From the Guidelines
Q fever is an uncommon reason for fever, particularly in individuals who have been exposed to infected animals or contaminated environments. This condition is caused by the bacterium Coxiella burnetii, which can be transmitted through inhalation of contaminated particles or contact with infected animals 1. The diagnosis of Q fever is based on serologic testing, including the measurement of phase I and phase II IgG and IgM antibodies, and clinical evaluation to identify potential organ infection 1.
Some key points to consider in the diagnosis and management of Q fever include:
- Patients who are healthy and have no identified risk factor for chronic illness should receive a clinical and serologic evaluation approximately 6 months after diagnosis of acute infection to identify potential progression to chronic disease 1.
- Patients with cardiovascular risk factors for chronic disease should be serologically monitored and receive a physical examination at intervals of 3, 6, 12, 18, and 24 months 1.
- The treatment regimen for chronic Q fever typically consists of a combination of doxycycline and hydroxychloroquine, with the duration of treatment varying depending on the site of infection 1.
- Other uncommon causes of fever in returned travelers include Rickettsial infections, such as R. africae, R. conorii, and R. typhi, which are transmitted by ticks or fleas, and O. tsutsugamushi, which is transmitted by the bites of a mite 2.
In terms of morbidity, mortality, and quality of life, it is essential to promptly diagnose and treat Q fever and other uncommon causes of fever to prevent complications and improve patient outcomes. Early recognition and treatment of these conditions can significantly reduce the risk of chronic infection, organ damage, and mortality. Therefore, healthcare providers should consider these uncommon causes of fever in their differential diagnosis, particularly in patients with a history of exposure to infected animals or contaminated environments.
From the FDA Drug Label
Other serious and sometimes fatal events, some due to hypersensitivity, and some due to uncertain etiology, have been reported rarely in patients receiving therapy with quinolones, including ciprofloxacin. These events may be severe and generally occur following the administration of multiple doses Clinical manifestations may include one or more of the following: fever, rash, or severe dermatologic reactions (e.g., toxic epidermal necrolysis, Stevens-Johnson syndrome);
From the Research
Uncommon Reasons for Fever
- Rickettsial infections, such as anaplasmosis, ehrlichiosis, and Q fever, can cause fever 4, 5
- Q fever can present as a fever of unknown origin and can be challenging to diagnose due to its rare incidence 6
- Rickettsial diseases can be under-diagnosed causes of arthropod-borne acute febrile illness, presenting with a range of symptoms from mild self-limiting fever to fatal sepsis 5
- Typhoid and brucellosis are also prevalent diseases diagnosed among patients reporting to hospitals with undifferentiated febrile illness 4
Characteristics of Rickettsial Infections
- The prevalence of rickettsial disease was found to be 11.3% in a study of undifferentiated febrile patients 4
- Rickettsial diseases can present with respiratory symptoms, jaundice, abdominal pain, diarrhea, vesicular rash, vomiting, loss of appetite, headache, leukocytosis, and thrombocytopenia 5
- The median age of patients with rickettsial diseases was 22 years, and the median duration of fever was 3 days 5
Diagnosis and Treatment
- Serological tests, such as Weil Felix Assay, enzyme-linked immunosorbent assay, and indirect immunofluorescence assay, can be used to detect anti-rickettsial antibodies 4
- Molecular methods, such as nested PCR, can be used to identify rickettsial etiology in acute febrile illness 5
- Empiric antimicrobial therapy has not been shown to be effective in the treatment of fever of unknown origin, except in patients who are neutropenic, immunocompromised, or critically ill 7