Pyloric Obstruction (Stenosis) in Dogs

Pyloric obstruction is a dangerous condition that can quickly become a life threatening emergency. Complications due to the obstruction may include extreme weight loss, vitamin deficiency, metabolic disturbances, and aspiration pneumonia, which can be fatal. This obstruction most often affects males and young dogs with short faces (brachycephalic) such as the bulldog and Boston Terrier. Toy breeds such as the Maltese, Shih Tzu, and Lhasa Apso are also susceptible to pyloric stenosis and obstruction when they are over seven years old.

Pyloric stenosis in dogs is when the pyloric canal is too narrow and induces a pyloric obstruction. This means that there is a thickening of the pyloric valve or sphincter that is stopping the food from digesting properly. It could also be spasms causing the pyloric sphincter to contract and not let the food pass from the stomach. The response is that the vomiting reflex is triggered because the food has no other way to get out of the stomach. Once your dog has vomited, eating is usually continued because your pet is still hungry and not getting any nutrients from the food that was vomited. This condition can be serious if your dog inhales food or vomit into the lungs because it can cause pneumonia.

There are many symptoms of pyloric obstruction or stenosis, which may include:

• Vomiting
• Regurgitating food right after eating
• Difficulty swallowing
• Bloating after eating
• Abdominal pain
• Weaknes
• Depression
• Diarrhe
• Loss of weight
• Appetite changes (either increased or decreased)
• Wheezing from aspiration pneumonia

Types

Pyloric obstruction has two forms, which are:

• Acquired pyloric obstruction can show up at any age in any type of dog and is usually caused by many factors such as gastritis, stress, and ulcers
• Genetic pyloric obstruction is usually noticed when your puppy is being introduced to solid foods

Pyloric obstruction is more common in males than females. In addition, there are several breeds that are most affected, which include:

• Boston Terriers
• Boxers
• Lhasa Apso
• Maltese
• Pekingese
• Shih Tzus

Other causes include:

• Acquired antral pyloric gastropathy
• Stenosis
• Herni
• Hypertrophic gastropathy
• Foreign objects
• Gastritis (granulomatous, hypertrophic, atrophic, and eosinophilic)
• Gastroenteritis
• Adenocarcinomas (tumors)

Your dog’s health background is the most important factor in determining pyloric obstruction because the symptoms are usually only seen after a meal. However, the veterinarian will be able to notice signs of the condition by doing an endoscopic examination as well as a comprehensive physical assessment. The endoscopic examination is done by inserting an endoscope (long flexible lighted tube) through your dog’s mouth and into the digestive tract. Your dog will be sedated during the procedure for safety and it only takes about 10-15 minutes.

Afterwards the veterinarian will do a detailed examination including mucous membrane color, coat condition, and reflexes. A radiographic examination may be done next and may consist of x-rays with and without contrast (barium) and ultrasound to check for thickened walls in the pyloric area. CT scans or an MRI may also be helpful, though will only be done if earlier testing does not provide the required information. Laboratory tests are performed last, including a urinalysis and complete blood count.

There are several treatments (both medical and surgical) depending on what caused the pyloric obstruction. However, surgery is usually needed to fix the problem permanently.

Medications

Intravenous fluids and electrolytes will be started if not already started during endoscopy. Also, your veterinarian may prescribe prokinetic medication such as erythromycin, cisapride, or metoclopramide.

Surgery

In most cases, surgery is needed to fix the obstruction, especially if it is causing serious complications. The procedures used to fix the problem may be a pyloroplasty to open the area using a flap, a pyloromyotomy to open the area through the layer of muscle, or a gastroduodenostomy to bypass the pylorus if one of the other methods are not possible.

Special Diet

In any case, you will need to provide your pet with a special diet after treatment. Most often, it will include a soft and bland diet with a high nutrient count.

Prognosis depends on the cause, but it is generally good if the condition is found and treated right away. If there is an underlying condition or complication the prognosis may be a bit different. For example, adenocarcinomas can be serious, gastroenteritis and gastritis can be recurrent, and acquired antral pyloric gastropathy may be difficult to treat.