Pyloric Obstruction/Stenosis in Dogs


Overview of Canine Pyloric Obstruction or Stenosis 

The pylorus is the lower portion of the stomach that leads into the small intestine of the dog. Pyloric obstruction or stenosis usually refers to a thickening of the various layers of muscle and mucosa (stomach lining tissue) that make up this region, leading to obstruction of flow of food or water through the stomach. This thickening is a benign, non-cancerous process.

Pyloric obstruction or stenosis is most commonly seen in brachycephalic (short-faced) breeds of dog such as boxers, Boston terriers and bulldogs. These dogs tend to be young and predominantly male. It can also occur as a more chronic condition in small breeds of dog such as Lhasa apso, shih tzu and Maltese terrier. These dogs tend to be middle-aged to older.

If food and water cannot move through the stomach, the dog will regurgitate or vomit and become sick, dehydrated, and depressed. Untreated, the chronic vomiting can lead to significant metabolic problems, weight loss and the risk of aspiration pneumonia. This combination of problems could easily become fatal.

What to Watch For

  • Young brachycephalic breed of dog
  • Older small breed dog
  • Chronic vomiting
  • Regurgitation

    In young animals, vomiting often occurs at the time of weaning onto solid foods.

  • Diagnosis of Pyloric Obstruction/Stenosis in Dogs

    A detailed history and physical examination can initially lead your veterinarian to suspect pyloric obstruction. Additional tests are necessary to make a definitive diagnosis. Tests may include:

  • Radiographs (X-rays) may be taken of the abdomen, but neither plain radiographs, contrast radiographs using liquid barium or ultrasound are as good as gastroscopy for diagnosing the type of pyloric disease present.
  • Gastroscopy involves placing an endoscope down through the stomach in order to visualize and biopsy the pylorus.
  • Many changes may be present in the blood work of an animal that has been vomiting for some time. The loss of acid from the stomach will cause a loss of chloride and a relative increase in the amount of alkali present (metabolic alkalosis). Elevations in kidney parameters can occur, reflecting dehydration.
  • There is no specific blood test to determine pyloric obstruction or stenosis.
  • Treatment for Pyloric Obstruction/Stenosis in Dogs

  • Medical management is important to correct the metabolic abnormalities of chronic pyloric obstruction, but definitive treatment requires surgery.
  • Your pet may be given intravenous fluids, antacids and antibiotics prior to anesthesia, in order to be in as stable a condition as possible going into the surgical procedure.
  • There are multiple different types of corrective surgery for the thickened pylorus and the type selected can depend on the surgeon’s experience and which layers of the pylorus are affected by the disorder.
  • Whichever type of surgery is performed, the aim of the procedure is to restore the normal size of the opening from the pylorus to the duodenum, the first part of the small intestine.
  • Home Care and Prevention 

    Your dog’s abdominal skin incision will need to be monitored for swelling, redness or discharge. Staples or stitches can be removed in 10 to 14 days.

    Your pet will have received pain-killers (analgesics) during the period of hospitalization and these may continue in oral form when he goes home.

    Follow your veterinarian’s recommendations regarding feeding and contact your veterinarian if your dog begins vomiting or does not eat.

    The cause of this disease is not known. For this reason there is nothing an owner can do to prevent the problem from occurring. Prompt veterinary care for your vomiting pet is the best course of action.

    In-depth Information on Canine Pyloric Obstruction or Stenosis 

    Related Diseases

    Many disorders can lead to vomiting and most of them are far more common than pyloric obstruction or stenosis.  These conditions may include: 

  • Gastrointestinal foreign bodies are ingested material that is either not digested or slowly digested. These can cause obstruction or irritation to the stomach and intestinal tract. Common foreign bodies include rocks, bones, plastic toys, socks, pantyhose and various other objects. String, yarn and thread can create linear foreign bodies. These can get anchored at the base of the tongue or the stomach and cause the bowel to bunch up or be plicate. Young dogs are more commonly interested in foreign bodies and on physical examination they may not be painful on abdominal palpation. Radiography and endoscopy will help discriminate a foreign body from pyloric obstruction or stenosis.
  • Vomiting can be a component of many viral causes of gastroenteritis, such as distemper or parvovirus. Again, young unvaccinated dogs may be affected and are often painful on abdominal palpation. These animals usually have concurrent diarrhea and other clinical abnormalities that are quite different from pyloric obstruction or stenosis.
  • Several metabolic disorders can lead to vomiting such as uremia secondary to kidney disease, diabetes, and liver insufficiency. Laboratory analysis of blood samples obtained from the patient should lead your veterinarian to pursue these disorders.
  • Diseases of the pancreas such as pancreatitis, pancreatic tumors and pancreatic abscesses can produce vomiting. Most animals with pancreatic disorders are painful on abdominal palpation.
  • Peritonitis is an inflammation of the peritoneum, the lining of the abdomen. The most common cause of peritonitis results from intestinal or gall bladder rupture, and animals have vague clinical signs often accompanied by vomiting and diarrhea. Again, dogs with peritonitis are usually painful on palpation of their abdomen, but this may be localized rather than generalized, dependent on the extent of the problem.
  • Gastric tumors can cause vomiting. The most common type of tumor in dogs is called a gastric adenocarcinoma, and it occurs most commonly in the pyloric region and therefore needs to be differentiated from benign pyloric obstruction typically seen in middle aged to older small breed dogs. Endoscopy with biopsies will be important to discriminate these two diseases.
  • Gastric ulceration is most often secondary to taking anti-inflammatory medication such as aspirin, ibuprofen, phenylbutazone etc. The pylorus is a common location for an ulcer to occur. Endoscopy is the most sensitive test to allow visualization and biopsy of an ulcer.
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