Evaluation of thyrotrophic and lactotrophic reserves in patients with pituitary dwarfism with and without empty sella turcica.

OBJECTIVES

Empty sella turcica (ES) is commonly observed in idiopathic growth hormone deficiency (GHD) in children. This study aims to determine the frequency of ES in children with GHD, assess their pituitary thyroid-stimulating hormone (TSH) and prolactin (PRL) reserves using the thyrotropin-releasing hormone (TRH) stimulation test, and investigate whether ES is associated with a higher prevalence of combined pituitary hormonal deficiencies.

METHODS

TSH and PRL pituitary reserves were assessed through the TRH stimulation test in 22 patients with ES and 31 without this finding (non-ES). All participants had childhood-onset GHD and underwent pituitary imaging, primarily by computed tomography (CT) Anti-thyroid peroxidase (anti-TPO) antibodies were measured in all patients with elevated basal TSH.

RESULTS

Among 125 children diagnosed with GHD between 1988 and 1996, ES was identified in 29 cases (23 %). Fifty-three patients agreed to participate (86.8 % male), with ES present in 43.5 % of males and 28.6 % of females. No significant differences in TSH and PRL responses to TRH were observed between the ES and non-ES groups. Mildly elevated basal TSH was observed in 50 % of patients with ES and 55 % without ES, most of who tested negative for anti-TPO antibodies. Among patients with elevated basal TSH and hypothyroidism, the majority exhibited exaggerated or delayed TSH responses to TRH and elevated basal PRL, findings suggestive of hypothalamic dysfunction. Four patients presented combined GH, TSH, and PRL deficiencies.

CONCLUSIONS

ES is common in children with GHD but presents distinct features compared to adults. Central hypothyroidism (CeH) was observed in 45.6 % of patients with ES and 54.8 % without ES. Mild TSH elevation was frequent and rarely associated with anti-TPO antibodies, supporting the exclusion of primary hypothyroidism and suggesting underlying hypothalamic dysfunction. Subclinical hormonal abnormalities were also frequent among euthyroid patients. The TRH stimulation test proved valuable in distinguishing hypothalamic dysfunction from pituitary or primary hypothyroidism. Genetic testing for POU1F1 and PROP1 mutations may be warranted in selected cases with combined deficiencies.