Insulinoma in Ferrets

Insulinoma refers to the insulin-producing tumor of the pancreas in the ferret. Too much insulin causes blood glucose (sugar) to drop below normal levels, resulting in hypoglycemia and symptoms of generalized weakness.

The cause of insulinoma is poorly understood. It appears to be a spontaneous event within the pancreas of older ferrets. Once diagnosed, insulinomas will require treatment throughout the ferret’s life. Treatment is either medical or surgical.

This is a common disease in ferrets over three years old. Both males and females are at risk. Onset can be subtle in some cases. Other ferrets appear normal until they collapse or start to seizure.

Low blood sugar is responsible for the symptoms of insulinoma which are mild initially: weakness, sluggish behavior, sleepiness. The symptoms get worse as the disease progresses: difficulty walking, especially in the rear legs, stupor, and in some cases, seizures.

What To Watch For

• Increased amounts of sleeping
• General lack of energy
• Episodes of drooling

Diagnosis

• The most important test is a blood glucose level. Because the release of insulin from the tumor is sporadic, blood glucose levels will fluctuate and are not always critically low. Sometimes a series of blood tests are needed in order to document hypoglycemia. A short fasting period (three hours) can help pinpoint the problem.
• Blood insulin levels can be run but this test is not always a reliable indicator of insulinoma.
• Plasma biochemistry panel should be run on all older ferrets to check for other conditions and to evaluate the general health of the ferret.
• Radiographs (X-ray’s) and sonograms are not as helpful in the diagnosis of insulinoma.

Treatment

Treatment can be surgical or medical.

• Surgical treatment requires removal of the affected part of the pancreas. This procedure does not cure the condition, but rather gives the ferret more time before he relapses. Insulinomas usually arise in other areas of the pancreas and because this organ cannot be totally removed, it is likely the insulinoma will return at some point.
• Medical treatment is directed at stabilizing the blood sugar levels and keep it from dropping too low. There are two drugs commonly used for this purpose: prednisone and diazoxide. Prednisone raises blood glucose and the diazoxide lowers the insulin levels.
• Nutritional management. The goal of dietary management in the ferret with insulinoma is to try to stabilize blood sugar and avoid the “sugar swings” brought on by sweet foods. This is best accomplished by feeding a high fat, high protein diet and avoiding sugary supplements like Nutrical® and treats like watermelon or raisins. Ferretone® is OK.
• Chromium supplements. Chromium is thought to help stabilize blood sugar in people. Brewer’s yeast is a natural source of chromium and 1/8 teaspoon can be sprinkled on the ferret’s food daily.

Home Care

If the ferret stops eating for whatever reason, hand feed or force feed chicken baby food (like Gerber’s) or a veterinary formulation like Hill’s AD. Soaked and blenderized ferret or cat kibble can also be given. Veterinary care is advised in any ferret that stops eating or changes eating habits abruptly.

Once diagnosed with insulinoma, the ferret needs to be on the medication for life, unless surgery is performed. Even with surgery, some ferrets still need medication. Missing even one dose can cause hypoglycemia and missing several doses can be very serious.

Weak and/or seizing ferrets need emergency care as soon as possible. If an insulinoma ferret becomes weak or stuporous at home and cannot swallow, try rubbing honey or maple syrup on the gums. Veterinary care must be sought right away. Do not allow a ferret to seizure uncontrollably for prolonged periods (more than a few minutes).