Overview of Canine Colitis
Colitis is an inflammation of the colon, or large intestine. It may be acute, with sudden onset and short duration, or chronic, that is present for at least two to three weeks or exhibiting a pattern of episodic recurrence.
Causes of Colitis in Dogs
There are many potential causes of colitis. These include:
Specific inflammatory disorders of the colon. Lymphocytic-plasmacytic, histiocytic, granulomatous, suppurative, and eosinophilic are terms that describe colitis on the basis of the predominant type of cell present in the inflamed colon.
Infectious agents, such as bacteria, viruses, fungi, or parasites
Dietary intolerance or allergy
Cancer of the colon
Trauma, internal or external
Intussusception, which is a mechanical problem characterized by telescoping of the bowel into itself.
Hemorrhagic Gastroenteritis (HGE), which is an inflammatory disorder of the intestinal tract characterized by hemorrhage and production of a “raspberry jam” appearance to the stool
Pancreatitis (inflammation of the pancreas)
There is no age or gender association with colitis. One exception is histiocytic ulcerative colitis, which most often affects young boxer dogs.
Most often, colitis causes some combination of fresh bright red blood in the stool, mucus in the stool, straining to defecate, and increased frequency of defecation, often many times per day. With acute colitis, the dog usually does not show signs of systemic illness, but dogs with chronic colitis can experience clinically important weight loss.
What To Watch For
An occasional bout of acute colitis is not uncommon in the small animal patient. However, it is important to watch for frequent recurrence or worsening of signs, especially if they include systemic signs of illness. Although occasional vomiting occurs in otherwise healthy dogs, repeated vomiting, poor appetite, weight loss and general lethargy should be reported promptly to your veterinarian.
Veterinary care should include diagnostic tests and subsequent treatment recommendations.
Diagnosis of Colitis in Dogs
Your veterinarian will recommend diagnostic tests in order to recognize colitis and confirm the diagnosis. Tests may include:
A complete medical history and thorough physical examination
Fecal examination to evaluate for the presence of disease-causing bacteria or parasites
A complete blood count (CBC or hemogram) to evaluate for anemia, systemic inflammation, and presence of inflammatory cells (i.e., eosinophils) that may indicate an underlying allergic cause
Serum biochemistry tests to evaluate the general health of your dog and to identify problems in other organ systems
Urinalysis to evaluate kidney function
Abdominal X-rays to look for tumors or enlargement of abdominal organs
Serum trypsin-like immunoreactivity (TLI) in dogs to evaluate for pancreatic disorders
Colonoscopic examination to identify the presence of colitis or colon cancer and biopsy to determine the type of inflammation (eosinophilic, granulomatous, lymphoplasmacytic) or neoplasia (adenocarcinoma, lymphosarcoma). This procedure requires anesthesia, adequate cleansing of the bowel by enemas, and special equipment (a flexible fiberoptic endoscope) that may only be available at veterinary specialty referral centers.
Treatment of Colitis in Dogs
Treatment for colitis is most effective when directed at the underlying cause. Your veterinarian may recommend several symptomatic treatments for an animal with signs of colitis before recommending an extensive diagnostic evaluation.
These treatments include:
Empirical de-worming medication (because whipworms are a common parasitic cause of colitis and they only intermittently shed their eggs in the feces)
Home Care for Dogs with Colitis
Administer as directed any medications prescribed by your veterinarian and follow recommendations for dietary modification. Also, observe your dog’s general condition, watching for worsening of symptoms and bringing any changes to the attention of your veterinarian.
Although some causes of colitis cannot be prevented, try to avoid exposure of your dog to infectious agents or abrupt dietary changes.
Information In-depth on Dogs with Colitis
The history and clinical symptoms of dogs with colitis may vary and other illnesses may cause similar clinical symptoms. Therefore, several different diseases may initially be considered when evaluating a dog with symptoms compatible with colitis.
Common symptoms of colitis include loose stools that contain fresh (bright red) blood or mucus, frequent attempts to defecate, production of small amounts of stool, and straining to defecate.
Many types of inflammatory disorders can cause or be associated with colitis. These disorders collectively are known as “inflammatory bowel disease” because the clinical symptoms of several specific disorders are very similar to one another. Definitive diagnosis of the specific disorder is necessary for proper treatment. The different inflammatory bowel diseases include:
Lymphocytic-plasmacytic colitis is the most common inflammatory bowel disease of dogs. The definitive cause is not known, but it is thought to be caused by an overreaction of the immune system.
Histiocytic ulcerative colitis is characterized by ulcers and inflammation of the colon. It is seen most commonly in young boxer dogs.
Granulomatous colitis is an uncommon, poorly understood and severe disease of the colon that resembles Crohn’s disease in people. The word “granulomatous” refers to the specific types of inflammatory cells that are present in the colon in this disorder.
Eosinophilic colitis is characterized by eosinophils (a type of white blood cell associated with allergic reactions or parasites) in the inflammation. The cause of eosinophilic colitis is unknown, but food allergy or parasitic infection may be involved.
Many infectious agents can cause symptoms of colitis:
Bacteria (Clostridia, Salmonella, E. coli, Campylobacter, and others)
Viruses (corona virus, parvo virus)
Fungal agents (such as the causative agents of histoplasmosis, pythiosis, and protothecosis)
Parasitic worms (whipworms, hookworms)
Parasitic protozoa (Trichomonas, Ameba, Balantidium, Giardia)
Dietary intolerance or allergic reactions also can cause colitis. In this case, colitis often occurs as a reaction to a specific protein, but also can be associated with lactose, high fat content and certain food additives.
Dietary indiscretion may cause acute (abrupt onset and short course) colitis. Examples of dietary indiscretion include eating spoiled food, overeating, ingesting foreign material and sudden dietary changes.
Colonic cancer can cause symptoms similar to those that occur in colitis such as fresh (bright red) blood in the stool, mucus in the stool, straining to defecate, increased frequency of defecation and painful defecation. The most common types of colon cancer in dogs are adenocarcinoma and lymphosarcoma.
Trauma, either internal (foreign bodies) or external (blunt trauma by an automobile) can cause colitis.
Intussusception (telescoping of the bowel into itself) can cause partial or complete blockage and can result in symptoms such as straining to defecate (“tenesmus”)or blood or mucusin the stool.
Hemorrhagic gastroenteritis (“HGE”) is a dramatic, potentially fatal disorder of unknown cause. It occurs primarily in small breeds of dogs. It is characterized by a sudden onset of profuse bloody diarrhea (often “raspberry jam” appearance and consistency) and occasional vomiting.
Pancreatitis (inflammation of the pancreas) can cause blood and mucus in the stools.
Antibiotic-associated colitis can occur after administration of some antibiotics. It usually is self-limiting and ceases after antibiotic treatment is discontinued.
Blood clotting disorders (“coagulopathies”) including clotting problems due to liver failure, some rat poisons, and low platelet count (“thrombocytopenia”) can result in blood in the stool and be mistaken for colitis.