Stomach and Intestinal Inflammation in Dogs

Inflammation is often the body’s response to an infection. Over the short term, it can rid cells of bacteria and disease, but kept up indefinitely, chronic inflammation creates its own problem. Inflammatory responses can be triggered in a dog’s stomach and intestine, sometimes in response to an actual infection, sometimes in response to a food or allergen, and occasionally due to a hereditary weakness. Once triggered, these responses can self-perpetuate to some degree since inflamed mucosa become even more sensitive to allergens. The result may be prolonged symptoms of digestive upset without an obvious cause. The problem can sometimes be alleviated by a change in diet. Severe cases may need medication to reduce the animal’s autoimmune response.

Inflammation of the stomach and intestine can cause acute and chronic symptoms of digestive upset. Long term conditions will put stress on a dog’s system and undermine overall health. A number of veterinarian defined diseases create this condition, including gastritis and inflammatory bowel disease.

Frequent vomiting is a symptom which may contain the following:

• Undigested food
• Fresh blood
• Digested blood that looks like coffee grounds
• Froth
• Bile

Other signs which may present are:

• Diarrhea often with blood
• Dark tar-like feces that contains blood (melena)
• Straining to pass mucus covered feces
• Weight loss
• Lack of appetite
• Abdominal pain 

Types

Inflammation can occur at almost any point along the gastrointestinal tract. Most forms of inflammation can be either short term or chronic.

• Acute gastritis - short term inflammation of the stomach that results in vomiting of blood, bile or undigested food
• Chronic gastritis - results when the vomiting has persisted regularly for more than a week and cannot be attributed to an isolated cause like food poisoning
• Eosinophilic gastroenteritis and Lymphocytic- plasmacytic gastroenteritis - severe forms of chronic gastritis which occur when eosinophil, or lymphocyte and plasma cells infiltrate the gastric mucosa
• Chronic atrophic gastritis - a form of chronic gastritis characterized by thinning of the mucosa, gastric gland atrophy and infiltration of mononuclear cells
• Chronic hypertrophic gastropathy - a rare form of chronic gastritis in which inflammation constricts the muscles and reduces gastric outflow
• Inflammation of the large intestine or colon - inflammation of the colon can be short term or long term, like gastritis. It is more likely to present bowel symptoms such as diarrhea and blood or mucus in the feces, than vomiting
• Eosinophilic enterocolitis and Lymphocytic-plasmacytic enterocolitis - similar versions of these gastric diseases in the colon.
• Granulomatous enteritis - a rare condition in which long term inflammation narrows the bowel opening
• Inflammatory Bowel Disease (IBD) - a diverse group of long-term inflammatory diseases including chronic forms of gastritis and colon inflammation where the mucosa on the walls of the gastrointestinal tract are infiltrated by immune-system, antibody cells

Short term inflammation can often be attributed to poisoning, bad food or even overeating. Some possible causes of long term inflammation include:

• Allergens to chemicals in processed food
• Allergic reaction to a medication
• Unknown bacterial or parasite infection
• Hyper-immune response originally triggered by an allergen or infection that has become self-perpetuating
• Defective lymphoid tissue
• Genetic predisposition- some breeds are considered more likely to develop long-term inflammation including Norwegian Lundehunds, German Shepherds, Yorkshire and Wheaten Terriers, Basenjis, Boxers, English Bulldogs, Irish Settlers, Rottweilers, Chinese Shar-Peis, and Cocker Spaniels
• Psychosomatic factors
• Idiopathic (unknown)

Diagnosis of inflammation is often a system of elimination. There are many known viral and bacterial infections which cause vomiting, including canine parvovirus, so the veterinarian will first try to eliminate these as a possibility. Radiographs and ultrasound might be necessary to help with the diagnosis.  Complete blood work will usually be taken. This often shows deficiency from constant vomiting and poor nutrition absorption, but if no other abnormalities are present it can rule out other conditions. Urine and feces tests can help to eliminate some known diseases.

The veterinarian may recommend an endoscopy or a colonoscopy to evaluate the state of the mucosa on the gastrointestinal walls. Biopsies are usually taken during these procedures to evaluate the cells at a microscopic level. Both of these procedures are somewhat invasive and will require an anesthetic. Your dog will also have to fast for several hours. Exploratory surgery is another option to ascertain the extent of the inflammation on the walls of the stomach or intestine. 

All the information you can give the veterinarian regarding the type and frequency of the symptoms as well as when they first started will be important in making an accurate diagnosis.

Most dogs will be given medication to aid with the vomiting symptoms. Antacids and anti-inflammatory drugs are also commonly prescribed. Fiber is often added to the diet for dogs with colon inflammation. This can be effective for short term problems, but long term issues will often return.

Changing your dog’s diet is usually the first treatment for chronic inflammation. You may need to withhold food for several days, and start your dog back eating on the “novel protein diet.” This involves feeding your dog a type of protein he has never eaten before such as duck, or even kangaroo in order not to immediately retrigger the same allergic response. The veterinarian may also give you hydrolyzed protein, which has been specifically designed to minimalize the chance of an allergic reaction. Starting with the novel protein, you will slowly add elements back into your dog’s diet. If the symptoms start again, you will know what specific food triggered it, and you may be able to find a substitute.

If diets are unsuccessful, several medications can help reduce long term inflammation of the stomach and intestine. An immune suppressant, cyclosporine, is one common choice for limiting the auto-immune response and reducing inflammation. The steroid prednisone is also effective, and some veterinarians are turning to a dog adapted from of CellCept, the drug which is given to humans to avoid rejection of a new organ after a transplant. 

Inflammation of the stomach and intestine isn’t usually dangerous or life threatening, but it can cause your dog a lot of misery. Follow the veterinarian’s advice and stick strictly to any dietary program. This may be difficult at times, especially when it requires withholding foods your dog loves, but it can be important for his recovery. In some cases your dog may be able to return to a more normal diet once the triggering factor is found; in others, you may have to manage his diet for some time. If the veterinarian prescribes a long term medication, check the side effects and try to give the smallest effective dosage.