Congenital adrenal hyperplasia

Question 1

what is congenital adrenal hyperplasia (cause, risk factors)

Answer 1

Recessive disorder -disorder of hydroxylase enzyme in Testo/Oestro/Cortisone/Aldo pathway
98% are 21 hydrxylase defs (cant make aldosterone -forced down cortisol/testo pathway-EXCESS)

also exist  17a def (cant make testo)
3b def (lower testo
11B def cant make aldo/cortisol. all sex

no risk factors of note

Question 2

Signs Sx and Ix of Congenital adrenal hyperplasia

Answer 2

Sx of excess sex hormones, and Sx of low aldosterone

Classical CAH -
Female: at birth due to atypical genitalia (clitoral enlargement, fused labora, urogenital sinus
Males at birth - rarely seable. maybe pigmentation from excess ACTH

Hyperpigmentation

Hyperadrogenism - precocious puberty, early facial, pubic, axiallary hair, rapid somatic growth
accompanied with premature epiphyseal closure-shorter than parents (tall children, short adults)
Acne, temporal balding (even in women), irregular menses, hirsutism, inferitility

SALT WASTING CAH
in addition to excess adrogen, low aldo can cause in infants -renal salt waste

Poor feeding, weight loss, failure to thrive
Vom, dehydration,
HYPOTENSION
Hyponatremia, hyperkalemia, hyperkalemic metabolic acidosis

Investigation –
serum 17-hydroxyprogestrone (precursor, v high in 21a def)
ACTH simulation test -levels high and no change

U&E=hyponatraemic, hyperkalaemic, metabolic acidosis; azotaemia

Question 3

Management and complications of CAH

Answer 3

Acute -salt-loss crisis -high dose steroids, fluids

classical CAH - replacement hydrocortisone -
+replace aldo (fludrocoritsone) + sodium chloride ensure adequate Na repletion in infancy)

genital surgery -for women virrilised at birth can improve QOL

In children - GH (somatropin) to improve final height

adults - just hydrocorstisone and fludrocortisone lifelong

complications - adrenal crisus, short stature, osteopenia