Internal Medicine

0521779407-09 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:13

784 Hypogonadism in Men

■Total testosterone level; if <200 ng/dL, androgen deficiency likely; if

>400 ng/dL, androgen deficiency unlikely

■Free testosterone by equilibrium dialysis, or bioavailable testos-

terone by ammonium sulfate precipitation, if total testosterone level

is between 200 and 400 ng/dL, particularly in obese or older men and

in chronic illness

■Elevated serum LH indicates primary testicular dysfunction; obtain

karyotype to rule out Klinefelter syndrome (XXY)

■Prolactin if low testosterone but low or normal LH

Imaging

■MRI of hypothalamic-pituitary region if low testosterone but normal

or low LH (hypogonadotropic hypogonadism)

■Bone age in children with delayed pubertal development

Other Tests

■Evaluation of other pituitary hormones in hypogonadotropic hypog-

onadism

differential diagnosis

■Normal aging

■Obesity

■Erectile dysfunction

■Systemic illness

management

What to Do First

■High index of suspicion

■Exclude systemic illness, eating disorders, excessive exercise, drug

abuse, or medication-induced androgen deficiency

■Confirm diagnosis by proper tests

General Measures

■Diagnose underlying cause

■Counsel patient and partner about risks and benefits

■Evaluate patient for possible contraindications

■Must diagnose and treat androgen deficiency because untreated, it

can contribute to osteoporosis, loss of muscle mass and function,

impaired sexual function, lowered mood and energy level, increased

fat mass, insulin resistance