Chronic vomiting (intermittently or continuously for at least 7 days) in dogs and cats is a common and frustrating problem
for clients and veterinarians. Because many diseases cause chronic vomiting, a thorough evaluation must be performed to arrive
at an accurate diagnosis. Definitive diagnosis of many diseases requires mucosal biopsy. In the past, exploratory laparotomy
was necessary to obtain biopsy specimens. However, the increased availability of flexible fiberoptic endoscopy in veterinary
medicine has allowed less invasive tissue biopsy.
The first step in the approach to the chronically vomiting patient is to determine that vomiting and not regurgitation is
present. Vomiting is associated with signs of nausea (depression, salivation, frequent swallowing, and vocalization in some
cats) that is followed by abdominal contractions prior to the expulsion of material. Regurgitation is associated with esophageal
disorders and occurs passively, usually associated with increased intrathoracic pressure that may be caused by excitement,
activity, or changes in body position.
Once you have determined vomiting is present the history and physical examination can contain many clues to the etiology.
A thorough dietary history should be obtained. In some cases, correcting dietary indiscretion or instituting a highly digestible
diet for 3-4 weeks will resolve the vomiting. Dietary indiscretion can be due to a recent diet change, feeding of table scraps,
free-roaming behavior allowing ingestion of garbage, ingestion of foreign objects, exposure to toxins (including house plants),
excessive ingestion of hair, or feeding a low quality poorly digestible diet. The history may identify the use of drugs, such
as NSAIDs, that can cause vomiting due to gastritis or ulceration. The presence of diarrhea or signs of systemic disease may
help to rank the rule-out list.
Physical examination may be normal or only demonstrate signs of weight loss. An abdominal mass or dilated loop of small bowel
may be identified as a cause of high partial small bowel obstruction. If vomiting has recently become more frequent, signs
of dehydration may be present (delayed capillary refill time, enophthalmos, decreased skin turgor, tachycardia, pale mucous
membranes, and cold extremities). Signs suggesting systemic disease include: polyuria / polydipsia, polyphagia, hepatomegaly,
cataract formation, icterus, encephalopathy, ascites, pyrexia, bradycardia, tachycardia, small irregular kidneys, oral ulceration,
pale mucous membranes, splenomegaly, or an abdominal mass.
Table 1 - Some Causes of Chronic Vomiting
Table 1 lists some causes of chronic vomiting in dogs and cats. Systemic diseases can usually be ruled out by a thorough history,
careful physical examination and routine laboratory tests (complete blood count, biochemical profile, urinalysis, amylase
and lipase, heartworm antibody test, and T4). Correction of dietary indiscretion or a 3-4 week trial with a highly digestible
diet should be performed before more invasive testing. Gastrointestinal causes of chronic vomiting may involve either the
stomach or orad small intestine. An efficient plan to evaluate gastrointestinal causes includes fecal examination for parasites,
survey abdominal radiography, and endoscopic examination with mucosal biopsy. If endoscopy is not available, a barium contrast
upper GI series and exploratory laparotomy can be used (Table 2). Although helpful in some cases, the diagnostic utility of
abdominal ultrasound has not yet been fully determined. Abnormalities that can be detected include thickened stomach or small
bowel, gastric, small bowel or pancreatic mass, enlarged regional lymph nodes, enlarged hypoechoic pancreas, dilated small
bowel, abnormal gastric or small bowel motility, or evidence of an intraluminal foreign body.
Table 2: Comparison of Diagnostic Modalities
Survey abdominal radiographs rarely establish a cause for chronic vomiting (unless a radiodense foreign body is seen) and
a barium upper GI series is usually indicated. Advantages of contrast radiography versus endoscopy and laparotomy include
the following: 1) available in all practices, 2) noninvasive, 3) does not require general anesthesia, 4) always visualizes
the duodenum, 5) evaluates gastric size and position, 6) provides a qualitative description of gastric motility and emptying
of liquids, and 7) detects extraluminal and submucosal / muscular masses. A barium series is time consuming to perform, costly
to the client, and is a source of radiation exposure to the hospital staff. If lesions are identified, tissue biopsy is needed
to confirm a diagnosis. If a foreign body is detected, it must be removed via endoscopy or exploratory laparotomy. The upper
GI series is insensitive for mucosal lesions. Abdominal ultrasonography has recently been added to the diagnostic plan for
many dogs and cats with chronic vomiting. It has been shown to be very helpful in animals with a mass lesion. An ultrasound
guided fine needle aspirate or trucut biopsy can be performed. Ultrasound has also been shown to helpful in cases with chronic
pancreatitis. Other advantages of ultrasound include: being noninvasive, imaging of the liver and biliary system, imaging
of the small and large bowel and mesenteric lymph nodes, and assessment of the layers of the GI tract and its motility. Disadvantages
include the need for expensive equipment and specialized training, interference by gas within the GI tract, difficulty in
imaging the pancreas, and the overall diagnostic utility has not been establishedIn a group of dogs with chronic vomiting,
the following factors were associated with a high diagnostic utility of abdominal ultrasound: presence of weight loss, higher
percentage of body weight lost, increasing age, increasing duration of vomiting, and an increased frequency of vomiting/week.