Etiology and clinical characteristics of fever of unknown origin in children: a 15-year experience in a single center

Abstract

Purpose: Fever is one of the most common symptoms in children. In previous studies, infectious disease was the most common cause of pediatric fever of unknown origin (FUO). The aim of this study is to investigate the etiology, clinical characteristics and prognosis of pediatric FUO in 21 century with more diagnostics available and to analyze the factors for certain disease categories.

Methods: Among the children under 18 years old who were hospitalized at Samsung Medical Center from January 2000 to December 2014, the patients who met the criteria including fever of ≥38.0℃ for longer than ≥14 days and failure to reach a diagnosis after one week of investigations were included.

Results: Total 100 patients were identified. Confirmed diagnosis was achieved in 57 patients (57%). Among them, infectious diseases (n=19, 19%) were most common, followed by connective tissue diseases (n=15, 15%), necrotizing lymphadenitis (n=8, 8%), and malignancies (n=7, 7%). Children with fever duration over 28 days had a trend for higher frequency of connective tissue diseases (28.3%) except undiagnosed etiology. The symptoms such as arthritis, lymph node enlargement and only fever without other symptoms were significantly related with connective tissue diseases, necrotizing lymphadenitis and undiagnosed respectively (P<0.001). Ninety-two patients have become afebrile at discharge and 1 patient died (1%).

Conclusion: Almost half of our patients were left without diagnosis. Although it has been known that infectious disease was most common cause of pediatric FUO in the past, undiagnosed portion of FUO have now increased due to development of diagnostic techniques for infectious diseases.

Keywords: Child; Fever of unknown origin; Infection.

Fig. 1. Distribution of age (A) and fever duration (B) of fever of unknown origin.

Fig. 2. The relationship between symptoms and final diagnosis in fever of unknown origin. Abdominal pain, vomiting or diarrhea refer to gastrointestinal (GI) symptoms; Cough, sputum or rhinorrhea refer to respiratory symptoms; Lymph node enlargement (LNE) includes cervical or axillary LNE; Neurologic symptoms contained headache, seizure, gait disturbance or anhidrosis; Others contained skin rash, oral ulcer, oral vesicle or conjunctival injection.