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GASTRIC DILATATION/VOLVULUS SYNDROME IN DOGS
Overview
Gastric dilatation is a condition that can develop in many different breeds of dogs. The condition is commonly associated with large meals and causes the stomach to dilate because of food and gas and may get to a point where neither may be expelled. As the stomach begins to dilate and expand, the pressure in the stomach begins to increase. The increased pressure and size of the stomach may have several severe consequences, including preventing adequate blood return to the heart from the abdomen, loss of blood flow to the lining of the stomach, and rupture of the stomach wall. As the stomach expands, it may also put pressure on the diaphragm preventing the lungs from adequately expanding, which leads to decreased ability to maintain normal breathing (ventilation) (Figure 1).
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Figure 1. A lateral radiograph of a dog with a gastric volvulus. Note the stomach is markedly distended with gas (which shows up as black on the radiograph) and the stomach is occupying nearly the entire abdomen.
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The entire body suffers from the poor ventilation leading to death of cells in many tissues. Additionally, the stomach can become dilated enough to rotate in the abdomen, a condition called volvulus. The rotation can occasionally lead to blockage to the blood supply to the spleen and the stomach wall requiring surgical removal of the dead tissues. Most of these patients are in shock due to the effects on the entire body. The treatment of this condition involves stabilization of the patient, decompression of the stomach and surgery to return the stomach to the normal position permanently (gastropexy) and evaluate abdominal organs for damage and treat them appropriately as determined at the time of surgery.
Causes
Several studies have been published that have evaluated risk factors and causes for gastric dilatation and volvulus in dogs. This syndrome is not completely understood; however, we know that there is an association in dogs that have a deep chest (increased thoracic height to width ratio), dogs that are fed a single large meal once daily, older dogs and dogs that are related to other dogs that have had the condition. Additionally, it has been suggested that elevated feeding, dogs that have previously had a spleen removed, large or giant breed dogs, and stress may result in an increased incidence of this condition. A 2006 study also determined that dogs fed dry dog foods that list oils (e.g. sunflower oil, animal fat) among the first four label ingredients predispose a high risk dog to GDV.
Incidence and Prevalence
Nearly all breeds of dogs have been reported to have had gastric dilatation with or without volvulus, but many of the commonly seen breeds are Great Danes, Weimaraners, St. Bernards, Irish setters and Gordon setters. Female and male dogs are represented equally and dogs as young as 10 months and as old as 14 years have been recognized. The true number of cases in a population of dogs remains undetermined although it is reported to affect approximately 60,000 dogs per year.
Signs and Symptoms
Initial signs are often associated with abdominal pain. These can include but are not limited to:
- an anxious look or looking at the abdomen
- standing and stretching
- drooling
- distending abdomen
- retching without producing anything
As the disease progresses, the animal may begin to pant, have abdominal distension, or be weak and collapse and be recumbent. On physical examination, patients often have elevated heart and respiratory rates, have poor pulse quality, and have poor capillary refill times. Abdominal distension is commonly noted.
When to Seek Veterinary Advice
Stabilization and surgery are best when performed early in the course of the disease and mortality rates increase with the severity of disease. If your pet has exhibited any of the above clinical signs, they should be evaluated by a veterinarian immediately. Additionally, as many breeds and body conformation types (deep chest) are predisposing factors, evaluating if your pet is among those discussed here, will allow early detection and treatment. Surgery is indicated if the diagnosis of gastric dilatation with or without volvulus has been established. Your pet may be referred to a surgical specialist for treatment if this condition is diagnosed. Find an ACVS Veterinary Surgeon.
Exam Screening Tests and Imaging
Most veterinarians require initial bloodwork that includes a complete blood count (CBC), serum chemistry, and a urinalysis. These allow for the determination of the nature of the metabolic disturbances that may be concurrently happening. It also allows the veterinarian to rule out certain diseases which may mimic the clinical signs of gastric dilatation. Additionally, abdominal radiographs are used to confirm a diagnosis and an electrocardiogram (ECG) is used to evaluate the presence of cardiac arrhythmias (commonly seen later in the disease course). Blood gas analysis is also commonly performed to evaluate the nature and severity of the respiratory compromise. Additional tests may be recommended by your surgeon.
Differential Diagnosis
Gastric dilatation with or without volvulus may appear like many different conditions. This can occur because of the wide variety of clinical presentation the patient may exhibit depending on the severity of the disease. Some endocrine disease such as hypoadrenocorticism (Addison's disease) may cause signs of weakness and abdominal pain. Additionally, a variety of abdominal conditions including foreign body, neoplasia (cancer), mesenteric torsion, splenic torsion, and hernias may appear with similar clinical signs. All of these conditions warrant evaluation by a veterinarian.
Complications Caused by the Disease
As gastric dilatation worsens and full body effects become prolonged, many secondary complications may occur. Respiration and cardiac output are diminished throughout the course of the disease leading to poor oxygen delivery to many tissues (hypoxia). This leads to cell death in the liver, kidneys, and other vital organs. Cardiac arrhythmias (abnormal heart beats) are commonly seen because of the hypoxia. Additionally, the lining of the entire gastrointestinal tract is at risk of cell death and sloughing. As the condition progresses, toxins may be increasing locally and when gastric dilatation is relieved these may circulate through the body resulting in additional cardiac arrhythmias, acute renal failure, and liver failure. Bacteria also commonly gain access to the blood during this condition leading to bacteremia (bacteria in the blood) and sepsis.
Treatment Options
Stabilization of the patient is paramount and often begins with intravenous fluids and oxygen therapy. Gastric decompression often follows, which includes the passing of a tube down the esophagus into to stomach to release the air and fluid accumulation and can be frequently followed with lavage (flushing of water) into and out of the stomach to remove remaining food particles. In certain cases this is not possible and a needle or catheter may be placed into the stomach from outside the body to release air and aid in the passing of the tube. The time for general anesthesia and surgical stabilization will be determined by the stability of your pet and at the discretion of the surgeon. Surgery involves full exploration of the abdomen and de-rotation of the stomach. Additionally, the viability of the stomach wall, the spleen, and all other organs will be determined. Removal of part of the stomach wall (partial gastrectomy) or the spleen (splenectomy) is occasionally performed. Once the stomach is returned to the normal position in the abdomen, it should be fixed to the body wall (gastropexy) (Figure 2).
Figure 2. A gastropexy. Note that the stomach has been sutured to the abdominal wall in order to prevent it from expanding and twisting again.
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The purpose of this procedure is to prevent volvulus (rotation) if subsequent gastric dilation occurs again. Several gastropexy procedures exist including, but not limited to the following:
- incisional gastropexy
- belt-loop gastropexy
- circumcostal gastropexy
- tube gastropexy
Complications following Treatment
General anesthesia remains the most important risk to patients affected by gastric dilatation. Death may occur before, during, or after the procedure because of the disease. Following the procedure, cardiac arrhythmias are commonly seen, although relatively few are life threatening and require treatment. Further cell death and loss of organs may occur because of the toxins released when the stomach is returned to its normal position. Additionally, many dogs will have some degree of gastric dilatation; however, the gastropexy serves to prevent the life threatening complication of rotation. Surgery always carries a low risk of infection or breakdown of suture line (dehiscence) leading to a second surgery.
Aftercare
Most pets will be hospitalized and given intravenous fluids for several days and evaluated for cardiac arrhythmias and other postoperative complications. Immediate postoperative care will include exercise restriction for a few weeks to allow the incisions to heal. Long term, dietary management will likely be recommended including multiple small meals (2-3) per day rather than a single large meal and continued monitoring for recurrence of clinical signs.
Prognosis
Mortality (death) rates associated with gastric dilatation and volvulus have been reported to be approximately 15%. Mortality and morbidity (complication) rates increase as disease severity and time increase. Factors that have been shown to increase mortality rate include:
- patients with clinical signs for >6 hours
- patients with cardiac arrhythmias prior to surgery
- patients requiring removal of a portion of the stomach due to loss of blood supply
- patients requiring removal of the spleen
Median survival time is significantly longer for dogs that have had a gastropexy at the time of surgery for gastric dilatation and recurrence rates are significantly lower.
Prevention
Prophylactic gastropexy is currently being recommended by many veterinary surgeons for breeds at risk for development of the condition or in dogs that have relatives that have been related to others that have had this condition. Prophylactic gastropexy can often be done at the same time as sterilization surgeries (spay/neuter). Although any of the gastropexy procedures listed above can be use, minimally invasive techniques such as laparoscopic assisted gastropexy, endoscopically assisted gastropexy and grid (limited approach) gastropexy also are possible for prophylactic gastropexies).
View of graspers holding stomach prior to gastropexy
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Laparoscopic view of a completed gastropexy
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Determination if prophylactic gastropexy is recommended is on a case by case basis.
—Greg Marsolais, DVM, MS, Diplomate ACVS, Small Animal Surgery 2007
First posting 8/13/2004 and photos courtesy of Dr. Marsolais
Reviewed and updated 12/25/2008 by Mitchell A. Robbins, DVM, Diplomate ACVS
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