Congenital Adrenal Hyperplasia

Question 1

What is congenital adrenal hyperplasia?

Answer 1

• Group of autosomal recessive disorders which is caused by a deficiency in 21-hydroxylase.
• This causes low cortisol and high levels of ACTH which results in adrenal hyperplasia.
  Corticosteroids are not produced so more of the sex steroids are made instead.

Question 2

What is the pathophysiology of CAH?

Answer 2

• Either faulty or absent 21-hydroxylase enzyme. This is responsible for converting progesterone into aldosterone and cortisol.
• This results in a build up of precursors such as progesterone and 17-hydroxyprogesterone. These get shunted into a different pathway which produce androgens.
  https://www.youtube.com/watch?v=MrXIHQ11gD4

Question 3

What are the different types of CAH?

Answer 3

1. Salt wasting CAH - No aldosterone or cortisol.
2. Simple virilization CAH - Sufficient aldosterone but still excess androgens

Question 4

What is the presentation of congenital adrenal hyperplasia

Answer 4

Variable presentation:
- Ambiguous genitalia in girls,
- Hypotention, hyponatraemia and hyperkalaemia.
- Salt wasting crisis and dehydration
- Vomiting,
- Virilisation
- Precocious puberty (early puberty)

Question 5

What are the symptoms of virilization which may be present in CAH?

Answer 5

• Deepened voice,
• Increased sex drive,
• Small breasts,
• Enlarged clitoris,
• Irregular menstrual cycle,
• Male pattern baldness,
• Acne

Question 6

Describe features of salt wasting CAH

Answer 6

Caused by a 21-hydroxylase deficiency causing reduced cortisol and aldosterone
Abundance of steroid precursors causes excess androgens eg, testosterone and DHEA

Question 7

When does salt wasting CAH present?

Answer 7

Presents a few weeks after birth as baby received aldosterone from placenta. Suddenly they have no aldosterone so baby will present with hypotension, dehydration and circulatory shock

Question 8

What is the pathophysiology of simple virilising CAH?

Answer 8

Occur when there is residual 21-hydroxylase activity. There is enough aldosterone but still excessive androgens (testosterone). It causes females to be born with ambiguous genitalia. In males it causes early puberty

Question 9

What are the investigations for CAH?

Answer 9

Bloods - 17-hydroxyprogesterone, cortisol and ACTH levels

Question 10

What is the management of congenital adrenal hyperplasia

Answer 10

Salt wasting emergency - IV saline and hydrocortisone.
Life long hydrocortisone and fludrocortisone.