Ascites is an abnormal accumulation of fluid in the abdomen.In medicine (gastroenterology), ascites is an accumulation of fluid in the peritoneal cavity. Although most commonly due to cirrhosis and severe liver disease, its presence can portend other significant medical problems. Typically described in terms of transudate (low protein concentration) and exudate (high protein), the serum-ascites albumin gradient (SAAG) is probably a better discriminate.
In Ayurveda, there have a similar condition to ascites named Udara.
Synonyms and related keywords
Fluid collection, fluid accumulation, fluid retention, distended abdomen, portal hypertension, hypoalbuminemia, hepatic congestion, congestive heart failure, constrictive pericarditis, tricuspid insufficiency, Budd-Chiari syndrome, liver disease, cirrhosis, alcoholic hepatitis, fulminant hepatic failure, massive hepatic metastases, nephrotic syndrome, protein-losing enteropathy, severe malnutrition, anasarca, chylous ascites, pancreatic ascites, bile ascites, nephrogenic ascites, urine ascites, ovarian disease, bacterial peritonitis, tuberculous peritonitis, fungal peritonitis, HIV-associated peritonitis, malignancy, peritoneal carcinomatosis, primary mesothelioma, pseudomyxoma peritonei, hepatocellular carcinoma, HCC, familial Mediterranean fever, vasculitis, granulomatous peritonitis, eosinophilic peritonitis, alcohol use, chronic viral hepatitis, jaundice, intravenous drug use, blood transfusions, alcoholic liver disease, obesity, hypercholesterolemia, type 2 diabetes mellitus, nonalcoholic steatohepatitis, gastrointestinal cancer, malignant ascites, cirrhotic ascites, nephrotic ascites, palmar erythema, spider angiomas, puddle sign, Sister Mary Joseph nodule, gastric malignancy, pancreatic malignancy, hepatic primary malignancy, left-sided supraclavicular node, Virchow node, anasarca
The word ascites is of Greek origin (askos) and means bag or sac. Ascites describes the condition of pathologic fluid accumulation within the abdominal cavity. Healthy men have little or no intraperitoneal fluid, but women may normally have as much as 20 mL depending on the phase of the menstrual cycle. This article focuses only on ascites associated with cirrhosis.
The accumulation of ascitic fluid represents a state of total-body sodium and water excess, but the event that initiates the unbalance is unclear. Three theories of ascites formation have been proposed.
The underfilling theory suggests that the primary abnormality is inappropriate sequestration of fluid within the splanchnic vascular bed due to portal hypertension and a consequent decrease in effective circulating blood volume. This activates the plasma renin, aldosterone, and sympathetic nervous system, resulting in renal sodium and water retention.
The overflow theory suggests that the primary abnormality is inappropriate renal retention of sodium and water in the absence of volume depletion. This theory was developed in accordance with the observation that patients with cirrhosis have intravascular hypervolemia rather than hypovolemia.
The most recent theory, the peripheral arterial vasodilation hypothesis, includes components of both of the other theories. It suggests that portal hypertension leads to vasodilation, which causes decreased effective arterial blood volume. As the natural history of the disease progresses, neurohumoral excitation increases, more renal sodium is retained, and plasma volume expands. This leads to overflow of fluid into the peritoneal cavity. According to the vasodilation theory, the underfilling theory is proposed to be operative early and the overflow theory is proposed to be operative late in the natural history of cirrhosis.
Although the sequence of events that occurs between the development of portal hypertension and renal sodium retention is not entirely clear, portal hypertension apparently leads to an increase in nitric oxide levels. Nitric oxide mediates splanchnic and peripheral vasodilation. Patients with ascites have greater hepatic artery nitric oxide synthase activity compared to patients without ascites.