Fever of unknown origin in elderly patients.

OBJECTIVE: To describe the spectrum of diseases that may give rise to fever of unknown origin in elderly patients and to delineate the diagnostic approach in these patients. DESIGN: Subgroup analysis of a prospectively collected case series followed more than 2 years. SETTING: General Internal Medicine Service based at University hospital, Leuven, Belgium. PATIENTS: Forty-seven consecutive patients, older than 65 years, meeting the classic criteria of fever of unknown origin. MEASUREMENTS: The final diagnosis established and the clinical value of diagnostic procedures. RESULTS: Infections, tumors and multisystem diseases (encompassing rheumatic diseases, connective tissue disorders, vasculitis including temporal arteritis, polymyalgia rheumatica, and sarcoidosis) were found in 12 (25%), six (12%) and 15 patients (31%), respectively. Drug-related fever was the cause in three patients (6%), miscellaneous conditions were found in five patients (10%), and six patients (12%) remained undiagnosed. Microbiologic investigations were diagnostic in eight cases (16%), serologic tests yielded one diagnosis, immunologic investigations had a diagnostic value in four cases, standard X-rays yielded a diagnostic contribution in 10 cases, ultrasonography and computed tomography were diagnostic in 11 cases, Gallium scintigraphy had a diagnostic contribution in 17 cases, and biopsies yielded the final diagnosis in 18 cases. CONCLUSIONS: Multisystem diseases emerged as the most frequent cause of fever of unknown origin in the elderly, and temporal arteritis was the most frequent specific diagnosis. Infections, particularly tuberculosis, remain an important group. The percentage of tumors was higher in our elderly patients than in the younger ones but still clearly lower than in other recent series of FUO in adults. The number of undiagnosed cases was significantly lower in elderly patients than in younger individuals (P < or = 0.01). The investigation of elderly patients with FUO should encompass routine temporal artery biopsy and extensive search for tuberculosis if the classic tests such as blood count, chemistry, urinalysis, cultures, chest X-rays, and abdominal ultrasonography do not yield any clue. Gallium scintigraphy should be considered as the next step and not as a last-resort procedure.

Recurrent or episodic fever of unknown origin. Review of 45 cases and survey of the literature.

We describe a series of 45 patients with episodic fever of unknown origin (FUO) who meet the classic criteria for FUO. Recurrent or episodic fever is defined as cyclical fever with seeming remission of the disease and fever-free intervals of at least 2 weeks. The traditional mix of infections, malignancies, and inflammatory diseases (multisystem diseases) represent only 20% of the causes of episodic FUO, in contrast to 60 to 70% in cases of continuous fever. The "miscellaneous" group of patients with episodic FUO is the most numerous and about half of the cases remain undiagnosed. This spectrum of causative diseases resembles the spectrum of so-called "prolonged" FUO, i.e., a feverish illness lasting at least half a year. Follow-up of the undiagnosed cases revealed a good prognosis. Only 1 patient died and only 1 more required continuous treatment with corticosteroids. Seven of the 21 undiagnosed cases required intermittent short-term treatment with either nonsteroidal anti-inflammatory drugs or corticosteroids. The remaining 14 seem to be "cured". Diagnosis was frequently based on the clinical course and on exclusion of other diseases. Gastrointestinal investigation was useful, but serologic and immunologic tests yielded only minimal benefit. Ultrasonography, computerized tomographic scans, and gallium scintigraphy were diagnostically useful. Invasive procedures are rarely required, and careful ambulatory follow-up is probably the best approach in cases of unresolved episodic FUO.

Fever of unknown origin in the 1980s. An update of the diagnostic spectrum.

OBJECTIVE: To determine the relative proportions of the diagnostic categories in patients with fever of unknown origin who were examined in the 1980s. STUDY DESIGN: Prospective case series. SETTING: General Internal Medicine Service based at University Hospital, Leuven, Belgium. PATIENTS: One hundred ninety-nine consecutive patients meeting the classic criteria of fever of unknown origin who were treated in the 1980s. MAIN OUTCOME MEASUREMENT: The final diagnosis established at discharge or during follow-up. RESULTS: Infections were found in 45 patients (22.6%), tumors were found in 14 (7%), multisystem diseases were found in 42 (21.5%), drug-related fever was found in six (3%), factitious fever was found in seven (3.5%), habitual hyperthermia was found in five (2.5%), miscellaneous diseases were found in 29 (14.5%), and no diagnosis was reached in 51 (25.6%). CONCLUSIONS: Tumors were a less important cause of fever of unknown origin in the 1980s. The same holds true for some infectious diseases, such as abscesses and hepatobiliary disorders. Multisystem diseases were more frequently found, and the number of undiagnosed cases increased. Although these shifts in the disease spectrum in fever of unknown origin most probably resulted from a constellation of factors, we suspect that these changes are mainly due to easy and early diagnosis by new diagnostic modalities, such as ultrasonography and computed tomography, of previously common causes of fever of unknown origin.