Introduction

Gastric dilatation (GD) and gastric dilatation and volvulus (GDV) are acute life-threatening conditions in dogs. GD is characterized by a rapid accumulation of gas, fluid, ingesta or a combination thereof in the stomach which results in increased intragastric pressure. In GDV the dilatation is accompanied by torsion of the stomach. In both GD and GDV, dilatation of the stomach results in compression of major blood vessels in the abdomen with impaired venous return to the heart and results in shock, and frequently death if left untreated (Glickman et al. 1994).

GD and GDV are more common in large or giant breeds of dogs such as Great Danes, German Shepherd dogs, large mixed-breed dogs, Standard Poodles, Blood hounds and German Pointers (Brockman et al. 1995; Evans, Adams 2010). A North American study reported that the frequency of GD and GDV was 2.9 and 6.8 per 1,000 canine hospital admissions, respectively (Glickman et al. 1994). A study of dogs working on farms in New Zealand, found GD or GDV accounted for 4% of the 1,024 visits to a veterinarian that were unrelated to trauma, and was the most important reason for a dog being unable to return to work that was unrelated to trauma (Cave et al. 2009).

No single cause of GDV or GD has been identified. Suggested risk factors for GDV include those related to age, gender, breed, feeding practices, exercise and bodyweight. A recent study of pure breed dogs found that the median age of death because of GDV was 8 years of age (Evans and Adams 2010). Dogs fed large, single meals per day are at risk of developing GDV (Raghavan et al. 2006). Recent work on military dogs has shown that meteorological changes may also play a role in the development of GDV in these dogs, with 50% of cases occurring in winter and often after large hourly drops in temperature, and higher barometric pressure readings (Moore et al. 2008).

General Goal of Management for GDV in Dogs

Therapeutic goals of GDV management (Tivers, Brockman 2009)

1.  Restore and support the circulation

2.  Decompress the stomach

3.  Establish whether GDV or a simple gastric dilation (GD) is present

4.  Rapid surgical correction if volvulus has occurred

5.  Prophylaxis:

a.  Surgical

b.  Environmental

General Recommendations to Clients to Try and Prevent GDV

 Feed several small meals a day rather than one large meal (Raghavan et al. 2006).

 Avoid stress during feeding (if necessary, separate dogs in multiple-dog households during feeding) (Glickman et al. 1997).

 Restrict exercise before and after meals (of questionable benefit and research evidence is scant).

 Do not use an elevated feed bowl (Glickman et al. 2000).

 Do not breed dogs with a first-degree relative that has a history of GDV (Glickman et al. 2000).

 For high-risk dogs, consider prophylactic gastropexy.

 Seek veterinary care as soon as signs of bloat are noted (Beck et al. 2006).

Prognosis for GDV in Dogs

Mortality rates for dogs undergoing surgery for GDV range from 15–33% (Brockman et al. 1995; Glickman et al. 1998). A recent study in working farm dogs in New Zealand found that 65% of dogs were successfully treated and returned to their owner (Hendriks et al. 2012).

The dogs with the highest rate of survival are those without gastric necrosis. Dogs with gastric wall necrosis or a high serum lactate concentration have more post-operative complications and a higher death rate (Brockman et al. 1995; Glickman et al. 1998; de Papp et al. 1999; Green et al. 2011).

A study in working farm dogs in New Zealand found that 45% of dogs had gastric wall necrosis, with 61% of these dogs dying and 9% of dogs without gastric wall necrosis dying (Hendriks et al. 2012). This survival percentage is lower than that reported in a study of the general canine population, where 98% (62/63) of dogs survived if there was no gastric wall necrosis and 66% (25/38) survived if there was necrosis (de Papp et al. 1999).

Two recent studies have shown that obtaining veterinary attention within six hours of the onset of clinical signs of GD or GDV improved the chance of survival (Beck et al. 2006; Buber et al. 2007).

GDV in Working Dogs

Working dogs encompass the entire spectrum of dogs, from police dogs, to guide dogs to working farm dogs. Police dogs in New Zealand are predominantly German shepherd dogs, and working farm dogs in New Zealand are a mixture of heading dogs and Huntaways. The German Shepherd and the Huntaway are deep chested breeds that are predisposed to developing GDV. Military dogs in the USA are predominantly German Shepherd or Belgian shepherd, and GDV was the 4th most likely cause of euthanasia or death in this population, resulting in many military dogs now receiving prophylactic gastropexies (Moore et al. 2001).

In a recent survey of 2 214 visits of working farm dogs to veterinarians in New Zealand GD or GDV accounted for 1.6% of all (n = 2214) admissions to the veterinarian, but 3.5% of 1024 non-traumatic admissions. However GD or GDV was the most important (4% of 270 cases) non-traumatic reason for loss of return to work (Cave et al. 2009). The inability of a dog to return to work results in considerable loss of farm income as well as the time and cost to train a new dog and cost of replacing the dog. This outcome makes GDV a very important disease in working farm dogs in NZ.

A recent retrospective study on GDV in working farm dogs found that 40/62 (65%) cases of GD or GDV that were examined and treated at the veterinary clinics returned to work (Hendriks et al. 2012). Of the 41 dogs where the gastric contents were recorded, 25 (61%) had predominantly food or bones in the stomach, and 26/27 dogs had a history of having eaten meat, bones or scavenged a carcass. At surgery, 8/28 (29%) dogs underwent a gastrotomy to remove food material. This data differs dramatically from that reported for a wider canine population with GDV, where gas was the most common stomach content and gastrotomy was only rarely required to remove impacted food or foreign material (Tivers, Brockman 2009a, 2009b). Further prospective research is required to determine whether large meals and the type of food are risk factors for GDV in working farm dogs. Further research is also required to determine whether GDV in working farm dogs is more common after a meal, during or after work and the timing between a meal and heavy exercise and the risk of developing GD or GDV.

Risk factors for GD or GDV in working farm dogs in New Zealand included advancing age and season of the year (summer), but in each case the reason for these associations was not clear. This study also showed that there are some differences in the nature of GD or GDV in working farm dogs in New Zealand (remove full stop) compared with dogs in previous studies (solid stomach contents, most cases occurring in the morning before work and a relatively low survival rate (Hendriks et al. 2012). Further research is required into GDV in working farm dogs.

References

1.  Brockman DJ, Washabau RJ, Drobatz KJ. Canine gastric dilatation/volvulus syndrome in a veterinary critical care unit - 295 cases (1986–1992). Journal of the American Veterinary Medical Association. 1995;207:460–4.

2.  Cave NJ, Bridges JP, Cogger N, Farman RS. A survey of diseases of working farm dogs in New Zealand. New Zealand Veterinary Journal. 2009;57:305–12.

3.  de Papp E, Drobatz KJ, Hughes D. Plasma lactate concentration as a predictor of gastric necrosis and survival among dogs with gastric dilatation-volvulus: 102 cases (1995–1998). Journal of the American Veterinary Medical Association. 1999;215:49–52.

4.  Hendriks MM, Hill KE, Cogger N, Jones BR, Cave NJ. A retrospective study of gastric dilatation and gastric dilatation and volvulus in working farm dogs in New Zealand. New Zealand Veterinary Journal. 2012;60:165–70.

5.  Moore GE, Burkman KD, Carter MN, Peterson MR. Causes of death or reasons for euthanasia in military working dogs: 927 cases (1993–1996). Journal of the American Veterinary Medical Association. 2001;219:209–14.

6.  Moore GE, Levine M, Anderson JD, Trapp RJ. Meteorological influence on the occurrence of gastric dilatation-volvulus in military working dogs in Texas. International Journal of Biometeorology. 2008;52:219–22.

7.  Tivers M, Brockman D. Gastric dilation-volvulus syndrome in dogs 1. Pathophysiology, diagnosis and stabilisation. In Practice. 2009;31:66–9.

8.  Tivers M, Brockman D. Gastric dilation-volvulus syndrome in dogs 2. Surgical and postoperative management. In Practice. 2009b;31:114–21.