Q: What does the physical exam reveal?
In hypogonadotropic hy pogonadism, physical examination does not usually provide much information, as compared to congenital hypogonadal syndromes (eg, Klinefelter and Kallmann syndromes). However, small testicular volume and/or gynecomastia would indicate hypogonadism.
Q: What lab tests should be ordered?
Serum total and free testosterone should be measured, preferably by liquid gas chromatography. The sample should be drawn before 10 am to limit the effects of diurnal variation. If the total testosterone is less than
300 ng/dL, a second morning sample should be drawn and tested. Serum prolactin, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), complete blood count, prostate-specific antigen (PSA), comprehensive metabolic panel, and ferritin should also be measured.
There is generally little benefit to testosterone therapy when total testosterone is greater than 350 ng/dL.8 The level of testosterone at which hypogonadal symptoms manifest and testosterone replacement provides improvement is yet to be determined. Buvat et al suggest that men with total testosterone levels less than 230 ng/dL usually benefit from therapy.8 If the total testosterone level is less than 150 ng/dL in the setting of secondary hypogonadism (low to low-normal LH/FSH) or if prolactin is elevated, MRI of the sella is recommended to rule out pituitary adenoma.1
Q: Once the diagnosis is confirmed, what treatment should you recommend?
The goal of therapy for confirmed hypogonadism is to normalize the testosterone level. Testosterone replacement therapy may help to improve libido, fatigue, muscle strength, and bone density. However, in the elderly (particularly those older than 70), these therapeutic benefits have not been proven. Therefore, before initiating therapy, the clinician should discuss in detail the risks versus the benefits of testosterone replacement for a particular patient.
Simple lifestyle modifications, such as weight loss and exercise, have been shown to increase total and free testosterone levels.3,8 For patients with obstructive sleep apnea (OSA), a known risk factor for hypogonadism, compliance with CPAP therapy has been associated with modest improvement in testosterone level. If it is appropriate for the patient to discontinue use of certain medications, such as opiates, he or she may experience an improvement in testosterone level as a result.
If the patient’s testosterone levels remain low after these changes have been implemented, consider testosterone therapy. Testosterone products currently available in the United States include transdermal preparations (gel, patch), intramuscular injection, and subcutaneous pellets.
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