Endo 7 - Hypoadrenal Disorders

Question 1

Which enzyme converts cholesterol to pregnenalone?

Answer 1

CP450

Question 2

Which set of enzymes are switched on by ACTH?

Answer 2

Sex steroid enzymes

Cortisol synthesis enzymes

Question 3

The pituitary produces ACTH in response to?

Answer 3

Stress

Question 4

State 3 causes of adrenocortical failure

Answer 4

• Tuberculosis Addisons - worldwide
• Autoimmune Addisons - UK
• Congenital Adrenal Hyperplasia

Question 5

Name some of the features of Addisons

Answer 5

Hypotension
Hyperkalaemia
Loss of salt in urine
Fall in blood glucose
High ACTH
Pigmentation
Vitiligo
Eventual death due to hypotension

Question 6

Why do Addison’s patients get vitiligo?

Answer 6

Vitiligo is an autoimmune disease where the body produces antibodies against melanin

autoimmune disease go hand in hand

Question 7

Why do Addison’s patient get pigmentation?

Answer 7

Lack of cortisol causes high ACTH

ACTH comes from POMC

POMC = ACTH + MSH

MSH is melanocyte stimulating hormone so causes pigmentation of skin

Question 8

Why do Addison’s patients get hypotension?

Answer 8

Fall in aldosterone

Question 9

Why is there excess loss of sodium in Addison’s patients?

Answer 9

fall in aldosterone = reduced reabsorption of sodium

Question 10

State some tests for Addisons

Answer 10

1. 9am cortisol level - would be high in a normal person
2. measure ACTH - this would be high in Addisons
3. synACTHen - functioning adrenals - produce cortisol

Addison’s patient will not be able to produce cortisol
could also measure glucose, sodum, potassium

Question 11

What is the most common cause of congenital adrenal hyperplasia?

Answer 11

21-b-hydroxylase

Question 12

What are the two degrees of CAH that you can have?

Answer 12

partial or complete

Question 13

Why are foetus’ in utero fine?

Answer 13

They have maternal cortisol and aldosterone so don’t need to produce any of their own

Question 14

Which hormones are absent in 21-hydroxylase deficiency>?

Answer 14

cortisol and aldosterone

Question 15

What effect does 21-hydroxylase deficiency have on sex steroids?

Answer 15

Precursors are funnelled towards the sex steroid synthesis pathway so you get an increase in adrenal sex steroids

Question 16

What will happen to a baby born with complete 21 hydroxylase deficiency?

Answer 16

Salt losing crisis straight away as they have no aldosterone

Question 17

What are the two main features of complete 21 hydroxylase deficiency?

Answer 17

Hypotension

Virilisation - female babies born with ambiguous genitalia

Question 18

Describe the presentation of partial 21 hydroxylase deficiency?

Answer 18

may present much later on

may present with effects of excess adrenal androgens

Question 19

Name 2 other types of congenital adrenal hyperplasia?

Answer 19

• 11 beta hydroxylase deficiency

- 17 beta hydroxylase deficiency

Question 20

What is the precursor that builds up in 11 hydroxylase deficiency CAH?

Answer 20

build up of 11 deoxycorticosterone

Question 21

What is 11 deoxycorticosterone?

Answer 21

aldosterone receptor agonist

Question 22

What will a patient with 11 beta hydroxylase deficiency present with?

Answer 22

• will NOT have salt losing crisis as have an aldosterone receptor agonist
• will present with having too much aldosterone
• e.g. hypertensive and hypokalaemic
• virilised, hypertension,

Question 23

Describe and explain the presentation of 17 beta hydroxylase deficiency?

Answer 23

• high levels of aldosterone
• so hypertensive and hypokalaemic
• present with absent puberty as missing sex steroids and cortisol
• a lot of infections as need cortisol to deal with infection