Susan M. Scott

Effect of Gestational Age, Postnatal Age, and Illness on Plasma Cortisol Concentrations in Premature Infants

ABSTRACT: The purpose of this study was to define the pattern of postnatal plasma cortisol concentrations during the first week of life in premature infants, and to evaluate the effect of developmental and clinical factors on this pattern. We measured plasma cortisol concentrations in the morning and afternoon on d 2, 4, and 6 in 120 premature infants (gestational age 24–36 wk) and examined the effects of gestational age, postnatal age, and illness. We described an inverse relationship between gestational age and cortisol concentrations, with the youngest infants having the highest random cortisol values (F = 5.14, p = 0.0073). Illness had a significant negative effect such that the cofactors ventilatory support pattern (F = 6.62, p = 0.0016) or “use of surfactant” (F = 6.63, p = 0.001) defined a pattern where cortisol values were lower in infants that had the highest ventilatory requirements or that received surfactant compared with values from those infants who did not have these requirements. The postnatal pattern in cortisol values depended on gestational age. Ill infants more than 27 wk gestational age increased their cortisol values from d 2 to d 6 although cortisol values decreased in well infants. These patterns resulted in a nonsignificant change over time for these age groups. In contrast, cortisol values significantly decreased from d 2 to d 6 in both well and ill infants that were less than or equal to 27 wk. We conclude that plasma cortisol concentrations in the premature infant are significantly correlated with gestational age and to markers of illness. Interpretation of the physiologic significance of random cortisol values in this patient population must be made with consideration for the statistically significant effects described above.

Bloody Nipple Discharge in an Infant and a Proposed Diagnostic Approach

Bloody nipple discharge is a rare finding in infants and is associated most often with benign mammary duct ectasia. The rarity of this symptom in infants and its association with breast carcinoma in adults can lead to unnecessary investigation and treatment. Here we describe a 4-month-old boy with bilateral bloody nipple discharge that resolved spontaneously without treatment by 6 months of age. Furthermore, we propose a strategic method for the evaluation of such infants.

Evidence for Developmental Hypopituitarism in Ill Preterm Infants

OBJECTIVE: The relationship between the concentrations of cortisol and T4 with outcome in the preterm infants has not been well studied.STUDY DESIGN: Mean cortisol (days 2, 4, and 6) and T4 values were correlated to gestational age, illness, and outcome in 210 infants using ANOVA.RESULTS: Cortisol significantly decreased and T4 increased across gestational age. For both hormones, higher values were found in infants on low ventilatory settings. Combined lower cortisol (mean <5 μg/dl (138 nmol/l)) and T4 concentrations (<4 μg/dl) were found in 20/210 (9.5%) infants; 11/20 in a high-acuity group (22% of total) including 48% (12/25) of the deaths. Lower cortisol values were found in infants who died (p<0.005) in contrast to a lack of relationship with T4.CONCLUSIONS: Lower cortisol values in infants who died are consistent with the role for cortisol in survival. Combined lower cortisol and T4 concentrations in infants who failed to improve clinical status may suggest that these hormones are markers of a poor physiological state. In contrast, we suggest that these results reflect a developmental hypopituitarism, a necessary role for cortisone and T4 in successful early neonatal transition. Treatment of hypothyroidism in the setting of coexistent low cortisol concentrations (central dysfunction of the hypothalamic–pituitary axes) is known to precipitate cortisol crisis in older populations. Therefore, we caution against treatment of low neonatal thyroid concentrations until more is known about the relationship between cortisol and T4 preterm infant population.

Effect of calcium therapy in the sick premature infant with early neonatal hypocalcemia

Twenty-seven sick premature infants with serum calcium concentrations less than 6.0 mg/dl during the first day of age were enrolled in a prospective controlled study involving two treatment regimens--calcium given as a bolus or a drip--or no treatment. Mean total calcium concentration was 5.5 +/- 0.8 mg/dl, and ionized calcium was 3.1 +/- .3 mg/dl, with no significant difference between treatment groups. By 24 hours, in all groups total calcium had increased to greater than 6.0 mg/dl (bolus 6.5 +/- 1.1, drip 7.0 +/- 0.4, control 6.6 +/- 0.4) and ionized calcium to greater than 3.5 mg/dl (bolus 3.9 +/- 0.3, drip 3.6 +/- 0.6, control 3.6 +/- 0.3). Ionized and total calcium concentrations were significantly correlated (r = 0.562; P less than 0.001), but total calcium did not predict ionized calcium in any group. These data support the concept that, even in sick infants, early neonatal hypocalcemia is a physiologic phenomenon that may not require treatment.

Positive Relationship of Cortisol Concentrations and Oral Nutrition to Epidermal Growth Factor Concentrations in Preterm Infants

We have suggested from previous studies that increases in early neonatal epidermal growth factor (EGF) concentrations were dependent on adequate glucocorticoid hormone concentrations. In order to examine this relationship, matched values for cortisol and EGF in 193 preterm infants on days 2 and 6 were compared. Gestational age had a significant positive effect on EGF concentrations for those infants receiving oral nutrition and there was also a positive relationship between nutrition and cortisol concentration. Cortisol was then used as an independent factor and was significantly (p = 0.01) related to EGF values such that as cortisol concentrations increased, EGF values also increased. In summary, we suggest that these results are consistent with a role for cortisol in the control of the EGF pattern in the newborn period.

A Pilot Walking School Bus Program to Prevent Obesity in Hispanic Elementary School Children: Role of Physician Involvement With the School Community

Forty-three percent of Hispanic children, 6 to 11 years old, in the United States are overweight or obese.1 Minority status and poverty in urban communities have been found to contribute to childhood obesity.2,3 Given the clear role of environmental contributors to obesity, physicians are increasingly asked to go beyond their clinical practice to support school and community programs that help prevent obesity.4 The Walking School Bus (WSB), an innovative program designed to cut down on traffic congestion while providing a safe way to walk children to school, may offer clinicians a novel approach to obesity prevention.5 Walking to school is an affordable mode of transportation that may help reduce the high prevalence of childhood obesity.6 This brief report outlines principal findings from a pilot WSB program used by school-based health center physicians in collaboration with their school and community. Full details of implementation are reported elsewhere.7 The University of New Mexico School-Based Health Center (UNM SBHC) provides primary care to a predominantly Hispanic elementary school located in the zip code area with the highest percentage of families less than 185% of the federal poverty level in Albuquerque. Student obesity was voiced as a concern by parents and teachers to SBHC physicians at the elementary school. This prompted UNM SBHC to collaborate with the school and community to test the feasibility of a modified WSB program as a strategy to prevent obesity among the elementary school students.

Adrenal and Thyroid Axis Function in Preterm Ventilated Baboons

Cortisol and thyroid hormones are critical to normal fetal development and neonatal transition, and baseline values and stimulation tests are abnormal after preterm birth. To evaluate cortisol and thyroxine (T4) responses that are not influenced by uncontrolled antenatal events associated with human preterm labor, we measured cortisol and T4 after standard-dose adrenocorticotropin (ACTH) and corticotropin-releasing hormone (CRH) stimulation tests, as well as high-dose CRH and thyrotropin-releasing hormone stimulation tests in baboons that were delivered for 3 separate protocols at 125 days of gestation (term is 186 days). The animals were surfactant treated and ventilated for up to 14 days. Some fetuses were exposed to fetal or maternal betamethasone, and some newborns were treated with 10 µg/kg T4 for 9 days after birth. Baseline cortisol levels were in a stress range of 30–60 µg/dl by day 5. Cortisol did not increase consistently until day 11 in response to a high CRH dose or ACTH. T4 treatment for 9 days after birth suppressed the cortisol responses and subsequent baseline T4 levels. The hypothalamic-pituitary-adrenal (HPA) axis was unresponsive to standard dose stimulation tests until 11 days of age in preterm baboons, indicating HPA immaturity.

Developmental Susceptibility to Intestinal Injury by Platelet-Activating Factor in the Newborn Rat

Platelet-activating factor (PAF) is an important endogenous mediator of neonatal necrotizing enterocolitis (NEC). Injection of PAF into weanling and adult rats causes ischemic bowel necrosis that is morphologically similar to NEC. The purpose of this study was to adapt the PAF model of intestinal injury to the suckling rat and to attempt to alter susceptibility to PAF-induced bowel necrosis by early weaning and formula feeds. At ages 15 to 20 days, rat pups were selected to be weaned to either formula or 5% dextrose or to nurse ad lib (total n = 54). At ages 16, 18, 20, 21, 23, or 25 days of life, animals received PAF (50 micrograms/kg) and endotoxin (1 mg/kg) by intraperitoneal injection. Animals were sacrificed 2 h after injection. Intestinal samples were submitted to be graded by a pathologist in a blinded fashion. Injury scores ranged from 0 to 10, based on the percentage of villous necrosis. Prior to age 20 days, minimal histologic injury was present (mean scores on days 16, 18 = 1.7 +/- 0.9, 1.7 +/- 0.6). Combined injury scores for weaned and nursed animals on days 20 and 23 were significantly greater than on days 16 and 18 (p = .0001). Histologic injury in the dextrose group was significantly less than the formula-fed group on day 21 and greater on day 25. Suckling rats showed resistance to PAF-induced bowel necrosis prior to 20 days of age, during the middle of the weaning period. Early weaning to formula did not alter susceptibility to injury, which suggests that PAF-acetylhydrolase from breast milk does not confer this resistance to PAF.

Expert Witness Participation in Civil and Criminal Proceedings

The interests of the public and both the medical and legal professions are best served when scientifically sound and unbiased expert witness testimony is readily available in civil and criminal proceedings. As members of the medical community, patient advocates, and private citizens, pediatricians have ethical and professional obligations to assist in the civil and criminal judicial processes. This technical report explains how the role of the expert witness differs in civil and criminal proceedings, legal and ethical standards for expert witnesses, and strategies that have been employed to deter unscientific and irresponsible testimony. A companion policy statement offers recommendations on advocacy, education, research, qualifications, standards, and ethical business practices all aimed at improving expert testimony.

Disclosure of adverse events in pediatrics

Despite increasing attention to issues of patient safety, preventable adverse events (AEs) continue to occur, causing direct and consequential injuries to patients, families, and health care providers. Pediatricians generally agree that there is an ethical obligation to inform patients and families about preventable AEs and medical errors. Nonetheless, barriers, such as fear of liability, interfere with disclosure regarding preventable AEs. Changes to the legal system, improved communications skills, and carefully developed disclosure policies and programs can improve the quality and frequency of appropriate AE disclosure communications.