Endocrine / Reproductive Flashcards
Where do the testes develop?
Abdomen and then gradually migrate down - through the inguinal canal into the scrotum
They have normally reached the scrotum prior to birth.
In about 5% of boys the testes have not made it out of the abdomen by birth. At this point they are called undescended testes. This can also be referred to as cryptorchidism.
If you can’t palpate the testes in the scrotum of a newborn boy, where else could they be?
They might be palpable in the inguinal canal (in the inguinal region), which is not technically classed as undescended testes, although they have not fully descended at that point.
What are the 3 major complications of undescended testes?
- Testicular torsion
- Infertility
- Testicular cancer
Risk factors for undescended testes
- Family history of undescended testes
- Low birth weight
- Small for gestational age
- Prematurity
- Maternal smoking during pregnancy
Management of undescended testes
- 3-6 months: Watch and wait (most descend)
- 6-12 months: Orchidopexy (surgical correction of undescended testes)
What is the cresmasteric reflex?
It is normal in boys that have not reached puberty for the testes to move out of the scrotum and into the inguinal canal when it is cold or the cremasteric reflex is activated
What are retractile testicles?
Considered a normal variant
* They have the cremasteric reflex - but usually resolves as they go through puberty and the testes settle in the scrotum. Occasionally they may fully retract or fail to descend and require surgical correction with orchidopexy
A 2-day-old male neonate is not feeding well, appears lethargic and dehydrated. Bedside glucose monitoring reveals hypoglycaemia. They are found to have profound hyponatraemia on blood tests. Possible diagnosis?
Congenital adrenal hyperplasia?
What is congenital adrenal hyperplasia caused by?
Congenital deficiency of the 21-hydroxylase enzyme
This causes, from birth:
* Underproduction of cortisol + aldosterone
* Overproduction of androgens
What is the inheritence pattern of congenital adrenal hyperplasia?
Autosomal recessive
In a small number of cases it is caused by a deficiency of 11-beta-hydroxylase rather than 21-hydroxylase
Congenital adrenal hyperplasia pathophysiology
- 21-hydroxylase = enzyme responsible for converting: progesterone → aldosterone + cortisol
In CAH:
* Defect in 21-hydroxylase enzyme → therefore there is extra progesterone floating around - that cannot be converted to aldosterone + cortisol → gets converted into testosterone instead
As a result:
* Low aldosterone
* Low cortisol
* High testosterone
- 21-hydroxylase = converts progesterone into aldosterone + cortisol.
- Progesterone is also used to create testosterone, but this conversion does not rely on the 21-hydroxylase enzyme
What are the abnormal hormone levels does congenital hyperplasia cause?
- Low aldosterone
- Low cortisol
- High testosterone
How do severe cases of CAH present?
Features of mineralcorticoid + glucocortoid deficiency:
* Hypoglycaemia
* Hyponatraemia
* Hyperkalaemia
Leads to:
* Poor feeding
* Vomiting
* Dehydration
* Arrhythmias
- Females: virilised genitalia AKA “ambiguous genitalia” (due to high testosterone)
- Males: virilised genitalia (large penis)
How do mild cases of CAH generally present?
Patients who are less severely affected present during childhood or after puberty. Their symptoms tend to be related to high androgen levels.
How do mild case of CAH present in females?
- Tall for their age
- Facial hair
- Absent periods
- Deep voice
- Early puberty
How do mild case of CAH present in males?
- Tall for their age
- Deep voice
- Large penis
- Small testicles
- Early puberty
Tom Tip: Congenital adrenal hyperplasia
TOM TIP: A textbook and exam clue that a patient has CAH is skin hyperpigmentation. Hyperpigmentation occurs because the anterior pituitary gland responds to the low levels of cortisol by producing increasing amounts of ACTH. A byproduct of the production of ACTH is melanocyte simulating hormone. This hormone stimulates the production of melanin (pigment) within skin cells.
Investigations for congenital adrenal hyperplasia
- Serum 17-hydroxyprogesterone levels: this is precursor of the enzyme, 21-hydroxylase and is diagnostic of classical 21-hydroxylase deficiency (21-OHD)
- Serum electrolytes: To assess for hyponatremia, hyperkalemia, and acidosis
- Serum hormone levels: elevated ACTH + renin will be expected in salt-wasting CAH, with associated low cortisol + aldosterone
Ix to consider:
* Genetic testing: To confirm the specific enzyme deficiency, as well as to karyotype for genotypic sex
* Imaging: Pelvic ultrasound for internal genital anatomy in cases of ambiguous genitalia
Management for congenital adrenal hyperplasia
- Cortisol replacement: Hydrocortisone (similar to adrenal insufficiency)
- Alsosterone replacement: fludrocortisone
- Corrective surgery for female patients with ‘virilised’ genitals
Complications for congenital adrenal hyperplasia
- Adrenal crisis
- Infertility
- Psychological issues: gender identity + body image
What is androgen insensitivity syndrome?
Androgen insensitivity syndrome = cells are unable to respond to androgen hormones - due to a lack of androgen receptors
Previoulsy known as testicular feminisation syndrome
What is the inheritence pattern for androgen insensitivity syndrome?
X-linked recessive genetic condition → caused by a mutation in the androgen receptor gene on the X chromosome
Pathophysiology of androgen insensitivity syndrome
- Mutation in the androgen receptor gene on the X chromosome
- Extra androgens = converted into oestrogen → resulting in female secondary sexual characteristics
- Patients = genetically male with XY sex chromosome → However, no response to testerone + additional androgens to oestrogen → result in female phenotype externally → male sexual characteristics don’t develop + develop normal female external genitalia + breast tissue
Apart from reproductive organs, how else may patients with androgen insensitivity syndrome present?
Due to the insensitivity to androgens:
* Lack of pubic hair
* Facial hair
* Male muscle development
* Slightly taller than female average
* Infertile
* Increased risk of testicular cancer (unless removed)
