Fever in infancy and childhood Flashcards
Temperature measurement
Rectal - reference standard for core temperature. Recommended in children younger than 4 yrs
Oral - in children old enough to cooperate, 0.6 deg lower than rectal
Axillary thermometry
Infrared - The accuracy of such measurements may be affected by sweating or vascular changes. Readings may be greater or lower than rectal temperature.
Temperature homeostasis
Body temperature is controlled by the thermoregulatory center of the hypothalamus
The thermoregulatory center balances heat production, derived primarily from metabolic activity in muscle and the liver, with heat dissipation from the skin and lungs.
Normal body temperature
In a more recent study of young adults, the upper limit of normal body temperature (measured orally) was 37.2°C (98.9°F) in the morning and 37.7°C (99.9°F) overall.
Infants and young children generally have higher temperatures than older children and adults. This relates to the greater surface-area-to-body-weight ratio and the higher metabolic rate of infants and small children.
Elevated body temperature
Elevated body temperature may result from fever (increased body temperature with elevated hypothalamic set-point) or
hyperthermia (increased body temperature with normal hypothalamic set-point)
Fever
Fever is an abnormal elevation of body temperature that occurs as part of a specific biologic response that is mediated and controlled by the central nervous system. Rectal temp fever of concern Neonate > 38 degree In children 3-36 months > 39 Older children ≥37.8 to 39.4°C
Pathogenesis
synthesis and release of
interleukin (IL)-1,
IL-6,
tumor necrosis factor,
interferon-alpha, and other endogenous pyrogenic cytokines by phagocytic cells in the blood or tissues
These cytokines enter the blood and are carried to the anterior hypothalamus, where they induce an abrupt increase in the synthesis of prostaglandins, especially prostaglandin E2
The induction of PGE2 in the brain raises the hypothalamic set-point for body temperature
After the set-point is raised, the thermoregulatory center recognizes current body temperature to be too low and initiates a series of events to raise body temperature to the new set-point.
Benefits vs harm
Potential benefits – Potential benefits of fever include retardation of the growth and reproduction of some bacteria and viruses
Potential harms – Fever can make patients uncomfortable. It is associated with
increased metabolic rate, oxygen consumption, carbon dioxide production, and demands on the cardiovascular and pulmonary systems.
For the normal child, these stresses are of little or no consequence.
However, for the child in shock or for the child with a pulmonary or cardiac abnormality, the increased demands can be detrimental and may offset any immunologic benefit from the fever.
Definition of Hyperthermia
An abnormal elevation of body temperature that occurs without a change in the thermoregulatory set point in the hypothalamus
Red flags
>39 degrees < 2yrs/o occult bacteremia presence of bacteria in the blood stream - Age < 1mo - Lethargy, toxic appaerance - Respiratory distress - Petechiae or purpura
Common causes
< 1 = TORCH infection
>1 mo = Enterovirus, respiratory viruses, EBV, HSV
Bacteria:
Group B strep, E.Coli, Listeria monocytogenes
Strep pneumonia, N. Meningitidis, H. Influenza, UTI
Common causes
< 1 = TORCH infection
>1 mo = Enterovirus, respiratory viruses, EBV, HSV
Bacteria:
Group B strep, E.Coli, Listeria monocytogenes
Strep pneumonia, N. Meningitidis, H. Influenza, UTI
Tx
Directed to underlying disorder:
Fever in an otherwise healthy child does not necessarily require treatment.
Although antipyretics can provide comfort, they do not change the course of an infection
Antipyretics:
Acetaminophen - 1st line, avoid in kids with asthma
Ibuprofen
Bath slightly colder than temp. of child
