Bloat

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This article is about the medical condition. The term is also used figuratively to describe the uncontrolled and damaging growth of a system (as in software bloat). It is also a collective noun for a group of hippopotami. For the symptom in humans, see Gas/bloat syndrome, flatulence, and burping.

Bloat, also known as torsion, gastric torsion, and gastric dilatation-volvulus (GDV) is a medical condition in which the stomach becomes overstretched by excessive gas content. Meteorism, its name derived from the writings of Hippocrates, is now rarely used in English. The distortion of the stomach constricts the esophagus, preventing the gas from escaping. The condition occurs most commonly in domesticated animals, especially dogs and cattle, but rarely in cats. Deep-chested breeds, such as Great Danes, Airedales, and Boxers, are most at risk for bloat. Basset Hounds have the greatest risk for dogs less than 23 kg.^[1] Mortality rates in dogs range from 10 to 60 percent, even with treatment.^[1]

X-ray of a dog with bloat

[edit] Pathology

Splenic necrosis following bloat

If the stomach twists around the axis of the digestive tract, the condition is known as torsion, and if the axis of movement is perpendicular to the digestive tract, the condition is known as volvulus. Usually the stomach twists in both directions. In either case, the oesophagus is closed off, thereby preventing the animal from relieving the condition by belching or vomiting. The most common direction for rotation is clockwise, viewing the animal from behind. The stomach can rotate up to 360° in this direction and 90° counterclockwise. At the other end of the stomach, the spleen may be damaged if the twisting interrupts its blood supply. If not quickly treated, the condition can lead to blood poisoning, peritonitis and death by toxic shock.

[edit] Causes

In dogs, the causes of bloat are unclear, and currently there is little agreement on the factors that may contribute. Some of the more widely acknowledged factors are stress, eating foods such as kibble that expand in the stomach, swallowing too much air while eating, overfeeding, and other causes of gastrointestinal distress. There is also no consensus on ways in which to prevent bloat from happening, and suggestions are sometimes contradictory, for example, "Raise your dog's feeding dish - he will not swallow as much air while eating" as opposed to "Lower your dog's feeding dish so that he eats slower, and thus swallows less air." However, precautions that are likely to help include feeding small meals throughout the day instead of one big meal and not exercising immediately before or after a meal.^[2]

[edit] Symptoms

Symptoms are not necessarily distinguishable from other kinds of distress. A dog might stand uncomfortably and seem to be in extreme discomfort for no apparent reason. Other possible symptoms include firm distension of the abdomen, weakness, hypersalivation, and retching without vomiting.

[edit] Treatment

Bloat is an emergency medical condition: having the animal examined by a veterinarian is imperative. Bloat can become fatal within a matter of minutes. Treatment usually involves resuscitation with intravenous fluid therapy and emergency surgery. The stomach is initially decompressed by passing a stomach tube, or if that is not possible, multiple trocars can be passed through the skin into the stomach to remove the gas. During surgery, the stomach is placed back into its correct position, the abdomen is examined for any devitalized tissue (especially the stomach and spleen), and a gastropexy is performed, which by a variety of methods attaches the stomach wall to the body wall, to prevent future twisting. A gastropexy does not prevent future bloating, i.e. the stomach can still fill up with gas, but it will not twist. A partial gastrectomy may be necessary if there is any necrosis of the stomach wall. If this is necessary the prognosis is worse.^[1]

[edit] Bloat in cattle

In cattle, bloating is most often caused by the animal eating damp, green alfalfa. New (green) alfalfa hay, especially that made from the first cutting of the year, must be kept from cattle until it has aged for several weeks. When a calf has become bloated, often a section of hose is inserted down the throat and into the stomach to relieve the gas pressure that builds up. A veterinarian should be called for treatment. Death of the animal often results if bloat is not quickly treated.

[edit] References

1. ^ ^{a b c} Aronson, Lillian R., Brockman, Daniel J., Brown, Dorothy Cimino (2000). "Gastrointestinal Emergencies". The Veterinary Clinics of North America 30: 558-569.
2. ^ Wingfield, Wayne E. (1997). Veterinary Emergency Medicine Secrets. Hanley & Belfus, Inc. ISBN 1-56053-215-7.

[edit] External links

• Dog Owner's Guide: Bloat