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
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