Hypoadenal Disorders

Question 1

Describe the role of cholesterol and its pathway into becoming an adrenal steroid.

Answer 1

The carbons on the molecular structure of cholesterol are 27. If you hydroxylate them at different positions then you get different substances. The enzymes at different positions make different steroids.

1. Zona glomerulosa: cholesterol to pregnelone
2. Zona fascilatis: different enzymes so glucocorticoid and mineralcorticoid

Sex steroids: sex steroids via 17-hydroxylase, cortisol via 21-hydroxylase and 11-hydroxylase, aldosterone via 21-hydroxylase, 11-hydroxylase, 18-hydroxylase.

Question 2

Describe the causes, features, consequences, diagnostic tests of adrenocortical failure

Answer 2

1. Autoimmune Addison’s disease (adrenal gland destroyed)
2. Tuberculosis Addisons (when you stop treatment early)
3. Congenital adrenal hyperplasia (born with big adrenals caused by enzyme deficiency so adrenals don’t make hormones properly

Features: mucous membrane pigmentation, skin pigmentation, darkening of hair, freckling, vitiligo, pigment accumulation at Nipples and other areas

Consequences: low BP (postural hypotension), loss of salt in the urine due to high aldosterone, high potassium, low glucose, high ACTH.

Tests for addisons:

1. Measure the hormones at 9am (cortisol high in morning)
2. Measure ACTH (also has to be high)
3. Short synACTHen test (should increase ACTH and increase cortisol)
4. Low sodium, high potassium

Question 3

Discuss the effects of 21-hydroxylase deficiency

Answer 3

Cortisol and aldosterone cannot be made and therefore cholesterol is funnelled into sex steroid (increases), survival is very low, testosterone in excess.

Presentation at neonate with Addisonian crisis, hruitism, virilisation, ambitious genitalia

Question 4

Describe the effects of 11-deoxycortisone and 17-hydroxylase deficiency

Answer 4

Look at notes