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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Under normal circumstances, the fetus is exposed to very low concentrations of cortisol until late in gestation. Perturbations of the intra-uterine environment resulting in fetal exposure to increased cortisol may have consequences not only in infancy, but also into adult life. In the postnatal period, developmental immaturity and/or the effects of critical illness on adrenal function may result in insufficient cortisol production to maintain homeostasis in the face of acute stress or illness, a situation that has been labelled 'relative adrenal insufficiency' in other acutely ill populations. The definition of inadequate adrenal function in the newborn and its possible relationship to adverse outcomes in both premature and term infants are only beginning to be characterized.
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PMID:Adrenocortical function and dysfunction in the fetus and neonate. 1501 72

Adrenal hypoplasia congenita (AHC) is a rare inherited condition characterised by primary adrenal failure and hypogonadotropic hypogonadism. Most cases arise from mutations in the NR0B1 gene (Xp21.3), which encodes an orphan nuclear receptor DAX-1. A 20-year-old patient was recently diagnosed with AHC. Adrenal failure had been recognized and treated since his infancy. During adolescence, gradual decrease in growth velocity and low body mass were noted. Lack of puberty and skeletal immaturity were observed. Serum DHEA-S and testosterone were undetectable. Low gonadotropin levels failed to rise after stimulation. Neither dysfunction of the somatotropic nor pituitary-thyroid axis was found and no hypothalamo-pituitary pathology was visible on MRI. Androgen replacement therapy induced the development of secondary sexual characteristics, remarkably improved patient's growth and advanced his bone age. NR0B1 mutation screening revealed nucleotide transversion C>A, resulting in premature stop codon (Y399X). Same mutation was previously identified in a Scottish family, however, phenotypic differences suggest the role of additional factors modifying the disease course. Although it does not change therapeutic strategy, accurate molecular diagnosis allows genetic counselling in family members. Autoimmunity remains the major cause of adrenal failure; however, other rare conditions should always be considered.
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PMID:Adrenal hypoplasia congenita - an uncommon reason of primary adrenal insufficiency. 2054 58

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.
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PMID:Adrenal and thyroid function in the fetus and preterm infant. 2537 42

The intricate fetal circulatory blood flow undergoes abrupt changes and restructuring at birth, allowing transition to extrauterine life and survival. In the extremely low-birth-weight newborn infant (birth weight <1000 g), these changes are affected by the immaturity of the fetal cardiovascular and pulmonary systems. The immature physiology associated with the inability to transition properly can lead to a poor prognosis and create problematic issues for the clinical management of these infants. Potentially problematic issues and complications include immature myocardium, adrenal insufficiency, patent ductus arteriosus, hypotension, and anemia. Understanding the unique transition to extrauterine life for these infants, problems that arise from immaturity and incomplete transition, and current approaches to management will help nurses and physicians caring for ELBW infants to improve the care they give and minimize mortality and morbidity in this vulnerable population. This article will review transitional physiology for term and preterm newborns, potential problems and complications, and current management approaches.
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PMID:Cardiovascular Transition of the Extremely Premature Infant and Challenges to Maintain Hemodynamic Stability. 2681 94

Neonatal hyperglycemia is common in extremely low birth weight (ELBW) infants because of physiologic stress, exogenous glucose infusion, and postnatal corticosteroid therapy for hypotension, adrenal insufficiency, and pulmonary immaturity. The use of long-acting insulin glargine has been described in the treatment of transient neonatal diabetes in the premature infant, but in these reports is a lack of regard to its use in the treatment of iatrogenic neonatal hyperglycemia. We present the case of an ELBW infant with significant hyperglycemia that was refractory to usual treatment but demonstrated a favorable response to long-acting subcutaneous insulin glargine. The pharmacokinetics on regular insulin and long-acting insulin are different. Regular insulin is broken down into biologically active monomers after subcutaneous injection, and long-acting insulin forms microprecipitates and is gradually released to the body at a neutral physiologic pH after subcutaneous injection. Pharmacokinetics of both regular insulin and long-acting insulin are not clear in ELBW infants. However, with further research on long-acting insulin, it can be used safely to achieve consistent euglycemia with once-daily administration in neonatal hyperglycemia.
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PMID:Use of Insulin Glargine in the Management of Neonatal Hyperglycemia in an ELBW Infant. 2961 Jan 59