Neonatal Hypopituitarism: Approaches to Diagnosis and Treatment

The molecular basis of hypoprolactinaemia

Hypoprolactinaemia is an endocrinopathy which is typically encountered as part of a combined pituitary hormone deficiency picture. The vast majority of genetic causes identified to date have been in the context of congenital hypopituitarism with multiple co-existent endocrinopathies. This is primarily with its closest hormonal relation, namely growth hormone. Acquired hypoprolactinaemia is generally rare in paediatric patients, and usually occurs together with other hormonal deficiencies. Congenital hypopituitarism occurs with an incidence of 1:4,000-10,000 cases and mutations in the following transcription factors account for the majority of documented genetic causes: PROP-1, POU1F1, LHX3/4 as well as documented case reports for a smaller subset of transcription factors and other molecules implicated in lactotroph development and prolactin secretion. Isolated prolactin deficiency has been described in a number of sporadic case reports in the literature, but no cases of mutations in the gene have been described to date. A range of genetic polymorphisms affecting multiple components of the prolactin signalling pathway have been identified in the literature, ranging from RNA spliceosome mutations (RNPC3) to loss of function mutations in IGSF-1. As paediatricians gain a greater understanding of the long-term ramifications of hypoprolactinaemia in terms of metabolic syndrome, type 2 diabetes mellitus and impaired fertility, the expectation is that clinicians will measure prolactin more frequently over time. Ultimately, we will encounter further reports of hypoprolactinaemia-related clinical presentations with further genetic mutations, in turn leading to a greater insight into the molecular basis of hypoprolactinaemia in terms of signalling pathways and downstream mediators. In the interim, the greatest untapped reserve of genetic causes remains within the phenotypic spectrum of congenital hypopituitarism.

Mini-Puberty, Physiological and Disordered: Consequences, and Potential for Therapeutic Replacement

There are 3 physiological waves of central hypothalamic-pituitary-gonadal (HPG) axis activity over the lifetime. The first occurs during fetal life, the second-termed "mini-puberty"-in the first months after birth, and the third at puberty. After adolescence, the axis remains active all through adulthood. Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disorder characterized by a deficiency in hypothalamic gonadotropin-releasing hormone (GnRH) secretion or action. In cases of severe CHH, all 3 waves of GnRH pulsatility are absent. The absence of fetal HPG axis activation manifests in around 50% of male newborns with micropenis and/or undescended testes (cryptorchidism). In these boys, the lack of the mini-puberty phase accentuates testicular immaturity. This is characterized by a low number of Sertoli cells, which are important for future reproductive capacity. Thus, absent mini-puberty will have detrimental effects on later fertility in these males. The diagnosis of CHH is often missed in infants, and even if recognized, there is no consensus on optimal therapeutic management. Here we review physiological mini-puberty and consequences of central HPG axis disorders; provide a diagnostic approach to allow for early identification of these conditions; and review current treatment options for replacement of mini-puberty in male infants with CHH. There is evidence from small case series that replacement with gonadotropins to mimic "mini-puberty" in males could have beneficial outcomes not only regarding testis descent, but also normalization of testis and penile sizes. Moreover, such therapeutic replacement regimens in disordered mini-puberty could address both reproductive and nonreproductive implications.

Neonatal Endocrine Diseases

Endocrine diseases are rare and can present very subtly in the neonatal period. Most are diagnosed using newborn screening in the United States; however, some infants may present with false negatives or more subtle findings. Endocrine etiologies should be considered during the management of critically ill infants. This article will give an overview of endocrine emergencies encountered in the neonatal period, including disorders of glucose metabolism, thyroid disorders, adrenal disorders, and pituitary disorders.

Management of Neonatal Isolated and Combined Growth Hormone Deficiency: Current Status

Congenital growth hormone deficiency (GHD) is a rare disease caused by disorders affecting the morphogenesis and function of the pituitary gland. It is sometimes found in isolation but is more frequently associated with multiple pituitary hormone deficiency. In some cases, GHD may have a genetic basis. The many clinical signs and symptoms include hypoglycaemia, neonatal cholestasis and micropenis. Diagnosis should be made by laboratory analyses of the growth hormone and other pituitary hormones, rather than by cranial imaging with magnetic resonance imaging. When diagnosis is confirmed, hormone replacement should be initiated. Early GH replacement therapy leads to more positive outcomes, including reduced hypoglycaemia, growth recovery, metabolic asset, and neurodevelopmental improvements.

Normal or elevated prolactin is a good indicator to show pituitary stalk interruption syndrome in patients with multiple pituitary hormone deficiency

OBJECTIVES

To determine the importance of serum prolactin (PRL) in the detection of pituitary stalk interruption syndrome (PSIS) in children with multiple pituitary hormone deficiency (MPHD). We hypothesized that PRL elevation might be a diagnostic indicator of pituitary stalk pathologies.

METHODS

Clinical, radiological, and laboratory features of the 50 cases of MPHD were studied.

RESULTS

The median age at presentation of the 50 cases (52%, n=26 were female) was 6.61 (0.02-18.9) years. PSIS was detected in 60% (n=30), pituitary hypoplasia in 32% (n=16), partial empty sella in 6% (n=3), and only 2% (n=1) was reported as normal. Out of 50 patients, 21.3% (n=10) were hypoprolactinemic, 44.7% (n=19) were normoprolactinemic, and 34% (n=16) were hyperprolactinemic. The median PRL value was 27.85 (4.21-130) ng/mL in patients with PSIS and 5.57 (0-41.8) ng/mL in patients without PSIS. Additional hormone deficiencies, especially ACTH and LH were detected in follow-up.

CONCLUSIONS

Patients with normal or high prolactin levels deserve special attention regarding the possibility of PSIS. Furthermore, we emphasize the importance of regular follow-up and monitoring for multiple pituitary hormone deficiencies in all patients with a single pituitary hormone deficiency.

Transfontanelle photoacoustic imaging for in-vivo cerebral oxygenation measurement

The capability of photoacoustic (PA) imaging to measure oxygen saturation through a fontanelle has been demonstrated in large animals in-vivo. We called this method, transfontanelle photoacoustic imaging (TFPAI). A surgically induced 2.5 cm diameter cranial window was created in an adult sheep skull to model the human anterior fontanelle. The performance of the TFPAI has been evaluated by comparing the PA-based predicted results against the gold standard of blood gas analyzer measurements.

Septo-Optic Dysplasia Diagnosed in a Newborn Infant with Normoglycemia: The Importance of Thorough Physical Examination

A newborn male infant was admitted to the neonatal intensive care unit due to suspected sepsis. He was clinically stable with normal electrolyte levels on admission. However, he was noted to have micropenis and bilateral nonpalpable testes. Ultrasound imaging confirmed the presence of both gonads in the inguinal canal, with no Müllerian structures visualized. Laboratory examination revealed an undetectable random plasma cortisol level; subsequent ACTH stimulation testing confirmed adrenal insufficiency. Further testing revealed additional pituitary hormone deficiencies, and the infant was started on multiple hormone replacement therapies. Magnetic resonance imaging identified absent septum pellucidum, pointing of the frontal horns, and optic nerve hypoplasia. A diagnosis of septo-optic dysplasia was made based on this combination of findings. This case highlights the importance of thorough physical examination in newborn infants, which may reveal the only sign of underlying pathology in the absence of other concerning findings.

PES Syndrome Presenting as Severe Hyponatremia in an Asymptomatic Septuagenarian

Background

Hyponatremia is commonly seen in hospitalized patients. In euvolemic individuals, syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common differential. However, before establishing a diagnosis of SIADH, it is imperative to evaluate for hypocortisolism and hypothyroidism. The finding of endocrine abnormalities determined to be of pituitary origin should prompt evaluation by brain MRI. Furthermore, primary empty sella (PES) is commonly seen as an incidental neuroradiological finding. However, PES in association with endocrine abnormalities is recognized as a separate entity called primary empty sella syndrome (PESS). Case Presentation. We report the case of a 71-year-old male sans neurological symptoms who presented to us with severe hyponatremia in whom we used a stepwise approach which led us to the diagnosis of PESS. This methodical approach was crucial for timely correction of the endocrine abnormalities which in turn rectified hyponatremia. Intriguingly, the presence of an ectopic pituitary which is a very rare entity and the sudden manifestation of his underlying endocrine deficiencies in the 8th decade of life make this clinical scenario highly unusual.

Conclusion

Clinicians should be aware that absence of an orderly approach to workup presumed SIADH or an assumption of PES (instead of PESS) could both lead to serious consequences in the face of missed endocrine deficiencies.

Ectopic Posterior Pituitary, Polydactyly, Midfacial Hypoplasia and Multiple Pituitary Hormone Deficiency due to a Novel Heterozygous IVS11-2A>C(c.1957-2A>C) Mutation in the GLI2 Gene

A novel heterozygous IVS11-2A>C(c.1957-2A>C) mutation in the GLI2 gene is reported. There was an extremely distinct phenotypical expression in two siblings and their father. The index case was a boy who developed cholestasis and hypoglycaemia in the neonatal period. He had bilateral postaxial polydactyly, mid-facial hypoplasia, high palatal arch, micropenis, and bilateral cryptorchidism. Laboratory examination revealed a diagnosis of multiple pituitary hormone deficiency. There was severe anterior pituitary hypoplasia, absent pituitary stalk and ectopic posterior pituitary on magnetic resonance imaging which suggested pituitary stalk interruption syndrome with no other midline structural abnormality. Molecular genetic analysis revealed a novel heterozygous splicing IVS11-2A>C(c.1957-2A>C) mutation detected in the GLI2 gene. His father and a six-year-old brother with the identical mutation also had unilateral postaxial polydactyly and mid-facial hypoplasia although there was no pituitary hormone deficiency. This novel heterozygous GLI2 mutation detected appears to present with an extremely variable clinical phenotype, even in related individuals with an identical mutation, suggesting incomplete penetrance of this GLI2 mutation.

Characteristics of Patients with Hypopituitarism having Onset Symptoms of Pseudo-Intestinal Obstruction: A Case Report

BACKGROUND

Gastrointestinal symptoms are often the first symptoms of hypopituitarism. However, pseudo-intestinal obstruction is not a common manifestation of hypopituitarism. Some patients presenting with gastrointestinal symptoms as their chief complaint were admitted to the Department of Gastroenterology and were accurately diagnosed with hypopituitarism at the Department of Endocrinology.

CASE SUMMARY

This case pertains to a 57-year-old man with poor appetite, fatigue, weakness, and recent onset recurring abdominal pain. An erect, abdominal X-ray indicated flatulence and gas-fluid levels in the midsection of the abdomen, and pseudo-intestinal obstruction was diagnosed. Subsequently, the patient was referred to the Department of Gastroenterology to identify the cause of the pseudo-intestinal obstruction. An examination of the digestive system did not reveal any abnormalities, but the patient developed hyponatremia and exhibited drowsiness. The patient was transferred to the Department of Endocrinology for further treatment. The patient was eventually diagnosed with hypopituitarism, caused by empty sella syndrome. The patient received prednisone and euthyrox replacement therapy, and pseudo-intestinal obstruction did not occur again.

CONCLUSION

In general, endocrine diseases, including hypopituitarism, hypothyroidism, and hyponatremia, should be considered for patients with pseudo-intestinal obstruction combined with hyponatremia and drowsiness, especially if the symptoms of the digestive system are not complicated and the drowsiness is obvious.