HYPOGONADISM Flashcards
refers to a decrease in one or both of the two major function of the testes: sperm production or testosterone production
Hypogonadism.
Presentation of a patient with Hypogonadism.
(1) Fatigue
(2) Decreased strength
(3) Poor libido
(4) Hot flushes
(5) Erectile dysfunction
(6) Gynecomastia
(7) Infertility
(8) Small testes
Laboratory evaluation of a patient with Hypogonadism.
(1) Total Testosterone
(a) General rule is <200ng/dl is low and >350ng/dl is normal however per societal
guidelines you should use the reference ranges published with specific assay
used
(b) For values between 200-350ng/dl measure Free Testosterone with Albumin to calculate Bioavailable Testosterone
(c) If Testosterone is low, obtain LH, FSH, and Prolactin
1) High FSH/LH indicates primary testicular failure from:
a) Atrophy from previous Mumps orichitis
b) Autoimmune destruction
c) Previous chemo/radiation exposure
2) High Prolactin indicates possible prolactinoma
3) Low FSH/LH indicates secondary hypogonadism from:
a) Hypogonadotropic hypogonadism
b) Hyperprolactinemia
c) Use of opiates or steroids
d) Other hypothalamus or pituitary disorders
4) Low FSH/LH should prompt additional screening for:
a) Hemochromatosis with Transferrin, Ferritin, and genotypic for HFE Gene
b) Pituitary mass with MRI of the Sella (where the pituitary gland resides)
c) Anabolic steroid or supplement use
Treatment of a patient with Hypogonadism.
(SHOULD ONLY BE INITIATED WITH GUIDANCE FROM MEDICAL OFFICER)
(1) First must check additional labs
(a) Hematocrit (HCT): Testosterone increased red cell mass. Pre-treatment HCT of 55% or greater is of high risk of developing erythrocytosis (secondary
polycythemia)
(b) Prostate Specific Antigen (PSA): Testosterone replacement is contraindicated in prostate cancer
(2) Medication delivery modalities
(a) Transdermal Testosterone (preferred)
1) AndroGel, Testim, Fortesta, Axiron) – Daily applications delivering 25-100mg testosterone which is adequate to achieve therapeutic levels in most instances.
(b) Intramuscular Testosterone (longer acting)
1) Testosterone enanthate or cypionate
a) Typical regimen is 100mg IM dose which will be mildly supratherapeutic following injection and nadiring just before next dose. Higher doses are sometimes used to spread out injection intervals to 2-4 weeks however peak/nadir fluctuations are more pronounced.
(c) Alternate routes for Testosterone (Buccal, implantable, intranasal)
1) Examples include Striant SR and Testopel, and Natesto
2) Hepatic metabolism and side effects including cholestatic jaundice, hepatitis,
hypertension, and increased risk for cardiovascular complications limit use.
(d) Indirect stimulation
1) Normal hypothalamus-pituitary-gonadal (HPG) axis is down regulated by
estrogen sensing in the hypothalamus. This negative feedback mechanism
can be blocked by inhibiting the hypothalamic estrogen receptors with
clomiphene (Clomid). This will result in increased FSH/LH secretion and
increased testosterone synthesis and spermatogenesis.
a) Preferable therapy if patient desires fertility (note that spermatogenesis is inhibited with direct testosterone replacement due to down-regulation of FSH)
b) This modality is also used in attempt to restore normal physiology before committing life-long testosterone replacement therapy.
c) Typical regimen includes daily administration of clomiphene 25mg for 3
months, followed by a 6 week “off” period to determine if intrinsictestosterone pathway is self-sustaining. Testosterone, PSA, and HCT/HGB are checked at 6 week intervals to monitor for efficacy and
complications. This “pulse therapy” may be attempted up to 3 times, at which point if the intrinsic HPG axis is not corrected a patient may elect for life-long testosterone replacement therapy.
(3) Therapeutic target is 0800 Testosterone levels in middle of normal range (approximately 800ng/dl). DO NOT titrate testosterone dose to patient reported symptoms as comorbid conditions such as deconditioning, poor
sleep habits, anxiety/depression, psychosocial stressors may account for
residual symptoms.
