Thread: Pleural effusion and ascites fluid analysis

Pleural fluid analysis

Main aim is to differentiate transudative and exudative type.

Transudative pleural effusion

Causes : congestive heart failure
Cirrhosis of liver
Nephrotic syndrome
Severe protein malnutrition
- ultrafiltrate of plasma, due to increased hydrostatic pressure or decreased serum oncotic pressure. Occurs within a normal pleura

1) Appearance : clear

2) Protein; absolute- < 3.0 G/dl
P.fluid/serum ratio < 0.5

3) Lactic dehydrogenase
Absolute < 200 IU/L
P.fluid/serum ratio < 0.6

4) Glucose : > 3.33mmol/L
(same as blood)

5) Leukocytes
Total : <1000/ mm3
DLC : > 50 % lymphocytes or mononuclear cells

6) Erythrocytes : < 5000/mm3

Exudative effusion

Causes : Tuberculosis , malignancy, pneumonia, pulmonary infarction, Rheum. Arthritis
SLE, Dressler’s syndrome, Meig’s syndrome, drug induced effusion, benign asbestos related effusion.

- rich in proteins, resembles plasma; occurs in diseased pleura, due to increased capillary permeability.

1) Appearance : clear
Cloudy or hemorrhagic (malignant effusion)

2) Protein; absolute- > 3.0 G/dl
P.fluid/serum ratio > 0.5

3) Lactic dehydrogenase
Absolute > 200 IU/L
P.fluid/serum ratio > 0.6

4) Glucose : < 3.33mmol/L
(variable)
Low glucose : empyema, malignancy, TB
Very low glucose : rheumatoid effusions

5) Leukocytes
Total : >1000/ mm3
DLC : > 50 % lymphocytes – TB or malignancy
> 50 % polymorphs – acute inflammation eg. Syn pneumonic effusion
Eosinophilia (>10%) – hydropneumothorax, asbestos related effusions

6) Erythrocytes : Variable
If > 100 000 /mm3 – in malignancy or pulmonary embolism

Other parameters :

- Pleural fluid amylase : elevated in pancreatitis and esophageal rupture
- Anti nuclear Ab / rheumatoid factor – connective tissue diseases
- Pleural biopsy (USG guided) – in undiagnosed cases



Ascitic Fluid Analysis

A. Causes
a. Commonest causes:
i. Cirrhosis of liver (transudate).
ii. Malignant ascites (exudates).
iii. Congestive cardiac failure (transudate).
iv. Mycobacterium Tuberculosis (exudates).


b. The causes can be divided as those due to Transudate or Exudate.
i. Transudate
1. cirrhosis of liver
2. congestive cardiac failure
3. Budd Chiari syndrome
4. portal vein thrombosis
5. splenic vein thrombosis
6. Hypoproteinemia of any cause
7. beri beri
8. Constrictive pericarditis
ii. Exudate
1. Inflammation
a. acute bacterial peritonitis
b. Tuberculous bacterial peritonitis
c. pancreatitis

2. Traumatic - injury to spleen and liver.
3. Neoplastic - malignant ascites due to malignancy
(primary or secondary) in abdomen
4. Miscellaneous - Meig’s syndrome; Chylous ascites

Parameters :

1)Appearance :

Clear, straw colored/light green – cirrhosis, CCF , nephritic syndrome
Hemorrhagic – Malignancy ,TB , pancreatitis
Cloudy, turbid – bacterial peritonitis
Deep green – biliary leak

2)Specific gravity : < 1.016 in transudative
>1.016 in exudative

3)Protein :
< 2.5 g/ dl in transudative
> 2.5 g/dl in exudative

4)Glucose – low in malignancy, TB and peritonitis

5)Amylase activity : raised to > 1000 U/L in Pancreatitis

6)Total cell count :
Transudative – considerably low ; <250/ µl
Exudative - considerably high ; >250/ µl

* White cell count greater than 350/ µl - suggestive of infection.
If most cells are polymorphonuclear, bacterial infection suspected. If predominant mononuclear cells , tuberculosis or fungal infection likely.

* Red cell count : when > 50.000/ µl denotes hemorrhagic ascites (usually seen in malignancy, tuberculosis or trauma).

7) Differential Count:
Transudative – predominant mesothelial cells/lymphocytes
Exudative – predominant polymorphs, lymphocytes, RBCs



8) Microscopy :

Polymorphs : < 250/mm3 in cirrhosis
> 250/ mm3 in bacterial peritonitis

Lymphocytes : Tuberculosis, malignancy
Gram’s stain : Bacterial peritonitis
Ziehl Nielsen’s stain : Tuberculosis
Cytology : Malignant cells

9) Culture : Pyogenic bacteria (predominant Gram –ve ) in bacterial peritonitis
Acid fast bacteria in tuberculosis

10)Other parameters :

• Serum-ascitic albumin gradient (SAAG)

Calculated by subtracting albumim concentration of the ascitic fluid from the albumin concentration of serum specimen obtained on the same day.

SAAG correlates directly with portal pressure, and patients with gradients greater than or equal to 1.1 g/dl have portal hypertension (transudative ascites) and patients with gradients lesser than 1.1 g/dl do not (exudative ascites).

High Gradient ( > or = 1.1 g/dl) - Cirrhosis
Alcoholic Hepatitis
Cardiac Failure
Fulminant Hepatic Failure
Portal-vein Thrombosis

Low Gradient ( < 1.1 g/dl) - Peritoneal Carcinomatosis
Pancreatic ascites
Biliary ascites
Peritoneal Tuberculosis
Nephrotic Syndrome
Bowel obstruction or infarction

b. Triglyceride concentration - elevated in chylous ascites.

Pleural Effusion and Ascites Fluid Analysis


Causes of transudative and exudative effusion:

Transudative Effusion:

• CHF (90%)
• Cirrhosis (hepatic hydrothorax)
• Pulmonary embolism
• Nephrotic syndrome
• Pritoneal dialysis
• Mxedema
• Constrictive pericarditis

Exudative Effusion:

• Infection
• Cancer
• Connective tissue disease
• Pancreatitis
• Uremia
• Drug reaction
• Post-MI/CABG
• Esophageal rupture

Check serum and fluid LDH and total using Light’s criteria
(Satisfying any ONE criteria means it is exudative)

• Pleural Total Protein/ Serum Total Protein > 0.5
• Pleural LDH/ Serum LDH > 0.6
• Pleural LDH > 2/3s of the upper limit of normal for serum LDH

If exudative, obtain the following pleural fluid tests:

Cell Count with differential:

• PMNs > 50%: Parapneumonic, PE, pancreatitis.
• Lymphs >50%: Cancer, TB, fungus or post-surgicery
• Eos >10%: PTX, hemothorax, drug reaction, asbestos, parasite infection, Churg-Strauss

Culture and Smear/Gram Stain:

• Yield is increased if fluid sent in blood culture bottles. Send for fungus and ycobacteria if pleural lymphs > 50 % or clinical picture is suspicious. Yield in Tb is <50%.

Glucose:

• Level <60 mg/dL is seen in complicated parapneumonic effusion, malignancy, hemothorax, Tb,RA, SLE, Churg-Strauss, parasite infection.

Cytology:

• A case series of 971 lung cancer patients reported 7% prevalence of pleural effusion on chest ray and 40% of these pleural effusions had positive cytology. If cytology is negative and cancer is suspected, pleural biopsy should be performed.

Consider Adenosine Deaminase(ADA) for Tb:

• At least 50% of tuberculous pleural effusions do not involve other organs and are therefore difficult to diagnose. ADA levels >40-60 U/L in the setting of a lymphocytic effusion are specific for Tb.

Consider Amylase:

• Elevated in patients with pancreatitis, esophageal rupture, and malignancies.

The cause of 15% of exudative effusions is not determined. For both transudative and exudative effusions without a cause, pulmonary embolism should be considered. Further evaluation by pleural biopsy via thoracoscopy or open biopsy is indicated for
undiagnosed, unresolved exudative effusion.

PLEURAL EFFUSION FLUID ANALYSIS

It is the accumulation of fluid in the pleural space.
Causes:-
Transudative: Congestive cardiac failure, nephritic syndrome,
cirrhosis of liver, renal failure
severe protein malnutrition.

Exudative: Tuberculosis, pneumonia, lung abscess, various other lung
infections, Pulmonary infarction, malignancy, trauma,
subdiaphragmatic abscess, Acute pancreatitis, SLE,
rheumatoid arthritis.

Pleural Efussion Fluid Analysis
Transudative: Appearance is clear
Protein level: < 3gm/dl; pleural fluid/serum protein ratio:
<0.5
Lactate dehydrogenase(LDH) level: <200IU/L; ratio:<0.6
Pleural fluid LDH <2/3 of the upper limit of serum LDH
Ph is normal, more than 7.3
Glucose is same as blood > 3.33mmol/L
Amylase level is normal
Fat < 3g/L
Differential count of WBC normal (<1000/mm3)
RBC <5000/mm3
Cytology negative

Exudative: Appearance is cloudy, purulent, loculated or bloody
Protein level: > 3gm/dl; pleural fluid/serum protein ratio:>0.5
Lactate dehydrogenase(LDH) level: >200IU/L; ratio: >0.6
Pleural fluid LDH >2/3 of the upper limit of serum LDH
Ph is normal, less than 7.3
Glucose is same as blood < 3.33mmol/L can be very low
Amylase level is raised (in esophageal rupture)
Fat > 3g/L
Differential count of WBC normal (>1000/mm3)
RBC >5000/mm3 if hemorrhagic
Cytology positive in malignant cause.
Gram stain, Zeihl Nielsen stain, culture will be positive
according to the organism.

ASCITES FLUID ANALYSIS

It is the accumulation of fluid in the peritoneal space.
Causes:-
Transudative: Hypoproteinemia, cardiac failure, portal hypertension,
cirrhosis nephrotic syndrome, renal failure, anemia

Exudative: Peritonitis due to various infections (bacterial, tuberculosis,
parasitic), collagen disorders, malignancies, Meig's syndrome
trauma.
Others: Chylous, pancreatic

Ascites Fluid Analysis

Transudative: Appearance is clear
Protein level: < 25g/l; ascites fluid/serum protein
ratio: <0.5
Lactate dehydrogenase(LDH) level: <200IU/L; ratio:<0.6
Ascitic fluid LDH <2/3 of the upper limit of serum LDH
Glucose is same as blood > 3.33mmol/L
Amylase level is normal
Specific gravity: <1.015
Clot formation none
Differential count of WBC normal (<250/mm3)
Serum-ascites albumin ratio > 1.5

Non transudative: Appearance is cloudy, purulent, or bloody
Protein level: > 25g/l; ascites fluid/serum protein ratio:
>0.5
Lactate dehydrogenase(LDH) level: >200IU/L; ratio:
>0.6
Ascitic fluid LDH >2/3 of the upper limit of serum LDH
Glucose is same as blood < 3.33mmol/L very low in
tuberulosis and malignancy
Amylase level is more than 1000U/l in pancreatic cause
Specific gravity: >1.015
Clot formation present
Blood count more than 50000u/l is suggestive of
hemorrhagic cause
Differential count of WBC normal (>250/mm3) in
infection
Serum-ascites albumin ratio < 1.5
Cytology will show malignant cells
Gram stain, Zeihl Nielsen stain (tuberculosis) and
culture will be positive and specific to the organism

Pleural effusion fluid analysis

Pleural fluid is collected in the pleural space.
A sample of pleural fluid is obtained by a procedure called thoracentesis.

Transudative effusions are caused by some combination of increased hydrostatic pressure and decreased oncotic pressure in the pulmonary or systemic circulation. Heart failure is the most common cause, followed by cirrhosis with ascites and hypoalbuminemia, usually from the nephrotic syndrome.

Exudative effusions are caused by local processes leading to increased capillary permeability resulting in exudation of fluid, protein, cells, and other serum constituents. Causes are numerous, the most common being pneumonia, malignancy, pulmonary embolism, viral infection, and TB.

Pleural fluid analysis:
Transudate:

• Appearance - clear
• protein - absolute value - <3.0g/dl, fluid : serum ratio - <0.5
• lactic dehydrogenase - absolute value - <200iu/L, fluid : serum ratio - <0.6
• Glucose - >60mg/dl
• leucocytes - total <1000/mm3, differential - >50% lymphocytes or mononuclear cells
• erythrocytes - <5000/mm3

Exudate:

• Appearance - clear, cloudy or hemorrhagic
• protein - absolute value - >3.0g/dl, fluid : serum ratio - >0.5
• lactic dehydrogenase - absolute value - >200iu/l, fluid : serum ratio - >0.6
• Glucose - <0.6mg/dl
• leucocytes - total - >1000/mm3, differential - >50% polymorphs or lymphocytes
• erythrocytes - variable

Low glucose concentration (<60mg/dl) suggest - empyema, malignancy, TB
very low glucose concentration(<15mg/dl) is characteristic of rheumatoid effusion
pleural fluid erythrocytes count exceeding 100000/mm3 are most often seen in malignancy and pulmonary embolism.
pleural fluid amylase is elevated in patients with pancreatic disease and esophageal rupture.

Ascites fluid analysis:
The ascitic fluid should be analyzed for:

• The serum-ascitic albumin gradient (SAAG) is calculated by subtracting the albumim concentration of the ascitic fluid from the albumin concentration of a serum specimen obtained on the same day.
• The amylase concentration is elevated in pancreatic ascites.
• The triglyceride concentration is elevated in chylous ascites.
• White cell count when greater than 350/microliter is suggestive of infection. Bacterial infection should be suspected if predominant cells are polymorphonuclear cells. Suspect TB or fungal infection if mononuclear cells is predominant.
• Red cell count greater than 50.000/microliter denotes hemorrhagic ascites, which usually is due to malignancy, tuberculosis or trauma.
• Gram stain and culture can confirm the diagnosis of bacterial infection.
• pH less than 7 suggests bacterial infection
• Cytology can be positive in malignancy.

Types of Ascites according to the level of the serum-ascites albumin gradient:

- High Gradient ( > or = 1.1 g/dl)

• Cirrhosis
• Alcoholic Hepatitis
• Cardiac Failure
• Fulminant Hepatic Failure
• Portal-vein Thrombosis

- Low Gradient ( < 1.1 g/dl)

• Peritoneal Carcinomatosis
• Pancreatic ascites
• Biliary ascites
• Peritoneal Tuberculosis
• Nephrotic Syndrome
• Serositis
• Bowel obstruction or infarction

Pleural effusion

Measure protein, lactate dehydrogenase, glucose concentration and pH in pleural fluid and serum.

Exudative effusion
Pleural fluid:serum protein ratio > 0.5
Pleural fluid:serum LDH ratio > 0.6
Pleural fluid glucose very low (<1.4mmol/l) in tuberculous and rheumatoid effusions.
Pleural fluid cholestrol usually high (>45 mg/dl)
pH normal or low (<7.3); low in empyema and very low in esophageal rupture.
Amylase high in effusions associated with pancreatitis and esophageal rupture.
Cloudy or milky appearance (fat >4 g/l) indicates chylous effusion.
Pleural fluid complement levels low in rhematoid or SLE related effusions.

Transudative effusion
Pleural fluid:serum protein ratio < 0.5
Pleural fluid:serum LDH ratio < 0.6
Pleural fluid glucose, amylase, cholestrol, and pH all normal.
Causes: heart failure, liver failure, renal failure, thyroid failure, malnutrition.

Asceitic fluid analysis

Appearance

Cirrhosis- clear, straw coloured or light green
Malignant disease- bloody
Infection- cloudy
Biliary communication- heavy bile staining
Lymphatic obstruction- milky white (chylous)
The ascities protein concentration and serum-ascites albumin gradient are used to separate ascites due to transudation from ascites due to exudation. Ascites with protein concentrations below 25 g/l or serum-ascites albumin gradient above 1.5 (transudates) are usually due to cirrhosis. Exudative ascites (ascites protein concentration above 25 g/l or serum-albumin ratio below 1.5) raises the possibility of infection, malignancy, hepatic venous obstruction, pancreatic asitesor rarely hypothyroidism. Ascites amylase activity above 1000 U/I identifies pancreatic ascites, and low ascites glucose concentrations suggest malignant disease or tuberculosis. Cytological examination can reveal malignant cells, and polymorphonuclear leucocyte counts above 250/mm3 strongly suggest infection