Treatment of acute insulinoma must be individualized based on the severity of your dog's condition and other factors that must be analyzed by your veterinarian. Treatments may include surgery, medical management, or a combination of both.Surgical removal
Surgery is usually the first approach to management and allows the possibility of cure for a dog with a single, easily removable tumor. Unfortunately, the tumor has usually spread to other abdominal sites, often the liver and regional lymph nodes, by the time a diagnosis is made, and surgery is only a temporary help. If the entire tumor is not removable, or if there has been spread to other organs, removal of as much abnormal tissue as possible usually results in remission of the symptoms of hypoglycemia and improves the response to medical therapy.Medical therapy Emergency treatment at home. If your dog is having a hypoglycemic seizure, administer a sugar solution, such as Karo syrup or sugar water by mouth. Do not pour the sugar solution directly into your dog's mouth, because the normal swallowing reflex may be impaired during the seizure and aspiration of the solution into the lungs could occur. Instead, dip your fingers into the sugar solution and rub it onto the gums and inside the mouth of your pet. Most pets will respond within 30 seconds to 2 minutes. Avoid placing your hand directly in your dog's mouth because you may be inadvertently bitten due to involuntary jaw movements during a seizure.
If your dog responds to the emergency treatment with the glucose solution, give him a small, high protein meal once the seizure subsides and the animal is sitting up and aware of his surroundings.
Emergency treatment in the hospital. If your dog has a seizure in the hospital, your veterinarian will administer a glucose solution, often 25 to 50 percent dextrose, intravenously to control the clinical signs of hypoglycemia. After the seizure has been controlled, further diagnostic testing and long-term therapy can be considered.
Long-term medical therapy is instituted if surgery is declined, the tumor cannot be completely removed or the tumor has spread to the liver and regional lymph nodes. Also, if a large amount of the tumor was removed surgically and clinical symptoms were controlled initially but have now reappeared, long-term therapy should be initiated, consisting of:
Dietary therapy. If a constant source of calories is provided as a substrate for the excessive insulin, hypoglycemia and its associated clinical symptoms can be minimized. Diets high in protein, fat, and complex carbohydrates are recommended. Feed a combination of canned and dry food in several small meals throughout the day. Exercise should be limited to short leash walks. Simple sugars such as those found in soft-moist dog foods should be avoided because they rapidly stimulate insulin secretion.
Feed your dog immediately at the first sign of hypoglycemia like weakness, incoordination, collapse, muscle tremors. Feed him a regular diet because administering honey or corn syrup will only delay hypoglycemia. A more severe episode could occur 30 to 120 minutes later as the simple sugar in the honey or corn syrup stimulates additional insulin release from the tumor. Honey or corn syrup should be reserved for emergency situations and generalized seizures.
Glucocorticoids (cortisone-like drugs). When dietary manipulations alone are not effective in preventing signs of hypoglycemia, glucocorticoids should be administered. A glucocorticoid such as prednisone is given at a dosage of 0.12 mg per pound of body weight twice a day. This dosage is continued as long as it controls the clinical symptoms. If symptoms return, consult your veterinarian. Your veterinarian will instruct you on how to increase the dosage of prednisone to control the clinical symptoms. Dogs may develop adverse effects as a result of prolonged and excessive glucocorticoid treatment (excessive water consumption, increased urinations, increased appetite, panting, weight gain, hair loss). If these effects occur, your veterinarian may lower the dosage of prednisone and add diazoxide.
Diazoxide inhibits the secretion of insulin from beta cells. It also stimulates the liver to produce more glucose. The end result is a rise in the blood sugar concentration. Administration of the diuretic hydrochlorothiazide may potentiate the effects of the diazoxide, and the two drugs may be administered together if diazoxide alone is ineffective. Unfortunately, diazoxide is fairly expensive and is difficult to obtain.
Somatostatin. Somatostatin is a hormone made by the pancreas that inhibits the synthesis and secretion of insulin by normal and malignant beta cells. Its inhibitory action on insulin secretion can be maintained for several hours it is injected subcutaneously (under the skin). Not all dogs respond well to somatostatin and some dogs respond initially but become refractory later. Your veterinarian can teach you how to give subcutaneous injections of somatostatin if necessary.
Chemotherapy. Specific chemotherapy agents have been tried, but many of these drugs are very toxic and the results have been poor.
Streptozotocin selectively destroys pancreatic beta cells. It can cause severe kidney damage unless intensive intravenous fluid therapy is provided first. It is an investigational drug, and owners should provide informed consent before its use. The estimated success rate in insulinoma using streptozotocin is 30 percent.
Alloxan also is toxic to pancreatic beta cells, and it also can cause severe kidney damage in dogs. A study of eight dogs showed initial control of hypoglycemia in four dogs for several months, but hypoglycemia eventually recurred in the four dogs that responded.
Adriamycin has been effective in some human patients with insulinoma, but its efficacy for insulinomas in veterinary patients is not known.