New born 7 days old with vomiting and dehydration clinical examination was normal except for hyperpigmentation of nipple. Electrolytes Na: 120 meq. K: 9 meq. mostlikelydiagnosis -: (A) Primary hypothyroidism, (B) Cong, adrenal hyperplasia, (C) Panhypopituitarism, (D) Pyloric stenosis
Answer is B. Congenital adrenal hyperplasia due to defect in CYP21A2 is suggested by episodes of acute adrenal insufficiency with hyponatremia , hyperkalemia , dehydration & vomiting ( Harrison 17 pg 2267)