Introduction: Stimulation tests form the basis for the diagnostic process in growth hormone deficiency (GHD). One of these tests uses the GH releasing hormone (GHRH). This provides the potential to differentiate patients with pituitary dysfunction from patients with hypothalamus abnormalities. However, the routine use of the GHRH test is still being debated. The aim of this study was to assess the diagnostic usefulness of the GHRH test in the diagnostics of GHD.
Material and methods: The study group consisted of 20 prepubertal children with GHD. In all the children, one of the performed stimulation tests was the GHRH test.
Results: The results showed that the mean peak concentration of GH in the GHRH test was 14.7 ± 11.3 ng/mL. In eight children the MRI showed pituitary hypoplasia, in one patient pituitary hypoplasia and pituitary stalk agenesis, and in one patient septo-optic dysplasia. All patients with pituitary malformations, except for one patient with a hypoplastic pituitary gland, presented GH levels < 10 ng/mL in the GHRH test. The sensitivity of the GHRH test in the diagnostics of GHD was 45%.
Conclusions: The high correlation between the GHRH test and anatomical changes in the pituitary provides this test with a high predictive value. In individual clinical cases, knowledge about the level of damage in the hypothalamic-pituitary area can determine diagnostic and therapeutic procedures.