Hello and welcome to the Zero to Finals podcast.

My name is Tom and in this episode I'm going to be talking to you about

congenital adrenal hyperplasia.

And if you want to follow along with written notes on this topic,

you can follow along at zero definals.com slash CAH or in the endocrinology section of the zero definals pediatrics book.

So let's get straight into it.

Congenital adrenal hyperplasia is caused by a congenital deficiency of the 21 hydroxylase enzyme.

And this causes underproduction of cortisol and aldosterone and overproduction of

androgens or male sex hormones from birth. This is a genetic condition that's inherited in an

autosomal recessive pattern and in a small of cases, it's caused by a deficiency of 11

beta hydroxylase rather than 21 hydroxylase.

Let's talk about steroid hormones. Testosterone is an androgen hormone. It's found in high

levels in men and in low levels in women, and it acts to promote

male sexual characteristics. Glucocorticoid hormones act to help the body deal with stress,

they raise blood glucose levels, they reduce inflammation and they suppress the immune system.

Cortisol is the main glucocorticoid hormone.

The levels of cortisol fluctuate during the day with higher levels in the morning and during

times of stress and cortisol is released in response to adrenocortico-trophic hormone from the anterior pituitary gland.

Mineralocorticoid hormones act on the kidneys to control the balance of salt and water in the blood.

Aldosterone is the main mineralocorticoid hormone.

It's released by the adrenal gland in response to renin. Aldosterone acts on the kidneys to

increase sodium reabsorption into the blood and increase potassium excretion into the urine.

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