or auto-immune disorder. Methods: Seven cases of Q fever diagnosed between 1995 and 2007 in Nantes University Hospital (France) are described. They occurred in a nonendemic region and were selected on the basis of initial clinical presentation suggesting systemic immune disease. C. burnetii was detected using indirect immunofluorescence serology. Results: Q fever was acute in 4 of the 7 patients and chronic in 3. None had endocarditis. The initial presentations suggested Crohn's disease, Goodpasture's syndrome, polymyalgia rheumatica, adult-onset Still's disease, polyarteritis nodosa, giant-cell arteritis, and essential type II cryoglobulinemia. Two patients had antiphospholipid antibodies, 1 had transient IgG kappa monoclonal gammopathy, and 1 had polyclonal T CD8+ large granular lymphocyte expansion. Conclusion: Clinicians must be aware of the potential diagnosis of Q fever, and C. burnetii serology is a helpful diagnostic tool in the investigation of fever of unknown origin with atypical systemic symptoms suggesting vasculitis or inflammatory disease. (C) 2010 Elsevier Inc. All rights reserved. Semin Arthritis Rheum 39:405-409