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==Description==

==Description==  

Gastric Dilatation and Volvulus (GDV) is an acute, life-threatening emergency affecting large and giant breed dogs. The condition is characterized by accumulation of gas in the stomach and malpositioning of the stomach with obstruction of eructation and pyloric outflow. Commonly affected breeds include German Shepherds, Great Danes, Irish Wolfhounds, St Bernards and Doberman Pinschers. GDV has also been reported to occur in cats, primates and rarely small breed dogs such as Dachshunds and Miniature Poodles.

Gastric Dilatation and Volvulus (GDV) is an acute, life-threatening emergency affecting large and giant breed dogs. The condition is characterized by accumulation of gas in the stomach and malpositioning of the stomach with obstruction of eructation and pyloric outflow. Commonly affected breeds include German Shepherds, Great Danes, Irish Wolfhounds, St Bernards and Doberman Pinschers. GDV has also been reported to occur in cats, primates and rarely small breed dogs such as Dachshunds and Miniature Poodles.

==Pathogenesis==

==Pathogenesis==

An obstruction to gastric emptying due to fluid or gas leads to gastric distention and a rapid increase in intra-gastric pressure.  As the stomach dilates, the pylorus shifts in a clockwise direction through an angle of between 180 and 360^o from its normal position to a dorsal, cranial and leftward location. The most immediate effect is impairment of the gastric blood supply, leading to severe congestion of the gastric wall and infarction and ulceration of the gastric mucosa. Venous return to heart is reduced due to mechanical compression of the caudal vena cava by the distended stomach, leading to decreased cardiac output and hypovolaemic shock. Gastric distension also causes a mechanical impediment to movement of the diaphragm resulting in reduced tidal volume, hypoxia and hypercapnia.

An obstruction to gastric emptying due to fluid or gas leads to gastric distention and a rapid increase in intra-gastric pressure.  As the stomach dilates, the pylorus shifts in a clockwise direction through an angle of between 180 and 360^o from its normal position to a dorsal, cranial and leftward location. The most immediate effect is impairment of the gastric blood supply, leading to severe congestion of the gastric wall and infarction and ulceration of the gastric mucosa. Venous return to heart is reduced due to mechanical compression of the caudal vena cava by the distended stomach, leading to decreased cardiac output and hypovolaemic shock. Gastric distension also causes a mechanical impediment to movement of the diaphragm resulting in reduced tidal volume, hypoxia and hypercapnia.

==Risk factors==

==Risk factors==

Studies have shown that dogs with a reduced thoracic width to depth ratio are at an in increased risk of developing GDV. Other risk factors include obesity, stress, exercise following feeding and feeding of a dry food diet. Female dogs are also more likely to develop GDV than males. Dogs with an aggressive temperament are also more prone to developing GDV.  

Studies have shown that dogs with a reduced thoracic width to depth ratio are at an in increased risk of developing GDV. Other risk factors include obesity, stress, exercise following feeding and feeding of a dry food diet. Female dogs are also more likely to develop GDV than males. Dogs with an aggressive temperament are also more prone to developing GDV.  

==History and Clinical signs==

==History and Clinical signs==

The clinical signs of GDV are usually acute in onset and may follow a periood of exercise and/or feeding of a large meal. Affected dogs typically display non-productive vomiting and abdominal distension. On physical examination, the dog may be collapsed or reluctant to stand. Signs of cardiovascular shock may be present including tachycardia, pale mucous membranes, prolonged capillary refill time and poor peripheral pulses. Abdominal tympany is often displayed and the animal may be painful.

The clinical signs of GDV are usually acute in onset and may follow a periood of exercise and/or feeding of a large meal. Affected dogs typically display non-productive vomiting and abdominal distension. On physical examination, the dog may be collapsed or reluctant to stand. Signs of cardiovascular shock may be present including tachycardia, pale mucous membranes, prolonged capillary refill time and poor peripheral pulses. Abdominal tympany is often displayed and the animal may be painful.

==Diagnosis==  

==Diagnosis==  

Diagnosis is usually based on the patient's history of unproductive vomiting and abdominal distension and signalment (i.e. a large breed dog). Abdominal radiography may be beneficial in confirming a diagnosis of GDV and distinguishing between GDV and gastric dilatation. Radiography should not be carried out until gastric decompression has been performed and intravenous fluids have been started. A radiograph performed in right lateral recumbency shows a dorsally and cranially positioned pylorus to the left of the midline. The stomach will appear compartmentalised with a soft tissue strip separating the two compartments. The oesophagus may appear dilated with air or fluid. Evidence of air in the abdomen indicates that perforation has occurred and requires an exploratory surgical procedure. Loss of contrast in the abdomen may indicate peritonitis or haemoabdomen.

Diagnosis is usually based on the patient's history of unproductive vomiting and abdominal distension and signalment (i.e. a large breed dog). Abdominal radiography may be beneficial in confirming a diagnosis of GDV and distinguishing between GDV and gastric dilatation. Radiography should not be carried out until gastric decompression has been performed and intravenous fluids have been started. A radiograph performed in right lateral recumbency shows a dorsally and cranially positioned pylorus to the left of the midline. The stomach will appear compartmentalised with a soft tissue strip separating the two compartments. The oesophagus may appear dilated with air or fluid. Evidence of air in the abdomen indicates that perforation has occurred and requires an exploratory surgical procedure. Loss of contrast in the abdomen may indicate peritonitis or haemoabdomen.