The document discusses the peritoneal cavity, the causes and types of ascites, and the procedure and indications for abdominal paracentesis. It outlines the analysis of ascitic fluid, including laboratory tests to differentiate between transudates and exudates, and the evaluation of conditions like spontaneous bacterial peritonitis. It also notes potential complications of paracentesis and emphasizes the importance of careful examination of ascitic fluid for accurate diagnosis.

2. • Peritoneal cavity is a potential space in the abdomen lined by
mesothelial cells and normally containing about 30- 50ml of serous
fluid
• The fluid is an ultrafiltrate of plasma and its formation is dependent
upon hydrostatic pressure, plasma oncotic pressure, and capillary
permeability
• Pathological accumulation of fluid in peritoneal cavity is called as
ascites, and the accumulated fluid is called as ascitic fluid

3. Causes of Ascites
Transudate (increased hydrostatic pressure or plasma
oncotic pressure)
Exudate (Increased capillary permeability or
lymphatic obstruction)
1. Cirrhosis of liver 1. Bacterial peritonitis (primary or secondary)
2. Congestive cardiac failure 2. Tuberculosis
3. Hypoproteinemia 3. Malignancy (lymphoma, hepatoma, metastatic
carcinoma)
4. Abdominal injury
5. Biliary peritonitis (rupture of gallbladder)
6. Pancreatitis
7. Chylous ascites (obstruction of or injury to thoracic
duct)

4. Indications for Abdominal Paracentesis
• Abdominal paracentesis refers to removal of ascitic fluid through
puncture of the peritoneal cavity
• Indications
• 1.All patients with new-onset ascites
• 2. At admission in all patients with ascites for detection of asymptomatic
infection
• 3. All patients with ascites who develop clinical features of bacterial infection,
hepatic encephalopathy, gastrointestinal hemorrhage, or impairment of renal
function.
• 4. Symptomatic ascites (therapeutic paracentesis)

5. Collection of sample
• Presence of ascites can usually be detected
by clinical examination; if clinical examination
is not definitive, ultrasound can be helpful.
• Ultrasonography can also be useful for
determining the cause of ascites. A hollow
needle is inserted through the abdominal wall
(usually left lower quadrant of abdomen
below the border of shifting dullness) into the
peritoneal cavity and fluid (20-50 ml) is
removed under aseptic precautions. Sites for paracentesis (blue filled circles)

6. • For cytology, to maximize the yield of malignant cells, 100 ml should
be submitted
• For cell count sample is collected in EDTA-containing tube
• For microbiologic culture, sample is inoculated in blood culture
bottles at bedside
• Complications of the procedure include hemorrhage, perforation of
viscus, and introduction of infection
• Evidence of fibrinolysis or of disseminated intravascular coagulation in
liver disease is a contraindication for paracentesis

7. Examination of Ascitic Fluid
• Laboratory analysis of ascitic fluid helps in the differential diagnosis of
ascites
• A variety of tests can be carried out; however, the tests should be
decided in an individual patient according to the clinical presentation
• The commonly performed tests include estimation of total proteins
and albumin, cell count, cytological examination, and bacterial culture

8. Appearance
• Transudates are pale yellow or strawcolored and clear, whereas
exudates are opaque or turbid.
• Turbid fluid results from leucocytes, malignant cells, or proteins.
• Bloody or hemorrhagic fluid indicates traumatic tap, recent surgery,
abdominal trauma, or malignancy
• A traumatic tap shows gradual clearing of fluid during aspiration.
• Milky or chylous fluid results from obstruction of lymphatic duct due
to inflammation or malignancy (lymphoma, carcinomatosis), or from
abdominal injury

9. Chemical examination
• Proteins:
• Traditionally, fluid is called as a transudate if protein content is low, and an
exudate if its protein content is high
• However, this criterion alone is not always sufficient. In ascitic fluid,
distinction between transudates and exudates cannot be reliably made by
estimation of proteins
• A better indicator is albumin gradient (calculated as serum albumin minus
ascitic fluid albumin done on the same day)
• Total protein concentration in ascitic fluid can be helpful in differentiating
spontaneous (total protein <1gm/dL) from secondary bacterial peritonitis
(total protein >1gm/dL)

11. • Lactate dehydrogenase
• Lactate dehydrogenase in ascitic fluid is elevated in spontaneous bacterial
peritonitis (i.e. there is no obvious source of infection), secondary bacterial
peritonitis (i.e. identifiable source of infection is present), and in peritoneal
carcinomatosis
• Amylase
• Normally, amylase in ascitic fluid is similar to serum amylase
• If ascitic fluid amylase is three times greater than serum amylase, ascites is
most likely to be due to pancreatic disease such as acute pancreatitis

12. • Bilirubin
• Ascitic fluid bilirubin greater than 6.0 mg/ dl and ascitic fluid
bilirubin/serum bilirubin ratio greater than 1.0 indicate perforation of
biliary tract (biliary peritonitis)
• Ascitic fluid is bile-stained

13. Cell count
• Cell count is usually done to distinguish cirrhotic ascites from
spontaneous bacterial peritonitis
• In ascitic fluid, total leukocyte count > 500/ml and absolute neutrophil
count >250/ml constitute the presumptive evidence of spontaneous
bacterial peritonitis

14. Differentiation of spontaneous from secondary bacterial peritonitis

15. Parameter Spontaneous bacterial peritonitis Secondary bacterial peritonitis
Obvious source of infection Absent Present, e.g. perforation of viscus,
abscess
Total ascitic fluid proteins <1gm/dL >1gm/dl
Severity Less severe More severe
Culture Single organism Multiple organisms
Treatment Rapid response to antibiotics Requires surgical treatment

16. Microbiological examination
• Gram smear is positive in 25% cases of spontaneous bacterial peritonitis
• If ascitic fluid is inoculated in blood-culture bottles at bedside, sensitivity
of isolation rises to 85% (as compared to conventional method of
inoculation in broth and agar plates in laboratory)
• In spontaneous bacterial peritonitis, a single organism is isolated, while
secondary bacterial peritonitis is polymicrobial
• In case of tuberculosis, Ziehl-Neelsen stain has sensitivity of 25-30%, while
culture is positive in about 50% of cases
• Laparoscopic biopsy is more helpful in diagnosis of tuberculous peritonitis

17. Cytological examination
• Cytological examination of peritoneal fluid can detect 40-65% cases of
malignant ascites

18. Ascitic fluid findings in various diseases