Causes of Abdominal Water Retention

Mild, temporary water retention in the hands or feet often occurs in hot weather or after overindulging in salty foods. While this type of water retention is usually harmless, fluid accumulation in the abdomen signals a health problem that requires medical evaluation. Water retention in the abdomen -- known medically as ascites -- most commonly occurs due to liver disease. Other possible causes include cancer, cardiovascular disease, kidney failure and infection.

Cirrhosis describes severe scarring of the liver that distorts its normal structure and can eventually lead to liver failure. Advanced cirrhosis is the most common cause of ascites, accounting for roughly 75 to 80 percent of cases. Cirrhosis impairs blood flow through the liver. This results in increased pressure in the blood vessels of the abdomen that flow into the liver, a condition called portal hypertension (PHT). PTH triggers a series of events that culminate in sodium and water retention, frequently leading to ascites over time. Cirrhosis occurs for many reasons. Chronic viral hepatitis and longstanding alcohol abuse are the leading medical conditions that result in cirrhosis among Americans, although other liver diseases can also cause the condition.

Approximately 15 percent of people with ascites have cancer, the second most common cause of the condition. Cancer of the liver, ovary, colon, pancreas, stomach, esophagus or gallbladder is often to blame. However, other types of cancer that have spread to the abdomen can also lead to ascites, including melanoma and cancer of the lung or breast. Cancer-related ascites is known as malignant ascites and typically signals advanced disease.

The liver receives a high volume of blood flow, roughly 1 quart per minute. The large volume of blood that passes through the liver is returned to the right side of the heart. Conditions that impede blood flow from the liver to the heart or through the right heart can lead to PHT and ascites. Examples include: -- severe weakness and impairment of the right heart, known as right-sided heart failure -- a clot or other obstruction in blood vessels between the liver and right heart -- a damaged or defective tricuspid valve, which lies between the chambers of the right heart -- scarring of the sac surrounding the heart due to longstanding inflammation, known as constrictive pericarditis

Although rare compared to cirrhosis, cancer and cardiovascular causes, other medical conditions can lead to ascites. Sudden, severe liver injury due to drug toxicity or acute hepatitis, for example, can cause ascites along with other symptoms of liver failure. Severe kidney failure is another possibility. Certain infections, severe protein malnutrition and digestive system illnesses that lead to loss of protein through the bowels are also considerations, along with other serious medical conditions.

Sudden or unexplained swelling of the abdomen requires medical evaluation to determine the cause -- which may or may not be due to ascites. However, because the medical problems that lead to ascites are serious, it's important not to ignore unexplained abdominal distention. Seek emergency medical care if you experience abdominal distention with one or more warning signs, including: -- sudden, severe or worsening abdominal pain -- dizziness, lightheadedness or fainting -- bloody or black stools -- persistent vomiting, or vomiting blood or material that resembles coffee grounds -- confusion, agitation, mental fogginess or excessive drowsiness -- yellow discoloration of the skin or whites of the eyes -- fever

Reviewed and revised by: Tina M. St. John, M.D.