Characteristics of Patients Referred to a Pediatric Infectious Diseases Clinic With Unexplained Fever.
Older case series established diagnostic considerations for children meeting a priori definitions of fever of unknown origin (FUO). No recent study has examined the final diagnoses of children referred for unexplained fever. This study was conducted with a retrospective chart review of patients referred to a pediatric infectious diseases clinic from 2008 to 2012 for unexplained fever. Sixty-nine of 221 patients were referred for "prolonged" unexplained fever. Ten of these were not actually having fever, and 11 had diagnoses that were readily apparent at the initial visit. The remaining 48 were classified as having FUO. The median duration of reported fever for these patients was 30 days; 15 had a diagnosis made, 5 of which were serious. None of the serious FUO diagnoses were infections. Of 152 patients with "recurrent" unexplained fever, 92 had an "intermittent" fever pattern, and most of these had sequential, self-limited viral illnesses or no definitive diagnosis made. Twenty of the 60 patients with a "periodic" fever pattern were diagnosed with periodic fever, aphthous stomatitis, pharyngitis, and adenitis syndrome. Overall, 166 patients either were not having fever, had self-limited illnesses, or ultimately had no cause of fever discovered. Only 12 had a serious illness, 2 of which were infections (malaria and typhoid fever). Most children referred with unexplained fever had either self-limited illnesses or no specific diagnosis established. Serious diagnoses were unusual, suggesting that these diagnoses rarely present with unexplained fever alone, or that, when they do, the diagnoses are made by primary care providers or other subspecialists.