A 40-year-old female nurse was admitted to the hospital because of fever to 39.4°C (103°F). Despite a thorough workup in the hospital for over 3 weeks, no etiology has been found, and she continues to have temperature spikes greater than 38.9°C (102°F). Which of the following statements about diagnosis is correct?A) Chronic infection, malignancy, and collagen vascular disease are the most common explanations for this presentation
Patients may develop fever as a result of infectious or noninfectious diseases. The term fever of unknown origin (FUO) is applied when significant fever (usually defined as > 38.3°C or > 101°F) persists without a known cause after an adequate evaluation. Several studies have found the leading causes of FUO to include infections, malignancies, collagen vascular diseases, and granulomatous diseases. As the ability to more rapidly diagnose some of these diseases increases, their likelihood of causing undiagnosed persistent fever lessens. Infections such as intra-abdominal abscesses, tuberculosis, hepatobiliary disease, endocarditis (especially if the patient had previously taken antibiotics), and osteomyelitis may cause FUO. In immunocompromised patients, such as those infected with HIV, a number of opportunistic infections or lymphomas may cause fever and escape early diagnosis. Self-limited infections such as influenza should not cause fever that persists for many weeks. Neoplastic diseases such as lymphomas and some solid tumors (eg, hypernephroma and primary or metastatic disease of the liver) are associated with FUO. A number of collagen vascular diseases may cause FUO. Since conditions such as systemic lupus erythematosus are more easily diagnosed today, they are less frequent causes of this syndrome. Adult Still disease, however, is often difficult to diagnose. Other causes of FUO include granulomatous diseases (ie, giant cell arteritis, regional enteritis, sarcoidosis, and granulomatous hepatitis), drug fever, and peripheral pulmonary emboli. Factitious fever is most common among young adults employed in health-related positions. A prior psychiatric history or multiple hospitalizations at other institutions may be difficult to obtain, since these patients often skirt around the truth. Such patients may induce infections by self-injection of nonsterile material, with resultant multiple abscesses or polymicrobial infections. Alternatively, some patients may manipulate their thermometers. In these cases, a discrepancy between temperature and pulse or between oral temperature and witnessed rectal temperature will be observed.