about the reliability of axillary, tympanic, or temporal artery measurements in this age group, rectal temperatures should be obtained in this population EVALUATION AND DECISION The importance of fever lies in its role as a sign of disease The physicians caring for a febrile child should concentrate on discovering the cause of the fever and treating the underlying illness Although any degree of fever may indicate an important infectious etiology, the risk of serious bacterial infection is slightly higher with hyperpyrexia (defined as a temperature of 41.1°C) in children and a thorough assessment for possible bacterial etiology (e.g., pneumonia, bacteremia, or meningitis) should be seriously considered However, the magnitude of reduction of fever in response to antipyretics does not distinguish children with serious bacterial illnesses from those with viral diseases If no specific treatment for the determined diagnosis is necessary, the physician’s goal is then to provide appropriate supportive care and follow-up Because many parents have “fever phobia,” instructions that explain the importance of fever as an indicator of disease, not as an inherently harmful entity, should be given A complete history and physical examination will provide the most important clues in determining the diagnosis of children with febrile illnesses The age of the infant or child should be carefully considered as it significantly impacts the risk of fever source and etiology Very young infants’ rate of serious bacterial illnesses is higher than other age groups and children under 24 months have distinct risks of certain infectious causes of fever (see Chapter 94 Infectious Disease Emergencies ) The general impression obtained in the first few moments of an evaluation is extremely important in the recognition of potentially lifethreatening causes of fever (indicated by a in Table 31.3 ) A great deal of information can be attained by visual assessment of the child while in the arms or lap of the parent The severity of the illness may become apparent if the child is agitated or uninterested in the surroundings while in this comfortable, safe position If the child appears nontoxic, observation of the child while the history of the present illness and medical history are being discussed may provide further insight into the diagnosis Specifics of fever have different management implications for distinct subsets of children Therefore, a clear understanding of the degree, mode of measurement, and duration of fever is especially important in the initial evaluation The physician should ask questions concerning associated signs and symptoms, medications being given (including antipyretics and antibiotics), presence of ill contacts, travel history, and pet or insect exposures (see Chapter 94 Infectious Disease Emergencies ) The medical history should