2 month old infant is presented with failure to thrive,recurrent emesis, hepatospleomegaly and adrenal insufficiency, Adrenal calcification is noted radio logically, What is the most probable diagnosis?
**Core Concept**
Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders caused by deficiency of enzymes involved in steroidogenesis, leading to accumulation of toxic precursors and cortisol deficiency. The most common form is 21-hydroxylase deficiency, accounting for 90-95% of cases.
**Why the Correct Answer is Right**
The clinical presentation of failure to thrive, recurrent emesis, hepatosplenomegaly, and adrenal insufficiency is suggestive of CAH due to 21-hydroxylase deficiency. The presence of adrenal calcification is a classic radiological finding in this condition. The enzyme deficiency leads to overproduction of androgens and precursors, which are toxic to the adrenal gland, causing calcification.
* The infant's failure to thrive and recurrent emesis are indicative of cortisol deficiency, which is essential for gluconeogenesis and maintaining blood pressure.
* Hepatosplenomegaly is due to the accumulation of toxic precursors, which cause liver and spleen enlargement.
* Adrenal insufficiency is a hallmark of CAH, leading to decreased production of cortisol and aldosterone.
**Why Each Wrong Option is Incorrect**
**Option A:** Congenital hypothyroidism presents with failure to thrive, but it does not typically cause hepatosplenomegaly or adrenal insufficiency.
**Option B:** Congenital rubella syndrome presents with hepatosplenomegaly, but it does not typically cause adrenal insufficiency or adrenal calcification.
**Option C:** Glycogen storage disease presents with failure to thrive and hepatomegaly, but it does not typically cause adrenal insufficiency or adrenal calcification.
**Clinical Pearl / High-Yield Fact**
CAH due to 21-hydroxylase deficiency is the most common cause of adrenal insufficiency in infants and children, and it is essential to diagnose it early to prevent complications.
**Correct Answer:** D. 21-hydroxylase deficiency.