A 2 month old baby who has ambiguous genitalia presents to the emergency department with vomiting. Lab results: Na+ 125mmol/L, K+ 6mmol/L. What is the most likely diagnosis?

The key is D. Congenital adrenal hyperplas. [ i) ambiguous genitalia ii) salt wasting manifested as hyponatremia and hyperkalemia (In mild forms of salt-wasting adrenal hyperplasia, salt wasting may not become apparent until an illness stresses the child). Here hyperkalaemia inspite of vomiting is indicating the disease].