Gastric Dilation in Rabbits
Gastric dilation is a syndrome in which the stomach expands (dilates) due to excess gas and fluid, resulting in complex local and systemic changes in the digestive tract. In most cases, it occurs due to foreign body obstruction. In rare instances, the stomach dilates in the absence of a foreign body. In either case, a mechanical or functional obstruction occurs at the opening of the stomach into the intestine, and fluid or semi-digested food accumulates in the stomach.
Twisting of the stomach, a condition called gastric volvulus, is rarely seen in concurrence with distension, but has been reported. More commonly, the pressure due to distension will result in a lack of blood supply and pressure on the nerves. These changes may account for acute (sudden and severe) clinical signs, such as severe abdominal pain, shock, and even heart failure.
Symptoms and Types
Although weakness and/or collapse are the most common historical findings associated with gastric dilation, rabbits may also have a history of loss of appetite. Other common symptoms include:
- Irregular blood pressure and heart rate
- Severe abdominal pain on palpation
- Progressive abdominal distension (does not happen suddenly)
- Hypovolemic shock (e.g., pale mucous membranes, decreased capillary, weak pulses, low body temperature)
Gastric dilation commonly occurs due to an obstruction caused by the swallowing of hair mats, cloth, or other fibers. Ferrets may also obstruct the pathway by swallowing small pieces of rubber or plastic toys, though it occurs less frequently. A low fiber diet can increase cravings for fiber-rich foods and lead to chewing of the aforementioned objects, increasing the risk of intestinal obstruction. Abdominal scar tissue is another posible cause for gastric dilation.
You will need to provide a thorough history of your rabbit's health leading up to the onset of symptoms to your veterinarian. He or she will then perform a thorough physical exam on the animal in the attempt to differentiate from other causes of abdominal pain, distention and appetite loss. The best method by which to make a diagnosis will be by visually examining the stomach cavity, which may be done by X-ray, ultrasonography, or endoscopy. The latter method uses a small camera that is attached to a flexible tube, and which can be inserted into the actual space to be examined. In this way, your veterinarian can get a more precise image of the cause of the blockage, and if indicated, take a tissue sample for biopsy.
As part of a standard physical examination, your doctor will also do a complete blood profile, including a chemical blood profile, a complete blood count, and a urinalysis. Blood and urine analyses, meanwhile, may show evidence of low blood volumes, an indication that shock has, or will set in.
As gastric dilation can quickly become fatal, it often warrants emergency inpatient medical management. Special attention will be paid to establishing improved heart function and fluid balance, followed by gastric decompression and resolution of the cause of the distention. Your veterinarian will perform gastric decompression by intubation of the stomach through the oral cavity. Surgery is indicated in most cases to remove the cause of obstruction, though it is not without risk, especially when the patient is in a critical condition. Blood pressure, meanwhile, will be maintained with fluid support until your rabbit has returned to a more balanced state. Antibiotics may also be given to prevent opportunistic infections.
Living and Management
Recovery may or may not occur. However, the condition may recur even if it is completely resolved. Your rabbit may resume normal activity after the foreign body is removed. Once your rabbit has been safely discharged from medical care, you can begin feeding it again, but the diet will need to be modified until the rabbit has had time to fully recover from the trauma. Pellets can be ground and mixed with fresh greens, vegetable baby foods, water, or juice to form a gruel that can be swallowed an digested more easily than solids. If your rabbit refuses food, you may assist-feed the gruel mixture. If sufficient volumes of food are not accepted in this manner either, feeding through tubes is indicated. Unless your veterinarian has specifically instructed it, do not feed your rabbit high-carbohydrate, high-fat nutritional supplements.
At home, monitor its appetite and production of feces, and regularly brush the rabbit to remove excess hair so as to prevent the rabbit from ingesting hair mats while self grooming.