Congenital Adrenal Hyperplasia (CAH)

the most common adrenal disorder of infancy and childhood

defect in CYP21A2

autosomal recessive; deficiency of enzymes required to synthesize cortisol

Consider in all infants exhibiting vomiting, dehydration, failure to thrive, especially those with episodes of acute adrenal insufficiency, hyponatremia (salt wasting), hypoglycemia and hyperkalemia

All forms of CAH have the following characteristics:

• Elevated ACTH.
• Low aldosterone and cortisol levels.
• Treatable with steroids such as prednisone, which inhibits the pituitary.

Different kinds of CAH:

95% C-21 hydroxylase deficiency (most common)

female at birth with ambiguous external genitalia (female pseudohermaphrodism);

associated with reduced cortisol and aldosterone >> salt wasting ->vomiting, hyponatremia, hyperkalemia, dehydration and HYPOtension

accumulation of upstream precursors:

pregnenolone, progesterone, 17-hydroxyprogesterone, androstenedione, androgens and DHEA, which lead to virilization of females

To confirm Dx, do 17-hydroxyprogesterone level which would be elevated

C-11 hydroxylase deficiency (5-8%)