Systemic Immune Presentations of Coxiella burnetii Infection (Q Fever)

ObjectivesQ 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.MethodsSeven 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.ResultsQ 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.ConclusionClinicians 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.