Causes of fasting hypoglycemia are following except-
**Core Concept**
Fasting hypoglycemia refers to abnormally low blood glucose levels that occur after an overnight fast, typically below 55 mg/dL. It can be caused by various factors, including hormonal imbalances, enzyme deficiencies, and medication-induced effects.
**Why the Correct Answer is Right**
Fasting hypoglycemia can be caused by several factors, including:
- **Insulinoma**: a rare tumor of the pancreas that produces excess insulin, leading to hypoglycemia.
- **Glucagon deficiency**: a condition where the pancreas does not produce enough glucagon, a hormone that raises blood glucose levels.
- **Glycogen storage diseases**: a group of genetic disorders that affect the body's ability to store and release glucose from glycogen, leading to hypoglycemia.
- **Medications**: certain medications, such as sulfonylureas and meglitinides, can stimulate insulin release and cause hypoglycemia.
**Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not list a known cause of fasting hypoglycemia.
- **Option B:** This option is incorrect because it lists a common cause of postprandial hypoglycemia, not fasting hypoglycemia.
- **Option C:** This option is incorrect because it lists a condition that typically causes hyperglycemia, not hypoglycemia.
**Clinical Pearl / High-Yield Fact**
When evaluating a patient with fasting hypoglycemia, it is essential to consider the possibility of an insulinoma or glucagon deficiency, as these conditions can be life-threatening if not treated promptly.
**Correct Answer:** A.