Insulinomas
General Information
An insulinoma is a rare tumor of the pancreas of dogs and cats. These tumors release large amounts of insulin and cause a severe decrease in blood sugar (glucose) levels. Low blood sugar levels rapidly cause abnormal brain activity, leading to incoordination, weakness, collapse, muscle twitching, blindness, depression, extreme hunger and seizures.
The cause of these tumors is unknown.
Important Points in Treatment
1. Surgical removal of the tumor is the best treatment. We will not know how large the tumor is until the time of the surgery. If the tumor occupies a large portion of the pancreas, or if it has spread to other areas, complete removal may not be possible. We will attempt to identify any sites of metastasis (spread) and remove them in surgery.
2. Some patients with inoperable tumors can be maintained in reasonable health with dietary therapy and medication for some period of time. If we cannot find a tumor at the time of surgery we will continue with medical treatment and watch for signs that the diagnosis was correct.
3. Inflammation of the pancreas is common after surgery. Hospitalization is often necessary for several days after surgery. We want to make sure that the inflammation doesn't cause a problem for you after your pet goes home.
4. Blood sugar levels must be monitored closely during both medical and surgical treatment. After surgery you will need to watch for signs of recurrance of the tumor which may cause episodes of low blood sugar to return. If you start to see these you should contact us so we can document the recurrance. We will want to start medications to control the hypoglycemia. It would be very unlikely that we would recommend operating a second time.
5. Give all the medication as directed. Call the doctor if you cannot perform any prescribed treatment.
6. Diet: Diet is important in both surgical and non-surgical patients. Feed as follows: Continue to feed the low fat, high complex carbohydrate diet. It will remain important to feed frequent small portions to help maintain normal blood sugar levels.
7. Activity: Exercise decreases blood sugar levels. Because insulin is still being released by the tumor, blood sugar levels may rapidly decrease during and after exercise. Keep exercise periods short. Frequent short periods of exercise should be OK. Allowable exercise includes:
Notify the Doctor if Any of the Following Occur:
* Your pet's signs continue or worsen.
* Your pet refuses to eat.
* Your pet seems to have abdominal pain.
* Your pet's general well-being declines.
* Your pet is depressed or vomits
Insulinoma
What is an insulinoma?
Insulinoma is a type of tumor found in the pancreas. Normally, the pancreas secretes insulin to control blood sugar in the body. Insulin is an essential factor for metabolism of carbohydrates. Insulinomas secrete an excess quantity of insulin. Excess insulin leads to low sugar (glucose) levels (hypoglycemia) in the blood. Low blood sugar may result in an emergency situation due to presence of seizures and weakness. Insulinoma is uncommon in dogs and rare in cats. Dog breeds more likely to develop insulinoma than other breeds are the standard poodle, boxer, fox terrier, Irish setter, German shepherd dog, golden retriever, and collie. In cats, the Siamese may have an increased likelihood of developing insulinoma than other breeds.
What causes insulinoma?
The cause of insulinoma is unknown. The cause of the low blood sugar that produces the signs of insulinoma is an insulin-producing tumor, usually malignant, of the pancreas.
What are the signs of insulinoma?
The signs of insulinoma are related to low blood sugar. Signs may or may not be related to eating, excitement, or exercise. Signs progress with time. The most common sign in dogs is seizures. Other signs in dogs include weakness, collapse, muscle twitching, abnormal behavior, lethargy, depression, wobbliness of the limbs, hunger, weight gain, excessive urination and excessive thirst, and fatigue. Signs in cats are seizures, wobbliness of the limbs, muscle twitching, weakness, lethargy, depression, lack of appetite, weight loss, and excessive thirst.
How is insulinoma diagnosed?
Insulinoma is diagnosed by a complete work-up to determine the cause of the low blood sugar. In most cases, the animal will have low blood sugar on routine blood tests. To further identify the cause of the low blood sugar, blood sugar levels and insulin levels are tested. This is done by withholding food and collecting blood samples every 1 to 2 hours to determine glucose and insulin levels. When the blood sugar drops (because the animal is fasting), the blood is analyzed for insulin. High insulin levels in an animal with low blood sugar indicate that an insulinoma is likely. Chest and abdominal radiographs (X-rays) may be done. They are usually normal in animals with insulinoma, but they help evaluate the animal for tumors outside the pancreas, which sometimes cause low blood sugar.
How is insulinoma treated?
The most important aspect of treatment for insulinoma is diet. The pet should be fed 4 to 6 small meals a day. The veterinarian will prescribe a diet high in protein, fat, and complex carbohydrates and low in simple sugars. Semi-moist food should be avoided. Surgical removal of the tumor is an option and helps animals with insulinoma have a longer lifespan than if they do not have surgery. If diet changes with or without surgery are ineffective in controlling blood sugar, steroids by mouth are started. If diet and steroids prove ineffective in controlling blood sugar, other drugs are available that can help control blood sugar.
What is the prognosis (outcome) for pets with insulinoma?
The prognosis for animals with insulinoma varies. The tumor has been shown to spread (metastasize) in 40% of animals with insulinoma. Dogs can survive for as little as 2 months or as long as 5 years. Cats have been shown to survive up to 18 months. Surgical removal of the tumor improves survival time.
The information on this page was obtained from the site www.vetmedcenter.com