Congenital adrenal hyperplasia

Question 1

What is the key feature of congenital adrenal hyperplasia?

Answer 1

Impaired cortisol synthesis

Question 2

What is the inheritance pattern of congenital adrenal hyperplasia?

Answer 2

Autosomal recessive

Question 3

What are the symptoms of congenital adrenal hyperplasia?

Answer 3

Vomiting due to salt-wasting, leading to dehydration and death
Excessive urination of sodium
Ambiguous genitalia 
Virilisation
Early, delayed or absent pubrety
Hyperandrogenism
Infertility

Question 4

What is the most common enzymatic defect in congenital adrenal hyperplasia?

Answer 4

21-hydroxylase

Question 5

How do females with congenital adrenal hyperplasia present?

Answer 5

Female infants with classic CAH have ambiguous genitalia due to exposure to high concentrations of androgens in utero

Less severely affected females may present with early pubarche

Question 6

How do males with congenital adrenal hyperplasia present?

Answer 6

Males with classic CAH generally have no signs of CAH at birth.

Some may present with hyperpigmentation, due to co-secretion with melanocyte-stimulating hormone, and possible penile enlargement. Age of diagnosis of males with CAH varies and depends on the severity of aldosterone deficiency. Boys with salt-wasting disease present early with symptoms of hyponatremia and hypovolemia.

Question 7

How would you manage someone with congenital adrenal hyperplasia?

Answer 7

Treatment of all forms of CAH may include any of:

1. Supplying enough glucocorticoid to reduce hyperplasia and overproduction of androgens or mineralocorticoids
2. Providing replacement mineralocorticoid and extra salt if the person is deficient
3. Providing replacement testosterone or estrogens at puberty if the person is deficient

Question 8

Why can congenital adrenal hyperplasia lead to lower levels of aldosterone?

Answer 8

21-hydroxylase converts progesterone into corticosterone, which can be converted into aldosterone

No sodium preservation