Ben the Vet

GDV/Bloat

Gastric Dilatation and Volvulus (GDV)

an information sheet for dog owners

Gastric dilatation and volvulus is an acute condition of dogs that can be rapidly fatal but is easily recognised and, if treated early, can have a favourable outcome.

What is it?

‘Gastric dilatation and volvulus’ is the term for when the stomach fills with gas (dilatation) and then rotates around its axis (volvulus). It is also known as ‘gastric torsion’ or ‘bloat’.

Predisposed Breeds

It most commonly occurs in deep-chested breeds of dogs, particularly Irish Setters, Rottweilers, Great Danes, Labrador Retrievers and German Shepherds. Individuals may be affected at any age, but it most commonly occurs in middle-aged to older dogs. Males and females are affected in equal numbers.

Causes

The underlying cause of GDV is not clear, though many theories exist, including obstruction of outflow of food from the stomach; neurological anomalies; aerophagia (air-swallowing) and simply excessive movement of the stomach following feeding. Exercising of deep-chested dogs within a couple of hours of eating is certainly linked with an increased incidence.

The outflow of food from the stomach is impaired and the stomach fills with gas. Aided by this buoyancy and possibly by exercise and its own contractions, the stomach rotates around its axis. It normally rotates in a clockwise direction between 90° and 180°, dragging the spleen with it and compressing many blood vessels, in particular the portal vein and the vena cava which is responsible for the return of blood to the heart.

The implications are several and serious:

reduction in blood flow to the stomach wall can result in necrosis of the stomach tissue;

the reduced blood return to the heart results in effective low blood volume and low blood pressure;

torsion of the spleen can result in necrosis or rupture;

suppression of breathing ability due to compression of diaphragm by the dilated stomach;

release of toxins from damaged tissue;

low blood potassium, resulting in heart arrhythmias.

Clinical Signs

Affected dogs become very restless and uncomfortable; may have difficulty breathing; they may salivate excessively and retch unproductively (as if they are trying to vomit). The most classic sign is distension of the stomach – the dog will look very swollen just behind the ribs and the swelling is very tense and tympanitic (taut like a drum). Some dogs will collapse.

If you suspect that your dog is showing these signs, DO NOT DELAY – immediately call your vet and take your dog to the clinic. Minutes can make a difference! This is not a condition that can be treated at home – a home visit would be futile.

Once at the clinic, the vet will complete a physical examination and may wish to take a radiograph (x-ray) to confirm the diagnosis.

Treatment

Without treatment, the condition is invariably fatal. With prompt treatment, up to 80% of patients may survive.

After confirming the diagnosis, the patient must be stabilised before surgery. Firstly, a stomach tube may be passed to try to decompress the stomach. Alternatively, the vet may decompress the stomach with a needle. Next the patient will be placed on intravenous fluids at a high rate to treat shock, restore circulating blood volume and to control the electrolytes and reduce the effects of the toxins. An ECG (electrocardiogram) may be performed to monitor the heart rhythm. As soon as the patient is stable they will be anaesthetised and surgery performed to rotate the stomach back into a normal position. The stomach will also be fixed to the inside of the abdominal wall (gastropexy) to prevent recurrence of the rotation. Patients that do not have a gastropexy performed have a recurrence rate of 80%, compared with a recurrence rate of 2-3% for those patients that do have a gastropexy.

If the spleen is damaged then this may be removed to reduce the chance of haemorrhage or necrosis.

It is undeniable that the surgery is relatively high risk, but without it the prognosis is far worse. In simple cases (i.e. without volvulus of the stomach) decompression may be sufficient, but the surgical fixation of the stomach must be performed at soon as possible to prevent recurrence.

Prevention

Sensible steps include feeding highly-digestible, high quality, low-bulk diets and allowing rest-time following a feed.

TAKE HOME MESSAGE – if you suspect a GDV, call your vet immediately –

DO NOT DELAY - timely treatment markedly improves prognosis.

Benjamin Harris MA VetMB (Cantab) MRCVS