Abdominal Distension in Dogs

Abdominal distension is an abnormal enlargement of the abdominal cavity. This term is usually reserved for abdominal enlargement due to causes other than simple obesity.

One cause of abdominal distension is fluid accumulation. The types of fluids include blood from internal hemorrhage (bleeding), urine from a tear in the urinary tract, exudate (cellular fluids similar to pus) from infection as with feline infectious peritonitis, and transudates (clear fluids), that are leaked from vessels.

Another cause of abdominal distension is enlargement of any abdominal organ including the liver, kidneys, or spleen. Distension of the stomach with air ("bloating") or fluid or distension of the uterus (womb) during pregnancy, can result in abdominal distension.

Tumors within the abdomen can also cause abdominal distension. The tumor may be malignant (an invasive cancer), or benign, (abnormal but not spreading to other tissues). Tumors can involve any of the abdominal organs, including the intestines or lymph nodes (glands).

Loss of abdominal muscle tone, with or without significant weight gain, also can lead to abdominal distension.

Pressure from the abdomen pushing into the chest may make breathing more difficult and pressure within the abdomen may decrease the appetite. NOTE: It is important to recognize abdominal distension because it can be a symptom of potentially life-threatening diseases and should be investigated thoroughly.

What to Watch For 

Sudden abdominal enlargement. Treat this as a medical emergency especially if associated with vomiting, retching, sudden weakness or collapse.

Distension that occurs over days to weeks. This requires prompt medical attention.

Slowly developing abdominal enlargement. This should be investigated if it is accompanied by loss of muscle or fat in other regions of the body, decreased appetite, vomiting or diarrhea, changes in urinary or bowel habits, or a diminished activity level.