Ascites - diagnosis, differential diagnosis, treatment
Ascites is a product of increased portal pressure (>12 mm Hg). The cirrhotic process sees the stenosis of sinusoids in the liver, increasing pressure in the portal and splanchnic veins. This causes the accumulation of intraperitoneal fluid, termed ascites.
Axial CT of the upper abdomen showing a shrunken, nodular cirrhotic liver surrounded by dark (low-density) ascitic fluid, marked by the arrow.
Image: “CirrhosisWithAscitesMark” by James Heilman, MD, CC BY-SA 4.0, via Wikimedia Commons.
The presence of ascites determines whether liver cirrhosis is compensated (no ascites) or decompensated (ascites). This is important when considering prognoses, decompensated cirrhosis has a median survival of 1.6 years, while compensated has a survival of >12.
Ascites is often described by the patient as a tightness around the waist, often considered as increased weight gain. When in moderate or large amounts, can be identified on examination by bulging flanks, flank dullness and shifting dullness. Diagnostic can be with ultrasound with doppler, diagnostic paracentesis (done in all patients) and urine analysis.
Cirrhosis is not the only condition to cause ascites, other conditions are:
- Budd-Chiari syndrome
- Very rare (1 in a million) caused by occlusion of hepatic veins by any method
- Right sided heart failure
- Increased inferior vena cava pressure, causes increased sinusoidal pressure causes increased portal pressure
- Nephrotic syndrome
- Changes protein osmolality of blood, causes extravasculation of fluid
In 25% of patients with cirrhosis and ascites, hyponatremia (sodium below 130 mEq/L) is present. While not commonly symptomatic, it is an indicator for severity of cirrhosis and typically is associated with poorer quality of life and development of hepatic encephalopathy.
Treatment
Treatment of ascites should be salt restriction and diuretics. Spironolactone is the most effective of the diuretics, start with 100 mg/day (once in the morning). Adjust up to a maximal dose of 400 mg/day. Furosemide can also be given in addition if ascites is tense, if weight loss is inadequate or hyperkalemia develops (40-160 mg/day).
In patients where diuretics do not have desired effect, consider high volume paracentesis.