Abdominal Distension in Dogs
Dr. Leah Cohn
Diagnostic tests are needed to recognize abdominal distention and exclude other diseases. These tests may include: A complete medical history and physical examination. Expect to answer questions regarding your dog's environment, dietary and elimination habits, the progression of symptoms and any other changes from the norm. Your veterinarian will likely be able to tell from physical examination if the swollen abdomen is the result of fluid or a solid mass.
Abdominal radiographs (X-rays) can show enlargement of abdominal organs and large tumors. Radiographs may not be requested if the abdomen is full of fluid, because fluid obscures the picture.
Abdominocentesis is the removal of fluid from the abdomen and may be both therapeutic and diagnostic. The fluid can be analyzed by chemical methods and viewed under a microscope to determine what type of fluid it is (blood, urine, exudate, transudate or a mixture) and thereby determine which causes are most likely.
Abdominal ultrasonography, in which a probe is held against the abdomen after clipping the hair, allows sound waves to produce a picture of the abdominal contents. Unlike radiographs, ultrasound works well when fluid is present. Yet another advantage of ultrasound over radiographs is that ultrasound allows visualization of the inside of the organs, rather than simply viewing the organ silhouette. Your veterinarian may request that a specialist perform this test.
Thoracic radiographs (chest X-rays,) may be requested to look for the spread of cancers or to evaluate the heart. Heart failure is an important cause of abdominal fluid accumulation.
A complete blood count (CBC,) may provide evidence of infection or anemia (deficiency of red blood cells).
Biochemical analysis of the blood can provide clues to the underlying cause of fluid accumulation and allow assessment of organ function.
Urinalysis can detect protein loss through the kidneys (one potential cause of abdominal fluid buildup,) and provide clues to both kidney and liver function.
Biopsies, obtained at surgery or with a needle, may be recommended if tumor or organ enlargement is detected.
On an individual basis, additional diagnostic tests may be needed to determine and/or diagnose other medical problems or to understand the overall impact abdominal distention may have on your dog. These include:
Bile acid measurements involve analyzing a blood sample obtained after fasting (usually 12 hours) and then giving the animal food. Eating causes bile to be released from the gallbladder but bile should be reabsorbed by the intestines and removed from the blood by the liver. Elevated blood bile acid levels suggest liver disease or abnormal circulation to the liver.
Urine protein quantification can be done by collecting all urine for 24 hours and measuring the protein content, or an estimate of protein can be made from a one-time urine measurement. Urinary protein loss can lead to abdominal fluid accumulation. This test is rarely done in dogs.
Biopsies of the intestines obtained either at surgery or with endoscopy, may be recommended if a very low albumin level is believed to be present due to loss of this protein through the intestines. Endoscopy involves passing a fiberoptic tube down the mouth of an anesthetized patient, and examining and/or taking a biopsy of the inner lining of the stomach and part of the intestine. An endoscopy cannot show the entire length of the intestine, nor can biopsies be taken from every layer of the intestines. Often, a specialist will perform this test.
Echocardiography uses ultrasound to examine the heart and its valves and the entrance of the caudal vena cava (the large vein that drains the abdomen). This test is similar to abdominal ultrasonography. Infrequently in dogs, heart failure can cause abdominal fluid accumulation. A specialist usually performs this test.
Bacterial cultures of any abdominal fluid may be performed to help determine the cause of fluid accumulation and to help pick the best possible antibiotics to treat infection.
Intravenous pyelography (IVP,) involves injection of a dye into the veins, followed by radiographs of the kidneys. This test may be indicated if a very enlarged kidney is found to be the cause of the abdominal distension. Kidneys can become very enlarged if urine flow is blocked, if tumors are present or in certain hereditary diseases in which fluid-filled cavities (cysts,) form within the kidney tissue.
Various specific tests may be performed to look for infectious diseases.
Exact treatment requires establishment of a diagnosis. Abdominal swelling in itself is seldom a threat to life, so symptomatic (nonspecific) treatments are often not indicated. However, severe abdominal distention can place pressure on the chest and interfere with comfortable breathing. The following is a list of potential nonspecific (symptomatic) treatments that may be applicable. These treatments cannot be a substitute for more definite treatment.
Abdominocentesis, the removal of abdominal fluid through the placement of a needle, is primarily used as a diagnostic aid but can also relieve pressure from excess fluid accumulation.
Certain types of fluid accumulation can be lessened with diuretic administration, which increases urination. Unfortunately, diuretics often fail to greatly reduce abdominal fluid accumulation.
Some causes of abdominal enlargement, including ruptured or twisted abdominal organs can be life threatening conditions, and must be treated immediately with surgery. See your veterinarian as soon as possible.