<prompt> Newborn 7 days old with vomiting and dehydration clinical examination was normal except for hyperpigmentation of nipple. Electrolytes Na: 120 meq. K: 9 meq. most likely diagnosis -Cong, adrenal hyperplasiaPrimary hypothyroidismPanhypopituitarismPyloric stenosis  <response>: Congenital adrenal hyperplasia due to a defect in CYP21A2 is suggested by episodes of acute adrenal insufficiency with hyponatremia, hyperkalemia, dehydration vomiting 