Hi, this is Tom, and in this episode I'm going to be going through congenital adrenal

hyperplasia, and you can find notes at zero to finals.com and in the zero to finals pediatrics book,

and you can find flashcards and questions at members.0.0.5.com.

And at the end of the episode, we'll go through some questions so you can test yourself on what you just heard.

So let's jump straight in.

Congenital adrenal hyperplasia is an autosomal recessive genetic condition causing a deficiency of the 21 hydroxylase enzyme,

which converts progesterone to aldosterone and cortisol. Deficiency of this enzyme causes

underproduction of cortisol and aldosterone and overproduction

of androgens like testosterone from birth. A small portion of cases are caused by a deficiency

of other enzymes, for example, 21 beta hydroxylase.

Let's talk about steroid hormones.

Testosterone is an androgen hormone.

It's typically found in high levels in men and low levels in women.

It has many functions including increasing muscle mass, bone density,

facial hair growth, libido and competitiveness. Glucocorticoid hormones, for example cortisol,

help the body to cope with stress. Cortisol increases alertness, raises blood glucose,

reduces inflammation and suppresses the immune system. Mineralocorticoids, for example,

aldosterone, help regulate the balance of electrolytes and the blood pressure.

They act on the nephrons in the kidneys to increase sodium reabsorption from the distal tubule,

increase potassium secretion from the distal tubule, and increase hydrogen secretion from the distal tubule and increase hydrogen secretion from the collecting ducts.

Let's go through the pathophysiology.

21 hydroxylase is the enzyme responsible for converting progesterone to aldosterone and cortisol.

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