Author: sids_82, Posted on Sunday, March 12 @ 11:08:06 IST by RxPG  

  Add to My Pages    Printer Friendly    Email Story   Download Story  Gastroenterology alerts 

Ever wondered what the hell is SAAG and what is the implication? What is a transudate and what is an exudate? This is an attempt to clarify some fundas of Ascites and it's differentials.

Ascites implies collection of fluid within the peritoneal cavity.

Atleast 1000 ml should be present to be detectable by Percussion.

USG Abdomen can detect as less as 100 ml!!

WHAT IS SAAG?

Serum : Ascites Albumin Gradient is a highly specific indicator of the cause of Ascites.

It is a ratio of Albumin in Serum : Albumin in Ascitic Fluid.

So what, you ask me?

A low SAAG would mean that Albumin is HIGHER IN ASCITIC FLUID than in serum. And poof! You jump to the conclusion that a Low SAAG indicates Exudate and vice - versa.

STOP

THIS IS NOT SO!!

A LOW SAAG ( 95% cases.

Conversely, a HIGH SAAG ( > 1.1 ) only implies that in > 95% cases, ASCITES IS DUE TO PORTAL HYPERTENSION!!

CONFUSED?? Ok. Just dont try to equate SAAG with exudate and transudate, just accept it on it's face value i.e. :-

SAAG 1.1 = Portal HTN.

Now let us proceed with this in mind.

STEP # 1 PARACENTESIS

Is a must in ALL CASES OF ASCITES.
50- 100 ml of fluid is withdrawn.

STEP # 2 ESTIMATE SAAG

STEP # 3

a) HIGH SAAG i.e. > 1.1
Implies Portal HTN, the causes being :-

RIGHT SIDED HEART FAILURE

- Proteins = 15-53 g/L (i.e either transudate/ exudate)

- Confirm Diag by ECHO/ CARDIAC CATH

CIRRHOSIS

- Transudate ( 1000/ microliter

Confirmed by = DIAGNOSTIC LAPAROSCOPY & BIOPSY

TUBERCULAR PERITONITS

- Hemorrhagic/ Straw colored/ Chlyous Fluid
+
- Exudate
+
-Predominant Lymhocytes, WBCs > 1000/microliter

Confirmed by Peritoneal Biopsy and Culture

PANCREATIC ASCITES

-Mostly Exudative
+
- Presence of Amylase in Ascitic Fluid

Confirmed by ERCP / CT Scan

NEPHROTIC SYNDROME

- TRANSUDATE is seen.

Confirmed by DERANGED RFTs

So, in a nutshell, SAAG SHOULD NOT BE INTERPRETED AS TRANSUDATE / EXUDATE.

- The only cause of HIGH SAAG WITH EXUDATIVE FLUID - RIGHT SIDED HEART FAILURE.

- The only cause of LOW SAAG WITH TRANSUDATIVE FLUID - NEPHROTIC SYNDROME.

Hope this article helped in clearing your fundas!!