Ascites and SBP

What is ascites?

abnormal accumulation of ascitic fluid in the abdomen/peritoneal cavity

What are causes of transudative ascites SAAG >11 g/l? (increased hydrostatic pressure forces fluid into extracellular spaces-these are protein using states)

this indicates portal hypertension:

cirrhosis/liver pathology

cardiac failure/cardiac pathology

nephrotic syndrome

What are causes of exudative ascites SAAG <11g/l? (leaky capillaries that allow protein through)

malignancy

pancreatitis

TB

What is SAAG?

serum ascites albumin gradient

What are the two causes of ascites?

• things that increase portal hypertension

• peritoneal pathologies

What are risk factors for ascites?

liver cirrhosis

portal hypertension

malignancy

infection

heart/kidney failure

high salt/low protein intake

How does ascites present?

abdominal distension

discomfort

nausea

vomiting

dyspnoea

anorexia and early satiety

shifting dullness

chronic ascites can cause weight loss as it increases base metabolism (as have to keep litres of fluid at body temp)

What are differentials for ascites presentation?

• cirrhosis

• heart failure

• peritoneal cancer

• TB

• nephrotic syndrome

• pancreatitis

What investigations should be done for ascites?

• FBC, U&Es, LFTs, PT, serum albumin

• Ascitic tap

• US- to assess echotexture of the liver and portal vein patency

• CXR- features of cardiac congestion

• CT- to assess for malignancy

What can be identified from an ascitic tap?

• ascites fluid albumin to calculate SAAG score which gives indication to cause

• ascitic fluid neutrophil count to screen for SBP

• ascotic fluid amylase- to diagnose pancreatitis ascites

What ascitic fluid neutrophil count is diagnostic of SBP?

>250 cells/mm³

How is ascites managed?

1. identify and treat cause

2. dietary salt restriction/fluid restriction

3. spironolactone (aldosterone antagonist)

4. add furosemide if spironolactone alone is unsuccessful

5. prophylactic antibiotics

6. therapeutic paracentesis if large and symptomatic and medical management unsuccessful (drain dependent ascites has bad prognosis)

7. trans jugular intrahepatic portosystemic shunt

What is the epidemiology of ascites?

1/3rd of people with liver cirrhosis who develop ascites can be due to SBP so important to check

most common cause (75%) is due to cirrhosis and the other from malignancy

Which patients with ascites should get prophylactic antibiotics?

offer prophylactic ciprofloxacin for people with cirrhosis and ascites with an ascitic protein of 15g/l or less until ascites has resolved

What is paracentesis induced circulatory dysfunction?

occurs when drainage of a large ascitic volume >5 litres

associated with recurrence, hepatorenal syndrome, dilutional hyponatraemia, mortality

therefore paracentesis of a large volume requires albumin cover to reduce this

How much ascitic fluid is there to be discernible by clinical exam?

approximately 1500ml to be detected by exam

therefore mild ascites may only be detected by US

What can the colour of ascitic fluid indicate?

• cirrhosis=clear

• turbid = infection

• milky= chylous

• bloody= malignancy/trauma

What is spontaneous bacterial peritonitis?

an infection of ascitic fluid in the absence of an intra-abdominal or surgically treatable cause

usually secondary to liver cirrhosis

What are causes of SBP?

results from haematogenous spread of bacteria into ascitic fluid.

commonly E.coli/klebsiella pneumoniae

What are risk factors for SBP?

liver cirrhosis

infection

endoscopy

GI bleed

previous paracentesis

How can SBP present?

can be asymptomatic so may not present as an infection

abdominal distension- ascites

fever

abdominal pain

nausea

encephalopathy

What investigations should be done for suspected SBP?

• paracentesis- neutrophil count >250 is diagnostic, cultures, sensitivity

• bloods: WCC, CRP, U&Es (hepatorenal syndrome), clotting factors, LFTs

How is SBP managed?

1. IV antibiotics eg: IV cefotaxime or IV piperacillin-tazobactam

2. treat associated disease

3. albumin may be indicated for patients with renal disease

4. prophylactic antibiotics long term

When are prophylactic antibiotics given for SBP?

• patients who have had an episode of SBP

• patients with fluid protein <15g/l and Child-Pugh score of 9 or hepatorenal syndrome