Males

Info

🌱 來自: Huppert’s Notes

Males🚧 施工中

Males

Physiology: GnRH pulse elicits pulses of LH/FSH. LH acts on Leydig cells → Testosterone. FSH acts on Sertoli cells → Spermatogenesis. Testosterone decreases with age.

Hypogonadism

•   Primary hypogonadism: Testicular failure, causing decreased testosterone and sperm production. Ddx: Klinefelter’s syndrome XXY, mumps orchitis, sequelae of radiation therapy, testicular trauma or torsion.

•   Secondary hypogonadism: Insufficient GnRH production by hypothalamus or deficient LH/FSH production by anterior pituitary. Ddx: Pituitary tumor/infiltrative disease, prolactin excess, Kallmann’s syndrome (associated with anosmia), OSA, obesity, idiopathic. Iatrogenic: Exogenous testosterone (often used for body building/energy/libido without frank hypogonadism), chronic opiates, steroids.

•   Clinical features: Decreased morning and spontaneous erections, decreased libido, gynecomastia, decreased axillary or genital hair, decreased mood/energy, problems with sleep and memory.

•   Diagnosis:

-   General screening is not recommended. In men with specific signs and symptoms, two early AM testosterone levels (fasting if possible) below reference range is indicative. In men with obesity, free testosterone can be measured since obesity lowers sex hormone–binding globulin (SHBG) leading to falsely low total testosterone. If low, check LH/FSH.

•   Elevated LH/FSH with low testosterone reflects primary hypogonadism.

•   Low/normal LH/FSH with low testosterone reflects secondary hypogonadism. Additional workup with prolactin, screening for hemochromatosis, consider pituitary imaging if evaluation suggestive of pituitary pathology.

-   Low testosterone common in chronic disease (e.g., ESRD, advanced COPD, HIV, malignancy), typically due to central hypothalamic–pituitary defects (low/normal LH/FSH).

•   Treatment: Can give testosterone replacement. If the patient is overweight, weight loss also increases testosterone levels.

Gynecomastia

•   Etiology: Excess estrogen or increased estrogen/androgen ratio.

•   Clinical features: Increase in breast size. Usually bilateral, can be benign in adolescents, patients with certain chronic medical conditions (e.g., cirrhosis, malnutrition, CKD), obesity (pseudogynecomastia), or associated with certain medications (e.g., anabolic steroids, spironolactone). Concerning features include unilateral, nontender, fixed breast masses.

•   Diagnosis: Review history and medications. If features concerning for malignancy (e.g., unilateral, palpable mass), order a mammogram. If no clear cause, also consider testicular exam, bHCG, estradiol, testosterone, LH, and prolactin.