Ascites

Definition

  1. Excessive free fluid in the peritoneal cavity. >1.5L before clinically apparent.

Physiology

Starling forces

  1. ↑venous pressure, ↑capillary permeability, hypoproteinaemia, lymphatic obstruction

Causes

  1. Liver cirrhosis (75%)
  2. Malignancy (15%)
    1. Ca colon, other GI
    2. Ca ovary(Meigs’ syndrome)
    3. Hepatic tumour
    4. Lymphoma
    5. Peritoneal mesothelioma
  3. CCF (3%)
  4. TB (2%)
  5. Pancreatitis (1%)
  6. Constrictive pericarditis
  7. Venous obstruction – e.g. Budd-Chiari
  8. Renal failure
  9. Myxoedema

Examination

  1. Ascites:
    1. Abdominal distension umbilicus down
    2. Shifting dullness to percussion
    3. Fluid thrill
  2. Look also for possible causes:
    1. Stigmata of chronic liver disease
    2. HSM
    3. Other masses: Ca colon/ovary, PR exam
    4. Lymphadenopathy
    5. Kussmaul’s sign for constrictive pericarditis
    6. Signs of CCF, hepatojugular reflex
    7. Signs of IBD
    8. Kayser-Fleischer Rings (Wilson’s)
    9. Jaundice
    10. Proteinuria

Investigations

Bloods

  1. FBC, LFT, UEC, Coags, TFT, Hepatitis screen

Imaging

  1. USS, CT, CXR

Paracentesis/Ascitic tap

Types

  1. Diagnostic – exudate vs transudate, ?infection, cancer, etc.
  2. Therapeutic or palliative – ↑comfort, ↓nausea, ↑pulmonary fn, ↓effect on venous return

Procedure

  1. Pre-procedure: FBC, coags ideallydone, but studies show no instances of sig bleeding even if plts<50 & INR>1.5.
  2. Preparation – equipment, explain to patient
  3. Aseptic technique
  4. Choose site: either lower flank (lateral to inf. Epigastric vessels ~15cm from midline) or in midline 2cm below umbilicus (but beware bladder).
  5. Skin prep & LA
  6. Pull skin caudally or use Z track technique & insert needle (18–22G needle or cannula).
  7. When popped through peritoneum, aspirate should be straw coloured typically.
  8. Withdraw 20–60ml for diagnostic tap or connect to a bag and allow as much as possible to drain over 4–6 hrs for therapeutic tap. Give 100ml albumin for every 1L over 3L drained.
  9. Albumin infusion not normally advised for palliative (Ca) paracentesis but is for cirrhosis as [>3L tap risks hepato-renal syndrome and post-paracentesis circulatory dysfn (PPCD)].
  10. Spironolactone after paracentesis may ↓ repeat rate from >90% to <20% in cirrhosis.

Complications

  1. All <2%. Serious Cx as haemoperitoneum and bowel perforation <0.1%

Analysis

  1. Protein & LDH – for exudate vs transudate. The serum ascites-albumin gradient (SA-AG) is superior: SA-AG = (serum albumin concentration) – (ascitic albumin concentration) where SA-AG <11g/l = Ca, pancreatitis and TB; ≥11g/l = cirrhosis, CCF, nephrotic syn
  2. WCC (for SBP: WCC>500 cells, PMN>250 cells, pH<7.35& blood-ascites pH grad>0.1) , RBC (↑in hepatocellular Ca, some cirrhotics), amylase (↑in pancreatic)
  3. Culture (in blood culture bottles)
  4. Cytology

Management

Non-drug Management

  1. Avoidance of alcohol is important in pancreatitis and cirrhosis
  2. A no added salt diet, restricted to <90 mmol/day (5.2 g of salt/day) useful in cirrhosis

Drugs

  1. Diuretics:
    1. Spironolactone: ↑sodium excretion and potassium reabsorption in the distal tubules. Initially 100mg/day gradually increased to 400mg as necessary. Monitor K levels Amiloride can be used but it is generally less effective.
    2. Loop diuretics, e.g. frusemide added when max doses of the spironolactone reached. Start with 40mg/day although up to 160mg/day may be used – watch electrolytes.
    3. If the underlying problem is CCF then treatment aggressively with usual Rx.
  2. Malignancy may respond to appropriate chemotherapy, depending upon the type.
  3. Myxoedema will resolve with gradual introduction of thyroxine.

Therapeutic Paracentesis

Surgical

  1. For malignancy and some patients may be suitable for liver transplantation.
  2. Options: Transjugular intrahepatic portosystemic shunt (TIPS), portocaval shunt, peritoneovenous shunt.
  3. Risks may incl blockage, encephalopathy, increased mortality.

Complications

  1. Hyponatraemia on diuretics
  2. Only fluid restrict patients who are not dehydrated and not taking diuretics whose creatinine is normal.
  3. Spontaneous Bacterial Peritonitis (SBP)
  4. Incidence: 10–30% of patients with ascites and has mortality rate of 20%.
  5. Organism is usually E. coli, streptococci and enterococci.

Prognosis

  1. Ascites is a major Cx of cirrhosis, occurring in 50% of patients over 10 years of f/u and associated with a 50% mortality over two years, and warrants consideration of liver Tx.
  2. In malignancy it tends to suggest widespread disease and a poor prognosis.
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