Patterns of illness in the highly febrile young child: epidemiologic, clinical, and laboratory correlates.

Three hundred one episodes of fever greater than or equal to 103 F were documented in 375 infants and young children observed in a comprehensive care clinic during the period October 1974 to October 1978. Of such highly febrile illnesses 79% were accompanied by respiratory tract signs or symptoms, 7% by disease at a site other than the respiratory tract, and 22% of illnesses had no localizing signs or symptoms. Viral cultures were obtained from the respiratory tract in 178 cases and were positive in 68: 57/134 from respiratory illness; 2/4 from illness at sites other than the respiratory tract; and 9/40 in children without localizing disease. Bacterial cultures of the upper respiratory tract were obtained in 191 illnesses, but the overall rate of isolation of Haemophilus influenzae, Streptococcus pneumoniae and group A streptococci (46%) did not differ from that in a group of well children (39%). Bacterial cultures of the blood were obtained in 89 patients with fever greater than or equal to 103 F and in an additional 41 children with lower temperatures. Nine children had documented systemic bacterial disease (eight positive blood cultures and one positive CSF). The rate of clinically apparent systemic bacterial disease in these otherwise normal infants was one bacteremic episode per 94 years of child care.