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FAQs - What is an insulinoma in a ferret? My six-year old ferret recently started having episodes of lethargy and shakiness lately. His eyes also get glassy looking and he drools when this happens. His veterinarian did a blood test and said the blood sugar was low and the insulin level was elevated. He explained that insulin lowers blood sugar. The doctor thinks my ferret may have an insulinoma. What is this? Thank you for your help! A tumor of the insulin-producing cells of the pancreas. Insulinomas are usually malignant and are among the most common tumors occurring in ferrets. Insulinoma usually develops in ferrets over four years old. Males and females are equally affected. These tumors arise from the insulin-producing beta cells of the pancreas. The tumor cells secrete excessive amounts of insulin, especially in response to food intake. The resulting hypoglycemia (low blood sugar) and the body's response to it produce the signs of the disease. The signs may develop gradually or suddenly. The signs of insulinoma may include weakness, lethargy, drooling and excess salivation, weight loss, vomiting, stumbling, rapid heart rate, tremors, pawing at the mouth, seizures, collapse, coma, and death. Affected hypoglycemic animals may have a glassy eyed appearance. Some animals have hair loss because of concurrent adrenal gland tumors. Generally, the lower the blood sugar, the more severe the clinical signs will be. Splenic enlargement is a common finding on physical examination of ferrets with insulinoma, but is not specific for this problem. Some affected ferrets may experience episodes of hypoglycemia with some of the attendant signs, followed by unassisted recovery. Others will require glucose administration in order to recover. In the former cases, it is probable that the tumor tissue has not reached a level of insulin production capable of overriding the liver's ability to produce and secrete glucose into the blood stream. Insulinoma may metastasize (spread) to the regional lymph nodes, liver and spleen. After tumor cells are situated and growing in the liver, signs of liver disease may result. Definitive diagnosis of insulinoma requires laboratory examination of a biopsy tissue sample. A presumptive diagnosis may be made by demonstrating a high blood insulin level concurrent with low blood sugar and then ruling out other causes of hypoglycemia. Other causes of hypoglycemia include loss of appetite, infection, other types of tumors, significant liver disease, and other problems. Ultrasound may demonstrate the presence of a pancreatic mass, but not consistently in every case. In cases where insulinoma-associated hypoglycemia episodes are severe, surgery to remove as much of the tumor as possible is usually the treatment of choice. In most cases complete removal is not feasible and cure is rare. Within several months after surgery hypoglycemic episodes will usually return as the tumor continues to grow from gross or microscopic remnants of the cancer. Frequent feedings are often required to maintain a sufficiently high blood glucose level following surgery. Surgeons will inspect the adrenal area for concurrent disease, which is common in ferrets with insulinoma. In some cases a medical approach may provide sufficient treatment. Although the tumor continues to grow and the tumor burden is likely to be greater than if surgery had been performed, some ferrets may do well for periods of up to a year and a half, although the hypoglycemic episodes usually get worse. Medical treatment includes the use of drugs that by several physiologic mechanisms raise the blood sugar. Frequent feedings and regular monitoring of blood sugar levels are essential elements of medical treatment. I recommend that you discuss the signs your ferret is having with your veterinarian. Your veterinarian will talk to you about ways to minimize the hypoglycemia and about the surgical options that are available. |
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