Fever, dyspnea, and hepatitis in an Iraq veteran
PREVENTING LONG-TERM SEQUELAE OF CHRONIC Q FEVER
5. At this point, what is the next step in the management of this patient?
- No further follow-up is indicated
- Transthoracic echocardiography (TTE)
- Repeat Q fever serologic testing in 3 to 6 months
- Whole-blood PCR testing and transesophageal echocardiography (TEE)
Long-term follow-up of patients with Q fever has been advocated to monitor for the development of chronic Q fever, but recent studies question the previously devised algorithms.50
The data the algorithms were based on suggested that preexisting valvular heart disease could be associated with up to a 39% risk of endocarditis, and a two-step approach was devised to prevent and identify early chronic infection.51,52 Patients with Q fever would undergo TTE at baseline, and if the findings were abnormal (including mild regurgitation), then 12 months of prophylactic treatment with hydroxychloroquine and doxycycline was recommended. If TTE was normal, serial serologic testing every 3 months was recommended. If the anti-phase I IgG titer was greater than 1:800 at any point, TEE and a whole-blood PCR assay were recommended to evaluate for endocarditis.51
These recommendations were based on data from the French National Reference Center and had not been prospectively evaluated. The 2007–2008 Dutch outbreak provided a large cohort of Q fever cases. After initial screening with TTE and serologic follow-up, 59% of patients were noted to have mild valvular abnormalities, and many had phase I IgG levels greater than 1:800 during follow-up despite being clinically free of disease. The Dutch subsequently stopped screening with TTE as part of routine follow-up and elected to follow patients clinically.
Similar findings have been noted from case follow-up in France and Taiwan, also supporting using serologic cutoffs alone in determining the need for evaluation (with TEE) or treatment of chronic disease.53,54 The usefulness of serologic testing every 3 months has also been questioned, and some have advocated extending the interval, especially since less emphasis is being placed on the results in favor of more practical clinical follow-up.39
One such clinical approach at follow-up is presented in Figure 1. TTE should be reserved for patients with known valvular disease or a clear murmur. Those with underlying valvular disease and acute Q fever should be managed on an individual basis by a specialist in infectious disease, and antibiotic prophylaxis should be considered. Patients without underlying disease should have regular follow-up examinations and serologic testing every 6 months, and clinical symptoms should guide further testing (eg, with TEE and PCR testing) for chronic disease.
In this patient, phase I and II antibody titers were notably elevated (in TABLE 2, phase I titers > 1:800 and 1:1600 cutoffs). Such high titers have been common in military cases from Iraq and Afghanistan, and to date no cases of endocarditis have been diagnosed despite close follow-up. Most cases in military personnel are in relatively young patients who lack risk factors for endocarditis. Based on emerging data from large overseas outbreaks and the potential toxicity of intensive preemptive dual-antimicrobial therapy, an approach of close follow-up was taken.
PRIMARY PREVENTION OF Q FEVER
Prevention of Q fever remains a challenge, as the organism is highly persistent in the environment. An effective licensed vaccine exists in Australia under the brand name Q-Vax, but no approved vaccine is currently available in the United States.55
THE PATIENT’S COURSE
The patient returned for follow-up about 1 year after his first presentation. He noted some ongoing fatigue but attributed this to his course work, and he said he otherwise felt well. He exercises regularly, with no shortness of breath, fevers, chills, or weight loss. He continued to have elevated Q fever titers. Because he had no symptoms, no heart murmur, and normal inflammatory markers, he had no further workup and continued to be followed with serial serologic testing and examinations.
