GASTROENTERITIS: ACUTE, NONSPECIFIC

About the Diagnosis

Inflammation can be defined as redness, pain, swelling, and heat in a tissue. Gastritis is inflammation of the stomach. Enteritis is inflammation of the intestine. Colitis is inflammation of the large bowel, also called the large intestine or the colon. Inflammation of each of these structures can occur in dogs and cats and can have subtle differences in symptoms. Your veterinarian will work with you to try to differentiate them. Gastritis, enteritis, and gastroenteritis are typically manifested as vomiting. Enteritis, enterocolitis, and colitis are typically manifested as diarrhea.

The following outlines will separate the inflammation of the intestinal structures for clarity of understanding, but there often is overlap because more than one region of the digestive tract may be inflamed at a time. This is because the stomach is connected to the intestine, which is connected to the large bowel/colon. Most pets with gastroenteritis also have colitis (the entire gastrointestinal tract is inflamed and irritated). "Acute nonspecific gastroenteritis" refers to symptoms of digestive upset (vomiting, diarrhea, or both) caused by transient inflammation of the digestive system, such as occurs when a pet eats a food or substance that is irritating, contaminated with bacteria, or otherwise unhealthy.

Gastritis: Some typical identifiable causes of gastritis should be considered before a presumptive diagnosis of acute nonspecific gastritis is reached. Foreign materials (strings in cats, toys in puppies) can block the digestive tract, like a cork in a bottle. Even without obstruction, certain foreign bodies can cause gastritis. Chemicals of many varieties can cause gastritis. These include household cleaners, soaps, and so forth. Prescribed and over-the-counter drugs can cause gastritis. Even some foods that we enjoy can cause gastritis in our pets, which is why table scraps and foods should not be fed to pets.

Bacterial gastritis can occur if pets eat old, stale, and rotting foods. Rarely, in certain parts of the country, fungal infections can cause gastritis/gastroenteritis or colitis. If your veterinarian is worried about fungal infection of the digestive tract, then appropriate testing should be considered as these can be life-threatening diseases.

Typically, the acidic nature of the stomach prevents infection and the stomach's thick mucous lining is involved in protecting against gastritis. However, if there is mechanical or chemical alteration of these protective layers of the stomach (mucus layers), as occurs when foreign bodies or corrosive chemicals are swallowed, then the acidity of the stomach reaches the inner layers of the stomach wall and itself causes gastritis.

Acute nonspecific gastritis is a type of digestive upset of unproven origin. It is a diagnosis of exclusion, meaning that only after excluding more serious disorders (based on symptoms and certain test results such as x-rays or blood tests) can the diagnosis of nonspecific gastritis be made. Acute nonspecific gastritis is usually a mild, self-limiting form of stomach upset that improves on its own after 24 to 48 hours.

Enteritis: All of the above causes of gastritis can also potentially extend "downstream" to the intestine, causing enteritis. Additionally, the intestine can become primarily inflamed, without stomach involvement. This is rare without underlying disease (because everything is passing through the stomach first). However, overgrowth of normal bacteria can occur for unknown reasons, a condition that causes diarrhea and which is called antibiotic-responsive diarrhea.

Colitis: Again, because most substances pass through the entire gastrointestinal tract, colitis may be part of an inflammatory process affecting the whole digestive tract, or it may exist on its own. Symptoms of colitis include frequent, urgent straining to defecate, flatulence, or passage of diarrhea containing or covered with mucus or fresh red blood, and occasionally, vomiting. Stress (of boarding, new pets in the house, moving, etc.) can cause a primary colitis and associated diarrhea, a condition often referred to as "nervous bowel." Another cause of colitis is the proliferation of certain bacteria or protozoa in the colon.

Gastroenteritis and colitis should resolve with appropriate treatment and removal of inciting causes. If symptoms recur, your veterinarian should follow up with additional testing to look for underlying causes because there are many diseases that will cause similar symptoms but require different types of specific treatment.

Living with the Diagnosis

Short-term management revolves around stopping the vomiting and/or diarrhea and preventing secondary effects of vomiting and diarrhea. Secondary effects include appetite loss, dehydration, and changes in blood electrolyte levels. These symptoms in and of themselves can become life-threatening, but with appropriate supportive care, this can generally be prevented. Medications should be discussed with your veterinarian and will be prescribed as appropriate. Hydration and electrolyte balance are easily managed if your pet is still eating and drinking. However, vomiting can cause enough gastritis that even water can become irritating to the stomach. Never offer anything by mouth less than 1 hour following vomiting. Discuss appropriate drinking and refeeding with your veterinarian based on severity of symptoms.

Symptoms can be severe enough that pets need to receive fluids intravenously (IV) to maintain adequate hydration and electrolyte balance. This can provide the stomach and intestinal tract enough time to heal and the inflammation to improve or resolve without worrying about life-threatening dehydration.

Cleanliness is a critical issue. Pets that feel sick, vomit, and have diarrhea may not take care of their normal elimination (defecating, urinating). Getting vomit, diarrhea, and/or urine in their hair and on their skin can cause skin inflammation/irritation, infection, and severe secondary problems. Helping them keep clean is an important part of preventing worsening problems and allowing healing.

Long-term management is centered on prevention. Eliminate problem toys that could be swallowed or irritating, dispose of bones after 24 hours to reduce contamination, and keep food and water bowls clean. Lock away household cleansers and detergents. Review previous medications you may have been giving your dog or cat with your veterinarian to be sure there is no risk of medication-induced stomach upset. Discuss prevention with your veterinarian.

Some pets truly have "sensitive" stomachs, and the smallest changes in diet can cause gastroenteritis. However, these pets are no more common than those that truly have an underlying condition requiring medical attention. Recurrence of symptoms should be addressed, and underlying disease should be investigated, especially if symptoms keep recurring without an obvious cause.

Treatment

The most important treatment is resting the intestinal tract. In pets with confirmed acute nonspecific gastroenteritis, it is important that you do not give anything for at least 1 hour following vomiting: remove the food and water bowls. Your pet may not know not to eat or drink. Intestinal rest may be 1 or 2 hours or may be several days. This is dependent on severity of signs. Discuss what appropriate treatment means for your pet with your veterinarian.

Refeeding should be done with an appropriate bland and easily digestible diet. These diets should be low in fat as well. There are several commercial prescription diets that your veterinarian may prescribe. A lean poultry protein source mixed with cooked white rice is often a palatable bland diet that is also low in fat. This can be a good short-term diet, but it is deficient in vitamins and minerals and should not be fed alone for more than 2 to 3 days.

There is a variety of oral gastrointestinal protective drugs (antacids, intestinal anti-inflammatory drugs and antibiotics), any of which may be appropriate depending on symptoms and history. More aggressive treatments such as gastric lavage, intravenous fluids, and intravenous medication should be recommended by your veterinarian if symptoms dictate.

DOs

- Refeed slowly; transition back to your pet's normal diet after several days without any vomiting or diarrhea.

- Rest and recover; remember how poorly you might feel after severe digestive upset.

- Administer medications, as directed by your veterinarian. Your veterinarian will also help guide refeeding and prevention based on the symptoms of your pet.

- Realize that medical tests like x-rays and bloodwork are necessary to eliminate underlying and more severe disease processes before arriving at a diagnosis of acute nonspecific gastroenteritis.

DON'Ts

- Treats should be stopped during recovery. Most treats are rich and not easily digested.

- Do not continue to feed a bland diet longer than necessary, particularly if you are home-cooking the diet for your dog or cat. Your pet needs a balanced diet with appropriate vitamins and minerals.

- Do not give medications longer than originally recommended, unless otherwise directed by your veterinarian. Even simple antacids can cause problems, if given for too long. Long-term medications may be necessary in more severe disease processes, but only under the guidance of your veterinarian. If your pet has a return of symptoms after you stop medications, they should be reevaluated by a veterinarian as there may be underlying disease(s).

When to Call Your Veterinarian

- Recurrence of symptoms, if your pet starts vomiting or having diarrhea again the days or weeks after you stop giving medications. Your veterinarian may refill a prescription, or they may recommend further testing, depending on the symptoms.

- Any worsening of symptoms (for example, if your pet continues vomiting despite being treated as described above) or appearance of new signs (for example, in addition to vomiting your dog or cat now seems lethargic). These can be additional warning signs of underlying disease that is more serious that acute nonspecific gastroenteritis.

- Bloody vomit or blood in the intestinal tract (see descriptions below) are signs of worsening problems and severe disease and should be addressed by a veterinarian promptly.

Signs to Watch For

- Vomiting, diarrhea, etc.; any recurrence of the original problem.

- Bloody vomit and diarrhea should be concerning. Blood in the stomach will quickly turn black and clot due to the stomach's natural acids. Therefore, when blood is vomited, it looks like coffee grounds within the vomit. Blood coming from the intestine will be digested and form a black, metallic-smelling, tarry stool, referred to as melena.

- Blood originating from inside the colon will generally appear as normal red blood.

- Additional signs to watch for should be provided by your veterinarian based on specifics of your dog or cat's disorder and on medications that are prescribed.

- If your pet fails to drink any water for 12 hours or does not eat for more than 24 hours, an immediate follow-up is warranted.

Routine Follow-Up

- Your veterinarian will discuss follow-up depending on the medications being prescribed and the severity of - symptoms.

- Your pet should be reevaluated if there are signs of blood in the intestinal tract, recurrence of symptoms, and/or you are worried about a worsening appearance such as the onset of lethargy, sluggishness, or labored breathing.