From the Guidelines
Ascites, the abnormal accumulation of fluid in the abdominal cavity, is primarily caused by liver cirrhosis, which accounts for about 80% of cases, as stated in the most recent guidelines 1.
Causes of Ascites
The causes of ascites can be categorized into several main groups:
- Liver cirrhosis: This is the most common cause of ascites, responsible for about 80% of cases, due to increased pressure in the portal vein (portal hypertension) combined with decreased albumin production leading to fluid leakage into the abdomen 1.
- Heart failure: The failing heart cannot effectively pump blood, leading to increased pressure in veins and fluid accumulation.
- Cancer: Particularly ovarian, pancreatic, liver, and colorectal cancers, can cause ascites through various mechanisms including lymphatic obstruction and increased fluid production.
- Kidney disease: Especially nephrotic syndrome, contributes to ascites by reducing protein levels in the blood.
- Other causes: Include tuberculosis, pancreatitis, and protein-losing enteropathy.
- Severe malnutrition: Can lead to hypoalbuminemia (low albumin levels), reducing the blood's ability to hold fluid within vessels.
- Certain medications: May also cause ascites as a side effect.
Diagnosis and Treatment
Diagnosis of ascites involves history, physical examination, abdominal ultrasound, and laboratory assessment of liver function, renal function, serum and urine electrolytes, as well as an analysis of the ascitic fluid 1. Treatment depends on addressing the underlying cause, often including diuretics like spironolactone and furosemide for symptom management, along with sodium restriction to about 2000 mg daily to reduce fluid retention 1. The initial treatment for patients with ascites involves taking medication, commonly known as 'water tablets' (diuretics), and restricting salt intake to less than 5g per day, as recommended in the latest guidelines 1.
From the Research
Causes of Ascites
The accumulation of fluid in the abdomen, also known as ascites, can be caused by various factors. Some of the main causes include:
- Cirrhosis, which is the most common cause of ascites, accounting for almost 85% of all cases 2
- Fluid retention due to increased renal sodium retention as a result of increased activity of the renin-angiotensin-aldosterone system in response to marked vasodilation of the splanchnic circulation 3
- Peripheral arterial vasodilation leading to underfilling of circulatory volume, triggering the baroreceptor-mediated activation of renin-angiotensin-aldosterone system, sympathetic nervous system and nonosmotic release of vasopressin to restore circulatory integrity 4
- Gastrointestinal malignancy, such as adenocarcinomas of the ovary, breast, colon, stomach and pancreas, which can cause ascites through peritoneal carcinomatosis, malignant obstruction of draining lymphatics, portal vein thrombosis, and other mechanisms 5
Other Possible Causes
Other possible causes of ascites include:
- Congestive heart failure
- Constrictive pericarditis
- Nephrotic syndrome
- Peritoneal infections
- Portal vein thrombosis
- Elevated portal venous pressure from cirrhosis
Key Findings
Key findings from the studies include:
- The development of ascites is a prognostic sign with 1-year and 5-year survival of 85% and 56%, respectively 4
- The management of ascites involves the proper evaluation of a patient with a thorough history and physical exam, complete laboratory, ascitic fluid, and radiological tests 3
- Treatment options for ascites include sodium-restricted diet, diuretics, paracentesis, transjugular intrahepatic portosystemic shunt (TIPS), and liver transplantation 2, 4, 3, 6