Overview of Gastrinoma in Dogs
Gastrinoma is a malignant tumor of the pancreas that secretes a hormone called gastrin that stimulates acid secretion in the stomach and in turn causes gastrointestinal ulceration. In human medicine gastrinomas are referred to as the Zollinger-Ellison syndrome.
There is no specific known cause or risk factor that is responsible for gastrinomas. This cancer is not very common in veterinary medicine and is seen more commonly in dogs than cats. Middle-aged to older dogs are most commonly affected. There does not appear to be a gender or breed predisposition.
What to Watch For
Although some dogs may have no clinical signs, some may have life threatening manifestations.
Vomiting (with or without blood)
Melena, which is black, tarry stool that contains digested blood
Pale mucus membranes
Diagnosis of Gastrinoma in Dogs
A complete blood cell count (CBC), biochemical profile and urinalysis should be performed in all cases.
Screening abdominal X-rays, although often within normal limits, may be of benefit in ruling out other disorders.
Abdominal ultrasound may identify a pancreatic mass, but it generally does not identify gastrointestinal ulceration itself.
A contrast upper gastrointestinal study may identify ulcers.
Gastroduodenal endoscopy is helpful in diagnosing gastrointestinal ulceration, although it does not always identify an underlying cause.
Gastrin levels may help to support a diagnosis of a gastrinoma.
Laparotomy and biopsy of the pancreatic mass is the only definitive way of documenting a gastrinoma.
Treatment of Gastrinoma in Dogs
Treatment of gastrinoma dogs should be directed at surgical excision of the tumor and control of excess gastric acid secretion.
In severe cases, hospitalization is warranted for intravenous fluid therapy and/or blood transfusions
If possible, treatment of choice is surgical removal of the tumor.
Large bleeding ulcers may also need to be removed surgically.
Individuals with gastrointestinal ulceration may be treated as outpatients if there are minimal signs and/or no systemic effects.
Food and water should be restricted if there is active vomiting, and an easily digestible diet with frequent small feedings should be reintroduced gradually.
Acid-blocking and stomach-coating drugs may be recommended.
Home Care and Prevention
Long term prognosis is poor because of the likelihood of malignancy with these types of tumors. Administer all medication and dietary recommendations as directed by your veterinarian. If your dog becomes weak, pale, or if he collapses or vomits blood, seek veterinary attention at once.
There is no preventative care for gastrinomas.
In-depth Information on Gastrinoma in Dogs
Gastrinomas are malignant tumors of the pancreas that often become progressively worse and result in death of the patient. These tumors secrete the hormone gastrin that stimulates stomach acid secretion and in turn, causes gastrointestinal ulceration. In human medicine gastrinomas are referred to as the Zollinger-Ellison syndrome. These tumors commonly metastasize, or spread to other organs, early in the disease process.
Gastrinomas are fairly uncommon in veterinary medicine, although have been reported in both dogs and cats. Signs can be extremely variable from patient to patient. Some patients may have no clinical signs, while others may be in immediate need of intensive support and hospitalization, to include very close monitoring and even blood transfusions.
Gastrointestinal ulceration has many other causes besides gastrinomas. It is important to realize that while some cases of ulceration are clear cut when reviewing the history, physical examination and diagnostic findings, it is sometimes more difficult to identify a gastrinoma as the primary cause.
Many diseases/disorders cause similar clinical signs to patients with gastrinomas.
The ingestion of certain drugs and medications may cause either gastrointestinal ulceration or signs similar to individuals with ulceration, including vomiting and lack of appetite.
Metabolic disorders such as kidney failure, liver disease, hypoadrenocorticism, hyperthyroidism in cats are often associated with vomiting and/or gastrointestinal ulceration and may need to be differentiated from gastrinomas.
Stress, pain, fear and/or major medical illness to include shock, low blood pressure, trauma, and major surgery can all be associated with vomiting and/or gastrointestinal ulceration.
Dietary indiscretion, or the ingestion of foreign bodies or inappropriate/excessive food items, is a common disorder seen in both cats and dogs. Vomiting, diarrhea and gastric ulceration are commonly seen.
Pancreatitis is an inflammation of the pancreas, and in certain cases, can be life-threatening. The most common clinical signs seen with pancreatitis are vomiting and inappetence. Pancreatitis is a common cause of GI ulceration.
Intestinal obstruction/blockage secondary to foreign bodies, tumors or an intussusception, which is the telescoping of one part of the bowel into itself, must be differentiated from and/or can cause GI ulceration.
Mast cell tumors are growths that occur anywhere in or on the body and secrete substances that can cause gastrointestinal ulceration.
Infiltrative diseases of the gastrointestinal tract, including inflammatory bowel disease and lymphosarcoma (a type of cancer) must be ruled out. Infiltrative diseases are microscopic diseases that penetrate and spread throughout the body.
Hemorrhagic gastroenteritis (HGE) is a syndrome seen in dogs that has no known cause. These animals often experience vomiting (with or without blood) and bloody diarrhea. HGE is most often seen in urban settings in small breed dogs.
Clotting disorders, such as thrombocytopenia (decreased platelet count) or warfarin toxicity (rat poison), may present with bloody diarrhea or vomiting.
Neurologic disorders, especially of the vestibular center that deals with balance and coordination, often causes vomiting.
Certain toxins, such as lead, can cause severe gastrointestinal signs and ulceration.