If the circumference of the abdomen increases, the cause is usually fat deposits that the body deposits for a rainy day. But disorders inside the abdomen can also be behind it: liver diseases in particular lead to fluid accumulation in the abdomen. Ascites, i.e. an accumulation of fluid (edema) in the abdominal cavity, is not a disease in its own right, but a symptom that can have various causes. In most cases, however, liver disease is behind it. Ascites is a sign that indicates advanced disease – which is why other symptoms have usually occurred before.
Causes of ascites
The most common cause is liver cirrhosis, which is the connective tissue remodeling of the liver tissue, which in turn is a result of various liver diseases. Cirrhosis makes the tissue stiffer than normal. which subjects the vessels to greater resistance. As a result, blood can no longer flow freely, backs up in the portal vein in front of the liver and is squeezed out of the vessels into the abdominal cavity.
In addition, cirrhosis impairs liver function, so fewer proteins are produced. These normally attract fluid to themselves and thus retain it in the vessels. Malignant tumors or metastases, e.g. in the peritoneum, can also alter the blood composition accordingly and thus lead to edema. In addition, they “sweat out” water themselves.
Another cause is right heart weakness, in which the pumping power of the right ventricle of the heart decreases and therefore the blood backs up in the veins of the systemic circulation. Again, water is squeezed out into the abdominal cavity, and water retention in the ankles is also typical. Something similar also happens with occlusions (thrombosis) of the splenic vein, portal vein or hepatic vein.
Symptoms of ascites
Initially, the symptoms of the underlying disease are in the foreground. The ascites itself is noticeable by the increasing abdominal girth – so gradually pants and belts no longer fit. The abdomen increasingly bulges outward, the border to the belly button becomes blurred or an umbilical hernia forms.
The amount of water in the abdomen (and thus the weight gain) can be enormous – 10 liters and more are not uncommon. This causes the abdomen to tighten enormously, which can be very painful and lead to shortness of breath.
Therapy of ascites
Ascites and its extent can be easily determined by ultrasound. The main focus is on therapy of the underlying disease, e.g., delaying the progression of liver cirrhosis, removing a tumor, treating heart failure. However, ascites is usually already a sign of a poor prognosis, so that it is usually not possible to cure the disease, but at best to delay it.
Ascites itself is treated by flushing out the fluid with diuretics and by limiting fluid intake. An ascites puncture is often performed, in which 0.5-1.5 liters of fluid are withdrawn from the abdomen using a cannula. This improves the symptoms, at least for a while.
Another – often last and dangerous – therapeutic option is to create a short-circuit connection (portosystemic shunt) between the portal vein (in front of the liver) and the vena cava (in front of the right heart) in order to bypass the blood to the liver and thus avoid the high pressure there. However, this also prevents the liver from performing its (remaining) function of detoxifying the blood, and there is an increased risk of brain damage (hepatic encephalopathy).
