Ascites

Introduction

Ascites is a pathologic accumulation of fluid in the peritoneal cavity most often caused by cirrhosis, but other causes include malignancy, nephrotic syndrome, heart failure, malnutrition and infections such as peritoneal tuberculosis.

  • It can lead to the development of spontaneous bacterial peritonitis (SBP) and hepatorenal syndrome (HRS).
The serum-ascites albumin gradient correlates directly with portal pressures.

  • A SAAG gradient ≥ 1.1 g/dL suggests portal hypertension, most likely due to cirrhosis. Other causes include venous congestion such as from right sided heart failure.
  • A SAAG gradient < 1.1 g/dL suggests other causes of ascites such as peritoneal carcinomatosis, chronic peritoneal infection, nephrotic syndrome, pancreatic ascites, and protein-losing enteropathy.

NOTE: Treat ascites with a SAAG gradient of <1.1 g/dL by addressing the underlying aetiology as diuretics are often ineffective and may lead to volume depletion.



Management

There are many treatment approaches to managing ascites, which are chosen based on the severity.

  • A small volume of ascitic fluid detected on imaging is considered mild ascites and is generally not treated.
  • All patients with cirrhosis and ascites should be considered for liver transplantation, with expedited evaluation if there is worsening renal dysfunction or rapid liver decompensation.
Patients with symptomatic ascites (i.e. causing abdominal discomfort or distension) due to portal hypertension should

  • Restrict dietary sodium intake to <2 grams/day
    • Reducing added salt and improved awareness of high sodium content in many pre-packaged and canned foodstuffs.
  • Adequate protein and energy intake - to manage malnutrition
  • Cease alcohol intake
  • Avoid sodium retaining medications (including NSAIDs, ACE inhibitors)
  • Use diuretics to increase fluid loss
  • Fluid restriction is not indicated unless there is severe hyponatremia (serum sodium <120 mEq/L).
Diuretic therapy for ascites can be initiated with either spironolactone monotherapy or with a combination of frusemide and spironolactone.

  • When used in combination, a ratio of 100 mg spironolactone to 40 mg frusemide (up to spironolactone 400 mg/day and frusemide 160 mg/day) should be used to maintain potassium balance.
  • Consider withholding furosemide if there is hypokalaemia and decreasing dose of spironolactone if there is hyperkalaemia.
  • Consider withholding diuretics if renal insufficiency develops.

In severe cases, abdominal paracentesis is needed to directly remove ascitic fluid.

  • Large volume of paracentesis (removal of >5 L over 1-6 hours) is associated with significant fluid shifts and the addition of albumin (6-8 grams per liter of fluid removed or 50 gram total) is recommended at the time of or soon after the procedure to avoid postparacentesis complications (e.g. hypovolemia, hyponatremia, kidney impairment.



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