From the Guidelines
Ascites is most commonly caused by liver cirrhosis, with other potential causes including malignancy, heart failure, tuberculosis, and pancreatic disease. The initial evaluation of ascites should include history, physical examination, abdominal doppler ultrasound, laboratory assessment of liver and renal function, serum and urine electrolytes, and a diagnostic paracentesis for analysis of the ascitic fluid 1.
Common Causes of Ascites
- Liver cirrhosis: accounts for about 75% of cases
- Malignancy: including ovarian, pancreatic, liver, and gastric cancers
- Heart failure: right-sided heart failure leading to fluid backup in the abdomen
- Tuberculosis: a less common cause of ascites
- Pancreatic disease: including pancreatitis and pancreatic cancer
Pathophysiology of Ascites
Portal hypertension from cirrhosis leads to increased pressure in blood vessels, forcing fluid into the abdominal cavity. Additionally, low albumin levels in liver disease reduce the body's ability to keep fluid in blood vessels.
Diagnosis and Treatment of Ascites
The serum albumin ascites gradient (SAAG) is calculated by subtracting the ascitic fluid albumin from the serum albumin in simultaneously obtained samples, and can help differentiate between portal hypertension and other causes of ascites 1. Treatment of ascites depends on the underlying cause, and may include sodium restriction, diuretics like spironolactone and furosemide, and in some cases, procedures like paracentesis to remove excess fluid.
Management of Ascites
Patients with ascites should be managed with a combination of dietary sodium restriction and oral diuretics, with the goal of reducing sodium intake to less than 5 g/day 1. Regular monitoring of urinary sodium excretion and ascitic fluid analysis can help guide treatment and prevent complications. In cases of refractory ascites, alternative treatments such as transjugular intrahepatic portosystemic shunt (TIPSS) or liver transplantation may be considered 1.
From the Research
Common Causes of Ascites
The common causes of ascites can be classified into several categories, including:
- Cirrhosis, which is the most frequent cause of ascites 2, 3, 4, 5
- Portal hypertension, which is responsible for the increase in hydrostatic pressure at the sinusoidal level and the alterations of splanchnic and systemic haemodynamics 3, 4
- Severe blood dyscrasia and peritoneal disease 3
- Renal sodium retention as a result of increased activity of the renin-angiotensin-aldosterone system in response to marked vasodilation of the splanchnic circulation 2
Pathophysiology of Ascites
The pathophysiology of ascites is multifactorial, involving:
- Severe sinusoidal portal hypertension and hepatic insufficiency 4
- Arterial vasodilation, arterial hypotension, high cardiac output, and hypervolemia 4
- Renal sodium and water retention 4
- Lymph leakage from the liver and other splanchnic organs 4
Diagnosis and Treatment of Ascites
The diagnosis and treatment of ascites involve:
- Assessment of the cause of ascites by determining the serum-ascites albumin gradient and the exclusion of complications 6
- Sodium restriction and diuretics as the cornerstone of ascites management 6, 5
- Repeated large-volume paracentesis and transjugular intrahepatic portosystemic shunts for refractory ascites 2, 6, 4, 5
- Liver transplantation as the only modality associated with improved survival 5