An 8 days old male infant is brought to the emergency depament with vomiting, lethargy, dehydration and features of shock. Clinical examination reveals hyperpigmentation of the genital skin and normal external genitalia. Abdominal examination is unremarkable. Blood tests revealed sodium of 124 meq/l, potassium of 7 meq/1 and hypoglycemia. Which of the following is the most likely diagnosis:

Ans is `a' i.e., Congenital Adrenal Hyperplasia (CAH) Presence of vomiting, lethargy, dehydration, hyponatremia, hyperkalemia, hypoglycemia and shock in this eight year old male infant suggest a diagnosis of neonatal adrenal insufficiency/crisis. Congenital Adrenal Hyperplasia is the most prevalent cause of adrenal insufficiency in neonates (typically 7-14 days post delivery) and the single best answer amongst the options provided. Clinical features of CAH (21 hvdroxlose deficiency) o Symptoms of classical CAH due to 21 hydroxylase deficiency are: i) Clinical: Lethargy, vomiting, Anorexia, weight loss, dehydration, hypotension, shock ii) Mineralocoicoid deficiency: Hyponatremia, hyperkalemia, hypotension iii) Coisol deficiency: Hypoglycemia, Hyperpgimention of areolar and scorial areas in males and genital creases in females (due to T ACTH secretion) iv) Excess Androgen Males: Phenotypically normal for some years, precocious pubey Females: Virilization (female pseudohermophrodite)