Ascites

GENERAL PRINCIPLES

Ascites is the abnormal (gt;25 mL) accumulation of fluid within the peritoneal cavity. Other causes of ascites, unrelated to portal hypertension, include cancer (peritoneal carcinomatosis), heart failure, TB, myxedema, pancreatic disease, nephrotic syndrome, surgery or trauma to the lymphatic system or ureters, and serositis.

DIAGNOSIS

• Presentation ranges from ascites detected only by imaging methods to a distended, bulging, and sometimes tender abdomen. Percussion of the abdomen may reveal shifting dullness.

• SAAG is calculated as serum albumin minus the ascites albumin; a gradient #8805;1.1 indicates portal hypertension-related ascites (97% specificity).³¹ A SAAG of lt;1.1 is found in nephrotic syndrome, peritoneal carcinomatosis, serositis, TB, and biliary or pancreatic ascites.

• Ultrasonography, CT, and MRI are sensitive methods to detect ascites.

• Diagnostic paracentesis (60 mL) should be performed in the setting of new-onset ascites, suspicion of malignant ascites, or to rule out SBP. Therapeutic paracentesis (large volume) should be performed when tense ascites causes significant discomfort or respiratory compromise or when suspecting abdominal compartment syndrome.

• Routine diagnostic testing should include SAAG calculation, red and white blood cell counts and differential, total protein, and culture. Amylase and triglyceride measurement, cytology, and mycobacterial smear/culture can be performed to confirm specific diagnoses.

• Bleeding, infection, persistent ascites leak, and intestinal perforation are possible complications.

• Large-volume paracentesis (gt;5 L) may lead to circulatory collapse, encephalopathy, and renal failure. Concomitant administration of IV albumin (6-8 g/L ascites removed) can be used to mitigate the risks of paracentesis-induced circulatory dysfunction and HRS.

TREATMENT

Medications

• Diuretic therapy is initiated along with salt restriction (lt;2 g sodium or 88 mmol Na⁺#8725;d). Diuretics should be used with caution.

• Spironolactone 100 mg PO daily is a reasonable starting dose. The daily dose can be increased by 50­100 mg every 7-10 days to a maximum dose of 400 mg until satisfactory weight loss or side effects occur. Hyperkalemia and gynecomastia are common side effects. Other potassium-sparing diuretics such as amiloride, triamterene, or eplerenone are substitutes that can be used in patients in whom painful gynecomastia develops.

• Loop diuretics, such as furosemide (20-40 mg, increasing to a maximum dose of 160 mg PO daily), can be added to spironolactone. Torsemide or bumetanide may be considered in patients with unresponsiveness to furosemide.

• Patients should be observed closely for signs of dehydration, electrolyte disturbances, encephalopathy, muscle cramps, and renal insufficiency. NSAIDs may blunt the effect of diuretics and increase the risk of renal dysfunction.

Other Nonpharmacologic Therapies

• TIPS is effective in the management of recurrent or refractory ascites.

• Complications of TIPS include shunt occlusion, bleeding, infection, cardiopulmonary compromise, hepatic encephalopathy, hepatic failure, and death.