Background: Isolated growth hormone deficiency is the most common pituitary hormone deficiency, although the majority of cases are idiopathic. The presence of pituitary structural abnormalities may influence growth hormone (GH) deficiency severeness.
Objective: Assess the effect of pituitary abnormalities in idiopathic isolated growth hormone deficiency (IIGHD).
Methods: We analysed 65 children with IIGHD and pituitary magnetic ressonance imaging [MRI] data. Height-for-age and IGF1-for-age Z-scores, and GH requirements were compared between patients with or without pituitary MRI abnormalities.
Results: Age at diagnosis (11.3±3.1 vs 11.8±2.6years) and gender proportion (female 25% vs 24%) were similar between patients with or without pituitary abnormalities, respectively. Most patients (61.5%) had MRI abnormalities (75% anterior pituitary hypoplasia, 40% thin pituitary stalk, 20% ectopic posterior pituitary, 7.5% intrasellar arachnoidocele, and one case of thickened pituitary stalk). After one year of treatment, children with pituitary anomalies had higher height-for-age Z-score gain (0.50±0.29 vs 0.34±0.23, P=0.03) and IGF1-for-age Z-score gain (2.16±1.87 vs 1.95±1.49, P=0.89). Furthermore, a positive correlation was found between the number of anomalies and height-for-age Z-score gain (rs=0.35, p<0.01). Patients with thin pituitary stalk (0.59±0.20, P<0.001) or ectopic posterior pituitary (0.61±0.31, P=0.04) had higher height-for-age Z-score gain than children without pituitary abnormalities (0.34±0.23). During follow-up, final height was reached by 36 (55%) children; those with pituitary anomalies required less GH dosages than those with normal pituitary (0.030±0.004 vs 0.032±0.004 mg/kg per day, P<0.001). However, no differences on height-for-age Z-score gain were found between both groups. Children with thin stalk had higher final height-for-age Z-score gain than those with normal pituitary (1.77±0.94 vs 0.93±0.60, P=0.02).
Conclusion: Structural pituitary abnormalities were associated with higher stature improvement during the first year of treatment and lower GH requirements during follow-up. Irrespective of the etiology, patients with structural abnormalities will need lifelong follow-up in adulthood owing to the risk of developing other pituitary hormone deficiencies.
10 Sep 2016 - 12 Sep 2016