How to diagnose and manage ascites?

From the Guidelines

Diagnosing and managing ascites requires a systematic approach, starting with a thorough clinical evaluation, including 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, as recommended by the American Association for the Study of Liver Diseases in 2021 1.

Initial Evaluation

The initial evaluation of ascites should consider various potential causes, including cirrhosis, malignancy, heart failure, tuberculosis, and pancreatic disease.

• History and physical examination are crucial to identify signs of portal hypertension and other underlying conditions.
• Abdominal Doppler ultrasound helps confirm the presence of fluid and assess liver morphology.
• Laboratory tests, including liver and renal function, serum and urine electrolytes, are essential for a comprehensive evaluation.

Diagnostic Paracentesis

Diagnostic paracentesis is essential in all patients investigated for ascites, prior to any therapy, to exclude causes of ascites other than cirrhosis and rule out spontaneous bacterial peritonitis (SBP) in cirrhosis, as emphasized in the 2021 practice guidance by the American Association for the Study of Liver Diseases 1.

• Collecting 30-50 mL of fluid for analysis of cell count, albumin, protein, culture, and cytology.
• The serum-ascites albumin gradient (SAAG) helps determine if ascites is portal hypertension-related (≥1.1 g/dL) or not, with a high accuracy of approximately 97% 1.

Management

Management of ascites focuses on treating the underlying cause while providing symptomatic relief, with moderate sodium restriction and diuretics being the first-line treatment for patients with cirrhosis and grade 2 ascites, as recommended in the 2021 guidance 1.

• Sodium restriction (2 g or 90 mmol/day) and diuretics (spironolactone with or without furosemide) are the cornerstone of treatment.
• Large-volume paracentesis (4-6 liters) with albumin replacement (6-8 g/L of fluid removed) is indicated for tense, uncomfortable ascites.
• For refractory cases, consider transjugular intrahepatic portosystemic shunt (TIPS) or serial paracenteses, and spontaneous bacterial peritonitis prophylaxis with norfloxacin 400 mg daily or trimethoprim-sulfamethoxazole for high-risk patients, as suggested by the evidence 1.

From the FDA Drug Label

By competing with aldosterone for receptor sites, Spironolactone provides effective therapy for the edema and ascites in those conditions.

To diagnose and manage ascites, investigation and treatment should be considered:

• Diagnosis: The FDA drug label does not provide specific guidance on how to investigate ascites.
• Management: Spironolactone can be used to provide effective therapy for ascites by competing with aldosterone for receptor sites 2. However, the FDA drug label does not answer the question of how to investigate ascites.

From the Research

Diagnosis of Ascites

• The diagnosis of ascites involves a combination of clinical evaluation, laboratory investigations, and diagnostic paracentesis 3, 4, 5.
• The serum-ascites albumin gradient is a useful parameter in differentiating between portal hypertension-related and non-related causes of ascites, with a diagnostic accuracy of > or = 97% 3, 6.
• Ascitic fluid analysis, including cell count, albumin, and lactic dehydrogenase levels, can help determine the cause of ascites and rule out complications such as spontaneous bacterial peritonitis 3, 4, 5, 6.

Management of Ascites

• The management of ascites depends on the underlying cause and may involve sodium restriction, diuretics, and repeated large-volume paracentesis 4, 5, 7.
• Transjugular intrahepatic portosystemic shunts (TIPS) may be considered in patients who are refractory to medical treatment 4, 7.
• Peritoneovenous shunting may be an option for intractable ascites, although it is associated with significant complications and mortality 5.
• Targeted therapies, such as diuretics and lymphangiography, may be used in specific cases, and societal guidelines exist for the management of cirrhotic ascites 7.

Diagnostic Tools

• Ultrasonography may be used to confirm the presence of ascites, especially in questionable cases 5.
• Paracentesis is a useful diagnostic tool for determining the etiology of ascites and ruling out complications such as spontaneous bacterial peritonitis 3, 4, 5.
• The serum-ascites albumin gradient is a primary diagnostic test for differentiating among causes of ascites, and additional fluid tests may be performed based on clinical suspicion 7.