Ascitic Fluid

OVERVIEW

  • classified according to serum-ascites albumin gradient (SAAG)

CAUSES

High SAAG (“transudate”)

  • cirrhosis, hepatic failure, hepatic venous occlusion, constrictive pericarditis, kwashiorkor, cardiac failure, alcoholic hepatitis, liver metastasis

Low SSAG (“exudate”)

  • malignancy, infection (bacterial, fungal, Tb), pancreatitis, nephrotic syndrome, bowel obstruction or infarction, bile leak

Rare

  • vasculitis, hypothyroidism

INDICATIONS

  • ICU (to rule out infection)
  • PUO
  • suspected malignancy

-> if sudden onset: order U/S to check patency of hepatic veins and portal system

ASCITIC FLUID

Things to put on the Lab Form:

  • albumin
  • LDH
  • glucose
  • amylase
  • pH
  • triglycerides
  • WCC
  • gram stain and culture (put some fluid into blood culture bottles)
  • cell count and differential
  • cytology

Serum:Ascitic Albumin Gradient (SAAG) = serum albumin – ascitic fluid albumin

  • > 11g/L = high SAAG = transudate
  • < 11g/L = low SAAG = exudate

Cell count and differential

  • > 250 neutrophils/mm3 = spontaneous bacterial peritonitis
  • > 250 WCC = spontaneous bacterial peritonitis
  • polymorphonuclear cells – bacterial
  • mononuclear cells – Tb or fungal

Gram stain and culture

  • monomicrobial = SBP
  • polymicrobial = secondary bacterial peritonitis -> search for perforated viscus

LDH

  • < 225U/L = transudate
  • > 225U/L = exudate

Glucose

  • normal in SBP
  • low in secondary bacterial peritonitis

Amylase

  • increased in pancreatic ascites

pH

  • < 7.0 suggests bacterial infection

Triglyceride

  • increased in chylous ascites

Cytology

  • malignant cells

MANAGEMENT

  • treat cause
  • drain for symptomatic relief
  • if draining > 5L -> give infusion of albumin (prevents circulatory dysfunction)
  • SBP: antibiotics + albumin infusion (1.5g/kg)
  • cirrhosis: frusemide, spironolactone, Na+ restriction, TIPS procedure
  • if no obvious cause found -> laparoscopy to find out whether malignant or infectious

References and Links


CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the  Clinician Educator Incubator programme, and a CICM First Part Examiner.

He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.

His one great achievement is being the father of three amazing children.

On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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