Background: The i.v. GnRH test remains the gold standard for the diagnosis of central precocious puberty (CPP). Unfortunately however, GnRH is expensive and is not available worldwide. GnRH analogues have been used as an alternative, but their place is not established, while very few studies have compared between the two tests.
Objective: To compare the effects of GnRH and Triptorelin on gonadotrophin secretion in patients with sexual precocity and hence evaluate the diagnostic accuracy of the Triptorelin test for the diagnosis of CPP compared with GnRH test.
Patients and methods: In this prospective study the GnRH test was carried out using 100 μg LHRH intravenously. Triptorelin test was performed at least 2 weeks after the GnRH test, using 0.1 mg of s.c. Triptorelin. LH, FSH, and E2 were determined at baseline, 30, 45, and 60 min during both tests. CPP was defined by clinical and radiological signs of precocious puberty associated with an LH peak >5 UI/l on GnRH and/or Triptorelin testing.
Results: We studied 26 patients (one boy) of whom ten (nine girls and one boy) had CPP, mean±S.D. age at diagnosis 5.08±2.61 years; four had precocious pseudopuberty (PPP); and 12 had premature thelarche (PT), age at diagnosis 6.03±1.86 years. CPP patients showed mean±S.D. (range) peak LH 13.35±14.4 (3.1942.62) mUI/ml after GnRH and 20.18±23.44 (5.1579) mUI/ml after Triptorelin. There was no difference between the two tests, 95% CI (−25.4141; 11.7141). In patients with PT or PPP, peak LH was 1.85±1.49 (0.144.74) mUI/ml after GnRH and 2.24±1.7 (0.24.95) mUI/ml after Triptorelin. There was no difference between the two tests, 95% CI (−1.5681; 0.7931). For the Triptorelin test both the sensitivity and specificity for the diagnosis of CPP were 100% for a LH peak of 5.15 UI/l.
Conclusion: Our study confirms that the LH profiles after s.c. Triptorelin and i.v. GnRH are similar. Triptorelin can be used as an alternative to GnRH for the diagnosis of CPP when the latter is unavailable, or too costly.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology