Gastrinoma in Dogs
In-depth Information on Diagnosis
A diagnosis of a gastrinoma can be made more easily in some cases than in others, depending on the individual case and stage of disease. It is extremely important that your veterinarian obtain a full diagnostic work up. A complete blood count (CBC) evaluates for the presence of infection, inflammation, and anemia, sometimes associated with gastrinoma. A reticulocyte count should be performed on anemic animals. This will help determine if the type of anemia is consistent with gastrointestinal ulceration seen in these patients. A biochemical profile evaluates the kidney, liver, electrolytes, total protein and blood sugar status. All of these parameters are important to establish in the patient with a gastrinoma, as abnormalities can be seen secondary to or associated with certain metabolic disorders as well. A urinalysis helps evaluate the kidneys and hydration status of the patient. It is usually within normal limits in these patients. Multiple fecal examinations are important to rule out gastrointestinal parasites as a cause of vomiting, diarrhea or other gastrointestinal signs. Abdominal X-rays evaluate the abdominal organs and may help visualize the presence of a foreign body or tumor. A mass in the area of the pancreas consistent with a gastrinoma can occasionally be visualized, although more often their purpose is to rule out other disorders whose signs may mimic those with gastrinomas. X-rays generally do not evaluate for the presence of an ulcer.
Your veterinarian may recommend additional tests to insure optimal medical care. These are selected on a case-by-case basis. A coagulogram, or clotting profile, may be recommended in cases where a clotting disorder is suspected. Patients with decreased platelets can present with bloody vomiting or diarrhea. An ACTH stimulation test may be recommended to rule out hypoadrenocorticism (Addison’s disease), which can cause gastrointestinal ulceration. It is a combination of two blood tests that measures adrenal function. It is safe, and can usually be performed at your local veterinary hospital. Bile acids are paired blood tests obtained before and after a meal that evaluates liver function, as certain liver diseases can predispose to gastrointestinal ulceration. The test is very safe and can be performed at your local veterinary hospital. A blood lead level may be indicated in the patient with ulceration, especially in cases of known or suspected exposure to lead. A gastrin level should be run on any patient with multiple or recurrent ulcers or signs of ulceration. This is a blood test that is performed only at certain laboratories; your veterinarian can draw the sample and submit it to the appropriated establishment. Elevated levels are usually seen in patients with gastrinomas. Gastrin stimulation tests may be recommended in those individuals who have borderline gastrin levels. These are specialized blood tests taken at different times in response to substances injected into the patient’s body and need to be sent to a specialty laboratory. An upper gastrointestinal barium (dye) series may be helpful in identifying ulcers. It may also help diagnose foreign objects or tumors that are not apparent on regular X-rays, or to confirm the location and extent of GI ulceration. A safe dye is given to the patient by mouth, and is then watched as it travels through the GI tract. It is a non-invasive test that can often be performed by your regular veterinarian, although in some cases it may necessitate transfer to a specialty hospital. An abdominal ultrasound evaluates the abdominal organs and helps assess for the presence of a mass in the area of the pancreas. Organs, lymph nodes and other masses can be sampled with a needle or biopsy instrument with the guidance of ultrasound. This procedure is relatively safe, but it may necessitate a mild sedative. It is often recommended that a specialist perform the procedure. A bone marrow aspirate may be recommended in some patients with anemia, to determine if it is secondary to an ulcer, or to reveal evidence of a different disease process such as a mast cell tumor that can cause an ulcer. It is a relatively noninvasive test. It allows analysis of a sample of the bone marrow, which is responsible for producing red blood cells, white blood cells and platelets. With a local anesthetic, a small needle is introduced into the core of the bone, and a small amount of marrow is withdrawn and analyzed. This test may be performed by your local veterinarian, although in some cases, it may be best to have it performed in a specialty hospital. Gastroduodenoscopy (upper GI endoscopy) may be of benefit in the patient with GI ulceration. It may facilitate the removal of foreign bodies, help evaluate for ulcer disease, and sample tissue for the presence of inflammation or cancer, which may be the cause for the ulcer. Hospitalization is brief, and healing is generally quick and uneventful. It does, however, necessitate general anesthesia, and therefore is associated with minor risks. It is often necessary to refer the patient to a specialist, and is performed when other diagnostics are either inconclusive, support the diagnosis of a gastric foreign body or tumor, or necessitate a definitive diagnosis of ulceration. Lastly, an exploratory laparotomy should be performed as a diagnostic and sometimes therapeutic tool in any individual that has had an extensive diagnostic and sometimes treatment course with little or no response. It is an invasive procedure, but it is necessary in some of these individuals along with a biopsy of the mass for a definitive diagnosis.