Male Hypogonadism Flashcards
Where is testosterone produced?
Leydig cells within the testes
What hormone controls testosterone production?
LH
How is the majority of the testosterone found?
Bound to SHBG Sex Hormone Binding Globulin
Some to albumin
0.5% is free
What is the active form of testosterone?
Dihydrotestosterone
What happens to dihydrotestosterone in adipose tissue?
Converted to oestradiol
What enzyme converts dihydrotestosterone to oestradiol?
Aromatase
What is the function of oestreadiol?
Epiphyseal fusion
Bone mass maintenance
Lipid control
What is primary hypogonadism?
Testes are affected
Spermatogenesis is more affected than testosterone
What is the most common primary hypogonadism?
Hypergonadotrophic hypogonadism
How does primary hypogonadism present?
Reduced testosterone
Increased LH and FSH
Low sperm count
Reduced testes volume
What is secondary hypogonadism?
Hypothalamus and pituitary is affected
Spermatogenesis and testosterone are both reduced
What is the main cause of secondary hypogonadism?
Hypogonadotrophic Hypogonadism
How does secondary hypogonadism present?
LH/FSH is low or inappropriately normal
Low testosterone
Some causes of primary hypogonadism
Genetic- Klinefelters, Cryptorchidism, Trauma - Surgery Torsion Varicole veins Orchitis (mumps) Infiltrative disease Medications
What is Cryptorchidism?
Y chromosome micro deletions
Failure of the testes to descend
What is klinefelters?
Non inherited, non disjunction mosaic
47XXY
Why is klinefelters difficult to diagnose, and how is it done?
The phenotype varies making difficult to initially diagnose.
Diagnosis is via karyotyping
What are some clinical signs of klinefelters?
Poor beard growth, no frontal balding, Narrow shoulder wide hips, Breasts, Long limbs, female type pub hair, small testes.
What is there an increased risk off with Klinefelters?
Learning difficulties
What medications can cause primary hypogonadism?
Glucocorticoids
Some causes of secondary hypogonadism
Congenital - Kallmans, Prader-willi
Aquired - Pituitary damage, tumour etc
-Medications
-Acute systemic disorders
-excessive exercise
-Eating disordersWhat is kallmans?
Isolated GnRH deficiency
How does kallmans present?
Hyposmia - no sense of smell
Reg green colour blind
Cleft lip or palate
If the onset of secondary hypogonadism occurs pre-puberty how does it present?
Small male sexual organs, Reduced libido
Decreased body hair, High voice, Gynaecomastia
Tall slim long arms and legs, Reduced bone and muscle mass
If the onset of secondary hypogonadism occurs post puberty how does it present?
Normal skeletal muscular mass and genitals
Decreased Libido and spontaneous errections
Reduced facial and pubic hair
Reducing muscle mass, gynaecomastia
Increased lethargy
If the patient presents with signs and symptoms of low testosterone what is the first step in diagnosing?
Perform semen analysis
AM testosterone levels
Following AM testosterone levels coming back low, what should be the follow up test?
Repeat in 4 weeks
Measure LH and FSH aswell
If testosterone comes back low but LH and FSH are high what is the main diagnosis?
Primary hypogonadism
Following the diagnosis of primary hypogonadism what should be done?
Karyotyping
Iron studies
What is incredibly important to take into consideration before administering testosterone replacement?
Prostate and other hormone responsive cancers will grow
NEVER administer if there is a suspicion of cancer.
What are the main goals in the management of hypogonadism?
Establish or maintain puberty and sexual function
Improve fertility and physique
What are the two main methods of administering testosterone?
Testogel
IM injection
What is Testogel
A gel which has a fast onset and mimic circadian rhythm
Can cause irritation and must be applied using gloves if being applied by another person.
What are the two main types of testosterone IM injection?
Nebido - long acting
Sustanon - 2-3 weeks
What are the issue with using a long acting testosterone injection like Nebido?
If there are side affects its very difficult to withdraw from the therapy.
