ESPE Abstracts

Introduction: Growth without growth hormone (GWGH) is a rare phenomenon described in patients with hypothalamic structural pathology who present a normal growth rate in spite of growth hormone (GH) deficiency and low concentrations of insulin-like growth factor-1 (IGF-1). Possible aetiologies involve hyperinsulinaemia, hyperprolactinaemia or hyperleptinaemia; however, the exact mechanism is still unknown.

Objective: We aimed to analyse clinical and biochemical parameters and imaging studies in patients who have been diagnosed with GWGH.

Patients and Methods: A single-centre, retrospective and descriptive study in paediatric patients diagnosed with GWGH within the last 20 years in a tertiary care hospital was carried-out.

Results: Eight patients (four boys and four girls) were studied, all of them with structural pathology in the central nervous system (four craniopharyngiomas, two dysgerminomas, one pilomyxoid astrocytoma, and one multisystem Langerhans cell histiocytosis). The median age at diagnosis of the underlying pathology was 6.5 years (interquartile range (IQR) 3.2-9.8) and the median age at the diagnosis of GH deficiency was 6.77 years (IQR 4.37-9.12). Both IGF-1 and IGFBP-3 were low in all the patients upon diagnosis of GH deficiency. Despite this, all patients had a normal growth rate. GH stimulation tests were performed in 6/8 patients, confirming the deficiency in all cases. Bone age was delayed in all patients and the median delay with respect to chronological age was 1.35 years (IQR 0.92-1.73). None of the patients developed acromegaloid features. Six patients presented with obesity at some point during their follow-up. Slightly elevated prolactin concentrations were observed in four patients (maximum value: 77 ng/ml); in two of these, the concentrations normalised within the first two years after the diagnosis of GH deficiency. Basal insulin concentrations were elevated in three patients, with a median of 14.4 mcg/ml (IQR: 5.4-24.1), and one patient had a maximum insulin concentration of 117 mcg/ml at 120 minutes during an oral glucose tolerance test. Five patients started treatment with recombinant human GH, at a median age of 12.6 years (IQR 9.5-12.9). Final height was available in three patients, all of whom reached a normal height, according to their mid-parental target height. All patients developed deficiency of TSH, ADH and ACTH. Five had reached an age compatible with onset of puberty, with four of them developing gonadotropin deficiency.

Conclusions: Excess weight, with or without hyperinsulinaemia and hyperprolactinaemia may contribute to GWGH. However, not all patients presented these characteristics. Hence, other factors could be involved.