Fever of unknown origin

National survey of childhood febrile illness cases with fever of unknown origin in Japan

BACKGROUND

In Japan, an actual condition survey on childhood febrile diseases with fever of unknown origin has never been performed. We carried out a national survey on childhood febrile illnesses in order to collect useful information for the differential diagnosis.

METHODS

A nationwide survey using questionnaires was performed on febrile illness cases with fever of unknown origin (FUO) experienced by 2843 pediatrics institutions with sick beds during a 5-year period before 2007. FUO was defined as a febrile illness of at least 2 weeks' duration with a temperature ≥ 38°C, and failure to establish a diagnosis in spite of intensive evaluation during seven days' hospitalization.

RESULTS

Two hundred fifty-five of 2843 questionnaire-surveyed institutions had 960 FUO cases, of which 132 could not be diagnosed, and 828 could be diagnosed after detailed medical examinations. The diagnoses they clarified included infectious diseases in 190 cases (23%), rheumatic diseases in 448 cases (54%), neoplasms in 67 cases (8%), and others in 123 cases (15%).

CONCLUSION

Clarification of illnesses that ought to be differentiated in the diagnostic approach to an FUO case is essential for arriving at its definitive diagnosis by exclusion.

Fever of unknown origin: a diagnostic approach to this vexing problem

Fever is a common complaint leading families to seek medical attention. Its routine management is the bread and butter of pediatric practice. When fever is seen as prolonged beyond the expected time course (eg, 10 days for a presumed viral respiratory tract infection or 3 weeks for mononucleosis), concern for fever of unknown origin (FUO) may ensue. This diagnosis is among the most challenging for health care providers to approach and often involves referral to subspecialists. Generally, the pace of the evaluation should be guided by the severity of the disease, rather than the anxiety of the family or of the health care providers. It is useful to recognize that uncommon manifestations of common diseases are more likely than are rare diseases. Furthermore, clues to the diagnosis are frequently present in the history and physical examination but are not elicited or unappreciated (perhaps due to time constraints). Therefore, thoroughness and repetition are vitally important. Although the differential diagnosis of FUO is vast, a thoughtful, focused approach based on information gleaned from a thorough history and physical examination (together with any laboratory or other study results) is preferable to a "shotgun" or "running the list" one. Finally, FUO in special populations, including children in the hospital, those with HIV infection or other immunocompromise, and those in the developing world, require special consideration. Most children do well, compared to adults with FUO, but true FUO is not always a benign condition, necessitating the best care a health care provider can offer.

Fever of unknown origin in 185 paediatric patients: a single-centre experience

AIM

We conducted a prospective study to evaluate the causes and outcome in children with fever of unknown origin (FUO).

METHODS

From 1990 to 1999, 185 children with FUO were evaluated. Initial evaluation included routine haematological analysis, Epstein-Barr virus (EBV) serology, urine, stool or blood cultures, chest X-ray and tuberculin probe.

RESULTS

In 131 (70%) patients diagnosis was established, and 70 (37.8%) had infectious disease. EBV infection was the most common infection followed by visceral leishmaniasis (VL), urinary tract infection (UTI) and tuberculosis. Autoimmune disorders were diagnosed in 24 (12.9%), Kawasaki disease in 12 (6.4%), malignant diseases in 12 (6.4%) and miscellaneous conditions in 15 (8.1%) patients. In the remaining 54 (30%) patients, diagnosis was not established and most of them had self-limited disease. During the investigation, 26 (14%) patients developed serious organ dysfunction and five patients (two with virus-associated haemophagocytic syndrome, one with VL and two unknown) died.

CONCLUSION

The most important infectious causes of FUO in our study were EBV infection and VL. Kawasaki disease represented a significant cause of FUO at the beginning of our study because it was not recognized by primary-care physicians. We report myelodysplastic syndrome as another emerging cause of paediatric FUO. Repeated clinical examination and careful use of specific laboratory examinations, invasive diagnostic procedures or imaging are crucial in approaching paediatric FUO.

Evaluation of 80 children with prolonged fever

BACKGROUND

Several studies have been published regarding the etiology and evaluation of a child with prolonged fever, however, the reasons for the prolonged fever have changed during the years. The present study aims to determine the causes of prolonged fever, to investigate the relationship of fever using some basic laboratory tests, and to establish guidelines for the approach in those children.

METHODS

The charts of 80 out of 17490 hospitalized children who were seen between 1996 and 2001 with prolonged fever of longer than 2 weeks and unknown origin were reviewed in the university hospital of Izmir, Turkey. Their charts were evaluated in respect of age, sex, growth curves, educational level of their families, the duration and the magnitude of fever, causes of fever, and basic laboratory investigations such as white blood cell, blood smear, hemoglobin, erythrocyte sedimentation rate, and C-reactive protein.

RESULTS

Forty-four (55.00%) were boys and 36 (45.00%) were girls. Forty-four children (55.00%) were aged between 1 month and 2 years, 21 (26.25%) were aged 3-6 years, seven (8.75%) were aged 7-10 years, and eight (10.00%) were older than 10 years. The mean age was 3.87 +/- 4.17 years (range 3 months-17 years). Forty-six children (57.50%) had a prolonged fever that had lasted from 15-30 days, 18 (22.50%) from 31-60 days, and 16 (20.00%) had fever lasting more than 60 days. Final diagnosis had been reached in 70 of the 80 children (87.50%). The most common causes were infection (47/80), followed by immune deficiency (6/80), collagen tissue disorder (5/80), neoplasia (2/80), and miscellaneous (10/80) such as central fever in three, diabetes insipidus in two, familial Mediterranean fever in two, Kawasaki disease, foreign body in the respiratory system, and Crohn disease in one patient each. Among the laboratory tests white blood cell count, hemoglobin level and blood smear distribution of infection group were statistically significant.

CONCLUSIONS

The most common cause of fever of unknown origin remains infection. The proportion of collagen tissue disorders and neoplasia have been found to be decreased. Unusual reasons such as diabetes insipidus and foreign body in the respiratory system in the miscellaneous group have been detected. Age plays important role in the diagnosis of prolonged fever, while some basic laboratory tests might give clues in the evaluation and may suggest a diagnosis.

Use of imaging in the differential diagnosis of rheumatic diseases in children

Imaging studies are important adjuncts in the evaluation of children with suspected rheumatic diseases. They are best used as follow-up investigations to exclude specific differential diagnoses, based upon a careful history and physical examination. Often, repeated examination over a period of time, sometimes months, is necessary before a diagnosis can be made. The addition of selected imaging studies can be important in the common circumstance where no diagnosis is made, but the physician must assure the child and family that all appropriate efforts have been made to exclude important illnesses.

[Management of prolonged fever in infants]

Prolonged fever is defined as an unexplained fever of more than 5 days duration. In infancy and early childhood, it is most often of infectious origin, viral infections being the most frequent. Mycoplasma pneumoniae infections, urinary tract infection and otitis media are also commonly involved. Kawasaki disease is the main inflammatory etiology, juvenile rhumatoïd arthritis in its systemic form (Still's disease) being much rarer. In most cases the etiological diagnosis can be made with a limited number of laboratory and/or imaging investigations based upon a careful clinical evaluation and an oriented chronological strategy.