2025 – PAGE 83 – ENDOCRINOLOGY

CONGENITAL ADRENAL HYPERPLASIA (CAH)

CONGENITAL ADRENAL HYPERPLASIA (CAH) LEADS TO A BUILD-UP OF ANDROGENS AND A LACK OF CORTISOL AND ALDOSTERONE. For the American Board of Pediatrics, CONGENITAL ADRENAL HYPERPLASIA usually equals 21-HYDROXYLASE DEFICIENCY (not 11-Hydroxylase Deficiency)! The patient may present with a picture similar to septic shock. The newborn screen usually tests for the most common form of Congenital Adrenal Hyperplasia, which is 21-hydroxylase deficiency. The newborn screen is considered positive if there is a high 17-hydroxyprogesterone level. Patients can develop adrenal insufficiency and an adrenal crisis-like picture with abnormal electrolytes and shock-like symptoms that resemble sepsis. Boys may have HYPERPIGMENTED scrotums from elevated ACTH being released from the pituitary. Girls usually present at birth with ambiguous genitalia. If the newborn screen is abnormal but the physical exam is okay, repeat a 17-hydroxyprogesterone level. In pregnancy, if the baby has a first degree relative with a history of CAH, order gene testing on fetal cells. TREATMENT requires both Hydrocortisone (for the lack of cortisol) and Fludrocortisone (for the lack of aldosterone), just like primary Adrenal Insufficiency (AKA Primary ADDison’s).

PEARL: In boys, testing for this on the newborn screen is extremely important. Since 21-Hydroxylase Deficiency results in increased androgens, male genitalia are often NORMAL. So, boys often do not present at birth. Girls, however, have ambiguous genitalia due to the increased androgens, so they are much more likely to present at birth and thus get timely treatment if they present with a “septic shock” type of picture.

PEARL: Late onset congenital adrenal hyperplasia (AKA Nonclassic Congenital Adrenal Hyperplasia) can present with signs of early puberty.

PEARL/MNEMONIC: You could be asked about which part of the adrenal gland makes a deficient hormone. Try to remember the layers of the adrenal cortex as GFR. Also, use the following as a memory aid: “The deeper you go, the sweeter it is.” Yes, it’s a sexual mnemonic. The layers go from salty to sweet. G = Glomerulosa = Aldosterone (salty!). F = Fasciculata = Cortisol/Glucocorticoids (sweet!). R = Reticularis = Sex steroids (deep and sexy!).

21-HYDROXYLASE DEFICIENCY

21-Hydroxylase Deficiency is the autosomal recessive disorder that’s usually responsible for Congenital Adrenal Hyperplasia on the pediatric boards. After birth, the baby will need steroid treatment. Due to lack of aldosterone, this is a SALT WASTING CAH, resulting in Hyponatremia and hypERkalemia. There is NO hypertension. On labs, expect 17- HYDROXYPROGESTERONE to be high.