Evaluation of men with central hypogonadism

Men with idiopathic central hypogonadism present with low serum testosterone (T) levels but normal FSH/LH and prolactin. The necessity to rule out a pituitary tumor can initiate a lime-consuming and expensive evaluation, often requiring a radiological imaging study. We reviewed the charts of all patients with central hypogonadism and/or non-functioning pituitary tumors (PT) seen by the Johns Hopkins Hospital endocrine faculty within the past fifteen years, aged twenty-one and up who had CAT or MRI documentation and available lab values.We compared 27 cases of idiopathic hypogonadism (IH) to 37 controls of PT (34 pituitary adenomas, 1 germinoma, 1 meningioma, 1 glioma) in a case-control study to determine if there were criteria that would help differentiate these two populations. IH men shared comparable rates of fertility (75.0% vs. 77.4%) and ages of presentation (52.6 vs. 56.3 yrs) with PT. Men with PT presented with visual field deficits (67.6%,n=37 vs. 3.7%; p=0.0001), headaches (32.4% vs. 7.4%; p=0.04) and hypothyroid symptoms (56.8% vs. 25.0%; p=0.03). In contrast, men with IH complained significantly more of erectile dysfunction (78.3% vs. 39.1%; p=0.017) and depression (66.7% vs. 6.7%; p=0.002) than men with PT. Hormone level analysis revealed that men with PT had similar serum T levels (235.2ng/dl.i30.4 vs. 223.5ng/dl±20.2), while having significantly higher serum levels of LH (6.4 IU/Lil.0 vs. 3.5 IU/L±0.4; p=0.007), FSH (8.2 IU/L±1.1 vs. 5.0 IU/L±0.4; p=0.01), and prolactin (20.3ng/ml±2,3 vs. 7. lng/ml.+0.8; p=0.0001) compared to men with IH. We conclude that neither serum T levels nor age at presentation predict a PT. However, men with PT are more likely to have higher serum gonadotropins, prolactin levels, and visual field deficits, and less likely to have sexual dysfunction.