Role of GnRH stimulation test in prediction of a neurogenic aetiology in girls with central precocious puberty

Abstract

Objective: To ascertain the utility of gonadotrophin releasing hormone (GnRH) test in diagnosis of neurogenic central precocious puberty (NCPP). Methods: We conducted a prospective observational study over a period of 4 years recruiting girls with early breast budding. Children underwent GnRH analogue stimulation test with injection luperide 20mcg/kg in subcutaneous route followed by assessment of gonadotropins (LH and FSH) at 4 hours and estradiol at 24 hours. MRI performed in everyone with CPP. Cases divided into those with neurogenic CPP (NCPP) and idiopathic CPP (ICPP). Results: During the study period, 59 girls presented with early sexual maturation; we included 19 subjects onto our study (12 girls with idiopathic central precocious puberty and 7 girls with neurogenic precocious puberty). Stimulated LH was higher in subjects with NCPP compared to those with ICPP (9.8±3.0 versus 8.4±3.6 mIU/mL, p0.55 is able to predict neurogenic precocious puberty with specificity of 82% and sensitivity of 66.7%. Conclusion: Elevated LH levels and LH/FSH ratio in GnRHa stimulation test gives an important clue to a possible underlying neurological pathology. A cut-off of 0.55 predicts neurogenic precocity with a specificity of 82%.

Keywords

• neurogenic
• precocious puberty
• gonadotrophin hormone