[The frequency of structural abnormalities in the hypothalamo-pituitary region and their clinical significance in patients with growth hormone deficiency]

Abstract

Introduction: In children with confirmed growth hormone deficiency (GHD) the most common diagnosis is idiopathic isolated GHD. Nevertheless, it cannot be ignored, that the GHD might also be caused by structural malformations or tumours in hypothalamo-pituitary region. The aim of the study was to evaluate the frequency of structural malformations in the hypothalamo-pituitary region in children with growth hormone deficiency and its correlation with clinical parameters.

Material and methods: 99 patients with growth hormone deficiency were examined (30 girls and 69 boys). Mean age of the patients was 10±3.4 years. The diagnosis of growth hormone deficiency was based on standard criteria: growth hormone level below 10 ng/ml in two stimulatory tests and auxological data. Magnetic resonance imaging was performed in pituitary protocol: (SE, TSE in T1- and T2-weighted pictures). Patients were divided into two groups: with malformations (ZM) of hypothalamo-pituitary region and without the malformations (BM). In the course of analysis, the ZM group was divided into the following subgroups: with a severe malformation (Mw) and with mild malformations (Mmn). The results of growth hormone stimulatory tests, IGF-1 level, additional hormonal disorders and auxological parameters were compared between the groups.

Results: In the examined group structural malformations of hypothalamo-pituitary region were found in 42% (n=42) of patients. The most common finding was pituitary hypoplasia and ectopy of the posterior lobe. The groups did not differ by age, mean height deficiency (in SDS) and mean height of parents. The mean IGF-1 level was statistically significantly lower in ZM group than in BM group (p <0.04). Similarly the maximal growth hormone secretion in stimulatory tests was lower in ZM patients. The age of diagnosis was statistically significantly younger in the Mw subgroup, and multihormonal hypopituitarism was diagnosed only in patients with a severe structural malformation of hypothalamo-pituitary region.

Conclusions: 1. The structural malformations of hypothalamo-pituitary region were found in 42% of patients. 2. The diagnosis of multihormonal hypopituitarism in a patient is connected with an increased risk of the presence of severe structural abnormalities in hypothalamo-pituitary region. 3. IGF-1 level and maximal GH secretion are negatively correlated with the presence of malformations of the hypothalamo-pituitary region.