A child presents with massive hepatomegaly and hypoglycemia. There is no improvement in blood glucose on administration of glucagon. The probable diagnosis is –
**Core Concept**
The underlying principle being tested involves **glycogen storage diseases** and the body's inability to regulate blood glucose levels. This scenario implies a defect in **glycogenolysis** or **gluconeogenesis**, crucial for maintaining **blood glucose homeostasis**.
**Why the Correct Answer is Right**
Given the lack of response to **glucagon**, which typically stimulates **glycogenolysis** to increase blood glucose, the issue likely lies in the glycogen storage or breakdown pathway. A disease like **Glycogen Storage Disease Type I (Von Gierke's disease)**, characterized by a deficiency in **glucose-6-phosphatase**, would lead to massive **hepatomegaly** due to glycogen accumulation and **hypoglycemia** because glucose cannot be released from glycogen into the bloodstream.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not directly relate to the inability to mobilize glucose from glycogen.
**Option B:** Incorrect as it might not directly explain the lack of response to glucagon.
**Option C:** Incorrect because, while related to glycogen storage, it may not perfectly match the clinical presentation described.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **glucagon** stimulates the breakdown of glycogen to glucose, and a lack of response suggests a defect in this pathway, such as in **Glycogen Storage Disease Type I**.
**Correct Answer:** D. Glycogen Storage Disease