Childhood fever: correlation of diagnosis with temperature response to acetaminophen.

Many people believe that temperature response to antipyretics in febrile children varies according to diagnosis. To evaluate the validity of this premise, we prospectively studied the temperature response to acetaminophen of febrile children who came to an urban pediatric emergency and walk-in facility. The study group consisted of 1,559 patients between the ages of 8 weeks and 6 years whose temperatures when seen were greater than 38.4 degrees C and who had not received antipyretic treatment within the previous four hours. Acetaminophen (15 mg/kg) was administered to each child and repeat temperatures were taken one and two hours later. Patient management was unaffected by the study, and physicians were unaware of the repeat temperature measurements. Telephone follow-up was conducted with the parents of each child within five days of the initial visit. Children with cultures positive for bacterial disease or chest x-ray films positive for pneumonia had slightly greater one- and two-hour temperature decreases compared with children with other diagnoses. Although statistically significant, we do not consider these differences in response to be clinically useful. We conclude that fever response to acetaminophen is not a clinically useful indicator by which to differentiate the causes of febrile illnesses in young children.