Category: Pituitary Disorders/Neuroendocrinology

Monitor: 3

3 - Utility of Gonadotropin-releasing hormone stimulation testing in a man with absence of pubertal changes

Thursday, Apr 25
1:00 PM – 1:30 PM

Objective :

Idiopathic hypogonadotropic hypogonadism (IHH) refers to a group of rare genetic disorders that results in impaired production of gonadotropin-releasing hormone (GnRH). These disorders often present as lack of complete sexual development at the time of puberty. Patients can have normal olfaction or can be anosmic due to abnormal migration of GnRH-secreting cells during embryonic development. IHH can be difficult to distinguish from other causes of hypogonadism, especially constitutional delay of puberty, but GnRH stimulation testing can be a useful tool in diagnosis. We report a case of IHH in a man who presented with absence of pubertal changes who was evaluated in our clinic.


Methods :

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Results :

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Discussion :

A 27-year-old African American man presented to clinic for evaluation of low testosterone. He reported never having experienced full pubertal changes during adolescence. He complained of persistently high voice, minimal body and facial hair, and weight gain. He denied deficiency in sense of smell. He had never been sexually active. Examination revealed a morbidly obese male (BMI 74 kg/m2) with minimal facial and axillary hair. 

Laboratory analysis showed total testosterone of 52 ng/dL (193–824 ng/dL), FSH 0.1 (1.5-12.4 mU/mL), and LH <0.1 mU/mL (1.8–10.8 mU/mL). Further pituitary hormonal workup was normal, including prolactin 8.2 ng/mL (4.0–15.2 ng/mL), IGF-1 140 (88-257 ng/dL), and TSH 3.8 (0.4–5.5 uU/mL). Karyotype analysis was normal, and screening for Cushing’s was negative. Scrotal ultrasound showed bilaterally small testes (right 2.7 x 1.2 x 2.1 cm, left 3.2 x 1.4 x 1.3 cm).  MRI pituitary revealed a small pituitary gland measuring 1.1 x 1.2 x 0.1 cm, but no mass was seen.


The patient underwent GnRH stimulation test with administration of 100 mcg SC leuprolide and 15-minute interval measurements of testosterone, estradiol, FSH, and LH for a total of 120 minutes. Results showed consistently low testosterone levels 83 pg/mL. FSH level rose from <0.1 to 0.5 mUmL, and LH rose from <0.1 to 2.2 at 120 minutes.


Conclusion :

IHH is a rare group of genetic disorders that can cause hypogonadism and lack of sexual development. In this patient with long standing morbid obesity and lack of pubertal changes, it was difficult to distinguish whether it was constitutional delay of puberty related to obesity or idiopathic hypogonadotropic hypogonadism. GnRH stimulation testing can be a useful tool in differentiating IHH from other causes of hypogonadism, but most adult endocrinologists have never ordered or interpreted the test. Our case highlights the use and interpretation of this test in the adult patient.

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Lauren A. Buehler

Fellow
Cleveland Clinic Foundation
Cleveland, Ohio

Endocrinology Fellow, Cleveland Clinic Foundation

Adi Mehta

Staff Endocrinologist
Cleveland Clinic

Staff Endocrinologist

Vinni Makin

Staff Endocrinologist
Cleveland Clinic

Staff Endocrinologist, Cleveland Clinic

Lauren A. Buehler

Fellow
Cleveland Clinic Foundation
Cleveland, Ohio

Endocrinology Fellow, Cleveland Clinic Foundation