Ascites

Aetiopathogenesis:

Ascites is the presence of fluid within the peritoneal cavity and is a common complication of cirrhosis. There are several factors involved in the formation of ascites:

Sodium and water retention:

Occur as a result of peripheral arterial vasodilatation and consequent reduction in blood volume

Portal hypertension:

Exerts a local hydrostatic pressure and leads to increased hepatic and splanchnic production of lymph and transudation of fluid into the peritoneal cavity

Low serum albumin:

Is a consequence of poor synthetic liver function

May further contribute by a reduction in plasma oncotic pressure

Clinical features:

The abdominal swelling may accumulate over many weeks or as rapidly as a few days

Precipitating factors include:

High sodium diet

Development of a HCC

Mild, generalised abdominal pain and discomfort

Respiratory distress may accompany tense ascites

The presence of fluid is confirmed by the demonstration of shifting dullness and a fluid thrill

Investigations:

Cell count:

A neutrophil count > 250 cells/mm³ is indicative of an underlying (usually spontaneous) bacterial peritonitis

Gram stain and culture

Protein

Cytology:

For malignant cells

Amylase:

To exclude pancreatic ascites

Management:

Diuretic therapy:

The aim is to both reduce sodium intake and to increase renal excretion of sodium and by doing so, produce a net reabsorption of fluid from the ascites back into the circulating volume.

The maximum rate at which ascites can be mobilised is 500-700ml/24 hours

The diuretic of choice is spironolactone 200mg daily. Chronic administration of spironolactone results in Gynaecomastia, so amiloride 10-15mg daily is then substituted

Ascites

Paracentesis:

This is used to relieve symptomatic tense ascites

It is also used as a means of rapid therapy in pts with ascites and peripheral oedema, thus avoiding a prolonged hospital stay

The main danger of this approach is the production of hypovolaemia as the ascites reaccumulates at the expense of the circulating volume

This can be somewhat overcome by the administration of albumin or a plasma expander

In practice, up to 20L can be removed over 4-6 hours

This procedure should not be performed in end-stage cirrhosis or if the pt has renal failure