9. Adrenal gland diseases

Question 1

What is a phaeochromocytoma? What are the symptoms?

Answer 1

• adrenaline overproduction by the adrenal medulla due to a tumour

- associated with:
1- hypertension
2- anxiety
3- palpitations
4- pallor
5- sweating
6- glucose intolerance

Question 2

What is congenital adrenal hyperplasia?

Answer 2

• autosomal recessive defect in 1 or more enzymes required for synthesis of corticosteroid hormones from cholesterol… lack of cortisol so AP not subject to negative feedback… secretes much ACTH… hyperplasia of adrenal cortex.

Question 3

What is the most common form of congenital adrenal hyperplasia?

Answer 3

deficiency in 21-hydroxylase enzyme (causing less glucocorticoid and mineralocorticoid production)

Question 4

What are the clinical consequences of congenital adrenal hyperplasia?

Answer 4

1. “salt-wasting” crises: due to high rate of Na+ loss in urine (from loss of aldosterone)
2. genital ambiguity in female infants

Question 5

What is Conn’s syndrome? What are the usual causes?

Answer 5

primary hyperaldosteronism caused by hyperactivity of 1 (unilateral disease) or both (bilateral disease) adrenal glands

• unilateral form usually caused by adenoma
• rare genetic syndromes like familial hyperaldosteronism type I and II may cause both glands to be hyperactive

Question 6

Name the signs and symptoms of Conn’s syndrome.

Answer 6

1. high BP
2. occasional muscular weakness and spasms
3. paraesthesia
4. excessive urination

Question 7

Explain the pathophysiology of Conn’s syndrome.

Answer 7

Most important effects in the kidney.

excess aldosterone… increases Na+ reabsorption and K+ secretion… increased blood volume and pressure… increased BP and renal perfusion cause decreased renin release from kidney… but no decrease in aldosterone in Conn’s.

Question 8

Why might excess cortisol cause mineralocorticoid- and androgen-like activity?

Answer 8

sequence homology in hormone binding regions of receptors - % homology of hormone-binding region of glucocorticoid R:

• mineralocorticoid R - 64%
• androgen R - 62%

So binding of cortisol to these Rs can be significant when high hormone levels are present.

Question 9

What are the effects of adrenal androgen over secretion in females?

Answer 9

1. excessive body hair growth (hirsutism)
2. acne
3. menstrual problems
4. virilisation
5. increased muscle bulk
6. deepening voice