Fever is one of the most common causes for sick child visits to healthcare providers (HCPs). Fever, as distinct from hyperthermia, is defined as a regulated rise in core body temperature. Most clinicians define fever as an oral or rectal temperature of 38°C (100.4°F) or higher. In the pediatric age group, infection due to a virus (most likely) or bacteria (eg, urinary tract infection) is the most common cause of fever, and the HCP must always be alert to serious etiologies. The tendency to seek medical attention for fever is very much age-dependent, with younger children brought to care most often. Although part of the tendency to seek medical attention for fever rests with parental anxiety, part rests appropriately with the increased risk of serious infection associated with fever in the youngest children (especially neonates), as well as in special high-risk groups.
Fever is not a diagnosis per se. Fever is a nonspecific response to many adverse stimuli, including inflammation, infection, and malignancy, among others. As noted, the challenge to the HCP is to separate serious causes of fever from more minor or self-limited illnesses. The most useful tool in the diagnosis of the etiology of fever is the clinical examination. One key goal of training and experience is to hone the HCP’s ability to identify the truly sick or “toxic” child. Perhaps no clinical skill is more important for an HCP, who is often dealing with young children who are not able to communicate directly. Often the signs of serious infection are subtle, and the child just “does not look right.” Listlessness, poor feeding, weakness, rapid pulse, and lethargy are all clues, as is the more sinister presence of poor perfusion of the extremities, shock, cyanosis, or purpura.
Once the child is identified as being potentially seriously ill, then, following appropriate resuscitation, laboratory evaluation should be undertaken including peripheral white blood cell (WBC) count with differential, electrolytes, and urinalysis, as well as cultures, often including urine, blood, and cerebrospinal fluid (CSF). The CSF may also be sent for other studies as appropriate (eg, polymerase chain reaction [PCR] for herpes simplex virus [HSV] or enterovirus). Some clinicians also use erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), or procalcitonin testing to evaluate febrile children, because these are often elevated in children with bacterial infection. For the truly toxic child and especially for younger children, age-appropriate antimicrobials that include treatment of sepsis and possibly meningitis should be started after obtaining appropriate studies. In most areas of the world, this must now include coverage against resistant gram-positive organisms through the inclusion of vancomycin.
For the child who is less seriously ill, a more measured evaluation is warranted. Such an evaluation should include a thorough history and physical examination to delineate the patient’s symptoms and clinical course. Knowledge of the most common infectious etiologies in a ...