Incidence of serious infection in infants under age two months with fever.

Infants less than eight weeks of age in a busy urban emergency department were prospectively reviewed during a six-month period, from October 1, 1981 to March 31, 1982. An axillary temperature of 37.8 degrees C or higher was arbitrarily defined as significantly elevated. A total of 1,655 young infants were seen during this time period, with 122 having temperatures of 37.8 degrees C or higher (7%). Four percent of the febrile patients were bacteremic. The degree of temperature elevation was not proportional to the severity of the illness. Total white blood cell count was less than 4,000/mm3 in two of the bacteremic patients. Cerebrospinal fluid pleocytosis was present in 13% of the patients undergoing lumbar puncture.