Written by Glenn Rosenberg
Ascites is the abnormal accumulation of fluid within the abdominal cavity. It is a condition with a wide range of causes. Ascites develops most frequently as a result of liver disease. It can also be seen in people who have cancer, kidney disease, and heart disease. Ascites is seen in people with pancreatic disease, as well as other conditions.
What is going on in the body?
Mechanisms in the body leading to ascites are complex and not completely understood.
- The accumulation of fluid in the abdominal cavity can be associated with portal hypertension. This means there is an increased blood pressure in the veins draining the liver. The higher pressure can be caused by liver damage. It can also be caused by impaired drainage in the lymph system. This system takes excess fluid and particles away from the liver.
- Low levels of albumin and other proteins in the blood also contribute to ascites. The force that holds plasma water within the blood vessels is reduced. Plasma water is lost into the abdominal cavity. Albumin in the ascitic fluid pulls yet more fluid across into this cavity.
- Blood flow to the kidneys might be reduced. This leads to increased secretion of the hormone aldosterone. This increase causes the kidneys to retain salt and water. Urinary output is decreased, and fluid is retained. In some cases, kidney disease contributes to impaired elimination of salt and water.
- Fluid may leak from capillaries, the pancreas, or the lymph system. Capillary fluid leakage can be caused by inflammation or infection.
All of these events may lead to a large volume of abdominal ascites. Adults with cirrhosis of the liver may have as much as 10 to 12 liters of fluid in their abdominal cavities.
What are the causes and risks of the condition?
Ascites is most often a result of liver disease, including the following:
- alcoholic liver disease
- chronic hepatitis
- cirrhosis, which is permanent scarring of the liver
- liver cancer
- sudden liver failure, which can be due to infection or drug reactions
Other common causes of ascites include the following:
- bile leaking into the abdomen
- blood or fluid leaking from the blood vessels into the abdomen
- certain kidney conditions
- congestive heart failure, a condition in which the weakened heart fails to pump blood effectively
- constrictive pericarditis, which is a tightening of the lining around the heart
- gastrointestinal diseases that cause a loss of protein, such as inflammatory bowel disease
- inflammation of the lining of the abdomen, known as peritonitis
- obstruction in the inferior vena cava, one of the largest veins in the body
- pancreatic fluid leaking into the abdomen
- severe malnutrition
- tuberculosis that has infected the peritoneum
- tumors on the lining of the abdomen