Localizing chronic Q fever: a challenging query.

Abstract

BACKGROUND:

Chronic Q fever usually presents as endocarditis or endovascular infection. We investigated whether 18F-FDG PET/CT and echocardiography were able to detect the localization of infection. Also, the utility of the modified Duke criteria was assessed.

METHODS:

Fifty-two patients, who had an IgG titre of  ≥ 1024 against C. burnetii phase I ≥ 3 months after primary infection or a positive PCR ≥ 1 month after primary infection, were retrospectively included. Data on serology, the results of all imaging studies, possible risk factors for developing proven chronic Q fever and clinical outcome were recorded.

RESULTS:

According to the Dutch consensus on Q fever diagnostics, 18 patients had proven chronic Q fever, 14 probable chronic Q fever, and 20 possible chronic Q fever. Of the patients with proven chronic Q fever, 22% were diagnosed with endocarditis, 17% with an infected vascular prosthesis, and 39% with a mycotic aneurysm. 56% of patients with proven chronic Q fever did not recall an episode of acute Q fever. Ten out of 13 18F-FDG PET/CT-scans in patients with proven chronic Q fever localized the infection. TTE and TEE were helpful in only 6% and 50% of patients, respectively.

CONCLUSIONS:

If chronic Q fever is diagnosed, 18F-FDG PET/CT is a helpful imaging technique for localization of vascular infections due to chronic Q fever. Patients with proven chronic Q fever were diagnosed significantly more often with mycotic aneurysms than in previous case series. Definite endocarditis due to chronic Q fever was less frequently diagnosed in the current study. Chronic Q fever often occurs in patients without a known episode of acute Q fever, so clinical suspicion should remain high, especially in endemic regions.

• Authors: Dennis G Barten, Corine E Delsing, Stephan P Keijmel, Tom Sprong, Janneke Timmermans, Wim J G Oyen, Marrigje H Nabuurs-Franssen, Chantal P Bleeker-Rovers
• Journal: BMC infectious diseases (BMC Infect Dis) Vol. 13 Pg. 413 (Sep 03 2013) ISSN: 1471-2334 [Electronic] England
• PMID: 24004470 (Publication Type: Journal Article)

Chemical References

• Antibodies, Bacterial

Topics

• Adult
• Aged
• Aged, 80 and over
• Antibodies, Bacterial (immunology)
• Coxiella burnetii (immunology, isolation & purification)
• Echocardiography
• Endocarditis (diagnosis, diagnostic imaging, immunology, microbiology)
• Endocarditis, Bacterial
• Female
• Humans
• Male
• Middle Aged
• Positron-Emission Tomography
• Q Fever (diagnosis, diagnostic imaging, immunology, microbiology)
• Retrospective Studies