Digestive System: Bowel Obstruction

Causes and Forms of Bowel Obstruction:

Canine bowel obstruction commonly occurs in two different forms i.e. gastric outflow obstruction and in a particularly intestinal obstruction — in simple words pathological (due to a disease or condition) and physical obstructions respectively. These forms are defined based on the causes.

• Gastric Outflow Obstruction: Pathological conditions, such as different infectious and non-infectious diseases, which can potentially cause severe inflammation, are the most common reasons for canine bowel obstruction. Most commonly, bacterial and viral infections that worsen may develop into ulcers and an inflammatory response which would cause the narrowing of the gastrointestinal tract, especially in the small intestine. Neoplasm (uncontrolled cell growth) and gastrointestinal hypertrophy (enlargement) are similar bowel problems that could cause a canine bowel obstruction. These involvements increase either the size or number of gut cells, which eventually may result into an obstruction.
• Intestinal Obstruction: This form is caused by physical factors, i.e. intake of foreign bodies, intussusceptions (twisting of the small intestine) or gastric bloat and/or secondary complications associated with a neoplasm (turmo).

  Foreign bodies such as plastic, fabric, string or bolus (a form or ball of of expired dog food) can cause a strangulated canine bowel obstruction, most commonly in small intestine. These materials sometimes get stuck in the gastrointestinal tract at one end of the oral cavity or somewhere else in the tract, which may hinder the passing of food and ultimately result in strangulation.

  The primary or secondary accumulation of gases in the intestine for any reason, such as malnutrition, allergy, obstruction or constipation may also cause a dog bowel obstruction. Similarly, there are some complications associated with neoplasm, like uncontrollable growth of cells, pressure on the intestine due to benign tumors in abdomen etc. that can cause a dog intestinal obstruction, that is not pathological but mechanical in nature.

See also our guide to canine bowel incontinence if your dog is suffering from these types of issues as well.

Symptoms:

A dog bowel obstruction may occur in any part of the gastrointestinal tract; therefore, clinical symptoms are also different for different locations. Obstruction in the small intestine is usually characterized by lethargy, anorexia, abdominal pain, vomiting and diarrhea. The body temperature remains subnormal, while dehydration is common. If an affected dog remains unattended to for 12 – 35 hours, shock may occur and within the next 3-4 days, the affected dog may die because of hypovolemia (diminished blood volume in the body).

An obstruction, in the upper duodenum and in the stomach, is commonly characterized by frequent and severe vomiting. Vomiting is usually not present if the obstruction occurs in the lower end of the small intestine. Lethargy, weight loss, dehydration, and ultimately starvation are common symptoms and thus death may occur if such a condition persists for 3 weeks or more.

Intussusceptions and/or twisting of the small intestine are more common in weak, immune depressed, young puppies and in hunting dogs. Due to intussusceptions, luminal obstruction (inside the intestine), loops in the intestinal gut and infraction (bone fracture) are common. The severity of the condition depends upon the length of the intestine involved and loop’s fixative index. Along with abdominal pain and vomiting, diarrhea with blood is common in such cases.

Diagnosis:

Feeding history, clinical signs and nutritional habits are very important for making a proper diagnosis. Here dogs must be thoroughly examined for the intake of any foreign body. Examination of the oral cavity for signs of injury due to needles, sharp objects and the presence of the end of any string etc. in oral cavity can also help.

Abdominal x-rays on the other hand can help in identifying foreign bodies, abdominal fluids and any other form of cancerous or non-cancerous cellular development in the gut. In order to confirm certain pathological conditions, such as infections and cancerous cell pathology, biochemical profiling and a CBC test can be very helpful.

Treatment:

Initially, severely affected dogs can be treated symptomatically, with fluid therapy. Ringer’s lactate and normal saline can help in this regard. Not only this, but some anti-emetic and anti-inflammatory drugs and anti diarrheal agents can also be added in low doses. This will not only restore vascular volume but will also help to reduce the effects of any symptoms.

Natural remedies such as Flatulence Preventer may help as a supportive option for controlling gas accumulation and discomfort.

Surgery is the most effective and convenient option for removing a canine bowel obstruction, if the physical form is confirmed. Both forms of surgery, whether of the small intestine or large intestine are usually similar in prognosis and in a study, it was clearly noted that mortality rate stands at 12% in all those dogs who undergo intestinal surgery.

Bowel surgery if done on both the small and large intestine at once, or if it is done to completely remove an intestinal section is called dual or two way surgery.  This type of surgery has relatively low survival rates due to post surgical complications and the involvement of a large area of the intestine. It is used to correct obstructions caused by an intestinal twist, removal of cancerous tissues or vascular congestion. Some post-surgical complications, such as peritonitis and death soon after surgery are also common, so any dog undergoing treatment should be monitored and handled carefully. In such circumstances as those described above, the dog owner must realize that a dog with a canine bowel obstruction has a “poor” prognosis.