An apparent cluster of congenital hypopituitarism in central Massachusetts: magnetic resonance imaging and hormonal studies

Effects of growth hormone (GH) on ghrelin, leptin, and adiponectin in GH-deficient patients

Ghrelin is a recently discovered gastric peptide that increases appetite, glucose oxidation, and lipogenesis and stimulates the secretion of GH. In contrast to ghrelin, GH promotes lipolysis, glucose production, and insulin secretion. Both ghrelin and GH are suppressed by intake of nutrients, especially glucose. The role of GH in the regulation of ghrelin has not yet been established. We investigated the effect of GH on circulating levels of ghrelin in relation to its effects on glucose, insulin, body composition, and the adipocyte-derived peptides leptin and adiponectin. Thirty-six patients with adult-onset GH deficiency received recombinant human GH for 9 months in a placebo-controlled study. Body composition and fasting serum analytes were assessed at baseline and at the end of the study. The GH treatment was accompanied by increased serum levels of IGF-I, reduced body weight (-2%) and body fat (-27%), and increased serum concentrations of glucose (+10%) and insulin (+48%). Ghrelin levels decreased in 30 of 36 subjects by a mean of -29%, and leptin decreased by a mean of -24%. Adiponectin increased in the women only. The decreases in ghrelin and leptin correlated with changes in fat mass, fat-free mass, and IGF-I. The reductions in ghrelin were predicted independently of the changes in IGF-I and fat mass. It is likely that the reductions in ghrelin and leptin reflect the metabolic effects of GH on lipid mobilization and glucose production. Possibly, a suppression of ghrelin promotes loss of body fat in GH-deficient patients receiving treatment. The observed correlation between the changes in ghrelin and IGF-I may suggest that the GH/IGF-I axis has a negative feedback on ghrelin secretion.

Posterior pituitary ectopy in children with idiopathic growth hormone deficiency

AIMS

To evaluate the underlying pathogenesis in children with pituitary hormone deficiency by means of high resolution MRI of the brain.

PATIENTS/METHODS

Thirty-seven children with short stature and isolated GH deficiency (IGHD, n = 17) or multiple pituitary hormone deficiency (MPHD, n = 20) were subjected to an MRI of the brain at the age of 1.0-17.3 years. The anatomic condition of the hypothalamo-pituitary area was analyzed and the height of the pituitary gland was measured and compared to the data of age-matched healthy subjects.

RESULTS

Seventy percent of the patients had a characteristic anomaly: the adenohypophysis was hypoplastic, the infundibulum was absent and the posterior pituitary lobe was ectopic at the bottom of the median eminence. The height of the anterior pituitary was significantly reduced in these patients (1.9 +/- 0.1 mm; mean +/- SD) when compared to age-matched healthy controls (4.1 +/- 0.8 mm, p<0.001) or hypopituitary patients with a normal MRI (4.3 +/- 0.8 mm). MPHD was found in 62% of patients with the pituitary anomaly whereas only 27% of children with a normal MRI had MPHD (p<0.05).

CONCLUSIONS

The pathogenesis of the pituitary anomaly is unknown; a disorder during embryonal development or perinatal events have been discussed as causal factors. MRI should have a prominent position in the work-up of hypopituitary children. When an anatomical malformation is visualized by MRI, the diagnostic terminology should be adapted accordingly.

[Hypopituitarism during the first year of life. A collaborative Italian study]

Literature data on statural growth effect of growth hormone (GH) treatment of children with GH deficiency (GHD) appears disappointing when treatment had late onset. It seems therefore that GH treatment should be started as early as possible, thus requiring early diagnosis. This study was undertaken: 1) to define the main characteristics of early onset GHD which may help the clinician for early diagnosis; 2) to evaluate the effect of a GH treatment on the statural growth of early onset GHD, when treatment is started before 1 year of age. Sixteen children with GHD diagnosed before 1 year of age were included in the study; all of them received a GH treatment before 1 year of age and for a minimal duration of 5 years; four had isolated GHD secondary to a GH gene deletion (type 1A GHD). Based on this series, the main anamnestic and clinical characteristics of early onset GHD are: frequent perinatal pathology, short birth height in more than half of the cases, relatively elevated birth weight in all cases, poor statural growth with neonatal onset, associated signs (hypoglycemia, special facies, micropenis, cryptorchidism, liver dysfunction). The effect of GH treatment (> or = 5 years) on statural growth was limited and transient in children with type 1A GHD, and resulted in an incomplete catch-up growth in children with sporadic GHD, their mean height remaining significantly below their target height.

Magnetic resonance imaging in growth hormone deficiency: relationship between endocrine function and morphological findings

Magnetic resonance imaging (MRI) using gadopentetate dimeglumine (Gd-DTPA) improves the delineation of hypothalamic-pituitary structures and facilitates the detection of anatomical abnormalities which are indicators of permanent growth hormone deficiency (GHD). The aim of this study was to determine the frequency of neuroradiological abnormalities in 85 (52 M, 33 F) patients with hereditary or idiopathic forms of isolated GHD (IGHD) or multiple pituitary hormone deficiency (MPHD) and also to investigate the relationship between anatomical findings and hormonal status. Pituitary hypoplasia with absent or thin infundibulum and ectopic posterior pituitary (EPP) were the most frequent findings in 39 patients with MPHD, whereas in 46 patients with IGHD the most frequent finding was pituitary hypoplasia without neuroradiological abnormalities. All patients whose infundibulum was not visualized after Gd-DTPA injection belonged to the MPHD group; therefore, absence of pituitary stalk can be a good indicator of the severity of hormonal deficiencies. Pituitary hypoplasia was found in all patients with familial IGHD. Among patients with abnormalities of the hypothalamic pituitary area on MRI, normal or breech delivery frequency distributed equally. Therefore it seems that mechanical or hypoxic prenatal events cannot be the primary etiological factor in all patients with neuroradiological abnormalities since half of these patients had normal delivery and birth history. The localization of the bright spot of the posterior pituitary at the level of the median eminence, midstalk position or at the end of the infundibulum may suggest a neuronal migration defect which may occur during early embryogenesis. In conclusion, in children with GHD a careful examination of the hypothalamic pituitary area by MRI after enhancement helps to establish the diagnosis and predicts the prognosis.

Sequential contrast-enhanced magnetic resonance imaging in the diagnosis of growth hormone deficiencies

The purpose of the present study was to assess the presence and the time-course of contrast-enhancement in the pituitary gland and pituitary stalk of 24 patients with isolated growth hormone (GH) deficiency and multiple pituitary hormone deficiency. The patients were evaluated clinically (auxological measurements), endocrinologically (spontaneous GH secretion and GH stimulation tests) and with conventional MRI scans. In addition, fast-framing dynamic magnetic resonance imaging (MRI) with Gd-DTPA enhancement was used to quantitate the time course of contrast enhancement within the neurohypophysis, pituitary stalk, postero-superior adenohypophysis and antero-inferior adenohypophysis. In 3 patients without evidence of abnormalities at normal conventional MRI scans (normal anterior lobe and pituitary stalk, normal posterior lobe) and a high response to the GRF provocation test, sequential time-resolved Gd-enhanced MRI demonstrates reduced contrast enhancement in the pituitary stalk. These findings are consistent with impairment in stalk vasculature, presumably located at the level of the portal venous system, and could play a role in the pathogenesis of pituitary hormonal deficiency.

Nasal pyriform aperture stenosis and absence of the anterior pituitary gland: report of two cases

We describe two female infants with congenital nasal pyriform aperture stenosis and severe pituitary insufficiency. The anterior pituitary gland was undetectable with magnetic resonance imaging. Consanguinity of parents in both cases suggests autosomal recessive inheritance of this disorder. An early fetal developmental defect may explain this syndrome, which affects midline craniofacial structures. In patients with congenital pyriform aperture stenosis, magnetic resonance imaging of the brain and endocrine investigations should be performed for rapid diagnosis and treatment of the latter to avoid major neurologic complications.

Posterior pituitary ectopia and hypopituitarism--magnetic resonance appearances of four cases and a review of the literature

In four patients presenting in childhood with varying degrees of hypopituitarism, magnetic resonance imaging (MRI) showed a reduction in size of the normal pituitary fossa contents and an absent or very narrow stalk. A high signal intensity, enhancing area at the base of the stalk, having the appearances and signal characteristics of the posterior pituitary, was seen in each case. We discuss the case histories and MR findings in our patients and review the relevant literature.

Auxological, clinical and neuroradiological findings in infants with early onset growth hormone deficiency

Sixteen infants less than 2 years of age with apparently idiopathic hypopituitarism were studied. At birth, 11 of 16 patients (69%) had subnormal length associated with relative adiposity and 10 of 16 (62%) showed significant deterioration in length deficiency from birth onwards. These findings suggest that: (a) growth hormone deficiency, in a number of patients, had started well before delivery; (b) growth hormones may play a role in intrauterine growth; and (c) growth hormone may also be involved in early postnatal growth. Magnetic resonance imaging in these patients was very similar to that described in hypopituitarism of later onset. This suggests that even in the latter case, hypopituitarism may have a prenatal onset. Finally, the severity of growth failure and the coexistence of other hypopituitary symptoms at the time of diagnosis in 31% of our patients indicate that early clinical screening of hypopituitarism is possible.

Transient central hypothyroidism as a cause of failure to thrive in newborns and infants

The course of two neonates and one 4-month-old infant with laboratory and clinical evidence of central hypothyroidism is described. All three presented with failure to thrive and improved after L-T4 therapy. Early recognition and treatment of newborns and infants with central hypothyroidism is important to maximize the potential for growth and development. Two of the three infants have been documented to have transient central hypothyroidism of hypothalamic origin, not previously reported.

Congenital panhypopituitarism of late onset

A 29-year-old male was diagnosed congenital panhypopituitarism due to pituitary hypoplasia, absence of pituitary stalk and ectopic neurohypophysis. This report, together with bibliographic review, may induce to reconsidering isolated GH failures, partial hypopituitarisms and panhypopituitarisms which have up to now been interpreted as idiopathic. The availability of new image techniques has allowed a better definition of the anatomic substrate of these alterations, and more subtle hormonal studies have pointed out, in some cases, their possible hypothalamic origin. On this basis, some of these cases may be interpreted as presenting the same alteration as those described in necropsy of newborns dead due to severe panhypopituitarism. Therefore, a unique clinical picture with various degrees of severity may be postulated.

Fetal hypopituitarism: perinatal endocrine and morphological studies in two cases

We report two infants with congenital absence of the anterior pituitary gland, documented by magnetic resonance imaging (MRI) or autopsy. In cord plasma obtained at birth from both infants, prolactin (PRL), pituitary growth hormone (hGH), placental growth hormone (hPGH) and thyrotropin (TSH) were undetectable; cortisol was low; thyroxine (T4) was 31 nmol/l in one infant and 85 nmol/l in the other infant who had been treated prenatally with intra-amniotic L-T4 administration. In maternal plasma at birth, PRL, hPGH and T4 were normal and hGH was undetectable. These observations suggest that plasma hGH and PRL in the fetus are exclusively of fetal pituitary origin, hPGH is secreted into the maternal circulation and is not transferred to the fetus and fetal growth can be normal in the absence of hGH, hPGH and PRL in fetal plasma.

Multiple pituitary hormone deficiencies in a patient with spinocerebellar ataxia: magnetic resonance imaging and hormonal studies

Degenerative spinocerebellar ataxia has a rare association with hypogonadotropic hypogonadism. In this report we present the results of the detailed endocrine evaluation and magnetic resonance imaging in one such patient. A 20-year-old male with progressive cerebellar ataxia, hypogonadism, and short stature was investigated. Basal testing revealed hypogonadotropic hypogonadism (LH < 5 mU/L, FSH < 5 mU/L, testosterone 2.5 nM/L). There was no rise in LH after stimulation with LHRH, peak LH level being < 5 mU/L. Insulin hypoglycemia testing was consistent with GH deficiency, with peak GH being 3.2 mU/L. On TRH stimulation, there was no significant rise in prolactin, though the TSH response was normal. Magnetic resonance imaging revealed cerebellar atrophy. The anterior pituitary was atrophic, with a height of 1.4 mm. The posterior pituitary and the pituitary stalk were normal in size and position. This patient with degenerative spinocerebellar ataxia had multiple pituitary hormone deficiencies. The results of our endocrine evaluation and MR imaging lead us to believe that these deficits may result from a lesion at the level of the pituitary gland.

Denervation of the rat posterior pituitary gland: validation of a stereotaxic method

A stereotaxic surgical method was developed for interrupting the nerve fibres running through the rat pituitary stalk to the posterior pituitary gland without obliterating the hypothalamo-pituitary portal circulation. The pituitary stalk was compressed by the blunt tip of an L-shaped rotating knife. Successful operations produced mild diabetes insipidus, disappearance of arginine vasopressin from the neural lobe, accumulation of arginine vasopressin and neurosecretory material in the pituitary stalk and no infarction in the anterior lobe of the pituitary gland. In female rats, the oestrous cycle was only temporarily disturbed. Plasma prolactin and corticosterone levels were high during the first 24 h after the stalk compression but returned to normal baseline levels from the second day after the operation. One week after the operation plasma adrenocorticotropin and prolactin levels were in the control range while plasma alpha-melanocyte-stimulating hormone was elevated. Denervation of the posterior pituitary gland may help in studying the neural control of intermediate lobe function and the role of the neural lobe in various endocrine conditions, and may serve as a model for lesions of the pituitary stalk and formation of ectopic neurohypophysis in the human.

Acquired growth hormone deficiency due to pituitary stalk transection after head trauma in childhood

Two patients are reported with growth hormone deficiency due to head trauma in childhood. Although their injuries were outwardly only slight and there was no loss of consciousness and no subsequent neurological deficits, they exhibited gradual growth retardation from the time of the trauma. Provocative endocrinological tests showed growth hormone deficiency and MRI showed transection of the pituitary stalk. These findings suggest that ordinary head trauma, as well as perinatal insult and congenital abnormalities, could be a cause of growth hormone deficiency.

Magnetic resonance imaging in patients with hypopituitarism

In patients with hypopituitarism, magnetic resonance (MR) imaging of the hypothalamus and pituitary has disclosed a high incidence of hypoplasia of the anterior pituitary lobe, attenuation or transection of the pituitary stalk, and formation of an "ectopic" posterior pituitary lobe at the base of the hypothalamus. These anatomic abnormalities may be associated with other congenital malformations of the central nervous system, or may be due to an in utero toxic or infectious insult, perinatal trauma, neonatal asphyxia and hypoxia, head injury, or hemorrhage into a pituitary adenoma. The progressive development of defects in pituitary hormone secretion in such patients is probably due to continued atrophy of an anterior pituitary remnant with a limited vascular supply unstimulated by hypothalamic neuropeptides. By contrast, in patients with isolated hypogonadotropic hypogonadism, hypothalamic pituitary anatomy is normal, although abnormalities of the olfactory sulcus are present in patients with anosmia and hypogonadotropism (Kallmann syndrome). In most patients with central diabetes insipidus, the neurohypophysis is absent on MR scan.

Magnetic resonance imaging in the diagnosis of growth hormone deficiency

Forty-six patients with idiopathic growth hormone deficiency were examined by magnetic resonance imaging at a mean (+/- SEM) age of 9 +/- 1 years (range 15 days to 20 years). They were classified into two groups according to MRI images: group 1 (n = 29) had pituitary stalk interruption syndrome and group 2 (n = 17) had normal pituitary anatomy. All patients with pituitary stalk interruption had a pituitary height at less than -2 SD for age; three had no visible anterior pituitary lobe. By contrast, the pituitary height was less than normal in only 10 patients (60%) with normal pituitary anatomy. Growth hormone deficiency was transient in one of the seven patients with normal pituitary anatomy and height. The group with pituitary stalk interruption had the first symptom of growth hormone deficiency at an earlier age (2.8 +/- 0.6 vs 5.5 +/- 1.2 years; p less than 0.001), were of smaller stature (-4 +/- 0.2 vs -3 +/- 0.2 SD; p less than 0.01) and had lower GH peak response to provocative testing (3 +/- 0.4 vs 5 +/- 0.5 ng/ml; p less than 0.001) than did the group with normal pituitary anatomy. Their pituitary gland was also shorter (2.5 +/- 0.2 vs 3.5 +/- 0.2 mm; p less than 0.01). All the patients with multiple pituitary deficiencies except one (n = 19) belonged to this group. One girl with pituitary stalk interruption and deficiencies in growth hormone and thyroid-stimulating hormone had advanced central precocious puberty. We conclude that the evaluation of the shape and height of the pituitary gland by MRI is an additional tool for the diagnosis of growth hormone deficiency. The presence of pituitary stalk interruption confirms this diagnosis and is predictive of multiple anterior pituitary deficiencies. The lack of a significant increase in perinatal abnormalities in this group and the association of pituitary stalk interruption with microphallus and with facial or sella abnormalities suggest that this appearance may have an early antenatal origin. The finding of a familial case of pituitary stalk interruption suggests a genetic origin.

Congenital hypopituitarism: results of pituitary stimulation tests and of magnetic resonance imaging in a newborn girl

We report the case of a newborn girl in whom hypopituitarism was diagnosed in the neonatal period. Clinical, biological and radiological evidence suggested that hypopituitarism must have existed before delivery, yet MRI findings were similar to those described in older children with hypopituitarism of later onset.

MR imaging of the pituitary gland in central precocious puberty

Cranial magnetic resonance imaging was performed in 17 children with central precocious puberty (CPP) and 19 aged-matched controls to compare the appearance of the pituitary gland. Gland size was measured on T1-weighted sagittal and coronal images. The gland was graded according to the concavity or convexity of the upper surface, and the signal intensity of the gland was assessed visually. The mean pituitary volume in 13 CPP children without hypothalamic tumor (292.6 mm3) was significantly greater than that in normal controls (181.35 mm3). The mean volume for the four CPP children with hypothalamic tumor was smaller (145.0 mm3). Compared to controls, the upper pituitary surface in CPP patients appeared convex in a higher proportion. The anterior pituitary was isointense to pons in all patients and controls. Although the posterior pituitary bright spot was present in 14 controls and 11 CPP patients, none with hypothalamic tumor showed it.