Fever is defined as a regulated rise in core body temperature.
That is, as distinct from hyperthermia, it is a measured response
to internal regulatory processes. Most clinicians define fever as
a rectal temperature of 38°C (101.4°F) or higher. Fever is the most
common cause for sick child visits to the pediatrician and emergency
room. Fever is part of the body’s response to many adverse
stimuli, including inflammation, infection, and malignancy, among
other causes. In the pediatric age group, infection due to a virus
or bacteria is the most common cause of fever. The tendency to seek medical
attention for fever is very much age dependent, with younger children
seeking 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, neonates, as well as in special risk groups.
The physiology of temperature regulation is detailed in Chapter 121 and further information on the management of the febrile
child can be found in Chapter 105.
Fever is not a diagnosis per se. Often the pediatrician’s
first goal is to separate serious causes of fever from minor self-limited
intercurrent illnesses. The most useful tool in the diagnosis of
the etiology of fever is the clinical examination. Many months of
residency and years in clinical practice hone the pediatrician’s
ability to identify the truly sick or “toxic” child.
Perhaps no clinical skill is more important for a pediatrician,
who is often dealing with young children who are not able to communicate
directly, than the ability to identify the seriously ill child.
Listlessness, poor feeding, poor perfusion of the extremities, weakness,
rapid pulse, or lethargy are all clues, as are the more sinister presence
of cyanosis or purpura. Often the signs are subtle and the child
just does “not look right.” Once the child is
identified as being toxic or seriously ill, then appropriate cultures, most
often including urine, blood, and CSF, as well as other laboratory
tests such as a peripheral white blood cell (WBC) count with differential,
electrolytes, and urinalysis, should be obtained. Some clinicians
also use C-reactive protein (CRP) or procalcitonin testing to evaluate
febrile children because these are selectively elevated in children
with bacterial infection.5 For the truly toxic
child and especially for younger children, age-appropriate antibiotics that
can treat sepsis and possible meningitis should be started. In most
areas of the country, this must now include coverage against resistant
gram-positive organisms through the inclusion of vancomycin. For
the child that is less seriously ill, a more measured clinical evaluation
is warranted. Such an evaluation should include history as well
a physical examination to delineate the patient’s symptoms
and clinical course. Knowledge of the most common infectious etiologies
in a given age group is also important. Pharyngitis, upper respiratory infection,
otitis media, gastroenteritis, and bronchiolitis are all common
causes of fever and can often ...