Summary

Ascites is defined as a pathological collection of fluid in the peritoneal cavity. The most common cause is cirrhosis, accounting for approximately 75% to 80% of cases. [1] [2] Other causes include malignancy (10%), heart failure (3%), tuberculosis (2%), pancreatitis (1%), and other rare conditions. [2]

Clinical features

Patients present with abdominal distension; fluid may be detected on physical examination with shifting dullness. Ultrasound or CT scan can confirm the diagnosis. In the majority of patients the history and examination will provide important clues as to the aetiology of ascites (e.g., signs of chronic liver disease or cardiac failure). Causes include diseases that lead to portal hypertension or hypoalbuminemia, and neoplasms.

Cirrhosis

In cirrhosis, ascites forms due to renal dysfunction and abnormalities in portal and splanchnic circulation. Sodium retention is a major factor in pathogenesis. [3] Splanchnic arterial vasodilatation (secondary to hepatic fibrosis) leads to increased lymph formation, activation of the renin angiotension system and sympathetic nervous system, and release of antidiuretic hormone. This causes renal sodium and water retention. There is increased resistance to portal flow resulting in portal hypertension, collateral vein formation and shunting of blood to the systemic circulation. [4] About 50% of patients with cirrhosis develop ascites within 10 years. [3]

Other causes

Causes of portal hypertension other than cirrhosis include congestive heart failure, constrictive pericarditis, alcoholic hepatitis, fulminant hepatitis, subacute hepatitis, massive liver metastasis, and Budd-Chiari syndrome, which may be associated with ascites. Conditions causing hypo-albuminaemia such as nephrotic syndrome and protein-losing enteropathy may result in ascites. Peritoneal diseases including infectious peritonitis and malignancies can also cause ascites.