Insulinoma is a type of cancer that affects the pancreas, causing low blood sugar (hypoglycemia).
Clinical signs can include lethargy (tiredness), inability to stand, and seizures.
Treatment may involve medication or surgery.Because of the frequency and severity of this disease, all ferrets that are at least 3 years old should have their blood sugar level checked every 6 months.
What Is an Insulinoma?
An insulinoma (also known as beta-cell carcinoma and islet cell carcinoma) is a tumor of the pancreas that causes an increase in the secretion of insulin, which leads to severely low blood sugar (hypoglycemia). Insulinomas are common in middle-aged to older ferrets, most commonly those aged 3 to 4 years and older. They can develop in both male and female ferrets.
What Are the Clinical Signs of Insulinoma?
Signs of the disease may appear suddenly as an episode of collapse lasting from minutes to hours. During such an episode, the ferret usually appears depressed, recumbent (unable to stand), and unresponsive. In severe cases, seizures may occur. However, in many ferrets, clinical signs appear gradually as progressive weakness and lethargy (tiredness) over weeks to months. Excessive salivation, pawing at the mouth, and weakness of the hindlimbs are also common. These signs may be intermittent, with periods of normal activity in between periods of lethargy.
Prolonged, severe hypoglycemia can lead to convulsions and even irreversible brain damage and death. Because of the frequency and severity of this disease, it is recommended that all ferrets 3 years old and older have their blood sugar (blood glucose) level checked every 6 months.
How Is the Problem Diagnosed?
If your ferret shows any of the signs described above, your veterinarian will need to make several blood glucose measurements to diagnose the condition. Blood glucose must be measured after your pet has been fasted (has not eaten) for 3 to 4 hours. Glucose levels consistently lower than 60 mg/dL support the diagnosis of insulinoma. In some cases, it may also be necessary to measure your pet’s insulin concentration.
How Are Ferrets Treated for Insulinoma?
Several treatments are available for insulinoma. Most ferrets with this disease are prescribed prednisolone or diazoxide, both of which help to increase the blood glucose concentration by interfering with insulin secretion and/or glucose metabolism. Unfortunately, neither of these medications prevent the continued growth of the tumor(s). For this reason, regular blood glucose monitoring is essential to help determine if medication dosages need to be changed. Depending on the severity of the disease, both drugs may be used in combination. Medical therapy alone is usually effective in controlling signs of the disease for 6 to 18 months.
Surgery is another option for treatment of insulinoma. The procedure involves removal of a portion of the pancreas and is usually combined with medical treatment. Typically, by the time clinical signs of the disease appear, there are microscopic tumors throughout the entire pancreas. Because it is not possible to remove the entire pancreas, surgery is not curative, but it slows the progression of the disease. Pets treated with a combination of surgery and medical therapy typically remain free of clinical signs for about 1 to 2 years.
More recently, chemotherapy protocols have been established for treatment of insulinoma in ferrets. Chemotherapy involves intravenous administration of the drug doxorubicin. Usually, four sessions of chemotherapy are given at 3-week intervals, although the protocol may be altered depending on the individual ferret. Chemotherapy is usually performed in combination with medical therapy and/or surgery. There is not enough information at this time to predict the symptom-free life span for ferrets treated with chemotherapy. Most ferrets tolerate doxorubicin therapy well and have noticeable improvement with this protocol.
Home Management of Ferrets With Insulinoma
If your ferret has been diagnosed with insulinoma, there are some simple things you can do at home to help improve your pet’s health and quality of life:
Make sure your ferret is eating a premium-quality, high-protein ferret food. Avoid foods and treats that contain high amounts of carbohydrates and sugar.
Your pet should not go for long periods of time without eating. Frequent, small meals are ideal.
If your pet experiences a hypoglycemic episode at home, offer a little honey or corn syrup using an oral syringe or eye dropper. If he/she has collapsed, rub honey or corn syrup on the gums, being very careful to avoid being bitten.
If your ferret is having seizures, do not try to put anything in the mouth. Seek veterinary attention immediately.
Routine blood glucose monitoring is an essential part of managing a ferret with insulinoma. Your veterinarian will discuss monitoring your ferret’s blood glucose levels with you.
With proper veterinary attention, ferrets with insulinoma may live long, happy, symptom-free lives. It is important to monitor these patients closely, and always contact your veterinarian if there are any questions or concerns.