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.