The document discusses ascites, its diagnosis, causes, and classification, with emphasis on the role of imaging tests and paracentesis in identifying fluid presence and its etiology. It outlines the grading system for ascites and the significance of laboratory tests performed on ascitic fluid, such as cell count, albumin gradient, and cultures. Additionally, the document highlights the differentiation between infections and other conditions causing ascites, including specific tests for tuberculosis peritonitis.
Ascitic Fluid
What doyou do
Muhammad Asim Rana
MBBS, MRCP, MRCPS, FCCP, EDIC, SF-CCM
Critical Care Medicine
King Saud Medical City
2.
Ascites
• Diagnosis:
• establishedwith a combination of a physical
examination & an imaging test (USG).
• Approx 1500 mL of fluid had to be present for
flank dullness to be detected
• lesser degrees of ascites can be missed.
• Ultrasonography can be helpful when the physical
examination is not definitive
3.
Causes of Ascites
•Ascites can be classified based on the underlying
pathophysiology:
• Portal hypertension
– Cirrhosis
– Alcoholic hepatitis
– Acute liver
– Hepatic veno-occlusive disease (eg, Budd-Chiari syndrome)
– Heart failure
– Constrictive pericarditis
– Hemodialysis-associated ascites (nephrogenic ascites)
International Ascites Club
Gradingsystem
• Grade 1
– Mild ascites detectable only by ultrasound
examination
• Grade 2
– Moderate ascites manifested by moderate
symmetrical distension of the abdomen
• Grade 3
– Large or gross ascites with marked abdominal
distension
8.
Older system grades
•However, the validity of the grading system
has not yet been established. In particular, the
natural history of "grade 1" ascites is unclear.
Grades ascites from 1+ to 4+ is also used.
– 1+ is minimal and barely detectable,
– 2+ is moderate
– 3+ is massive but not tense
– 4+ is massive and tense
9.
Abdominal Paracentesis
• Mostefficient way to confirm the presence of
ascites, diagnose its cause, and determine if the
fluid is infected.
• Safe procedure, with an extremely low incidence of
serious complications despite the coagulopathy that is
usually present in patients with cirrhosis.
• Coagulation parameters beyond which
paracentesis should be avoided.
• There are no data-supported however, patients with
clinically evident fibrinolysis or disseminated
intravascular coagulation should not undergo
paracentesis.
10.
Tests performed onascitic fluid
• Routine tests
• Cell count and differential
• Albumin concentration
• Total protein concentration
• Culture in blood culture
bottles
• Optional tests
• Glucose concentration
• LDH concentration
• Gram stain
• Amylase concentration
•Other tests
•Tuberculosis smear and culture
•Cytology
•Triglyceride concentration
•Bilirubin concentration
11.
Asitic Fluid Appearance
Appearanceinterpretation
Clear Uncomplicated ascites in the setting of cirrhosis is usually translucent
yellow
Turbid or cloudy Spontaneously infected
Milky
"chylous
ascites"
Milky fluid usually has a triglyceride concentration greater than serum
and greater than 200 mg/dL (2.26 mmol/L) and often greater than 1000
mg/dL (11.3 mmol/L).
Cirrhosis ,abdominal malignancy & lymphatic abnormalities.
Pink or bloody
(RBC of
>10,000/mm3)
"traumatic tap“, or malignancy
Brown Deeply jaundiced patients have brown ascitic fluid with a bilirubin
concentration approximately 40 percent of the serum value.
If the ascitic fluid is as brown as molasses and the bilirubin concentration
is greater than the serum value, the patient probably has a ruptured
gallbladder or perforated duodenal ulcer
12.
Cell count anddifferential
• The cell count with differential is the single
most helpful test performed on ascitic fluid to
evaluate for infection.
• Polymorphonuclear count ≥ 250/mm3
– spontaneous bacterial peritonitis.
• In bloody ascites:
– one neutrophil should be subtracted from the
absolute neutrophil count for every 250 red cells
to yield the "corrected neutrophil count“.
13.
Serum-to-Ascites Albumin gradient
•The serum-to-ascites albumin gradient (SAAG)
accurately identifies the presence of portal
hypertension and is more useful than the protein-
based exudate/transudate concept.
• SAAG
– serum albumin value - ascitic fluid albumin
– (obtained on the same day).
• SAAG ≥ 1.1 g/dL (11 g/L)
– Indicates portal hypertension
– (Budd-Chiari syndrome, heart failure, or liver cirrhosis)
• SAAG <1.1 g/dL (<11 g/L)
– Indicates that the patient does not have portal hypertension.
14.
Sending Cultures
• Bacterialcultures of ascitic fluid should be sent
from patients with
– new onset ascites
• admitted with ascites
• Who deteriorate with
– Fever,
– Abdominal pain
– Azotemia,
– Acidosis
– confusion
15.
Protein, Glucose, LDH
•Protein — Ascitic fluid had been classified as an exudate if the total
protein concentration is ≥2.5 or 3 g/dL and a transudate if it is
below this cut-off. However, the exudate/transudate system of
ascitic fluid classification has been replaced by the SAAG.
• Measurement of total protein, glucose, and lactate dehydrogenase
(LDH) in ascites may also be of value in distinguishing SBP from gut
perforation into ascites
• Patients with ascitic fluid that has a neutrophil count ≥250
cells/mm3 and meets two out of the following three criteria are
unlikely to have SBP and warrant immediate evaluation to
determine if gut perforation into ascites has occurred.
– Total protein >1 g/dL
– Glucose <50 mg/dL (2.8 mmol/L)
– LDH greater than the upper limit of normal for serum.
– Bilirubin concentration should be measured in patients with brown ascites
16.
Glucose, LDH, Amylase
ConditionGlucose
Uncomplicated cirrhotic ascites Similar to serum glucose
peritoneal carcinomatosis Low
gut perforation May be undetectable
Condition LDH ascitic fluid/serum (AF/S) ratio
uncomplicated cirrhotic
ascites
0.4
SBP ratio approaches 1.0
infection or tumor. more than 1.0
Condition ascitic Amylase AF/S ratio of amylase
uncomplicated cirrhotic
ascites
40 IU/L 0.4
pancreatitis or gut perforation ↑ ↑
Pancreatic ascites ↑↑↑ (2000 IU/L) ↑↑↑ ( 6.0)
17.
Tests for tuberculousperitonitis
• Direct smear
• 0 to 2% sensitivity in detecting Mycobacteria.
• Culture
• When one liter of fluid is cultured, sensitivity for Mycobacteria
62 to 83% .
• Fluid for PCR for tuberculosis .
• Cell count
• Tuberculous peritonitis can mimic the culture-negative variant
of SBP, but lymphocyte cells usually predominate in
tuberculosis.
• Adenosine deaminase
• Adenosine deaminase activity of ascitic fluid has been proposed
as a useful non-culture method of detecting tuberculous
peritonitis; however, patients with cirrhosis and tuberculous
peritonitis usually have falsely low values .