This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
An 8 days old male infant is brought to the emergency depament with vomiting, lethargy, dehydration and features of shock. Clinical examination reveals hyper pigmentation of the genital skin and normal external genitalia. Abdominal examination is unremarkable. Blood tests revealed sodium of 124 meq/1, potassium of 7 meq/1 and hypoglycemia. Which of the following is the most likely diagnosis: 
Select and explain. 
A. Congenital Adrenal Hyperplasia (CAH), B. Adrenal Haemorrhage, C. Acute Gastroenterit is with dehydration, D. Hyper aldosteronism
A: Congenital Adrenal Hyperplasia (CAH)
Answer: A: Congenital Adrenal Hyperplasia (CAH) 
Explanation: 8 day old male infant presenting with vomiting, lethargy, dehydration, hyponatremia, hyperkalemia, hypoglycemia, and shock suggests a diagnosis of neonatal adrenal insufficiency/crisis. Congenital adrenal hyperplasia is the cause of adrenal insufficiency in children of this age group. Ref: Essential pediatrics by O.P.Ghai 6th edn/page 489-90.