"Gastric" is defined as something that affects, pertains to or originates in the stomach. The suffix "-itis" refers to inflammation. Therefore, "gastritis" means inflammation of the stomach – or, more particularly, the lining of the stomach. Gastritis is one of the most common digestive disorders in domestic dogs. It occurs in acute and chronic forms.
The stomach's primary function is to act as a holding area that controls the amount and rate of passage of food and fluids ("ingesta") from the stomach out through an opening called the "pylorus" and into the first part of the small intestine. The stomach also secretes gastric acid and other substances that jump-start the process of digesting fats and proteins. The canine stomach is made up of four parts: the cardia, fundus, body and antrum. The cardia is the entrance from the tubular esophagus into the stomach; it is wider in diameter than the pylorus, which is the exit passagway from the stomach. The fundus and body are expandable, balloon-like areas of the stomach that expand and contract depending upon the amount of ingesta that they accumulate. The thick, muscular antrum is the last part of the stomach before the pylorus; it functions to mechanically grind food into smaller pieces so that nutrients are more easily digested and absorbed in the small intestine.
Causes of Canine Gastritis
Gastritis, which means inflammation of the stomach lining, can be either sudden (acute) or slow (chronic) in onset. Acute gastritis almost always involves severe abdominal pain and persistent vomiting and is most commonly associated with poisoning from drugs or other toxins, serious organ disease (kidney failure, liver failure, hypoadrenocorticism/Addison's disease), internal parasites, binging or overeating, eating the wrong thing ("dietary indiscretion") or infection with bacterial or viral microorganisms. Acute gastritis commonly occurs when dogs eat garbage, rotting or spoiled substances, toxic plants, caustic household chemicals, antifreeze, fertilizers, rodenticides or inanimate objects such as plastic wrap, bones, toys or needles. Some dogs develop sudden stomach inflammation from eating the feces of other animals or other unnatural articles of food; this unpleasant habit is called "pica." Irritating medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, corticosteroids and some antibiotics, can also cause acute gastric inflammation.
Chronic gastritis is caused by long-term disruption of the mucosal lining and normal bacterial flora of the digestive tract. Many of the things that can cause acute gastritis can also cause the chronic form of the condition. Prolonged gastrointestinal inflammation can be caused by ingestion of indigestible materials, such as plastic, rubber, paper, carpet remnants, hairballs or string. These items can remain in the stomach without being passed through the pylorus, causing increasingly severe inflammation of the lining of the stomach, with associated inflamation and physical discomfort. Bacterial and viral infections can also cause chronic gastritis. Parvovirus is a fairly common cause of severe gastritis, particularly in puppies that are not properly vaccinated. Distemper is another viral disease associated with chronic gastritis. Neoplasia (cancer), food allergies, chemical irritants, fertilizers, immune-mediated abnormalities, liver disease and kidney disease are common causes of chronic gastritis. Cancers that can cause long-term gastritis include gastrointestinal lymphoma, gastrinoma, plasma cell tumors, mast cell tumors and gastric adenocarcinoma. Gastric polyps and internal parasites are also on the list of possible suspects. Dogs that frequently eat grass or other plant material are prone to developing chronic gastrointestinal discomfort, as well. Stress is another culprit that can contribute to chronic inflammation of the sensitive stomach lining.
Prevention of Gastritis
The best way to prevent both acute and chronic gastritis is to keep dogs away from garbage and other inappropriate, indigestible but potentially swallow-able things. Dogs should not be allowed to roam freely around the neighborhood without supervision, because dietary indiscretion is much more common in those animals. Food and medications that a dog is known to be allergic to should obviously be avoided whenever possible. Appropriate vaccination of puppies, and booster vaccinations of adult dogs, can help prevent infectious causes of gastrointestinal disturbances and discomfort.
Gastritis is always uncomfortable for affected animals, but fortunately it usually is not life-threatening. The actual prognosis will depend upon the underlying cause of the condition. Unfortunately, in many cases, the cause of the dog's gastrointestinal discomfort will never be determined. However, regardless of the cause, most dogs with gastritis respond well to treatment, and the vast majority of them can be well-managed and successfully treated by owners at home, with the help of their veterinarian.
Effects of Gastritis
Gastritis, which refers to irritation and inflammation of the sensitive lining of the stomach, can come on suddenly (called "acute gastritis"), or can develop slowly over time (called "chronic gastritis"). Either way, it is always an uncomfortable condition for affected animals, who will be nauseous and have mild to severe stomach pain, depending upon the nature and extent of their gastrointestinal inflammation. They probably will lose their appetite and become listless, lethargic and depressed. They just will feel lousy. These fairly classic symptoms are pretty much the same as those experienced by people who develop gastritis. They are never pleasant and, in rare cases, can become extremely dangerous to the animal in question.
Symptoms of Gastritis
The hallmarks of both acute and chronic canine gastritis are vomiting and intense abdominal pain. Owners of affected animals will probably notice one or more of the following clinical signs:
Vomiting (severe; persistent in chronic cases; sudden onset and extreme in acute cases; may be tinged with bile [be yellow-ish], flecked with fresh blood [this is called "hematemesis"] and/or contain digested blood [this looks like used coffee-grounds])
Abdominal pain (can range from mild to extremely severe; can be debilitating; head hanging over the water bowl; "praying" or "bowing" stance)
Dehydration (from fluid loss due to vomiting)
Loss of appetite (inappetence; anorexia)
Blood in the stool (melena; caused by stomach ulceration; not especially common except in severe cases of gastritis)
Dull hair coat; unkempt condition
Pale mucous membranes (pallor; associated with blood loss)
Yellow mucous membranes (jaundice; usually associated with ingestion of toxins)
Drooling; excessive salivation (ptyalism; usually associated with ingestion of toxins)
Most dogs with gastritis produce a frothy, bile-tinged vomitus, and in many cases there are flecks of blood in the vomitus as well. Sometimes, if the stomach lining becomes so disrupted that it bleeds, the vomitus will be very dark and the digested blood will look like wet coffee grounds. Any dog with persistent attacks of vomiting should be seen by a veterinarian as soon as possible. Chronic vomiting must be distinguished from chronic regurgitation. Vomiting is an active event almost always accompanied by strong, unpleasant abdominal contractions. Regurgitation, on the other hand, is a passive reflexive process where undigested food suddenly "comes up" through the esophagus and out the mouth, without much prior warning or abdominal force.
Dogs at Increased Risk
There is no particular breed or gender predisposition to developing gastritis. Dogs that enjoy rummaging around in garbage, eating spoiled food or swallowing indigestible foreign objects are at an increased risk of gastrointestinal irritation and inflammation, as are dogs that eat animal feces or plant matter on a regular basis. Small, flat-faced (brachycephalic) breeds, such as Boston Terriers, Pugs and Bulldogs, as well as Lhasa Apsos, Shih Tzus, Basenjis, Drentse Patrijshonds and Miniature Poodles, are prone to developing hypertrophic gastropathy, which is a thickening of the stomach lining that tends to occur in middle-aged dogs and causes vomiting several hours after a meal. The cause of this particular type of gastritis is not well understood. Young, large-breed male dogs living along the Gulf Coast of the United States may be predisposed to developing a type of granulomatous gastritis that is caused by certain species of fungal microorganisms, especially during the fall, winter and spring months.
Most dogs with gastritis are brought to the veterinary clinic because they either had a very sudden onset of profuse vomiting, or they have been vomiting off-and-on for several weeks. The most important part of the veterinarian's initial evaluation is getting the dog's complete history from its owner, including its health background, diet, eating/chewing habits, access to garbage and household chemicals, free-roaming activities and whether it is on any oral medications. Of course, the discussion will include its current symptoms – that is, exactly why the owner brought the dog to the veterinarian at this point in time. The initial medical assessment usually will conclude with a thorough physical examination, during which the veterinarian will look in the patient's mouth and gently palpate (press and feel) its neck, chest and belly and flank areas.
In many cases – in fact, probably most of the time – the underlying cause of gastritis will never be identified. This is called "idiopathic gastritis." "Idiopathic" means "of unknown origin." This term is used in connection with a host of diseases and disorders, including gastritis. It indicates that doctors, scientists and other medical personnel have not yet figured out the precise cause of the condition it is being associated with.
The initial veterinary evaluation rarely discloses a specific cause of the dog's vomiting and abdominal discomfort. The diagnosis typically is made by ruling out possible causes of the dog's condition. This is called making a diagnosis of exclusion. In other words, the veterinary team will try to rule out as many potential causes of the dog's symptoms as they can, to narrow down the range of what might be responsible for its discomfort.
Inflammation of the stomach can be caused by many different things. These include obstruction by a foreign object, parvoviral infection, distemper, bacterial overgrowth, uremia/kidney disease, diabetes, hypoadrenocorticism (Addison's disease), hepatic (liver) disease, electrolyte imbalances, pancreatitis and stress, among a number of other things. Most cases of gastritis occur after a dog eats something that it shouldn't. Unfortunately, "dietary indiscretion" and "garbage gut" are phrases that veterinarians and dog owners are all too familiar with. When a dog is vomiting or showing other signs of abdominal discomfort, its veterinarian may recommend withholding food for a short period of time, to see if the situation improves. Depending on the severity of vomiting, water may also be withheld, or only offered periodically in small amounts. Anti-inflammatory and/or antibiotic medications may be administered under a veterinarian's supervision, even before the reason for the gastrointestinal distress is identified, to see whether the dog responds to treatment. If the dog improves with these noninvasive treatments, then the problem probably was caused by the dog swallowing something that didn't set well in its stomach or by a bacterial infection, and further treatment will likely not be necessary.
In severely acute or chronic cases of gastritis that don't respond to the initial diagnostic efforts, the veterinarian will want to perform routine blood and urine tests and abdominal radiographs (X-rays). She probably will also recommend taking a biopsy sample of a few different areas of the stomach lining in an attempt to find the cause of the condition. Blood tests are extremely useful to assess the dog's overall health and to rule out systemic illnesses such as parvovirus, distemper, diabetes, endocrine disorders, liver disease and kidney disease. Routine blood work also can reveal electrolyte and hormonal abnormalities and anemia. Radiographs, and ultrasonography, can help the veterinarian assess whether a mass or foreign object is blocking some part of the dog's gastrointestinal tract and whether the stomach lining is thickened, distended or inflamed. Special contrast studies can be done to detect obstructive foreign bodies, gastric outflow obstruction, defects in the stomach wall or delayed emptying of stomach contents. This procedure involves passing special radiopaque material, such as barium, through the dog's mouth into its digestive tract. The movement of that contrast material can be followed on a monitor screen in real-time. Any blockage, or abnormally long passage of ingesta from the stomach into the small intestine, usually will be obvious from this study, although the exact cause of those conditions still may not be clear.
The veterinarian can take tissue biopsies using an endoscope, which is a wand-like instrument with a camera at its tip that is passed through the dog's mouth, down its throat and esophagus and into its stomach. Various accessories can be attached to the endoscope that let the veterinarian move it around and rotate it, visualize all areas of the stomach lining and pinch off samples of tissue that looks red, inflamed, lumpy, bloody or otherwise abnormal. Biopsy samples usually will be taken even if the gastric lining looks normal. The samples will be sent to a pathology laboratory, processed and examined under a microscope through a procedure called "histopathology." They also may be cultured, which is a process that involves growing bacterial, viral or other infectious organisms in special culture media. Heavy sedation is necessary for this procedure.
Other possible diagnostic tools are fecal evaluation (to look for the presence of internal parasites which might be causing the dog's symptoms), and exploratory abdominal surgery, which usually is a last diagnostic resort.
Gastritis is a general term for inflammation of the lining of the stomach. It is important to identify the cause of gastritis – or at least to rule out as many potential causes as possible – so that the dog's treatment can be tailored appropriately.
Goals of Treating Canine Gastritis
There are a number of different treatment options for dogs with gastritis. They include restricting food intake, avoiding further contact with whatever caused the condition to develop in the first place, and in some cases stopping the administration of prescription medications. Of course, if cancer or some other systemic illness is causing the gastrointestinal discomfort, treatment options are more limited. Owners of affected dogs must discuss the appropriate treatment protocol with their veterinarian.
Irritation of the sensitive lining of the stomach is always uncomfortable. Sometimes, the discomfort becomes extremely severe and potentially can be quite dangerous, depending on the cause of the condition. The goals of treating a dog with acute or chronic gastritis are to provide good supportive care and remove the inciting cause of the condition, if it can be identified, so that the stomach lining and function can return to normal.
Treatment Options for Canine Gastritis
The symptoms of gastritis are usually first treated by withholding food from the animal for 12 to 48 hours. This is called "nothing per os," or "NPO," which means giving the dog nothing through its mouth. The purpose of this treatment is to give the dog's stomach and small intestinal lining a chance to recover from whatever insult they have encountered. Food usually is withheld until the dog has not vomited for at least 12 hours. Dogs with gastritis have a tendency to drink large amounts of water all at once, which can exacerbate stomach irritation and promote vomiting. Accordingly, the attending veterinarian may suggest that water be withheld for a short period of time. More commonly, water or crushed ice will be offered multiple times daily, but in very small quantities.
Supportive therapies and nutritional management usually are also among the early therapies for dogs showing symptoms of gastrointestinal discomfort. Supportive care usually involves administration of subcutaneous or intravenous fluids to rehydrate the dog and restore the proper balance of sodium, potassium and other electrolytes. Fluid and electrolytes are lost when an animal suffers from periodic or protracted vomiting. The initial diet after vomiting has stopped for at least 12 hours should be soft, low-fat and bland, ideally from only one easily-digestible carbohydrate and one low-protein source. Cooked rice, pasta and potatoes are common starch sources for this diet. Sources of protein include non-fat cottage cheese, skinless boiled white-meat chicken, boiled ground beef (hamburger) and tofu. Meals should be given in small amounts and frequently, for at least 2 to 3 weeks, to assess whether the dog's gastritis has fully resolved. Sometimes, bland low-fat and low-protein diets must be continued for several months, especially if a food allergy is the underlying cause of the dog's gastrointestinal inflammation.
Various drugs are available to treat stomach ulcers and other inflammatory gastric conditions. These include corticosteroids, antibiotics, anti-emetics (to alleviate vomiting), gastric protectants (to coat the stomach lining and prevent acid production) and medications that increase gastric emptying and intestinal motility. The attending veterinarian is the best person to prescribe the appropriate medications, if any, and to discuss potential side effects with the dog's owner.
If gastritis is caused by an indigestible foreign object that has become lodged in the dog's stomach or upper small intestine, surgery may be the only realistic therapeutic option. Occasionally, a small object can be removed through endoscopy.
Dogs with gastritis typically have a good prognosis, even if the cause of the condition is never fully identified. Acute gastritis often resolves on its own within several days. Chronic cases usually require treatment to resolve them completely.