Pyloric Obstruction/Stenosis in Dogs
It is important that you make sure that your dog is truly vomiting and not simply regurgitating food. Vomiting is an active process involving contraction of the abdominal musculature and partially digested food as opposed to passive regurgitation in which undigested food simply falls from the mouth when the head is lowered toward the ground.
Vomiting is the most common clinical sign of pyloric obstruction, but it may be intermittent and may not occur for several hours after feeding. Vomiting may occur several times a day or only once or twice a week. Since pyloric stenosis occurs frequently as a congenital problem your puppy is born with, vomiting often begins when after beginning to eat solid food.
Diagnostic Test In-Depth for Pyloric Obstruction/Stenosis in Dogs
Several findings may be noted by your veterinarian during a physical examination such as thinness, lethargy and dehydration, which can be detected by tenting of the skin when it is picked up and dryness in the mouth. Most animals with pyloric stenosis or obstruction are not painful during abdominal palpation.
Your veterinarian will carefully listen to your dog’s chest with a stethoscope. If vomiting has been going on for some time, there is an increased risk for aspiration pneumonia that may lead to crackles, wheezes or other harsh lung sounds.
Plain radiographs (X-rays) of the abdomen may be helpful to rule out other causes of vomiting, but they are unlikely to be diagnostic for pyloric obstruction or stenosis.
Your dog can swallow liquid barium before radiographs taken of the abdomen. This may show a delay in emptying of the stomach or a thickening of the stomach wall, and it can show an abnormal pattern or filling defect in the pylorus. This would not discriminate between benign pyloric obstruction or stenosis and, say, a tumor or abscess.
Ultrasound may determine that the cause of the vomiting lies in an abnormal structure in the pylorus, but would be unable to differentiate the cause. Ultrasound can be helpful to inspect regional lymph nodes that could be enlarged in the case of infection or tumor.
The single best diagnostic tool is endoscopy. This is placement of a flexible camera down the esophagus and into the stomach to allow visualization of the inside and even the ability to pass through the pylorus and into the duodenum.
Because gastric tumors and benign pyloric obstruction or stenosis can look extremely similar, it is essential to obtain biopsies of any abnormal areas during the time of endoscopy. These are obtained by passing an instrument down the endoscope and pinching off tiny pieces of the abnormal tissue that can be submitted to a pathologist for examination and identification.
There are no specific laboratory abnormalities for pyloric stenosis or obstruction. However, bloodwork is important to determine the extent of metabolic abnormalities present as a result of chronic vomiting, so that they may be corrected and to screen for other infectious or metabolic causes of vomiting.
Treatment In-Depth for Pyloric Obstruction/Stenosis in Dogs
The effects of chronic vomiting or regurgitation must be addressed in treatment. This will include placement of an intravenous catheter to initiate fluid therapy, not only to correct dehydration but also to correct for electrolyte imbalance.
Anti-emetic drugs. Chronic vomiting can lead to the acidic content of the stomach irritating and inflaming the esophagus. Your dog may also receive antacids such as Tagamet® (cimetidine).
Antibiotics. Concerns about gastric or esophageal ulceration and the possibility of having aspiration pneumonia, may prompt your vet to place your dog on antibiotics. If chest radiographs confirm the presence of pneumonia, then the selection of antibiotic may be based on a tracheal wash.
Surgery. All of the above treatments will be beneficial and supportive, but they do not address the pyloric disorder itself. To correct the problem surgery is indicated. Medical treatment also helps to insure that your animal is in the best possible shape for anesthesia and corrective stomach surgery.
The pyloric obstruction or stenosis can involve the muscular portion of the stomach, the lining layer or mucosa of the stomach, or both. Different surgical procedures were originally developed to address these different conditions.
The simplest procedure involves cutting the thickened muscular layer of the pylorus and leaving the mucosa intact. This does not allow inspection or biopsy of the mucosa and is probably only a temporary solution. For these reasons it is no longer recommended.
Other techniques cut through all the layers and then widen the lumen of the pylorus. These procedures can be performed using suture material or surgical stapling equipment.
Surgical resection. In some cases, the thickening may be such that altering the size of the outflow from the pylorus is not enough. In this instance a corrective surgery that either entirely removes the region of obstruction or stenosis, or by-passes that area of the stomach, may be more appropriate. In both examples the stomach would be joined to the small intestine so that food and liquids could resume their normal passage through the digestive system. Again, these procedures can be performed using suture material or surgical stapling equipment.
During any gastrointestinal surgery, care is taken not to contaminate the abdomen with any stomach or intestinal contents and the abdomen would be thoroughly irrigated during and after completion of the procedure.
Removed tissue is submitted to a pathologists for histopathological evaluation to ensure that the disease is benign.
Analgesics. Your dog will have received analgesics (pain-killers) in injectable form before and after the procedure. Oral analgesics may be prescribed for a short time, when your dog goes home.
Intravenous fluids. Fluids will continue after surgery to maintain normal hydration. The day after surgery small amounts of water will be offered. If no vomiting occurs, small amounts of moist food will be offered about 24 hours after the surgery. If this is kept down, intravenous fluid support will be removed and your dog will usually be able to go home.
Motility drugs. Because the surgical procedures involve the outflow portion of the stomach, sometimes the coordination and rhythm of the stomach’s contractions need some medical assistance. If your dog does vomit after surgery, medications e.g. Reglan® (metaclopromide), may be given to enhance and assist in the flow of food and liquid through the stomach. This may be continued for a short time at home.
Blood tests. Blood samples may be obtained in the early postoperative period, before eating and drinking has resumed, to make sure that electrolytes remain in balance.