The term “ascites” denotes the pathologic accumulation of fluid in the peritoneal cavity. Healthy men have little or no intraperitoneal fluid, but women normally may have up to 20 mL depending on the phase of the menstrual cycle. Cirrhosis of the liver is the most common cause of ascites, but other conditions such as heart failure, kidney failure, infection or cancer can also cause ascites. Ascites is most commonly caused by a combination of increased pressure in the blood vessels in and around the liver (portal hypertension) and a decrease in liver function. The most common cause of ascites is portal hypertension secondary to chronic liver disease, which accounts for over 80% of patients with ascites. The most common causes of nonportal hypertensive ascites include infections (tuberculous peritonitis), intra-abdominal malignancy, inflammatory disorders of the peritoneum, and ductal disruptions (chylous, pancreatic, biliary).
Signs and symptoms
The history usually is one of increasing abdominal girth, with the presence of abdominal pain depending on the cause.
Because most ascites is secondary to chronic liver disease with portal hypertension, patients should be asked about risk factors for liver disease, especially alcohol consumption, transfusions, tattoos, injection drug use, a history of viral hepatitis or jaundice, and birth in an area endemic for hepatitis. A history of cancer or marked weight loss arouses suspicion of malignant ascites.
Fevers may suggest infected peritoneal fluid, including bacterial peritonitis (spontaneous or secondary).
Patients with chronic liver disease and ascites are at greatest risk for developing spontaneous bacterial peritonitis. In immigrants, immunocompromised hosts, or severely malnourished alcoholics, tuberculous peritonitis should be considered.
Physical examination should emphasize signs of portal hypertension and chronic liver disease.
Elevated jugular venous pressure may suggest right-sided heart failure or constrictive pericarditis.
A large tender liver is characteristic of acute alcoholic hepatitis or Budd-Chiari syndrome (thrombosis of the hepatic veins).
The presence of large abdominal wall veins with cephalad flow also suggests portal hypertension; inferiorly directed flow implies hepatic vein obstruction.
Signs of chronic liver disease include palmar erythema, cutaneous spider angiomas, gynecomastia, and muscle wasting.
Asterixis secondary to hepatic encephalopathy may be present.
Anasarca results from cardiac failure or nephrotic syndrome with hypoalbuminemia.
Finally, firm lymph nodes in the left supraclavicular region or umbilicus may suggest intra-abdominal malignancy.
The physical examination is relatively insensitive for detecting ascitic fluid. In general, patients must have at least 1500 mL of fluid to be detected reliably by this method. Even the experienced clinician may find it difficult to distinguish between obesity and small-volume ascites. Abdominal ultrasound establishes the presence of fluid.
Your doctor will do a physical exam to determine if the swelling is likely due to fluid buildup in your belly.
You may also have the following tests to assess your liver and kidneys:
- 24-hour urine collection
- Electrolyte levels
- Kidney function tests
- Liver function tests
- Tests to measure the risk of bleeding and protein levels in the blood
- Abdominal ultrasound
- CT scan of the abdomen
Your doctor may also use a thin needle to withdraw ascites fluid from your belly. The fluid is tested to look for the cause of ascites and to check if the fluid is infected.
Ascites is treated with a low-sodium diet, medications called diuretics, removing the fluid, or surgery to reroute blood flow. Reducing sodium, or salt, is a first line therapy for ascites. If you have ascites, be sure to learn more from a nutritionist who specializes in the liver about your unique needs.
Medications called diuretics may be prescribed which make the kidneys excrete more sodium and water into your urine, causing you to pee more frequently.
Sometimes, diuretics are not enough, and the fluid will continue to build up. When this happens, someone may have a procedure called therapeutic paracentesis. During paracentesis, a doctor, usually an interventional radiologist, uses ultrasound to guide a needle into the abdomen and drain the fluid out of the body. The fluid will build back up and the procedure will need to be repeated.
If someone continues to have fluid build-up or other treatments do not work, a doctor may consider a TIPS procedure (transjuglar intrahepatic portosystemic shunt). During a TIPS procedure, a new pathway is made to connect the portal vein, or one of its branches, with a vein in general circulation, bypassing the liver. While this shunt placement can improve ascites, it can also cause a worsening in hepatic encephalopathy or in liver function.