How do I know if I have Insulinoma?

Insulinoma is a rare, typically benign tumor of the pancreas that causes the body to overproduce insulin, leading to recurrent episodes of low blood sugar (hypoglycemia). You may suspect Insulinoma if you experience neuroglycopenic symptoms—such as confusion, visual disturbances, or seizures—that resolve rapidly after consuming sugar, particularly when these occur during fasting or exercise.

What are the primary symptoms of Insulinoma?

The hallmark of Insulinoma is Whipple’s Triad: clinical symptoms of hypoglycemia, low blood glucose levels measured at the time of symptoms, and the relief of symptoms after glucose administration. Because Insulinoma causes unpredictable insulin spikes, patients often report symptoms such as:

• Episodes of dizziness, lightheadedness, or sudden confusion.


• Palpitations, sweating (diaphoresis), and tremors.


• Unexplained weight gain, as patients often eat frequently to prevent hypoglycemic episodes.


• Neurological changes, including blurred vision or, in severe cases, loss of consciousness.

How is Insulinoma diagnosed?

If you suspect you have Insulinoma, your physician will likely order a supervised 72-hour fast. During this period, blood is drawn periodically to measure insulin, C-peptide, and glucose levels to confirm the presence of hyperinsulinemic hypoglycemia. If the 72-hour fast is positive, imaging studies such as endoscopic ultrasound (EUS), CT, or MRI are used to locate the tumor. In our DiseaseMaps community, 15 members have shared their journeys, highlighting the importance of persistence when seeking these specific diagnostic tests.

When should I seek urgent medical care?

Seek immediate emergency medical attention if you experience a seizure, severe confusion, or loss of consciousness that does not fully resolve with a quick snack. These are red flags that your brain is not receiving adequate glucose. If your primary care provider dismisses your concerns, request a referral to an endocrinologist who specializes in neuroendocrine tumors and explicitly ask for a "fasting glucose and insulin panel" to rule out Insulinoma.

Next steps

• Keep a detailed log of your symptoms, including what you ate, the time of day, and how long after a meal or exercise the symptoms occurred.


• Consult an endocrinologist to discuss the necessity of a 72-hour supervised fast.


• Join the Insulinoma community on DiseaseMaps.org to connect with others who have navigated the diagnostic process.

Medical disclaimer: This information is for educational purposes and does not replace professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Insulinoma.


• Orphanet: Insulinoma (ORPHA:472).


• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) clinical resources.


• OMIM (Online Mendelian Inheritance in Man): Entry #606333 regarding Multiple Endocrine Neoplasia Type 1, which can be associated with Insulinoma.