A 4-month-old Female Infant with 36 Hours of Persistent High-Grade Fever

A family physician referred a 4-month-old Caucasian female infant to the pediatric emergency department because of 36 hours of persistent high-grade fever (T 39.2°C). Her mother mentions that before the fever began, she was well, feeding normally on breast milk. The fever started suddenly, peaked within a few hours and remained high despite receiving enough doses of oral acetaminophen. She had no other symptoms during these 36 hours, except intermittent lethargy and agitation. She is the result of a term birth with a birth-weight of 2970 g. She has two elder brothers (8 and 3 years, healthy). Her parents are healthy and non-consanguineous (Her mother is 29, and her father is 35 years old). Her general condition is poor probably because of high fever (T 39.2oC). However, she has normal growth and development. On physical examination, the heart rate is 150/min and the respiratory rate is 56/min. The conjunctiva is mildly erythematous in both eyes (Figure 1) and the pharynx is hyperemic. No peripheral lymph node is palpable. The heart, lung and abdomen examination are normal. The muscle tone is normal. There are no meningeal signs.