A mother brings her 20 day old baby for establishment of care in your pediatric office. She reports that the baby feels lethargic and not feeling well. Both parents are healthy, and there is no history of hormonal problems in the family. The vital signs of the baby are temperature 99.7 F, blood pressure 50/20 mm Hg, pulse 164 beats per minute and a breathing rate of 40 breaths per minute. On examination of the child, you notice that her genitalia are abnormal. The child has a penis-like clitoris and scrotum-like labia. There is hyperpigmentation around the genitalia. The child’s sex had been confirmed as female by karyotype (46,XX) from an amniocentesis performed during the pregnancy. Laboratory evaluation reveals a glucose level of 49 mg/dL (normal 70 to 150 mg/dL), sodium of 124 mEq/L (normal 135 – 145 mEq/L) and potassium of 6.2 mEq/L (normal 3.7 – 5.7 mEq/L). What is the most likely diagnosis in this baby?
