Evidence of morphological and functional abnormalities in the hypothalamus of growth-hormone-deficient children: a combined magnetic resonance imaging and endocrine study

Prevalence of brain MRI findings in children with nonacquired growth hormone deficiency: a systematic review and meta-analysis

PURPOSE

To verify and integrate the prevalence and phenotype of abnormalities in the sellar region in patients with growth hormone deficiency (GHD) using MRI data.

METHODS

We searched PubMed and EMBASE up to December 14, 2020. The inclusion criteria were as follows: (1) pediatric patients diagnosed with nonacquired GHD and (2) detailed data sufficient to assess the proportion of sellar and parasellar abnormalities on brain MRI scans. Finally, thirty-two studies with 39,060 children (mean or median age, 3.4-14.1 years) were included. The number and type of MRI findings from all included studies were pooled by two authors. The heterogeneity across studies was evaluated with the Q test or the inconsistency index (I²) statistic. Subgroup analyses were performed according to the type of GHD (isolated GHD [IGHD] vs. multiple pituitary hormone deficiency [MPHD]), MRI magnet, geographical region, and cutoff serum growth hormone (GH) level.

RESULTS

The pooled proportion of sellar and parasellar abnormalities was 58.0% (95% CI, 47.1-68.6%; I², 98.2%). The MPHD group showed a higher proportion of sellar and parasellar abnormalities and pituitary stalk interruption syndrome than the IGHD group (91.4% vs. 40.1%, P<0.001; 65.3% vs. 20.1%, P<0.001). The patients in studies with low peak GH levels on stimulation tests were more associated with severe MR abnormalities (cutoff GH ≤ 5 μg/l vs. cutoff GH = 10 μg/l; 72.8 % vs. 38.0%; P<0.001).

CONCLUSION

The types and incidence of MRI abnormalities of the sellar region differ significantly between the IGHD and MPHD groups.

The Severity of Growth Hormone Deficiency Does Not Predict the Presence or Absence of Brain Magnetic Resonance Imaging Abnormalities - A Retrospective Review

BACKGROUND

The Growth Hormone Research Society recommends that all patients diagnosed with growth hormone deficiency (GHD) should undergo brain magnetic resonance imaging (MRI). This is still a point of controversy in patients with mild GHD, as the level of peak growth-hormone (GH) as a predictor of brain MRI abnormality has not yet been established. The objective of this study was to determine if peak GH level, determined by stimulation tests, can predict the presence or absence of brain MRI abnormality.

METHODS

This study was a retrospective chart review from 2008-2015. Patients were aged 2-18 years, and had growth failure and GHD as determined by stimulation test. Patients with history of brain tumour, chemotherapy and brain surgery, prior to the diagnosis of GHD, were excluded.

RESULTS

A total of 386 patients were included. GH values (mild versus severe GHD) did not predict brain MRI abnormality with any agent (clonidine: p=0.07; arginine: p=0.17; glucagon: p=0.42). Abnormal MRI was apparent in 19.2% of the patients with mild GHD and 24.8% of the patients with severe GHD (p=0.17). Severe MRI abnormality was seen in 6.1% of the patients with mild GHD and 15.0% of the patients with severe GHD (p=0.009).

CONCLUSIONS

The severity of GHD based on peak GH levels on stimulation tests did not predict the presence or absence of brain MRI abnormalities in our study population; however, severe GHD was more strongly associated with severe brain MRI abnormalities. Based on these results we recommend obtaining brain MRI in all patients with GHD.

Differences between patients with isolated GH deficiency based on findings in brain magnetic resonance imaging

INTRODUCTION

Protocol for prescribing hormone replacement therapy in isolated growth hormone (GH) deficiency includes magnetic resonance imaging of the brain. There is controversy on the frequency of structural pituitary abnormalities and on the importance of abnormal MRI findings on prognosis and response to GH replacement.

METHODS

A descriptive, retrospective study of children of both sexes aged 0-14 years, who had undergone brain MRI, diagnosed with isolated GH deficiency at a tertiary hospital in the past 14 years, aimed at reporting the frequency of abnormal MRI findings in isolated GH deficiency, and to establish whether differences exist in height diagnosis and evolution according to MRI findings. MRI findings were also compared with the findings reported in healthy children in order to establish incidence.

RESULTS

96 patients were studied, of whom 74/96 (77%) reached adult age. Abnormal MRI findings were seen in 11.5% of them (8/11 of pituitary origin). No brain or pituitary tumor was seen in any case. Patients with abnormal images had a mean age at treatment start of 8 years, a target height of -0.8SD, and a final height of 1.04SD, while patients with normal MRI findings had an age at treatment start of 10 years old, a target height of -1.44SD, and a final height of -1.75SD, with statistically significant differences.

CONCLUSIONS

Patients with abnormal MRI findings show a more favorable response to GH replacement therapy.

Micropenis: etiology, diagnosis and treatment approaches

Micropenis is a medical diagnosis based on correct measurement of length. If stretched penile length is below the value corresponding to - 2.5 standard deviation of the mean in a patient with normal internal and external male genitalia, a diagnosis of micropenis is considered. Micropenis can be caused by a variety of factors including structural or hormonal defects of the hypothalamic-pituitary-gonadal axis. It can also be a component of a number of congenital syndromes. For the etiological evaluation, endocrinologic tests are important. This article reviews the etiology, diagnosis, treatment and management of micropenis.

Magnetic resonance imaging of CNS in 15,043 children with GH deficiency in KIGS (Pfizer International Growth Database)

OBJECTIVES

Neuroimaging has become an essential part of the diagnostic process in children with GH deficiency (GHD). The aim of the study was to document the frequency of neuroanatomical abnormalities in a very large cohort of children with GHD and to relate these findings to patient clinical characteristics.

DESIGN AND METHODS

Results of magnetic resonance imaging (MRI) were reported in 15,043 of 43,725 children with non-acquired GHD (idiopathic, neurosecretory dysfunction (NSD) and known congenital cause) who were enrolled in KIGS (Pfizer International Growth Database) between 1987 and 2011. Clinical characteristics of patients before GH treatment with normal MRI (idiopathic GHD (IGHD) and NSD) were compared with those of patients with abnormal pituitaries (hypoplasia, empty sella (ES), HME (hypoplastic anterior pituitary, missing pituitary stalk and ectopic posterior pituitary)).

RESULTS

Abnormal MRIs were found in 4032 (26.8%) children, within which ES (N=1178 (7.8%)) and HME (N=1019 (6.8%)) were the most frequent findings. In 2361 children diagnosed as IGHD or NSD before MRI examination, anatomical abnormalities ((pituitary hypoplasia: n=974); (HME: n=459)) were documented. Patients with anatomical abnormalities had more severe characteristics of GHD: normal MRI < pituitary hypoplasia < ES < HME.

CONCLUSIONS

GHD is associated with a great variety of neuroanatomical abnormalities as identified by MRI. The investigation and evaluation of MRI need to be conducted in a structured mode. There is an association between anatomical and functional abnormalities of the pituitary.

The use of neuroimaging for assessing disorders of pituitary development

Magnetic resonance imaging (MRI) is the radiological examination method of choice for evaluating hypothalamo-pituitary-related endocrine disease and is considered essential in the assessment of patients with suspected hypothalamo-pituitary pathology. Physicians involved in the care of such patients have, in MRI, a valuable tool that can aid them in determining the pathogenesis of their patients' underlying pituitary conditions. Indeed, the use of MRI has led to an enormous increase in our knowledge of pituitary morphology, improving, in particular, the differential diagnosis of hypopituitarism. Specifically, MRI allows detailed and precise anatomical study of the pituitary gland by differentiating between the anterior and posterior pituitary lobes. MRI recognition of pituitary hyperintensity in the posterior part of the sella, now considered a marker of neurohypophyseal functional integrity, has been the most striking finding in the diagnosis and understanding of certain forms of 'idiopathic' and permanent growth hormone deficiency (GHD). Published data show a number of correlations between pituitary abnormalities as observed on MRI and a patient's endocrine profile. Indeed, several trends have emerged and have been confirmed: (i) a normal MRI or anterior pituitary hypoplasia generally indicates isolated growth hormone deficiency that is mostly transient and resolves upon adult height achievement; (ii) patients with multiple pituitary hormone deficiencies (MPHD) seldom show a normal pituitary gland; and (iii) the classic triad of ectopic posterior pituitary, pituitary stalk hypoplasia/agenesis and anterior pituitary hypoplasia is more frequently reported in MPHD patients and is generally associated with permanent GHD. Pituitary abnormalities have also been reported in patients with hypopituitarism carrying mutations in several genes encoding transcription factors. Establishing endocrine and MRI phenotypes is extremely useful for the selection and management of patients with hypopituitarism, both in terms of possible genetic counselling and in the early diagnosis of evolving anterior pituitary hormone deficiencies. Going forward, neuroimaging techniques are expected to progressively expand and improve our knowledge and understanding of pituitary diseases.

Phenotype and radiological correlation in patients with growth hormone deficiency

OBJECTIVE

To confirm that MRI findings like hypoplastic anterior pituitary, thin or interrupted pituitary stalk, and ectopic posterior pituitary (EPP) in patients with growth hormone deficiency are a good indicator of the severity of hypopituitarism.

METHODS

MR images were obtained for 44 patients (IGHD: CPHD; 30:14) and analyzed to define one or more of the following triad of abnormalities: small/absent anterior pituitary, thin or interrupted pituitary stalk, and EPP, as well as for any other associated anomalies. The findings were correlated with the clinical and biochemical presentation.

RESULTS

Pituitary abnormalities were common in both groups (53% with IGHD, 79% with CPHD). Breech delivery, neonatal hypoglycemia, jaundice, micropenis, birth asphyxia occurred more commonly in CPHD compared to IGHD. In patients whose peak growth hormone (GH) level was less than 3 ng/ml (n: 37), 68% had the MR triad; while none of them with GH>3 ng/ml had pituitary abnormality on MRI.

CONCLUSIONS

The presence of structural anomalies in the hypothalamic pituitary area in patients with GHD suggests severity of hypopituitarism and MRI of hypothalamic pituitary area may aid in diagnosis of patients with suspected GHD.

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.

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.

[Pituitary stalk transection syndrome]

BACKGROUND

Pituitary stalk transection is a non-negligible cause of growth hormone (GH) deficiency.

POPULATION AND METHODS

We studied 22 children (13 boys, nine girls) aged at the first clinical manifestations from 2 days to 10 years (average = 5.33 +/- 2 years). Pituitary stalk transection was assessed by the means of magnetic resonance imaging (MRI). The children's past history showed fetal distress in 12 cases (54.5%), cranial trauma in three (13%) and a midline anomaly in three (13%). The first clinical manifestations were neonatal hypoglycemia (two cases), decreased growth velocity (18 cases) and diabetes insipidus (two cases).

RESULTS

GH deficiency was complete, present from the onset in 19 of 22 cases and isolated in four. Fifteen of 22 cases had adreno-corticotrophic hormone (ACTH) and thyroid stimulating hormone (TSH) deficiency. Diabetes insipidus was present in six cases and revealed the syndrome in two. All children older than normal age of puberty (n = 10) had gonadotropin deficiency. In our study, these hormonal anomalies progressed from isolated GH deficiency to multiple hormonal deficiencies.

CONCLUSION

The recently described stalk transection syndrome is relatively frequent and should be suspected after cranial trauma or fetal distress syndrome. The outcome is progressive evolution towards panhypopituitarism and these patients require regular clinical survey and hormonal controls.

Magnetic resonance and the diagnosis of short stature of hypothalamic-hypophyseal origin

Magnetic resonance imaging was performed in 23 patients with short stature (7 had multiple pituitary hormone defect, 11 had isolated growth hormone deficiency and 5 had normal variant short stature) to investigate if there is a relation between magnetic resonance findings and results of endocrine tests. Magnetic resonance imaging of patients with multiple pituitary hormone deficiency or with serious isolated growth hormone deficiency (growth hormone < 3 micrograms/l) revealed an interrupted pituitary stalk and ectopic neurohypophysis or a mass. In patients with less serious isolated growth hormone deficiency (growth hormone > 3 micrograms/l) or with normal variant short stature, the technique revealed a normal or hypoplastic hypophysis. Magnetic resonance appears to be a useful second-level diagnostic tool in defining the type of alteration in growth defects of endocrine origin.

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.

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.