Fever in adults. What to do when the cause is not obvious

The spectrum of diseases causing fever of unknown origin in Turkey: a multicenter study

OBJECTIVE

The purpose of this trial was to determine the spectrum of diseases with fever of unknown origin (FUO) in Turkey.

METHODS

A prospective multicenter study of 154 patients with FUO in twelve Turkish tertiary-care hospitals was conducted.

RESULTS

The mean age of the patients was 42+/-17 years (range 17-75). Fifty-three (34.4%) had infectious diseases (ID), 47 (30.5%) had non-infectious inflammatory diseases (NIID), 22 (14.3%) had malignant diseases (MD), and eight (5.2%) had miscellaneous diseases (Mi). In 24 (15.6%) of the cases, the reason for high fever could not be determined despite intensive efforts. The most common ID etiologies were tuberculosis (13.6%) and cytomegalovirus (CMV) infection (3.2%). Adult Still's disease was the most common NIID (13.6%) and hematological malignancy was the most common MD (7.8%). In patients with NIID, the mean duration of reaching a definite diagnosis (37+/-23 days) was significantly longer compared to the patients with ID (25+/-12 days) (p=0.007). In patients with MD, the mean duration of fever (51+/-35 days) was longer compared to patients with ID (37+/-38 days) (p=0.052).

CONCLUSIONS

Although infection remains the most common cause of FUO, with the highest percentage for tuberculosis, non-infectious etiologies seem to have increased when compared with previous studies.

Fever of unknown origin in adults: 40 years on

A revision of the criteria of fever of unknown origin (FUO), established in 1961, is desirable because of important evolutions in medical practice and the emergence of new patient populations. The development of rapid laboratory tests and powerful diagnostic tools, such as ultrasonography, computed tomography and magnetic resonance imaging often makes hospitalization unnecessary and new categories of patients such as those with HIV infection, neutropenia, immunosuppression and nosocomial illness require an approach different from classical FUO. The more then 200 reported causes of FUO can be classified into four diagnostic categories; infections, tumours, noninfectious inflammatory diseases (NIID) and miscellaneous. A uniform classification system is highly wanted to allow comparison between different series. The reports of the 1990s show slight changes in the distribution of causes, namely less infections, less tumours, more NIID and more undiagnosed cases. A uniform diagnostic strategy cannot be determined. The initial investigation should be directed by potentially diagnostic clues revealed by extensive history, meticulous physical examination and a standard set of laboratory tests. 18Fluoro-deoxy-glucose-positron-emitted-tomography is a new valuable total body scintigraphy in the search for the site of origin of the fever. In view of the rather good long-term prognosis, a wait-and-see strategy may be more appropriate than a systematic staged approach. Elderly patients and patients with episodic fever represent two specific groups of classical FUO that require a distinct approach. HIV-associated, nosocomial and neutropenic FUO should be considered as separate clinical entities.

Fever of unknown origin (FUO). II. Diagnostic procedures in a prospective multicenter study of 167 patients. The Netherlands FUO Study Group

From January 1992 until January 1994, we used a standardized diagnostic protocol for the 167 immunocompetent patients with fever of unknown origin (FUO) admitted on the internal medicine wards in all 8 university hospitals in the Netherlands. This protocol consisted of a standardized coded history and standardized physical examination for all 167 patients. A number of additional obligatory investigations had to be performed in the first week of admission for all patients, and all potentially diagnostic clues (PDCs) thus retrieved had to be registered. In the presence of PDCs, specific investigations had to be performed based on the differential diagnosis. In the absence of PDCs or in the presence of only misleading PDCs, patients underwent a screening 2-staged diagnostic protocol. In 162 (97%) patients, PDCs were present after 1 week of admission. In 61 patients these PDCs were all misleading. The likelihood of reaching a diagnosis in patients with PDCs was not significantly higher than that in patients without PDCs, probably because of the high proportion of misleading PDCs. The likelihood of establishing a diagnosis was significantly lower (< 10%) only for patients with recurrent fever, normal erythrocyte sedimentation rate (ESR), and normal hemoglobin. All other PDCs were not significantly different in patients with a diagnosis compared with patients without a diagnosis. The screening 2-staged diagnostic protocol proved useful in 10 of 43 patients in whom it was used. The screening value of immunologic and microbiologic serology and endocrine investigations was nil; these investigations probably should be performed only when PDCs for the disease searched for are present. Scintigraphic techniques, echocardiography, and other imaging procedures were never helpful in our population in the absence of PDCs. Many patients with FUO had nonspecific anemia and disturbed liver chemistry. In the presence of these findings alone, without other more specific PDCs, the likelihood of reaching a diagnosis with help of bone marrow aspiration was nil, and with help of liver biopsy, it was low. Enteric biopsy was never helpful. If lymphadenopathy was confined to the cervical or inguinal region (with negative chest X-ray and abdominal ultrasound), lymph node biopsy was not helpful, in contrast to patients having generalized lymphadenopathy, in whom the technique had a yield of 79%. As shown in this study, the search for PDCs remains an important tool for establishing the diagnosis in patients with FUO, although in many cases these PDCs appear to be misleading. Directed diagnostic workup--using the PDCs retrieved by repeated, meticulous history taking and physical examination--remains the most efficient and intellectually satisfactory way to solve the problem of FUO in the individual patient. A standard protocol in patients with FUO in whom the obligatory investigations, as used by us, do not lead to the diagnosis can be limited to the tests that proved to be of some use as screening procedure: temporal biopsy in patients older than 55 years; fundoscopy; serology (Western blot) for Yersinia enterocolitica; serum for cryoglobulin at an early stage of the diagnostic process; and bone biopsy, liver biopsy, abdominal computed tomography (CT), and chest CT at a later stage. Repeating a thorough history-taking, physical examination, and obligatory investigations and waiting for PDCs to appear probably is better than ordering more screening investigations in the hope that something abnormal will come up. Supportive treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) can be helpful at this stage. Only rarely do patients deteriorate while using NSAIDs without presenting new PDCs. In these rare patients, further diagnostic workup should be performed or a therapeutic trial with, for example, antibiotics, steroids, or antituberculous agents started.

Fever of unknown origin

Fever of unknown origin (FUO) is defined as a temperature elevation of 101 degrees F (38.3 degrees C) or higher for 3 weeks or longer, the cause of which is not diagnosed after 1 week of intensive in-hospital investigation. This article discusses the causes, diagnosis, and treatment of FUOs.

Fevers of unknown origin in patients requiring mechanical ventilation: an odontogenic problem?

Patients who are on continuous monitors and mechanical ventilators, and who are receiving medical care in an intensive care setting, do not meet the usual expectations for dental care. Two examples of odontogenic contribution to fevers of unknown origin are presented in the context of treatment of continuously monitored patients with mechanically supported respiration. It is intended that these cases show the need for active dental consultation and participation by dentists in the care of the patient who is chronically ill and who cannot be brought to the traditional dental care setting.

Fever of undetermined origin: not what it used to be

Eighty cases of fever of undetermined origin seen at Dallas VAMC from 1979 to 1985 were analyzed. Infectious etiology was the cause in one half, with equal numbers of localized infections or systemic infections. In contrast to older series, viral infections were frequently seen, but tuberculosis and malaria were less commonly noted. Solid tumors were the most frequently diagnosed non-infectious cause of fever. Fevers secondary to malignancy commonly responded to non-steroidal anti-inflammatory agents. Patterns of illness were helpful in defining certain diseases such as adult Still's disease and polymyalgia rheumatica. Diagnostic tests of value are discussed.

The role of dental disease in fever of unknown origin

The case presented emphasizes the need for evaluation of the oral cavity in the diagnostic workup of fever of unknown origin. Hurley stated, "Protracted fever of obscure cause remains one of the more daunting clinical challenges facing the physician. It calls for mobilization of all the physician's own skills and the expertise of colleagues as well as maintenance of an open mind to the patient's complaints and observations. Dogged determination and a systematic approach are the keys to solving the problem." When the possibility of dental disease is overlooked, the resulting search is sometimes long, tedious, and expensive. Early examination of the oral cavity by qualified personnel should be done even though pain is not present.