Blood spot glucocorticoid concentrations in ill preterm infants

Does Antenatal Progesterone Administration Modify the Risk of Neonatal Intraventricular Hemorrhage?

OBJECTIVE

Progesterone administration has been associated with improved neurological outcomes following traumatic brain injury in adults. However, studies examining the effect of progesterone on the risk of neonatal intraventricular hemorrhage (IVH) are inconsistent. We sought to determine if maternal administration of intramuscular 17-α-hydroxyprogesterone caproate (17-OHPC) is associated with decreased rates of IVH in infants born before 32-weeks gestation.

STUDY DESIGN

This is a retrospective study of liveborn singleton deliveries between 20- and 32-weeks gestation at two large academic medical centers from January 1, 2012 to August 30, 2020. Data were extracted from hospital electronic medical record data warehouses using standardized definitions and billing and diagnosis codes. We evaluated receipt of 17-OHPC in the antepartum period and diagnosis of IVH (grade I-IV, per Volpe classification) during the neonatal delivery hospitalization encounter. Bivariate and multivariate analyses were performed to examine the association between 17-OHPC and neonatal IVH adjusting for potential confounders. Odds ratio (ORs) and 95% confidence intervals (CIs) were presented.

RESULTS

Among 749 neonates born between 20- and 32-week gestation, 140 (18.7%) of their mothers had received antenatal 17-OHPC and 148 (19.8%) were diagnosed with IVH after birth. No significant association was observed between maternal 17-OHPC and neonatal IVH in unadjusted (OR 1.14, 95% CI 0.72-1.78) or adjusted analyses (adjusted odds ratio 1.14, 95% CI 0.71-1.84). Independent of exposure to 17-OHPC, as expected, infants born <28-weeks gestation or those with very low birthweight (<1,500 g) were at an increased risk of IVH (OR 2.32, 95% CI 1.55-3.48 and OR 2.19, 95% CI 1.09-4.38, respectively).

CONCLUSION

Antenatal maternal 17-OHPC administration was not associated with the risk of neonatal IVH. Further research may be warranted to determine whether timing, route of delivery, and duration of progesterone therapy impact rates of neonatal IVH.

KEY POINTS

· This study aimed to compare the frequency of intraventricular hemorrhage in preterm neonates exposed to antenatal 17-α-hydroxyprogesterone caproate to those not exposed.. · In neonates born at <32-weeks gestation, maternal use of progesterone is not associated with the risk of intraventricular hemorrhage.. · In contrast to preclinical and adult data, this study suggests that progesterone exposure is not associated with the prevention of neonatal brain injury..

Trends in narcotics and sedative use during mechanical ventilation of preterm infants in Canadian neonatal intensive care units

OBJECTIVE

Mechanical ventilation (MV) in preterm infants (PTI) causes discomfort. Whether it causes pain is controversial. Meta analysis reviews of published work on PTI during MV have shown no clinically significant impact of opioids on pain scales, and hence not recommended for routine use in neonatal intensive care units (NICUs). Similarly regular use of sedative midazolam is also not recommended. Therefore we hypothesized a downward trend in narcotics and sedatives used in MV of PTI in NICUs. This study aimed to assess trends of sedatives and narcotics use during MV of PTI in Canadian NICUs during 2004-2009.

METHODS

PTI born at gestational age (GA) of <35 weeks requiring invasive MV for >24 hours were identified retrospectively from the Canadian Neonatal Network database for 2004-2009. PTI were excluded if moribund on admission, had major congenital anomalies, surgery (except laser eye surgery), necrotizing enterocolitis, chest tube or history of maternal narcotic abuse. PTI were classified according to whether they received any narcotics (morphine, fentanyl, methadone, sufentanyl, meperidine, alfentynl and codiene) or sedatives (chloral hydrate, midazolam, lorazepam, phenobarbital, pentobarbital, ketamine and propofol) for >24 consecutive hours during MV. Trends of narcotics and sedatives were assessed using the Cochrane-Armitage Trend test separately for PTI born at <29 and 29-34 weeks of GA.

RESULTS

Among 5 638 study subjects, 2 169 (38.5%) received narcotics and 897 (15.9%) received sedatives. The most common narcotics were morphine (62.2%) and fentanyl (63.8%) and sedatives were phenobarbital (44.9%) and chloral hydrate (44.2%). A significant decreasing trend (P<0.01) in the use of any sedatives during MV was observed in PTI <29 and 29-34 weeks of GA. However, the use of any narcotics during MV increased significantly (P=0.03) among PTI <29 weeks of GA, and no change in trend was detected for PTI born at 29-34 weeks of GA.

CONCLUSIONS

The use of sedatives during MV in PTI born at <35 weeks of GA was positively affected, however the narcotics use during MV remained constant for PTI born at 29-34 weeks, and increased in extremely low GA group (less than 29 weeks) suggesting evidence based practice change was not observed during the study period.

No relative increase in intra-abdominal adipose tissue in healthy unstressed preterm infants at term

BACKGROUND

Preterm infants may be at risk for altered adiposity, a known risk factor for unfavorable metabolic and cardiovascular outcomes.

OBJECTIVES

The aim was to compare body composition (total body fat mass (FM), subcutaneous and intra-abdominal adipose tissue (AT)) between infants born preterm and at term.

METHODS

We conducted an observational, cross-sectional study that involved 50 infants born preterm free from major co-morbidities and 34 term healthy breastfed infants. Anthropometric measurements, body composition (total body FM, subcutaneous and intra-abdominal AT) were assessed at 40-42 weeks postconceptional age for preterm infants and within 15 days of birth for term infants. Total body FM was assessed by an air displacement plethysmography system and subcutaneous abdominal and intra-abdominal AT were assessed by magnetic resonance imaging using a commercially available software program.

RESULTS

Compared to term infants, mean (SD) total body FM (g) (636.7 (247) vs. 418.4 (253), p < 0.0001) and mean (SD) subcutaneous abdominal AT (g) (123 (36) vs. 98.9 (22), p < 0.001) were significantly higher in preterm infants but mean (SD) fat-free mass (g) (2,530 (420) vs. 2,965 (389), p < 0.0001) and mean (SD) intra-abdominal AT (10.9 (5.2) vs. 18.2 (13.2), p = 0.001) were significantly lower.

CONCLUSIONS

In the absence of severe illness during the hospital stay, prematurity, although associated with increased total body FM, does not appear to be associated with a relative increase in intra-abdominal AT compared to term infants.

Changes in neuroactive steroid concentrations after preterm delivery in the Guinea pig

BACKGROUND

Preterm birth is a major cause of neurodevelopmental disorders. Allopregnanolone, a key metabolite of progesterone, has neuroprotective and developmental effects in the brain. The objectives of this study were to measure the neuroactive steroid concentrations following preterm delivery in a neonatal guinea pig model and assess the potential for postnatal progesterone replacement therapy to affect neuroactive steroid brain and plasma concentrations in preterm neonates.

METHODS

Preterm (62-63 days) and term (69 days) guinea pig pups were delivered by cesarean section and tissue was collected at 24 hours. Plasma progesterone, cortisol, allopregnanolone, and brain allopregnanolone concentrations were measured by immunoassay. Brain 5α-reductase (5αR) expression was determined by Western blot. Neurodevelopmental maturity of preterm neonates was assessed by immunohistochemistry staining for myelination, glial cells, and neurons.

RESULTS

Brain allopregnanolone concentrations were significantly reduced after birth in both preterm and term neonates. Postnatal progesterone treatment in preterm neonates increased brain and plasma allopregnanolone concentrations. Preterm neonates had reduced myelination, low birth weight, and high mortality compared to term neonates. Brain 5αR expression was also significantly reduced in neonates compared to fetal expression.

CONCLUSIONS

Delivery results in a loss of neuroactive steroid concentrations resulting in a premature reduction in brain allopregnanolone in preterm neonates. Postnatal progesterone therapy reestablished neuroactive steroid levels in preterm brains, a finding that has implications for postnatal growth following preterm birth that occurs at a time of neurodevelopmental immaturity.

Plasma catecholamines and the counterregulatory responses to hypoglycemia in infants: a critical role for epinephrine and cortisol

The purpose of this study was to define plasma catecholamine responses as part of the counterregulatory hormonal reaction to hypoglycemia in infants after a regular 3- to 4-h feed was omitted. Hormone levels were assessed once, at the end of the fast or at hypoglycemia. The 121 infants were subdivided into three groups for analysis: normoglycemia (n = 94, 78%); transient hypoglycemia (n = 11, 9%); or severe and persistent hypoglycemia (n = 16, 13%). The severe and persistent hypoglycemic group had significantly higher levels of cortisol and epinephrine than the normoglycemic group. Norepinephrine and glucagon levels did not differ between the groups. Human GH levels were higher in the transiently hypoglycemic group but not in the severe and persistent hypoglycemic group. Prefeed blood lactate levels differed significantly among the groups and were highest in the severe and persistent groups. Multiple regression analysis showed that cortisol levels were significantly higher in infants who had severe and persistent hypoglycemia. The counterregulatory hormonal response in infants to severe and persistent hypoglycemia was limited to elevations in only cortisol and epinephrine levels but did not involve glucagon or human GH. This limited hormonal response may also contribute to the frequent occurrence of hypoglycemia in these infants.

Pain, opioid tolerance and sensitisation to nociception in the neonate

Pain is commonplace in newborn infants. Opioid analgesics have become increasingly used to reduce different types of pain in neonates, including pain from surgery, medical procedures and chronic conditions. Adverse effects of opioids include respiratory depression, hypotension and tolerance. These adverse effects can be minimised by utilising specific administration techniques and constant monitoring. Recent studies have demonstrated that untreated pain can have long-term effects on infant pain behaviours months beyond the events, thus, opioid analgesics may have a beneficial role that extends beyond the immediate painful event(s).

Saliva and bloodspot cortisol: novel sampling methods to assess hydrocortisone replacement therapy in hypoadrenal patients

BACKGROUND

In patients with hypoadrenalism, it is often difficult to assess the optimal dose of glucocorticoid replacement. Serial serum cortisol measurements for a cortisol day curve are sometimes used, but this has low acceptability for patients. In this study, we evaluate the reliability of saliva and capillary bloodspot cortisol as alternative methods in assessing cortisol profiles in hypoadrenal patients on hydrocortisone replacement.

METHODS

We first examined the correlations between serum cortisol, saliva and bloodspot cortisol in in-hospital patients not on glucocorticoid therapy. We then studied 18 hypoadrenal patients on hydrocortisone therapy and measured their serum, saliva and bloodspot cortisol concurrently at seven different time points in a single day.

RESULTS

For in-hospital patients, a significant correlation exists between saliva and serum cortisol (R = 0.7121, P < 0.0001), but there is a stronger correlation between bloodspot and serum cortisol (R = 0.9494, P < 0.0001). The correlations were weaker in hypoadrenal patients on hydrocortisone (saliva and serum cortisol: R = 0.6262, P < 0.001; bloodspot and serum cortisol: R = 0.7871, P < 0.001). When we evaluated each measurement with respect to an arbitrary target range, there was a greater degree of agreement between serum and capillary bloodspot cortisol (85% agreement) than between serum and saliva cortisol (65% agreement) (P < 0.001).

CONCLUSION

Bloodspot samplings provide a simple and convenient way for ambulant hypoadrenal patients on hydrocortisone replacement therapy to assess cortisol levels at multiple times in a single day. This may be useful in determining the optimal glucocorticoid dose for hypoadrenal patients.

Cortisol and growth hormone responses to spontaneous hypoglycaemia in infants and children

AIMS

To evaluate responses of cortisol and growth hormone (GH) to spontaneous hypoglycaemia in infants and children.

METHODS

Retrospective review of laboratory and clinical data in paediatric patients investigated for suspected hypoglycaemia over a five year period. Thirty patients (16 aged <3 months) had hypoglycaemia confirmed by laboratory analysis (glucose <2.5 mmol/l) and were compared with 26 patients (11 aged <3 months) with glucose > or =2.5 mmol/l.

RESULTS

The commonest causes of hypoglycaemia were transient hyperinsulinism in infants <3 months and intercurrent infection in those >6 months of age. In both hypo- and non-hypoglycaemic patients, cortisol was positively (r(s) +0.66 and +0.68) and GH inversely (r(s) -0.65 and -0.75) correlated with age. Hypo- and non-hypoglycaemic infants <3 months had median cortisol concentrations of 205 and 116 nmol/l respectively compared with 1370 and 736 nmol/l in hypo- and non-hypoglycaemic children >6 months. Conversely, median GH was 46.5 and 51.2 mU/l in hypo- and non-hypoglycaemic infants compared with 14.3 and 12.1 mU/l in older hypo- and non-hypoglycaemic patients. Older non-hypoglycaemic patients with glucose levels below the glycaemic thresholds established for cortisol and GH secretion in adults had higher cortisol and GH concentrations than patients whose glucose levels exceeded these thresholds.

CONCLUSIONS

Cortisol and GH responses to spontaneous hypoglycaemia in children are highly age dependent. Young infants mount a poor cortisol response compared with older infants and children. Children older than 6 months may have glycaemic thresholds for cortisol and GH similar to those established for adults.

Hyperinsulinaemic hypoglycaemia in preterm neonates

Hyperinsulinism in infancy (HI) is an important cause of severe and recurrent hypoglycaemia in newborn infants. It usually appears in infants born at term, and only one case of its occurrence in a prematurely born infant has been reported as an incidental finding. This is a report of seven infants born at 31-36 weeks gestation who experienced severe persistent hyperinsulinism. Two infants were large for dates. All infants were difficult to manage, suggesting that the occurrence of HI with prematurity may be associated with a particularly aggressive illness. HI should be considered in the differential diagnosis of severe hypoglycaemia in preterm infants.

Opioid analgesia for infants in the neonatal intensive care unit

There is an ethical obligation to relieve the pain and suffering in newborn infants. Opioids have been demonstrated to blunt the physiologic effects of pain and may prevent some of the clinical consequences of unmanaged pain. There are sufficient data to recommend the clinical use of opioid analgesics for the treatment of pain in the neonate. Neonates exposed to opioid analgesics can experience adverse effects. Adverse effects can be minimized by the use of various drug administration techniques and close monitoring. Further research is needed to determine how to optimize their effects. Data on the long-term effects of neonatal opioid exposure are warranted.

Infant handling in the NICU: does developmental care make a difference? An evaluative review of the literature

Infant handling and disruptions in the neonatal intensive care unit are environmental stressors over which nurses have the most control. Two of the major goals of developmental care are individualizing care by decreasing infant disruptions and handling by caregivers, and modulating or attenuating infant responses to the care they receive. However, it has yet to be established to what extent these goals have been achieved. This article will provide a comparative review of selected literature to ascertain what effect, if any, the introduction of developmental care has had on infant handling or disruption in the neonatal intensive care unit.

Cortisol in dried blood screening specimens from newborns with raised 17-hydroxyprogesterone and congenital adrenal hyperplasia

BACKGROUND AND OBJECTIVE

Screening for congenital adrenal hyperplasia (CAH) in newborns has become a routine part of many programmes by measuring levels of 17 alpha-hydroxyprogesterone (17-OHP) in the newborn filter-paper blood specimen. Unfortunately, raised levels of 17-OHP, which are largely the consequence of cross-reacting metabolites, are also found in low birth weight, premature and ill neonates. We speculated that differences in concentrations of cortisol in the newborn screening specimen would aid in distinguishing between CAH positive and CAH negative infants among those with raised levels of 17-OHP.

DESIGN

Comparison of cortisol concentrations was made between newborns with CAH and those without but with raised 17-OHP levels.

PATIENTS

Newborn filter-paper blood specimens from 31 infants with transient 17-OHP elevations and 16 infants with confirmed CAH were analysed for cortisol. In addition, assay performance was validated by comparing cortisol values obtained from dried whole blood on filter-paper with the corresponding plasma from 31 adults and six neonates.

MEASUREMENTS

Cortisol in filter-paper blood specimens was determined by adapting a commercial radioimmunoassay kit that had been designed for the determination of cortisol in serum.

RESULTS

The mean cortisol level in the CAH negative group was significantly higher than the mean value in the group with documented CAH (means 1190 +/- 795 nmol/l vs 627 +/- 210 nmol/l; P < 0.01). However, approximately half of the CAH negative infants had cortisol values that overlapped those from the CAH positive group. There was no relationship between the magnitude of the 17-OHP elevation and cortisol concentrations.

CONCLUSION

The measurements of cortisol in dried blood on filter-paper using a commercial radioimmunoassay kit has been shown to be reliable and simple to carry out. The level of cortisol in newborn blood specimens can be used to exclude some infants with elevated 17 alpha-hydroxyprogesterone levels from further testing for CAH. However, overlapping cortisol values between CAH positive and negative infants precludes the assay of cortisol from being used routinely as a reliable means of decision making.

The masculinized female and investigation of abnormal sexual development

The congenital adrenal hyperplasias are the commonest cause of ambiguity of the external genitalia at birth, although sexual differentiation in these disorders is strictly normal. The masculinized genetic female is invariably the result of 21-hydroxylase deficiency. The molecular features are well characterized and the phenotypic correlates are generally concordant. Prenatal treatment by maternal dexamethasone administration can successfully prevent virilization of the external genitalia in an affected female fetus. Placental aromatase is a rare and recently characterized alternative cause of a masculinized female which should be considered in the absence of fetal adrenal hyperplasia and maternal androgen-secreting tumours. The investigation of abnormal sexual development requires an initial karyotype analysis and serum 17OH progesterone measurement to determine whether 21-hydroxylase deficiency is the likeliest cause. Thereafter, the presence of a 46,XY karyotype determines the mode of investigation according to androgen production and action. Obtaining appropriate samples for DNA, biochemical and immunohistochemical analyses is essential if the diagnostic yield for the investigation of abnormal sexual development is to be improved.

Measurement of neonatal responses to painful stimuli: a research review

The measurement of neonatal responses to painful stimuli remains a significant clinical problem. Although numerous measures have been evaluated, instruments that are valid, reliable, and clinically feasible are not yet available. The purpose of this paper is to critique the studies that have been done using biochemical, physiological, and behavioral measures to evaluate neonatal responses to painful stimuli. Specific issues regarding measurement in premature and critically ill neonates are emphasized. The intent of this review and critique of the literature is to stimulate additional research into the assessment of neonatal pain.

Stress, severity of illness, and outcome in ventilated preterm infants

AIM

To determine physiological and hormonal stress responses in ventilated preterm infants.

METHODS

Physiological and hormonal stress responses were studied in 47 ventilated preterm infants who were judged clinically to require sedation. The correlation between the stress response and severity of illness was examined, and responses were compared between infants with different clinical outcomes.

RESULTS

Stress hormone concentrations were significantly correlated with severity of illness, assessed using the arterial: alveolar oxygen partial pressure ratio. Noradrenaline showed the strongest correlation, with an exponential pattern of increased secretion. Catecholamine concentrations before sedation were significantly higher among infants who subsequently died (n = 15, at a median age of 6 days) than among survivors: median noradrenaline 4.31 vs 2.16 nmol/l, median adrenaline 0.69 vs 0.31 nmol/l. The observed fall in noradrenaline with sedation was lower among those who died than survivors (median fall 2% vs 40%).

CONCLUSION

Preterm infants are capable of hormonal stress responses appropriate for the severity of their illness. Extreme catecholamine responses, in the sickest infants, are associated with the worst outcome.

Serum cortisol, dehydroepiandrosterone sulfate, and steroid-binding globulins in preterm neonates: effect of gestational age and dexamethasone therapy

Our aim was to assess adrenocortical function in very low birth weight infants, specifically to evaluate the impact of gestational age and dexamethasone (DEX) therapy on serum concentrations of total and free cortisol, dehydroepiandrosterone sulfate (DHEAS), and steroid-binding globulins. Twelve moderately preterm or full-term neonates of 38 +/- 4 (mean +/- SD) wk of gestation and 36 ill preterm neonates of 26 +/- 2 (mean +/- SD) wk of gestation were studied. Twenty-three of the 36 ill preterm neonates participated in a randomized neonatal DEX trial for the treatment of early chronic lung disease and received a 1-wk treatment of DEX or placebo. Serum concentrations of cortisol, corticosteroid-binding globulin (CBG), sex hormone-binding globulin (SHBG), and DHEAS were measured, and an ACTH test was performed. Gestational age correlated with the umbilical cord concentrations of total cortisol (r = 0.702, p < 0.01), free cortisol (r = 0.489, p < 0.05), DHEAS (r = 0.608, p < 0.01), and SHBG (r = 0.831, p < 0.01), but not significantly with the concentration of CBG (r = 0.428, p = 0.076). One-week DEX therapy decreased the serum concentrations of CBG (DEX 295 nmol/L, placebo 504 nmol/L; p < 0.01), DHEAS (DEX 6.5 mumol/L, placebo 11.8 mumol/L; p < 0.05), and the basal (DEX 81 nmol/L, placebo 176 nmol/L; p < 0.01) and ACTH-stimulated cortisol levels (DEX 458 nmol/L, placebo 817 nmol/L; p < 0.05). One week after discontinuation of DEX or placebo, basal cortisol concentrations did not differ significantly, but ACTH-stimulated cortisol levels were lower in the DEX-treated than in the placebo-treated infants. DEX therapy decreased the serum CBG and DHEAS concentrations and caused a transient suppression in the adrenocortical function. Despite severe illness, the very preterm neonates had relatively low basal cortisol concentrations, suggesting their reduced ability to respond adequately to stress during intensive care.

Inhibition of the contraction of the ductus arteriosus to oxygen by 1-aminobenzotriazole, a mechanism-based inactivator of cytochrome P450

1. We have proposed that contractile tension of the ductus arteriosus is sustained by a cytochrome P450-linked mechanism acting as a limiting step in the synthesis of endothelin-1 (ET-1). In the present study, we have used the isolated ductus from near-term foetal lambs and guinea-pigs to investigate the effect on both muscle tone and ET-1 formation of 1-aminobenzotriazole (ABT), a suicide substrate for mono-oxygenase reactions. 2. ABT relaxed the lamb ductus at rest (2.5% O2) and during the oxygen contraction (15 to 95% O2). The effect was seen at 40 microM, and at 0.8 mM active tone was almost completely abolished. ABT (1 mM) also reversed the oxygen contraction in the guinea-pig ductus. 3. In the lamb ductus, the ABT response was not affected by removal of the endothelium or by treatment with 2.8 microM indomethacin (at 2.5% O2) and the ensuing contraction. 4. At both low and high concentration, ABT relaxed marginally, or not at all, the potassium-contracted (55 mM) ductus from either species. 5. ET-1 release from either the intact or endothelium-denuded lamb ductus tended to decrease in the presence of ABT (1 mM), whilst during the same treatment cyclic GMP content of the tissue remained unchanged. 6. We conclude that ABT relaxation is due to suppression of a contractile mechanism and not to activation of prostaglandin- and NO-mediated relaxing mechanisms. This contractile mechanism has a cytochrome P450-based mono-oxygenase reaction as a key component.

High-performance liquid chromatographic analysis of corticosteroids

This review presents recent developments in high-performance liquid chromatographic (HPLC) analysis of corticosteroids for the determination of clinically important steroids in biological specimens. Various sample preparation techniques are described.

Randomised, double blind trial of two loading dose regimens of diamorphine in ventilated newborn infants

AIMS

To compare the safety and efficacy of two loading doses of diamorphine in 27 ventilated newborn infants in a randomised double blind trial.

METHODS

Fifty or 200 mcg/kg were infused intravenously over 30 minutes, followed by a 15 mcg/kg/hour continuous infusion. Serial measurements were made of physiology, behaviour, and stress hormones.

RESULTS

Both loading doses produced small but significant falls in blood pressure. The 200 mcg/kg dose produced greater respiratory depression, and two infants deteriorated clinically, requiring resuscitation. Loading reduced respiratory effort in most of the infants, but had little effect on behavioural activity. Stress hormone concentrations were reduced at six hours in both dosage groups; differences between loading doses were not significant. Morphine, morphine-3-glucuronide, and morphine-6-glucuronide were detected in the plasma of all patients. No significant differences in concentrations between loading doses were found.

CONCLUSIONS

Diamorphine reduces the stress response in ventilated newborn infants. A high loading dose confers no benefit, and may produce undesirable physiological effects. A 50 mcg/kg loading dose seems to be safe and effective.

Longitudinal study of plasma ACTH and cortisol in very low birth weight infants in the first 8 weeks of life

There are few published data on plasma ACTH and cortisol in very low birth weight (VLBW) infants beyond the first week of life. We therefore measured plasma ACTH and cortisol longitudinally in 25 infants (mean birth weight 1025 g, mean gestational age 28 weeks) at 1, 2, 4 and 8 postnatal weeks to document normative values for infants not receiving dexamethasone. We also examined the influence of clinical state and dexamethasone treatment on plasma ACTH and cortisol levels. Median plasma ACTH increased significantly with advancing postnatal age from 1 week to 8 weeks (21.0 vs. 40.0 ng/l; P = 0.01) but did not correlate with postconceptional age. Median plasma cortisol decreased significantly with advancing postnatal age from 1 week to 8 weeks (216 vs. 50 nmol/l; P = 0.001) and correlated inversely with postconceptional age (P = 0.004). At 8 weeks infants who were clinically well (n = 6) had lower plasma ACTH values compared with sick (n = 6) infants (median: 37.0 vs. 63.5 ng/l; P = 0.033). Plasma ACTH did not correlate with clinical state at 1, 2 and 4 weeks. At none of the postnatal ages studied was plasma cortisol influenced by the degree of sickness. Five infants received dexamethasone to assist weaning from mechanical ventilation. Their median plasma ACTH level, at 8 weeks, was significantly lower than that of the 12 infants who did not receive dexamethasone (11.0 vs. 40.0 ng/l; P = 0.0006). Plasma cortisol was not significantly influenced by dexamethasone treatment (P = 0.27). These data provide further information on the evolution of adrenocortical function in VLBW infants in the first months of life.

Hormonal and metabolic response to hypoglycaemia in small for gestational age infants

Little is known of the ability of hypoglycaemic infants who are small for gestational age (SGA) to mount the coordinated hormonal and metabolic counterregulatory response that is seen in healthy older subjects during glycopenia. This response was studied in 22 SGA infants (birth weight < 10th centile) by measuring the blood concentrations of glucose, intermediary metabolites, and glucoregulatory hormones. Plasma non-esterified fatty acid and blood ketone body concentrations were low, even when blood glucose concentrations were low. Plasma insulin and glucagon varied widely (< 1.0-53.1 mU/l and 16.6-87.1 pmol/l, respectively). Concentrations of noradrenaline and glucagon were raised, but cortisol and adrenaline were lower than those found in hypoglycaemic adults. There was no relationship between the concentration of any hormone and blood glucose concentration. We postulate that hypoglycaemia and the failure to mobilise alternative fuels in some SGA infants is secondary both to a poorly coordinated counterregulatory hormone response and to a peripheral insensitivity to the actions of the hormones. Those infants, who fail to mount a counterregulatory response, should be identified by accurate and reliable blood glucose monitoring, and an adequate exogenous supply of energy, either enteral or parenteral, should be ensured.

Response to treatment of congenital adrenal hyperplasia in infancy

Nine infants with congenital adrenal hyperplasia were started on replacement doses of hydrocortisone (20.6-32.6 mg/m2/day) without receiving a high dose for an initial period first. Plasma adrenal steroid concentrations fell to acceptable levels by 3 months of age. Adequate biochemical control was maintained and satisfactory growth achieved even though the mean dose of hydrocortisone had been reduced to 15 mg/m2/day by the age of 3 years. Inadvertent overtreatment and growth suppression in infants with congenital adrenal hyperplasia may be avoided by using replacement doses from the start, and by permitting the relative dose of hydrocortisone to fall as the body surface area increases during the first year of life.

Value of selective screening for congenital adrenal hyperplasia in Hungary

Measurement of the 17-hydroxyprogesterone concentration in blood spots was used to identify cases of congenital adrenal hyperplasia among patients with inappropriate virilisation, or salt wasting, or both. Between 1978 and 1986 61 were identified among 707 patients (278 neonates, 204 infants, and 225 children). The incidence of classic congenital adrenal hyperplasia was calculated for a seven year prospective trial period using the blood spot 17-hydroxyprogesterone method in selective screening. There were 38 salt losers and 14 simple virilisers in 968,303 live births, an incidence of congenital adrenal hyperplasia of 1:18,000 in the Hungarian population. Selective screening led to earlier diagnosis of congenital adrenal hyperplasia and a pronounced decrease in mortality. A central laboratory to measure the blood spot 17-hydroxyprogesterone concentrations is valuable for the investigation of patients at risk for congenital adrenal hyperplasia in countries where blood steroid assays are not readily available.

Postnatal course of plasma levels of adrenocortical steroids in premature infants with and without NaCl supplementation

To assess the adrenocortical response of premature infants to alterations in sodium balance, the postnatal course of plasma progesterone, 11-deoxycorticosterone, corticosteronoe, aldosterone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol and cortisone was compared in healthy premature infants kept on low (1-2 mEq/kg per day) or high (3-5 mEq/kg per day) sodium diet. The mean birthweight (1470 g, range: 1210-1670 g vs 1410 g, range: 1130-1750 g) and mean gestational age (30.5 weeks, range: 29-32 weeks vs 30.2 weeks, range: 28-32 weeks) in the low and high sodium groups, respectively, were similar. Simultaneous steroid hormone measurements were made weekly up to the 5th week of life using mechanized Sephadex LH-20 multicolumn chromatography and standardized radioimmunoassays. It was demonstrated that in response to renal salt wasting and negative sodium balance there was a significant rise in plasma aldosterone concentration. The plasma levels of other individual corticosteroids generally declined with advancing age, the initial fall, however, was followed by a transient and insignificant but simultaneous increase in 11-deoxycortisol, cortisol, cortisone and corticosterone in prematures on low a sodium diet. This effect could be prevented by giving NaCl supplement. The NaCl-suppressible increase in adrenocortical activity may be the result of the combined effect of stress or angiotensin 11-induced adrenocorticotropic hormone (ACTH) release and/or prolactin-mediated enhanced adrenal response to ACTH.