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

adrenal insufficiency in children.

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

you can follow along at zero definals.com slash adrenal insufficiency

or in the endocrinology section of the zero to finals pediatrics book.

So let's get straight into it.

Adrenal insufficiency occurs where the adrenal glands do not produce enough steroid hormones,

particularly cortisol and aldosterone.

Steroids are essential for life.

Therefore the condition is life-threatening unless the steroid hormones are replaced. Firstly, let's briefly recap the adrenal axis

physiology. Cortisol is secreted by the two adrenal glands, which sit above each of the kidneys.

The release of cortisol is controlled by the hypoth adrenal glands which sit above each of the kidneys. The release of cortisol is controlled by the hypothalamus in the brain. And cortisol is released in pulses and in response to a stressful stimulus.

It's called a stress hormone.

And it has diurnal variation, which basically means that it's high and low at different times of the day.

Typically cortisol peaks early in the morning, triggering us to wake up and get going,

and it's at its lowest late in the evening, prompting us to relax and get to sleep.

The hypothalamus releases corticotrophin releasing hormone or CRH, and this stimulates the anterior

pituitary to release adrenocortico-trophic hormone or AC-T-H, and this in turn stimulates the

adrenal gland to release cortisol.

The adrenal axis is controlled by negative feedback, which means that cortisol is sensed by the

hypothalamus and the anterior pituitary, and the cortisol suppresses the release of CRH and

...