Ascites is characterized by fluid that flows freely inside the abdomen. Ascites can stem from a variety of different pathological conditions.
Ascites itself is not a disease but a clinical symptom, and may be seen in a variety of conditions. The fluid found inside the abdomen is characterized by its protein content. If the fluid contains an equal or slightly higher amount of protein than the levels contained in blood, they are referred to as transudate. If the protein content exceeds this level, the fluid is called exudate. Exudate is mostly found when inflammatory processes are present or if a ruptured tumor is leaking fluid into the abdomen. Transudate can occur as the result of chronic liver failure or cardiac conditions.
The abdomen appears distended to varying degrees depending on nature and stage of the underlying disease. When dogs breathe or change position while lying down, sometimes the distended abdomen becomes visible to the naked eye–sometimes appearing as "wavy" movement on the side of the dog's belly. If fluid is building up due to an infection overall health of the dog is usually impaired, and they may have a fever. In the case of chronic organ failure, symptoms appear gradually over a much longer period of time. Thus, a swollen abdomen may be only the first obvious anomaly and cause for further detailed examination by a veterinarian.
Fluid inside the abdomen can be made visible by ultrasound or an examination by x-ray. By retrieving small amounts of the fluid through a syringe the exact the nature of the fluid can be determined through laboratory analysis. Treatment of ascites has to be focused on the underlying cause. A thorough clinical examination with hematology and heart examination is necessary in order to determine the root cause of the symptoms and plan treatment accordingly.
As this condition might be the result of a critical systemic condition, if ascites is suspected, a vet should be consulted immediately.