Adrenal insufficiency in the critically ill neonate and child

Critical Illness-Related Corticosteroid Insufficiency (CIRCI) After Pediatric Cardiac Surgery

Although current studies do not support the routine use of corticosteroids after cardiopulmonary bypass in pediatric patients, there is incomplete understanding of the potential hemodynamic contribution of postoperative critical illness-related corticosteroid insufficiency in the intensive care unit. By reviewing the available studies and underlying pathophysiology of these phenomena in critically ill neonates, we can identify a subset of patients that may benefit from optimal diagnosis and treatment of receiving postoperative steroids. A suggested algorithm used at our institution is provided as a guideline for treatment of this high-risk population.

A Randomized Controlled Study of Low-Dose Hydrocortisone Versus Placebo in Dopamine-Treated Hypotensive Neonates Undergoing Hypothermia Treatment for Hypoxic-Ischemic Encephalopathy

OBJECTIVE

To investigate whether hydrocortisone supplementation increases blood pressure and decreases inotrope requirements compared with placebo in cooled, asphyxiated neonates with volume-resistant hypotension.

STUDY DESIGN

A double-blind, randomized, placebo-controlled clinical trial was conducted in a Level III neonatal intensive care unit in 2016-2017. Thirty-five asphyxiated neonates with volume-resistant hypotension (defined as a mean arterial pressure [MAP] < gestational age in weeks) were randomly assigned to receive 0.5 mg/kg/6 hours of hydrocortisone or placebo in addition to standard dopamine treatment during hypothermia.

RESULTS

More patients reached the target of at least 5-mm Hg increment of MAP in 2 hours after randomization in the hydrocortisone group, compared with the placebo group (94% vs 58%, P = .02, intention-to-treat analysis). The duration of cardiovascular support (P = .001) as well as cumulative (P < .001) and peak inotrope dosage (P < .001) were lower in the hydrocortisone group. In a per-protocol analysis, regression modeling predicted that a 4-mm Hg increase in MAP in response to hydrocortisone treatment was comparable with the effect of 15 μg/kg/min of dopamine in this patient population. Serum cortisol concentrations were low before randomization in both the hydrocortisone and placebo groups (median 3.5 and 3.3 μg/dL, P = .87; respectively), suggesting inappropriate adrenal function. Short-term clinical outcomes were similar in the 2 groups.

CONCLUSIONS

Hydrocortisone administration was effective in raising the blood pressure and decreasing inotrope requirement in asphyxiated neonates with volume-resistant hypotension during hypothermia treatment.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02700828.

Adrenal insufficiency in neonates undergoing cardiopulmonary bypass and postoperative hypothalamic-pituitary-adrenal function after prophylactic glucocorticoids

OBJECTIVES

Determine incidence of preoperative adrenal insufficiency in neonates >35 weeks gestation with congenital heart disease undergoing cardiothoracic surgery with bypass and effects of prophylactic methylprednisolone on postoperative hypothalamic-pituitary-adrenal function and hemodynamic stability.

DESIGN

Prospective observational study in 36 neonates with preoperative adrenocorticotrophic hormone stimulation tests and serial total cortisol and adrenocorticotrophic hormone measurements before and after surgery. Data analyses: analysis of variance and regression.

RESULTS

Baseline circulating adrenocorticotrophic hormone and cortisol were unchanged 4-20 days postnatal (P > 0.1); however, cortisol levels rose with increasing adrenocorticotrophic hormone, P = 0.02. Ten neonates (29%) demonstrated preoperative adrenal insufficiency (∆cortisol ≤9 µg/dl); one had postoperative hemodynamic instability. Growth-restricted neonates had lower baseline cortisol, but normal stimulation tests and responded well to surgical stresses. Seventy-five percent of neonates receiving perioperative methylprednisolone demonstrated postoperative hypothalamic-pituitary-adrenal inhibition.

CONCLUSION

Adrenal insufficiency appears common in neonates >35 weeks gestation with congenital heart disease, but did not contribute to postoperative hemodynamic instability despite hypothalamic-pituitary-adrenal inhibition.

Salivary biomarkers may measure stress responses in critically ill children

OBJECTIVE

Measurement of salivary biomarkers can provide important information regarding hypothalamic-pituitary-adrenal axis activity both under normal conditions as well as in response to psychological or physical stress. Our aim was to correlate salivary stress markers, such as cortisol, α-amylase and immunoglobulin A, with the Pediatric Risk Index Score of Mortality, underlying disease (pathologic, trauma and postoperative), need for mechanical ventilation/sedation and time lag between onset of illness and admission in children admitted in the pediatric intensive care unit.

METHODS

We enrolled 79 pediatric intensive care unit patients (2-14 years) over a 2-year period, which satisfy the including criteria, but finally salivary biomarkers were evaluated in 65 patients. Saliva samples were collected within 24 h of admission at 8 a.m., 2 p.m. and 8 p.m. to examine potential disruption of circadian rhythm.

RESULTS

Overall, the salivary biomarkers were increased; specifically, median values were (a) cortisol at 8 a.m.: 50.04 nmol/L, 2 p.m.: 30.69 nmol/L and 8 p.m.: 247.12 nmol/L; (b) α-amylase: at 8 a.m.: 22.567 U/L; 2 p.m.: 22.702 U/L and 8 p.m.: 21.484 U/L and (c) IgA at 8 a.m.: 95.10 mg/dL, 2 p.m.: 88.55 mg/dL and 8 p.m.: 80.80 mg/dL. Significantly higher levels were demonstrated in children younger than 6 years and those with Pediatric Risk Index Score of Mortality ⩾8 upon admission. Disturbances in circadian rhythm were observed. Cortisol circadian rhythm disturbance was observed only in children with Pediatric Risk Index Score of Mortality score ⩾8 upon admission while maintaining normal α-amylase circadian rhythm, which was associated with less than 3 days hospitalization in pediatric intensive care unit. No daily variance in IgA was observed.

CONCLUSION

Salivary biomarkers may serve, in critically ill children, as a sensitive, non-invasive method, important for the early recognition of those at high risk and guiding intervention, before clinical deterioration, promoting the quality of health care in pediatric population.

Neonatal adrenal findings: significance and diagnostic approach. Description of two cases

Abnormal adrenal findings such as hemorrhage or calcifications in the neonate can stem from a variety of etiologies. Clinical presentation can vary significantly based on the degree of hemorrhage or the associated condition. Thorough work‐up is important to rule out critical underlying conditions as well as adrenal insufficiency.

Cortisol Levels in Children With Diabetic Ketoacidosis Associated With New-Onset Type 1 Diabetes Mellitus

There is little data documenting cortisol levels in children with diabetic ketoacidosis (DKA), despite the fact that untreated adrenal insufficiency (AI) could worsen the outcome of DKA. In this cross-sectional study, we assessed serum cortisol levels in 28 children with DKA and new onset type 1 diabetes mellitus evaluated at our center over a 5-year period. Average duration of diabetes-related symptoms was positively associated with age ( P = .002), and significantly lower hemoglobin A1c levels were observed in the youngest children. The mean cortisol level was 40.9 µg/dL, with a range of 7.8 to 119 µg/dL. Cortisol levels were found to be inversely associated with serum pH ( P = .007). There was no difference in the clinical outcome of the 4 patients who had cortisol levels less than 18 µg/dL. Overall, we did not find clinical or laboratory evidence of diminished cortisol reserve; however, the possibility of AI must be kept in mind when treating children with DKA.

Medical morbidities and DNA methylation of NR3C1 in preterm infants

BACKGROUND

Although there are no accepted "normal" levels of circulating cortisol in preterm infants, critically ill preterm infants show lower cortisol levels than healthy preterm infants. The regulation of cortisol reactivity by epigenetic changes in glucocorticoid receptor gene (NR3C1) expression has been demonstrated. This study aims to examine the relationship between medical morbidities in preterm infants and DNA methylation of NR3C1.

METHODS

Pyrosequencing was used to determine DNA methylation in CpG sites 1-4 of promoter region 1F of NR3C1. Cluster analysis placed 67 preterm infants born <1,500 g into groups based on medical morbidities. The DNA methylation pattern was compared across groups.

RESULTS

Cluster analysis identified a high medical risk cluster and a low medical risk cluster. A Mann-Whitney U-test showed lower methylation at CpG1 for infants in the high-risk group (M = 0.336, SE = 0.084) than infants in the low-risk group (M = 0.617, SE = 0.109, P = 0.032). The false discovery rate was low (q = 0.025). Cohen's D effect size was moderate (0.525).

CONCLUSION

Decreased DNA methylation of CpG1 of NR3C1 in high-risk infants may allow for increased binding of transcription factors involved in the stress response, repair and regulation of NR3C1. This may ensure healthy growth in high-risk preterm infants over increasing cortisol levels.

Term neonates with infection and shock display high cortisol precursors despite low levels of normal cortisol

AIM

Neonatal therapy-resistant septic shock is a common problem in middle and low-income countries. We investigated whether newborn infants with infection and therapy-resistant hypotension showed evidence of abnormal levels of cortisol or cortisol precursors.

METHODS

A total of 60 term or near term neonates with evidence of infection were enrolled after informed consent. Of these, 30 had an infection and refractory shock and 30 had an infection without shock. There were no detectable differences between the groups in the length of gestation, birth weight or gender distribution. Serum was obtained during days four and 14 after birth. Cortisol and cortisol precursor concentrations were analysed using liquid chromatography-tandem mass spectrometry.

RESULTS

The cortisol concentrations were low considering the expected responses to stress and they did not differ between the groups. The infants with infection and shock had higher serum dehydroepiandrosterone (DHEA) levels than those without shock (319.0 ± 110.3 μg/dL, versus 22.3 ± 18.3 μg/dL; p < 0.0001) and they also had higher 17-hydroxy-pregnenolone, pregnenolone and progesterone concentrations. There were no detectable differences in the levels of 17-hydroxy-progesterone, 11-deoxy-cortisol, cortisol or cortisone.

CONCLUSION

Septic newborn infants with therapy-resistant hypotension had very high DHEA levels, suggesting that 3-beta-hydroxysteroid dehydrogenase activity limited the rate of cortisol synthesis.

Endocrine and metabolic emergencies in children: hypocalcemia, hypoglycemia, adrenal insufficiency, and metabolic acidosis including diabetic ketoacidosis

It is important to fast diagnosis and management of the pediatric patients of the endocrine metabolic emergencies because the signs and symptoms of these disorders are nonspecific. Delayed diagnosis and treatment may lead to serious consequences of the pediatric patients, for example, cerebral dysfunction leading to coma or death of the patients with hypoglycemia, hypocalcemia, adrenal insufficiency, or diabetic ketoacidosis. The index of suspicion of the endocrine metabolic emergencies should be preceded prior to the starting nonspecific treatment. Importantly, proper diagnosis depends on the collection of blood and urine specimen before nonspecific therapy (intravenous hydration, electrolytes, glucose or calcium injection). At the same time, the taking of precise history and searching for pathognomonic physical findings should be performed. This review was described for fast diagnosis and proper management of hypoglycemic emergencies, hypocalcemia, adrenal insufficiency, and metabolic acidosis including diabetic ketoacidosis.

Glucocorticoid Receptor Expression in Peripheral WBCs of Critically Ill Children

OBJECTIVES

To characterize glucocorticoid receptor expression in peripheral WBCs of critically ill children using flow cytometry.

DESIGN

Prospective observational cohort.

SETTING

A university-affiliated, tertiary PICU.

PATIENTS

Fifty-two critically ill children.

INTERVENTIONS

Samples collected for measurement of glucocorticoid receptor expression and parallel cortisol levels.

MEASUREMENTS AND MAIN RESULTS

Subjects with cardiovascular failure had significantly lower glucocorticoid receptor expression both in CD4 lymphocytes (mean fluorescence intensity, 522 [354-787] vs 830 [511-1,219]; p = 0.036) and CD8 lymphocytes (mean fluorescence intensity, 686 [350-835] vs 946 [558-1,511]; p = 0.019) compared with subjects without cardiovascular failure. Subjects in the upper 50th percentile of Pediatric Risk of Mortality III scores and organ failure also had significantly lower glucocorticoid receptor expression in CD4 and CD8 lymphocytes. There was no linear correlation between cortisol concentrations and glucocorticoid receptor expression.

CONCLUSIONS

Our study suggests that patients with shock and increased severity of illness have lower glucocorticoid receptor expression in CD4 and CD8 lymphocytes. Glucocorticoid receptor expression does not correlate well with cortisol levels. Future studies could focus on studying glucocorticoid receptor expression variability and isoform distribution in the pediatric critically ill population as well as on different strategies to optimize glucocorticoid response.

Adrenal and thyroid function in the fetus and preterm infant

Adrenal and thyroid hormones are essential for the regulation of intrauterine homeostasis, and for the timely differentiation and maturation of fetal organs. These hormones play complex roles during fetal life, and are believed to underlie the cellular communication that coordinates maternal-fetal interactions. They serve to modulate the functional adaptation for extrauterine life during the perinatal period. The pathophysiology of systemic vasopressor-resistant hypotension is associated with low levels of circulating cortisol, a result of immaturity of hypothalamic-pituitary-adrenal axis in preterm infants under stress. Over the past few decades, studies in preterm infants have shown abnormal clinical findings that suggest adrenal or thyroid dysfunction, yet the criteria used to diagnose adrenal insufficiency in preterm infants continue to be arbitrary. In addition, although hypothyroidism is frequently observed in extremely low gestational age infants, the benefits of thyroid hormone replacement therapy remain controversial. Screening methods for congenital hypothyroidism or congenital adrenal hyperplasia in the preterm neonate are inconclusive. Thus, further understanding of fetal and perinatal adrenal and thyroid function will provide an insight into the management of adrenal and thyroid function in the preterm infant.

Adrenal insufficiency in children undergoing heart surgery does not correlate with more complex postoperative course

Although some evidence suggests benefit of steroid supplementation after pediatric cardiac surgery, data correlating adrenal function with the postoperative course is scarce. This study sought to determine if adrenal insufficiency (AI) after cardiac surgery is associated with a more complicated postoperative course in children. A prospective study was performed during a 6-month period at a pediatric medical center. Included were 119 children, 3 months and older, who underwent heart surgery with cardiopulmonary bypass. Cortisol levels were measured before and 18 h after surgery. Patients were divided into two groups by procedure complexity (low or high), and clinical and laboratory parameters were compared between patients with and without AI within each complexity group. In the low-complexity group, 45 of the 65 patients had AI. The normal adrenal function (NAF) subgroup had greater inotropic support at 12, 24, and 36 h after surgery and a higher lactate level at 12 and 24 h after surgery. There were no significant differences between subgroups in duration of ventilation, sedation, intensive care unit (ICU) stay, or urine output. In the high-complexity group, 27 patients had AI, and 27 did not. There were no significant differences between subgroups in inotropic support or urine output during the first 36 h or in mechanical ventilation, sedation, or ICU stay duration. Children with AI after heart surgery do not have a more complex postoperative course than children with NAF. The adrenal response of individual patients seems to be appropriate for their cardiovascular status.

Critical illness-related corticosteroid insufficiency in children

Adequate adrenocortical function is essential for survival in critical illness. Most critically ill patients display elevated plasma cortisol concentrations, which reflects activation of the hypothalamic-pituitary-adrenal axis and is considered to be a homeostatic adaptation. However, many critically ill patients have 'relative' or 'functional' adrenal insufficiency, which is characterized by an inadequate production of cortisol in relation to an increased demand during periods of severe stress. Recently, the term 'critical illness-related corticosteroid insufficiency' (CIRCI) was coined. CIRCI occurs as a result of a decrease in adrenal steroid production or tissue resistance to glucocorticoids. An international task force of the American College of Critical Care Medicine issued recommendations for the diagnosis and management of this condition in adult patients. We review the prevalence, diagnosis, and therapeutic approach to adrenal insufficiency in critically ill children. We found a lack of consensus within the pediatric field as to the optimal approach to CIRCI, and call for an international task force to establish unified guidelines.

Endocrine physiology in the newborn

Evaluation of suspected endocrine pathology in newborn infants requires knowledge of the dynamic changes that characterize normal hormonal function in the neonatal period. This article reviews normal endocrine physiology as it pertains to common clinical scenarios encountered in neonatal surgical patients. Topics covered include thyroid and adrenal function as well as glucose and calcium metabolism.

Dexmedetomidine infusion associated with transient adrenal insufficiency in a pediatric patient: a case report

Dexmedetomidine is a highly selective α₂-adrenoceptor agonist used for sedation due to its anxiolytic and analgesic properties without respiratory compromise. Due to its structural similarity to etomidate, there has been concern that dexmedetomidine may cause adrenal insufficiency. This concern was initially supported by animal studies, but subsequent human studies demonstrated mixed results. We describe the case of transient adrenal insufficiency in a 1-year-old male who presented with 24% total body surface 2nd degree burns. He required sedation with a prolonged, high-dose dexmedetomidine infusion with a peak infusion dose of 2.7 mcg/kg/hr and duration of 6.5 days. The patient developed lethargy and hypotension four days after discontinuation of his infusion. He had a random cortisol level which was low at 0.4 mcg/dL, and the concern for adrenal suppression was confirmed with an ACTH stimulation test with the baseline cortisol of 0.4 mcg/dL and inappropriate 60 minute post-ACTH stimulation cortisol of 7.8 mcg/dL. While further studies will be needed to clarify the risk of adrenal suppression secondary to dexmedetomidine, this case suggests that caution should be taken when administering dexmedetomidine to pediatric patients and highlights the need for future studies to look at appropriate dosing and duration of dexmedetomidine infusions.

The effects of three specific conditions related to critical care on adrenal function in children

PURPOSE

To evaluate the effects of three specific conditions related to critical care on adrenal function with special regard to the levels of serum cortisol, corticotropin (ACTH), dehydroepiandrosterone sulfate, and cytokines.

METHODS

The study enrolled a total of 74 children who were divided into three groups. Group 1 comprised 23 patients who had acute critical illness (ACI) associated with severe sepsis/septic shock. Group 2 comprised 27 patients who had ACI without sepsis. Group 3 comprised 24 patients who underwent major surgery. Blood samples were obtained for baseline measurements and a low-dose ACTH stimulation test (LD-ST) was performed. Serial ACTH and cortisol levels were measured with an interval of 3 days and LD-ST was repeated on day 14 for all groups.

RESULTS

Baseline cortisol, ACTH, and dehydroepiandrosterone sulfate levels were significantly higher in patients with adrenal insufficiency (AI) than those of without AI. AI was detected in four patients in group 1, seven in group 2, and ten in group 3. Consecutive cortisol and ACTH levels did not differ significantly among the groups. On day 14, the recovery rate in patients with AI was 82 % in the whole group. Patient's age and interleukin-10 level were found to be independent predictors of AI.

CONCLUSIONS

A considerable proportion of patients in these three groups had AI with a high spontaneous recovery rate in 2 weeks. The presence of sepsis was not associated with an increased risk of AI. Our serial cortisol and ACTH values in these different groups could be used as reference values for further studies.

Clinical course of sepsis in children with acute leukemia admitted to the pediatric intensive care unit

OBJECTIVE

To describe the clinical course, resource use, and mortality of patients with leukemia admitted to the pediatric intensive care unit with sepsis and nonsepsis diagnoses over a 10-yr period.

DESIGN

Retrospective analysis.

SETTING

Tertiary medical-surgical pediatric intensive care unit at C.S. Mott Children's Hospital, University of Michigan.

PATIENTS

All patients with leukemia admitted to the pediatric intensive care unit from January 1, 1998, to December 31, 2008.

INTERVENTIONS

None; chart review.

MEASUREMENTS AND MAIN RESULTS

Clinical course was characterized by demographics, leukemia diagnosis, phase of therapy, leukocyte count on admission, presence of sepsis, steroid administration, intensity of care, and Pediatric Risk of Mortality score on admission to the pediatric intensive care unit. The primary outcome was survival to pediatric intensive care unit discharge. Among 68 single admissions to the pediatric intensive care unit with leukemia during the study period, 33 (48.5%) were admitted with sepsis. Admission to the pediatric intensive care unit for sepsis was associated with greater compromise of hemodynamic and renal function and use of stress dose steroids (p = .016), inotropic and/or vasopressor drugs (p = .01), and renal replacement therapy (p = .028) than nonsepsis admission. There was higher mortality among children with sepsis than other diagnoses (52% vs. 17%, p = .004). Also, mortality among children with sepsis was higher among those with acute lymphoblastic leukemia (60% vs. 44%) compared with acute myelogenous leukemia. Administration of stress dose steroids was associated with higher mortality (50% vs. 17%, p = .005) and neutropenia. Patients with acute lymphoblastic leukemia and sepsis showed the greatest mortality and resource use.

CONCLUSIONS

Patients with acute leukemia and sepsis had a much higher mortality rate compared with previously described sepsis mortality rates for the general pediatric intensive care unit patient populations. Patients who received steroids had an increased mortality rate, but given the retrospective nature of this study, we maintain a position of equipoise with regard to this association. Variation in mortality and resource use by leukemia type suggests further research is needed to develop targeted intervention strategies to enhance patient outcomes.

Adrenal insufficiency in hemodynamically unstable neonates after open-heart surgery

OBJECTIVE

To investigate if the low dose (1 µg) ACTH stimulation test appropriately assesses adrenal responsiveness in neonates undergoing open-heart surgery requiring cardio-pulmonary bypass.

DESIGN

In this retrospective study, adrenal axis response was assessed on the first post-operative day with the low-dose (1 µg) ACTH stimulation test. Age, gender, weight, RACHS category, inotrope score, and baseline and post-stimulation cortisol levels were collected. The association between basal serum cortisol levels and degree of response to the ACTH stimulation test was also investigated.

SETTING

Tertiary care referral center.

PATIENTS

Twenty-one neonates who underwent neonatal cardiac surgery on cardiopulmonary bypass and underwent an ACTH stimulation test. Interventions.  Hydrocortisone 50 mg/m(2) bolus in four divided doses daily.

OUTCOME MEASURES

Response to the low dose (1 µg) ACTH stimulation was assessed.

RESULTS

All neonates with hemodynamic instability in the immediate post-operative period had low basal serum cortisol levels. The basal mean serum cortisol level for the 21 patients who underwent the low dose ACTH stimulation test was 7.3 µg/dL (median 2.2, range 0.7-42). The mean serum cortisol level increased after the ACTH stimulation test in the 21 patients to 39.6 µg/dL (median 38, range 79-17). The mean inotrope score in the first 24 hours after surgery was 24 (median 17.5, range 7-76.5) and decreased to 17 (median 14, range 5-52.3) 24-48 hours after surgery. At 48 hours post-surgery the mean arterial pressure in the groups with a serum cortisol increase after ACTH stimulation (<30 µg/dL vs. >50 µg/dL) was significantly different (P value 0.026).

CONCLUSIONS

The low dose (1 µg) ACTH stimulation test is a valid test to assess adrenal responsiveness among neonates after open heart surgery requiring CPB. Traditionally used basal serum cortisol level cutoff of <20 µg/dL used to define relative adrenal insufficiency may not be applicable in neonates undergoing open heart surgery on CPB thus indicating the need for re-defining adrenal insufficiency in this patient population.

Hydrocortisone administration increases pulmonary artery pressure in asphyxiated newborn piglets reoxygenated with 100% oxygen

In severely asphyxiated neonates developing vasopressor-resistant shock, hydrocortisone is commonly used to improve perfusion. However, its acute haemodynamic effects in asphyxiated neonates are largely unknown. In a swine model of neonatal asphyxia, effects of hydrocortisone on systemic and pulmonary circulations were examined. Piglets (1-3d, 1.5-2.4kg) were acutely instrumented to measure heart rate, systemic and pulmonary artery pressures, and pulmonary artery flow. After 2h of normocapnic hypoxia, animals were resuscitated with 100% oxygen for 1h followed by 21% oxygen for 3h. Intravenous hydrocortisone (1mg/kg) or saline was given in a blinded, randomized fashion 2h after reoxygenation (n=6/group). Haemodynamic parameters, blood gases, plasma cortisol, as well as levels of endothelin-1, nitrite/nitrate, nitrotyrosine, matrix metalloproteinases-2 and -9 in the lung were analysed. Severe hypoxia caused metabolic acidosis (mean pH: 6.91-6.97, mean plasma lactate: 17.2-18.3mM), tachycardia and shock. Hydrocortisone did not affect systemic haemodynamics which recovered with reoxygenation, but it increased pulmonary artery pressure at 90-120min after administration (36±3 vs. 27±2 and 26±1mmHg for hypoxia-reoxygenation control and sham-operated piglets, respectively, P<0.05). In the lung tissue, hydrocortisone significantly increased endothelin-1 and nitrite/nitrate levels, but had no effect on nitrotyrosine. Further, it decreased lung matrix metalloproteinase-9, but not matrix metalloproteinase-2, activity, which were both elevated with hypoxia-reoxygenation. It is most likely that the increase in pulmonary artery pressure observed after hydrocortisone treatment was associated with increased endothelin-1 level in the lung. Our findings caution the use of hydrocortisone as a first-intention treatment of shock in asphyxiated neonates.

Transient adrenal insufficiency in the premature newborn

PURPOSE OF REVIEW

Relative adrenal insufficiency is a controversial phenomenon described in adults and children with critical illness, especially septic shock. In the past 2 decades, relative adrenal insufficiency has also been reported in the critically ill premature as well as term newborn. The present study will review the initial and more recent studies addressing adrenal insufficiency in the premature infant.

RECENT FINDINGS

Studies suggest that 'relative adrenal insufficiency' is a contributing factor to hemodynamic instability in the sick preterm newborn. Many ill preterm newborns have inappropriately low serum cortisol concentrations and respond to steroid administration. Adrenal insufficiency is transient and likely reflects normal adrenal physiology at younger gestational ages. There is no general consensus on its diagnosis, effective minimum dose for treatment and duration of treatment.

SUMMARY

More large scale, multicenter, randomized, double-blind studies are needed to make the diagnosis of relative adrenal insufficiency and to determine the indication, dose, complications and outcome of glucocorticoid therapy.

Shock in the critically ill neonate

Shock is a clinical disorder that challenges caregivers in the neonatal intensive care unit. Critically ill neonates may develop shock due to a variety of causes but the predominant cause of shock in neonates is sepsis. This article provides the neonatal nurse with basic knowledge of the pathophysiology and the types of shock seen in the critically ill neonate. Treatment and supportive care of the neonate in shock is determined by the underlying cause of shock with the ultimate goal of treatment being adequate perfusion of tissues to deliver oxygen to the cells and remove metabolic waste products.

Baseline plasma cortisol and ACTH concentrations and response to low-dose ACTH stimulation testing in ill foals

OBJECTIVE

To evaluate baseline plasma cortisol and ACTH concentrations and responses to low-dose ACTH stimulation testing in ill foals.

DESIGN

Cross-sectional study.

ANIMALS

58 ill foals.

PROCEDURES

Baseline cortisol and ACTH concentrations and cortisol concentrations after administration of a low dose of cosyntropin were determined within 6 hours after admission. Foals were assigned to 4 groups on the basis of age (<or=24 hours vs 1 to 56 days) and presence of septicemia (yes vs no). Values were compared among groups and with values previously reported for healthy foals.

RESULTS

Plasma cortisol concentrations 30 and 60 minutes after cosyntropin administration in foals<or=24 hours old were significantly higher than corresponding cortisol concentrations in older foals. In all 4 groups, plasma cortisol concentration 30 minutes after cosyntropin administration was significantly higher than baseline cortisol concentration or concentration 60 minutes after cosyntropin administration. No differences in baseline cortisol or ACTH concentration or in the ACTH-to-cortisol ratio were detected between groups or when ill foals were compared with healthy foals. A small number of ill foals had low baseline cortisol and ACTH concentrations or low responses to cosyntropin administration, compared with healthy foals.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that most ill foals in the present study population had adequate responses to cosyntropin administration. However, a small subset of ill foals appeared to have dysfunction of the hypothalamic-pituitary-adrenal axis.

ACTH and cortisol response to critical illness in term and late preterm newborns

OBJECTIVE

To determine cortisol and adrenocorticotropic hormone (ACTH) responses to critical illness in term and late preterm newborns and examine the relationship of these values to measures of clinical illness, including markers of cardiovascular dysfunction.

STUDY DESIGN

In this prospective observational study, we measured ACTH, baseline cortisol and ACTH-stimulated cortisol concentrations in mechanically ventilated infants >or=34 weeks gestational age and <5 postnatal days. ACTH-stimulated cortisol concentrations were also measured in a comparison group of non-critically ill, non-mechanically ventilated infants. The relationship of these values to measures of severity of illness including SNAP (score for neonatal acute physiology) scores, blood pressure and vasopressor initiation was examined.

RESULT

Concentrations are presented as median (25th to 75th percentile). Baseline cortisol values in critically ill infants (n=35) were 4.6 microg per 100 ml (3.0 to 16.2); 26 (74%) of these were <15 microg per 100 ml. ACTH-stimulated cortisol values were not significantly different from the comparison group (41 microg per 100 ml (30.3 to 51.8) vs 34.2 microg per 100 ml (25.2 to 43.3)). ACTH concentrations in ill infants (n=10) were 12 pgml(-1) (5.5 to 19.2). None of baseline cortisol, stimulated cortisol and ACTH increased significantly with increasing severity of illness. Of the ill infants, 71% received vasopressor therapy for hypotension. Cortisol concentrations in these infants were similar to those infants who did not receive vasopressor therapy.

CONCLUSION

The majority of these critically ill newborns had very low cortisol and ACTH values without the expected increase in response to critical illness; however, their response to exogenous ACTH was normal. These results demonstrate that the inadequate response to critical illness in these newborns does not result from adrenal dysfunction. We therefore hypothesize that this is a secondary insufficiency arising from inadequate stimulation of the adrenal gland.

Adrenal axis function after high-dose steroid therapy for childhood acute lymphoblastic leukemia

BACKGROUND

A 4-week course of high-dose glucocorticoids may cause prolonged adrenal suppression even after a 9-day tapering phase. In this study, adrenal function and signs and symptoms of adrenal insufficiency were prospectively assessed in children with acute lymphoblastic leukemia (ALL) after induction treatment including high-dose prednisone (PDN) or dexamethasone (DXM).

PROCEDURES

Sixty-four children with ALL, treated according to the AIEOP ALL 2000 Study protocol, underwent low dose ACTH (LD-ACTH) stimulation 24 hr after the last tapered steroid dose. In those with impaired cortisol response, additional LD ACTH tests were performed every 1-2 weeks until cortisol levels normalized. Signs and symptoms of adrenal insufficiency were recorded during the observation period.

RESULTS

All patients had normal basal cortisol values at diagnosis. Twenty-four hours after last glucocorticoid dose, morning cortisol was reduced in 40/64 (62.5%) patients. LD-ACTH testing showed adrenal suppression in 52/64 (81.5%) patients. At the following ACTH test 7-14 days later, morning cortisol values were reduced in 8/52 (15.4%) patients and response to the test was impaired in 12/52 (23%). Adrenal function completely recovered in all patients within 10 weeks. No difference was found between patients treated with PDN or DXM. Almost 35% of children with impaired cortisol values at the first test developed signs or symptoms of adrenal insufficiency. One child developed a severe adrenal crisis during adrenal suppression.

CONCLUSIONS

High-dose glucocorticoid therapy in ALL children may cause prolonged adrenal suppression and related clinical symptoms. Laboratory monitoring of cortisol levels and steroid coverage during stress episodes may be indicated.