The early detection of pyrexia in the newborn

Fever after maxillofacial surgery: a critical review

PURPOSE

The aim of this paper is to review the pathophysiology of thermoregulation mechanism, various causes of fever after maxillofacial surgery and the different treatment protocols advised in the literature.

DISCUSSION

Fever is one of the most common complaints after major surgery and is also considered to be an important clinical sign which indicates developing pathology that may go unnoticed by the clinician during post operative period. Several factors are responsible for fever after the maxillofacial surgery, inflammation and infection being the commonest. However, other rare causes such as drug allergy, dehydration, malignancy and endocrinological disorders, etc. should be ruled out prior to any definite diagnosis and initiate the treatment. Proper history and clinical examination is an essential tool to predict the causative factors for fever. Common cooling methods like tepid sponging are usually effective alone or in conjunction with analgesics to reduce the temperature.

CONCLUSION

Fever is a common postoperative complaint and should not be underestimated as it may indicate a more serious underlying pathology. A specific guideline towards the management of such patients is necessary in every hospital setting to ensure optimal care towards the patients during post operative period.

Circulating cytokine concentrations and cytokine production by monocytes from newborn babies and adults

As a possible factor responsible for reduced fever responses in the newborn, we measured plasma cytokine concentrations and cytokine production by neonatal monocytes after lipopolysaccharide or IL (interleukin)-1 alpha stimulation in vitro and compared these data with those obtained from adult plasma and monocytes. Whole blood was collected from afebrile adults (n = 12) and the umbilical cord of normal term infants (n = 12). Plasma and peripheral blood monocytes were prepared by conventional techniques. Significantly lower concentrations of IL-1 alpha, IL-1 beta (P < 0.05, t-test) and IL-6 (P < 0.01, t-test) were found in the plasma of newborn babies compared with that of adults. There was no significant difference in plasma tumour necrosis factor (TNF) concentrations between the adults and newborn babies. Monocytes from newborn babies had the capacity to produce IL-1 alpha and IL-1 beta as readily as adult cells after stimulation with lipopolysaccharide or IL-1 alpha, and produced significantly lower concentrations of TNF and IL-6 than those produced by stimulated adult monocytes (P < 0.01, ANOVA). Our results suggest that the reduced production of IL-6 by monocytes of the newborn during infection could be partly responsible for attenuated fever responses observed in the neonate.

Interleukin-1 receptor antagonist in newborn babies and pregnant women

We have investigated the possible role of the interleukin-1 receptor antagonist (IL-1ra) in the attenuated fever response in the newborn. Umbilical cord blood was collected from normal full-term infants (n = 12), and venous blood was obtained from afebrile, non-pregnant adults, of both genders (n = 12) and women in late pregnancy (n = 12). Plasma IL-1ra, and IL-1ra produced in vitro by peripheral blood monocytes stimulated with IL-1 alpha or LPS, were assayed by ELISA. Significantly higher concentrations of IL-1ra (P < 0.01, t test) were found in umbilical cord plasma than in plasma of non-pregnant adults. Furthermore concentrations of IL-1ra in the plasma of women in late pregnancy were significantly higher than in the plasma of neonates and non-pregnant adults (P < 0.01, Mann-Whitney rank-sum test). Neonatal monocytes failed to produce significant amounts of IL-1ra upon stimulation in vitro. The monocytes of pregnant women produced much higher concentrations of IL-1ra than the monocytes of non-pregnant adults (P < 0.01 Mann-Whitney rank-sum test). We speculate that IL-1ra may attenuate the febrile response to Gram-negative pyrogens in women in late pregnancy, and by crossing the placenta, also in the newborn.

Fever responses in newborn lambs

Neonatal lambs failed to respond with an increase in body temperature to i.v. injection of both endotoxin (0.4 microgram/kg), a Gram-negative bacterial pyrogen, and the cell walls of Staphylococcus aureus (1 x 10(9), a Gram-positive bacterial pyrogen. However, the fall in serum iron concentration that normally accompanies injection of both the pyrogens in adults was not attenuated in the neonates. We believe that the central nervous system origin of the fever pathway is suppressed in neonatal lambs.

Maturation of pyrogen-elicited fever in the kitten

The febrile response to the endotoxin Salmonella typhosa was studied in developing kittens. We found that kittens younger than 30 days of age generated only a small rise in temperature in response to a standardized endotoxin challenge that consistently causes fever in adult cats. Some degree of febrile response was present at birth, but the dose of pyrogen necessary to elicit a fever was 10-15 times greater than that required in the adult. There was a gradual increase in both the magnitude and duration of fever as a function of age with the largest change occurring after 30 days of age. There was a direct relationship between the ability of the kitten to maintain its body temperature (Tbo) at the room ambient (Ta) and the magnitude of the elicited fever. However, increasing the Ta to thermoneutral (Ta = 30-32 degrees C) did not enhance the thermal response indicating that the failure to elicit the fever is not due to passive effects of Ta. These data suggest that the febrile response to an endotoxin develops over the first 6-7 weeks of the kitten's life and are discussed in relation to other physical variables of development.

Weight loss and body temperature changes in breast-fed and bottle-fed neonates

Among 1138 newborns in a Level II nursery, breast-fed and formula-fed infants were comparable in terms of sex, mode of delivery, gestational age, birth weight, and birth temperature. Breast-fed neonates subsequently lost more weight and a greater percentage of their birth weight (mean, 7.4% vs. 4.9%) than did formula-fed infants. Loss of more than 10 percent of birth weight was associated with short gestation and low birth weight and with breast feeding. Birth weight loss of greater than or equal to 3 percent was associated with a risk of fever (greater than or equal to 37.5 degrees C) among breast-fed and formula-fed infants, but there was no gradient of increasing risk of fever with increasing percentage weight loss beyond 3 percent. After weight loss and other significant variables were adjusted for in a multivariate analysis, breast feeding was not independently predictive of fever. Although breast feeding may be associated with weight loss, it is not prudent to assume that this is the cause of fever in a breast-fed neonate.

Hypothalamic sensitivity to leukocytic pyrogen of adult and new-born guinea-pigs

1. Experiments were conducted to localize the hypothalamic site of action of microinjected leucocytic pyrogen and to compare the pyrogenic sensitivity of this locus in adult and new-born guinea-pigs.2. To identify the site reactive to leucocytic pyrogen, bilateral (0.8-1.0 mm from the mid line) injections of 1 microliter were made into conscious adult guinea-pigs via cannulas stereotaxically palced at 0.5 mm intervals and varying depths from the olfactory tegmentum to the mammillary bodies. Injections into the preoptic area produced sharp monophasic fevers with short latencies, whereas injections into circumjacent sites evoked smaller fevers with longer latencies. 3. To assess the ontogeny of the pyrogenic sensitivity of this locus, the febrile response to 1.00, 0.50, and 0.25 microliter leucocytic pyrogen injected bilaterally was compared to 0 to 5-, 6 to 12-, and 13 to 16-day old and in adult guinea-pigs. The minimum pyrogenic dose in both new-born and adult guinea-pigs was 0.25 microliter, but the 0 to 5-day old animals which responded with a fever to this dose were few in number and large in weight; 'small-for age' neonates became hypothermic. 4. The number of febrile animals increased with age; it also could be increased by increasing the dose of leucocytic pyrogen at any age. 5. These results suggest that febrile responsiveness may depend on the stage of development of, presumably, the pyrogen-receptive mechanism. They further imply that the preoptic sites where leucocytic pyrogen acts and thermoafferents are integrated may not be the same, since thermoregulatory capability is fully competent from birth.

Influence of sex and age on febrile responses to peripheral and central administration of pyrogens in the rabbit

1. Intravenous injections of leucocytic pyrogen in doses of 15, 30 and 60 mul./kg caused febrile reactions in male rabbits that were related to age of the animal: rabbits under 2 yr of age developed fevers that were related to dose of pyrogen, while rabbits 2-3 yr old showed large febrile responses which were not dose-related.2. Female rabbits of comparable ages generally showed smaller febrile reactions to I.V. leucocytic pyrogen, and still older females (3-5 yr) developed fever only after the largest dose.3. Dose-related febrile responses to 2.5, 5 and 10 mul. leucocytic pyrogen given intracerebroventricularly (I.C.V.) were greater in male rabbits 1-3 yr old than in females of comparable age. Female rabbits 3-5 yr old showed dose-related fevers that were smaller than those of younger animals of both sexes.4. There were no major differences in response to 125, 250 and 500 ng PGE(2), given I.C.V., between male and female rabbits under 2 yr of age. Females 2-3 yr of age had greater responses to PGE(2) than males of comparable age whilst the oldest females showed smaller responses.5. It is concluded that the febrile response of the rabbit to peripheral and central leucocytic pyrogen varies with both age and sex. Differences in sensitivity of central fever controls to endogenous pyrogen in animals of different ages and sexes may account for the different responses to peripheral pyrogen.

66 infants with urinary tract infection in first month of life

Sixty-six newborn infants with urinary tract infection are described. The wide variation in clinical manifestations is stressed and suggested as an explanation for the variety of clinical descriptions, incidence, and prognosis noted by previous authors. The condition commonly presents on the sixth or seventh day, there is no seasonal incidence, boys are affected more frequently than girls. There was a correlation with maternal infection, perinatal anoxia, and birthweight either below or above the normal range. Unsatisfactory weight progress, lethargy, and anorexia were the most frequent clinical signs. The overall mortality was 11% and further infection occurred in 37% of girls and in 10% of the boys. A clinical classification for the condition is suggested.