[The status of the gonadotropin releasing hormone test in differential diagnosis of delayed puberty in adolescents over 14 years of age].
BACKGROUND
In patients with delayed puberty with a bone age less than 11 years in girls or 12 years in boys, the clinical and endocrinological examination allows the differentiation of patients with the various forms of hypergonadotropic hypogonadism, but not of patients with hypogonadotropic hypogonadism from more prevalent constitutional delay in puberty. Therefore, watchful waiting is generally recommended for differential diagnosis in patients with delayed puberty. On the other hand, the late onset of sexual hormone replacement in patients with hypogonadism will worsen their outcome.


METHODS
Therefore, we decided to carry out a retrospective study in 105 adolescents who were examined because of short stature or delayed puberty, who were aged 14 to 22 years at first visit and in whom the differential diagnosis of delayed puberty was documented after an at least one-year follow-up in order to find out which endocrinological parameters could have effectively predicted the final diagnosis already at the first visit.


RESULTS
Patients with hypogonadotropic hypogonadism differed from patients with constitutional delay in puberty by lower responses of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels to gonadotropin-releasing hormone stimulation (GnRH, 100 micrograms iv) (p < 0.01) as well as by smaller testicular volume (p < 0.05) and by lower testosterone levels (p < 0.01). Stimulated LH < 10 mU/ml differentiated patients with hypogonadotropic hypogonadism from constitutional delay in puberty with a sensitivity of 82% and a specificity of 98%.


CONCLUSIONS
In patients with delayed puberty aged 14 years and older bone age usually exceeds 11 years in girls or 12 years in boys. It thus is in the range, in which normal adult responses of LH to GnRH can be expected. In contrast to patients aged less than 14 years, therefore, measuring GnRH-stimulated LH levels in these patients allows the rapid and effective differential diagnosis of delayed puberty.
Jungmann
E
E
Schwerpunkt Diabetes-Endokrinologie, St.-Vinzenz-Hospital Wiedenbrück, Rheda-Wiedenbrück.
Trautermann
C
C
D000293:Adolescent; D000328:Adult; D000365:Age Determination by Skeleton; D003937:Diagnosis, Differential; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000209:etiology*; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D011628:Puberty, Delayed / Q000097:blood / Q000209:etiology*
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
Stellenwert des Gonadotropin-Releasing-Hormon-(GnRH-) Tests in der Differentialdiagnose der Pubertas tarda bei Heranwachsenden über 14 Jahren.