A 35-year-old male presents with symptoms of palpitations, tremors, nervousness and headache. His father has a history of type 2 DM and mother has a history of some psychiatric illness. He has no chronic medical conditions and takes no medications. He appears anxious, sweaty and shaky. His fingerstick glucose is 45 mg/dl. The patient as administered a bolus of 50% glucose which rapidly improves his symptoms. CECT abdomen shows a mass as follows. Which of the following is likely to be seen after overnight fasting?
A 35-year-old male presents with symptoms of palpitations, tremors, nervousness and headache. His father has a history of type 2 DM and mother has a history of some psychiatric illness. He has no chronic medical conditions and takes no medications. He appears anxious, sweaty and shaky. His fingerstick glucose is 45 mg/dl. The patient as administered a bolus of 50% glucose which rapidly improves his symptoms. CECT abdomen shows a mass as follows. Which of the following is likely to be seen after overnight fasting?
💡 Explanation
**Core Concept**
The patient's symptoms of palpitations, tremors, nervousness, and headache, along with a low fingerstick glucose level, suggest a diagnosis of hypoglycemia. The CECT abdomen showing a mass is likely to indicate a pancreatic lesion, which could be a cause of hypoglycemia due to excessive insulin secretion.
**Why the Correct Answer is Right**
The patient's symptoms improved rapidly after administration of a bolus of 50% glucose, confirming hypoglycemia. The presence of a pancreatic mass suggests a diagnosis of insulinoma, a tumor of the pancreas that secretes excessive amounts of insulin. Insulinomas are typically benign and can cause hypoglycemia by secreting insulin, leading to low blood glucose levels. After overnight fasting, insulinoma cells would continue to secrete insulin, leading to hypoglycemia.
**Why Each Wrong Option is Incorrect**
**Option A:** Glucagonoma is a tumor of the pancreas that secretes excessive amounts of glucagon, which can cause hyperglycemia, not hypoglycemia.
**Option B:** Somatostatinoma is a tumor of the pancreas that secretes excessive amounts of somatostatin, which can cause hypoglycemia, but it is less common than insulinoma.
**Option C:** Gastrinoma is a tumor of the pancreas that secretes excessive amounts of gastrin, which can cause peptic ulcers, not hypoglycemia.
**Option D:** VIPoma is a tumor of the pancreas that secretes excessive amounts of vasoactive intestinal peptide (VIP), which can cause watery diarrhea, not hypoglycemia.
**Clinical Pearl / High-Yield Fact**
Insulinomas are the most common cause of hypoglycemia due to a pancreatic tumor and can be diagnosed with a 72-hour fast, which can demonstrate the characteristic Whipple's triad of symptoms, low blood glucose, and relief with glucose administration.