Congenital Adrenal Hyperplasia(CAH)

Question 1

describe what congenital adrenal hyperplasia(CAH) is

Answer 1

a group of inherited conditions characterised by deficiency in one of the enzymes necessary for cortisol synthesis

Question 2

what is the most common enzyme deficiency in CAH

Answer 2

21alpha-hydroxylase deficiency(90% cases)

Question 3

what type of inheritance pattern is usually seen in CAH

Answer 3

autosomal recessive

Question 4

what is CAH classically diagnosed, and what can it present with

Answer 4

in infancy, can present with virilisation and salt-wasting

Question 5

when does non-classical CAH present and how

Answer 5

presents in adolescence/adulthood, with hirsutism, menstrual disturbance, infertility due to anovulation
(hyperandrogenaemia)

Question 6

what is the diagnosis of CAH based on

Answer 6

basal(or stimulated) 17-OH Progesterone levels

Question 7

how is 21alpha-hydroxylase involved in non-classical CAH

Answer 7

only partial deficiency of 21-alpha hydroxylase

Question 8

describe what effect does 21-alpha hydroxylase deficiency have on adrenal hormones

Answer 8

results in decrease/no production of aldosterone and cortisol
because 21-alpha hydroxylase is one of the enzymes needed in both these hormones pathways from conversion of cholesterol

Question 9

what hormones levels can be increased in 21alpha-hydroxylase deficiency and why

Answer 9

Progesterone, 17 OH Progesterone, Androstenedione, Testosterone, dihydrotestosterone
because pathway to cortisol and aldosterone blocked so more production in other pathway than normal

Question 10

describe the clinical features seen in presentation of classical CAH

Answer 10

adrenal insufficiency(often around first 2/3weeks of life), poor weight gain, biochemical pattern of Addison’s, genital ambiguity in females(virilisation)

Question 11

describe why virilisation can occur in females with classical CAH

Answer 11

due to increased testosterone production, can cause abnormal development of male characteristics

Question 12

what gender does non-classical CAH tend to affect

Answer 12

females

Question 13

what features are seen in a non-classical presentation of CAH

Answer 13

hirsutism, acne, oligomenorrhoea, precocious puberty, infertility or sub-fertility

Question 14

what are the principles of treatment in classical CAH when they are children

Answer 14

timely recognition, glucocorticoid replacement, mineralocorticoid replacement in some, achieve maximal growth potential

Question 15

what are the principles of treatment in classical CAH when they are adults

Answer 15

control androgen excess, restore fertility, avoid steroid over-replacement