Insulinoma In Dogs – Causes, Symptoms & Treatment

Insulinomas are rare, pancreatic functional islet cell tumors (neuroendocrine tumors) of dogs.

They are also the most represented tumors of the endocrine pancreas in dogs. These malignant tumors occur in the neoplastic ß-cells that retain the ability to produce and secrete insulin.

Most regularly, insulinomas result in producing excessive amounts of insulin resulting in low blood sugar levels (hypoglycemia) and pets feel light-headed and weak.

Most of the malignant islet cell carcinomas metastasize to regional lymph nodes and/or the liver.

Early diagnosis is crucial as the metastasized dog has drastically reduced survival times.

Symptoms are not reliable as insulin is released regularly and dogs often exhibit clinical signs attributable to hypoglycemia.

• Lack of coordination
• Loss of consciousness (syncope)
• Reduced ability or enthusiasm to exercise
• Disturbance of vision
• Seizures
• Extreme weakness
• Decrease in the reflex of appendages
• Muscle degeneration

Management of insulinomas should be directed at the reduction of insulin secretion, correction of hypoglycemia and specific treatment or removal of the tumor.

Discuss the best treatment option with your veterinarian or canine oncologist.

Surgical removal of tumor: the best chance for relief of clinical signs and the best survival times.

Partial pancreatectomy – removal of part of the pancreas

Exploratory abdominal surgery - dogs with hypoglycemia and inappropriate insulin production

Medical management:

Prednisolone - stimulates glycogenolysis and inhibits insulin production (0.5 to 1.0 mg/kg q d).

Other medications that might be used to treat insulinoma include:

• Diazoxide - 5 to 10 mg/kg PO /12 H
• Octreotide - somatostatin analogue
• Tyrosine Kinase Inhibitors - Toceranib phosphate( 2.75 mg/kg PO/48 H)
• Chemotherapeutic agents, such as streptozocin - nitrosourea alkylating agent
• Every 2 to 3 weeks -500 mg/m²

Check with your veterinarian or Veterinary oncologist for the post-surgical checks, usually once a month to ensure the health of the dog and to check for any infection.

Until the post-operative recovery period is over, do not allow your dogs to play outdoors. This will reduce the risk of infection and injuring the surgical site.

There is no way to prevent insulinoma.

Surgery, together with dietary management, can radically reduce insulinoma and hypoglycemia, and symptoms for your dog.

Medium to large breeds is overrepresented. Female dogs are more reported.

German Shepherd, Irish Setter, Boxer, Golden Retriever, Terrier Dog Breeds

Causes:

As with other forms of cancer, any definitive causation of pancreatic cancers, (including insulinoma) is not yet identified.

It is alleged that there is a genetic component linked to the odds of this cancer occurring, supported by higher incidence in certain breeds

Diagnosis:

• Analysis of insulin and glucose levels
• Abdominal ultrasound/x-rays
• Multiple blood tests
• computed tomography (CT), or magnetic resonance imaging (MRI)
• complete staging via biopsy of regional lymph nodes

Insulinoma staging:

• Stage I: limited to the pancreas
• Stage II: metastasis to regional lymph node
• Stage III: metastasis to distant organs.

Mortality:

For dogs undergoing surgery:  In stage 1:  785 days (MST –median survival time)

                                             In stage 2:  380 MST

                                             In Stage 3:  217 MST

For medical management - 2½ months (Tobin et al 1999)

                                        196 days (polton et al)

Prognosis:

Following a diagnosis of insulinoma in dogs, Life expectancy is related to the development of postoperative complications.

Life expectancy is greatly reduced for dogs that are not good surgical candidates or for owners who are not interested in surgery and receive medical therapy.

Time to visit the vet clinic for an examination, if you notice any of the following:

• When you see your dog has extreme fatigue after exercise and higher collapsing episodes
• When your dog has prolonged seizure activities
• Muscle degeneration

Not only do we have to make sure to pick a diet with the combination of the right nutrients, but we need to feed it properly!

• Feed 4-6 small meals spread through the day
• Diet high in protein, fat, and complex carbs
• Protein: High protein diet comprising 40% of dogs calories
• Fats: Omega-3 and other healthy fats.
• Complex Carbohydrates: fibers and starches (Whole Grains, Oatmeal, Brown Rice, Potatoes & Sweet Potatoes
• Supplemental dextrose (Karo Syrup)
• Overweight dogs - lower-calorie diets, for underweight dogs- Higher calorie diets
• Feed foods having a lower ( or moderate) Glycemic Index and Glycemic Load than others

The prognosis is guarded at best due to this malignant neoplasia’s high frequency of metastasis. Metastatic pets survive 6 to 9 months with a combination of surgery and medical therapy.

However, for dogs in the initial stages, Surgery is recommended as it provides the best-reported survival times (up to 2 years and more).

Medical management of dogs does not make them survive longer than 6 months from the onset of clinical signs.