How to Diagnose Insulinoma

An insulinoma is a tumor that usually arises from pancreatic islet cells. They produce excessive amounts of insulin and are a common cause of hypoglycemia. Insulinomas also may secrete other hormones causing a variety of masking symptoms. This made them difficult to diagnose in the past especially because they are benign 90 percent of the time. The following steps will show how to diagnose an insulinoma.

Instructions

1. Expect insulinomas to cause hypoglycemia in 85 percent of the cases along with blurred and double vision, palpitations and fatigue. Other symptoms may include amnesia, changes in behavior, confusion and loss of consciousness.

2. Observe less common symptoms of insulinomas. One patient in 8 may experience grand mal seizures. The hypoglycemia may cause an adrenalin release resulting in hunger, rapid heart rate and sweating.

3. Use hypoglycemia in conjunction with elevated insulin levels to diagnose an insulinoma. A fast of up to three days is used to establish the diagnosis biochemically in 95 percent of these cases.

4. Meet the required criteria to diagnose an insulinoma. The C-peptide level must be greater than 2.5 ng/mL, the glucose level must be less than 40 mg/dL, the serum insulin level must be greater than 10 uU/mL, the proinsulin level must be more than one fourth of the immunoreactive insulin and the blood sample must be negative for sulfonylurea.

5. Eliminate other possibilities in patients with malignant insulinomas. The effects of multiple endocrine neoplasmas type 1 (MEN 1) also may be caused by gastrinomas, parathyroid hyperplasia and a pituitary adnoma.