Chronic vomiting is a common problem in the dogs we see at the Animal Hospital at Thorndale. It may be related to relatively minor causes, such as chronic swallowing of hair, or it may be due to much more serious diseases.
Vomiting versus Regurgitation
Vomiting is an active process that involves abdominal compression. It is usually proceeded by salivation and active retching. The abdomen is seen to push upward and inward with force to produce the vomitus. Regurgitation is more passive. The dog simply opens its mouth with minimal preliminaries and whole food comes back up, generally shortly after being consumed. Regurgitation can be a sign of a serious problem with the esophagus, the swallowing tube that runs from the back of the throat, through the chest and diaphragm to enter the stomach. Megaesophagus, an excessive dilation of the esophagus, is often due to a stricture of blood vessels around the swallowing tube as it courses over top of the heart. It is identified on chest x-rays, not abdominal x-rays.
Urgency
Because there are so many causes, there are many tests that may be needed to make an accurate diagnosis. One of the factors that determine how quickly these tests must be performed is the condition of your dog. If the appetite is very poor or non-existent or if weight loss is occurring rapidly, it is important that a diagnosis be obtained rapidly. If pain or a mass is present in the abdomen, tests need to be performed quickly. However, if neither appetite nor weight is affected, the urgency is much less.
Source of Vomiting
Vomiting may be due to disease in the stomach or intestines, or it may be due to disease in many other parts of the body. As a rule, most of the latter diseases are detected with blood tests. However, few diseases in the stomach and intestines show up in x-rays and or abdominal ultrasound.
Testing Procedure
The sequence of tests will vary from dog to dog. The urgency issues already discussed are one of the most important factors that we must consider. However, as a rule, we recommend blood tests to eliminate the diseases that are not directly involving the stomach or intestines. A complete blood count, blood chemistry and urinalysis are initial blood tests. Other tests may include a vitamin B12, TLI, folate levels blood levels. If those do not detect the problem, the other tests, listed below, will be utilized.
Tests for Causes Outside the Digestive System
If the initial tests suggest causes outside the digestive system, additional blood tests for endocrine disorders may be needed. Abdominal x-rays and ultrasound are also recommended to look for masses in the abdomen. As discussed above, chest x-rays are needed if Megaesophagus is suspected.
Tests for Diseases of the Stomach or Intestines
The following tests are performed to evaluate the stomach and intestines. Their pros and cons are listed.
Radiographs (x-rays):
Radiographs are made with and without barium. Plain films, or those without barium, are always taken first. Those without barium find foreign materials if they are made of bone or metal or other very hard substances. Enlarged organs and masses, and proper position of the stomach can be seen. Fluid and gas patterns can help identify some but not all foreign bodies. If a foreign body is suspected and ultrasound is not readily available, radiographs are sometimes made with barium. The dog must either eat the barium mixture or be tube fed the barium. These x-rays are taken as a series. Barium is placed in the stomach and radiographs are made in intervals over several hours until the barium reaches the end of the intestines. These radiographs permit us to evaluate:
- How quickly the stomach empties
- If the barium moves completely through the intestines and how quickly that occurs
- If the intestines are dilated
- If there are areas in the intestines that are very irritated
- If there is a rupture of the stomach or intestines
These radiographs do not require sedation or anesthesia unless the dog is very uncooperative.
Ultrasound
An ultrasound study is performed with a machine that sends sound waves into the body. Their reflections are analyzed by a computer and formed into an image on a computer-type screen. There is no radiation involved. These images allow a trained operator to visualize the structure of the stomach and intestinal walls. It also permits evaluation of the liver, kidneys, and other abdominal organs. Biopsy of abnormal areas of most organs is also possible and can provide the needed tissue samples for a diagnosis to be made.
An ultrasound examination usually does not require sedation or anesthesia; however, the dog must lie on their side for 15-30 minutes. Some dogs will not do that without sedation. If biopsies are taken, sedation is usually required to prevent pain and to prevent damage to internal organs.
Endoscopy and Biopsy
An endoscope is a flexible scope that is inserted through the mouth, down the esophagus, and into the stomach and first few inches of the small intestines. (It may also be inserted through the anus and into the colon, but this is generally reserved for dogs with chronic diarrhea.) This permits us to look at the insides of the esophagus, stomach, and upper small intestines. It also permits biopsies to be taken, which is often the most important part of the procedure.
Endoscopy requires anesthesia so there is always a small degree of risk involved. However, it does not require a surgical incision. One of its limitations is that some tumors of the stomach do not go completely to the inner surface of the stomach. Since the biopsies are only made from the stomach lining, it is possible to miss them.
Surgery
Surgical exploration of the abdominal cavity is generally reserved for those dogs that cannot be diagnosed with the above tests. It is the most invasive procedure, but it permits us to see all parts of the stomach and intestines as well as the other abdominal organs. It also permits us to biopsy specific areas of any abdominal organ.
In some cases, surgery is performed as one of the first procedures if an intestinal obstruction is diagnosed or strongly suspected.
Chronic Vomiting Treatments
Based on the diagnosis, treatments vary greatly. Some may be as simple as changing the diet to a hypoallergenic food along with immunosuppressant medication or as complicated as tumor removal followed by chemotherapy. It is important to recognize that chronic vomiting is not a normal condition in dogs (or humans) and needs to be correctly diagnosed so that proper treatment can be initiated.