Cough, chest pain, and inspiratory rales develop after four or five days of fever. Chest radiographs show focal areas of pneumonitis, as observed in various types of primary atypical pneumonia. Radiologic changes may be more marked than symptoms or physical findings. Pulmonary involvement occurs in about 50 percent of patients, but the incidence of this complication may vary with geographic location. The illness usually lasts for one to two weeks and follows a benign, self-limited course.
Complications are rare.
Granulomatous hepatitis with hepatosplenomegaly, jaundice, and abnormal liver function tests can be the major manifestations of Q fever, particularly in patients in whom the febrile course continues for at least three or four weeks. In fact, hepatitis may be more common than pneumonia among patients with acute Q fever in certain parts of the world. Less often, bone and joint lesions have been associated with Q fever. In approximately two to 11 percent of infected individuals, a chronic form of Q fever will develop insidiously a few months to as long as 20 years after the acute illness. Risk factors for chronic Q fever include underlying valvular heart disease and immunocompromise.