King Saud University
College of Science
Department of Biochemistry
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• The texts, tables and images contained in this course
presentation (BCH 376) are not my own, they can be
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Chapter 16
Serous Fluid
Professor A. S. Alhomida
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Closed Cavities of the Body
1. Pleural Cavity
2. Pericardial Cavity
3. Peritoneal Cavity
2
Closed Cavities of the Body,
Cont’d
1. They are lined by two membranes referred to as
the serous membranes. One membrane lines
the cavity wall (parietal membrane, and the
other covers the organs within the cavity
(visceral membrane)
2. Fluid between the membranes is called serous
fluid
3
Function of Serous Fluid
1. Provide lubrication as the surfaces move against
each other
2. Normally, only small amount of serous fluid is
present, because production and reabsorption
take place at a constant rate
4
Formation of Serous Fluid
•
It is formed as ultrafiltrates of plasma, with no
additional material contributed by the membrane
cells depends on two different pressures:
1. Hydrostatic pressure
2. Colloid pressure
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Formation of Pleural Fluid
6
Formation of Pleural Fluid
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Pleural Cavity
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Effusion of Serous Fluid
• It is the disruption of the mechanism of serous
fluid formation and reabsroption causes an
increase in fluid between the membranes
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Effusion of Serous Fluid,
Cont’d
• Causes:
1. Increased Hydrostatic Pressure
• Congestive heart failure pressure
2. Decreased Colloid Pressure
• Hypoproteinemia
• Increased capillary permeability (inflammation and
infection)
• Lymphatic obstruction (tumors)
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Collection of Serous Fluid
• Fluid is collected by needle aspiration (100
mL) from the respective cavities
1. Thoracentesis for pleural cavity
2. Pericardiocentesis for pericardial cavity
3. Paracentesis for peritoneal cavity
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Thoracentesis
12
Pericardiocentesis
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Paracentesis
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Classification of Effusion
1. Transudates
• Causes
• They produced because of a systemic disorder that
disrupts the balance in the regulation of fluid
filtration and reabsorption as the change in
hydrostatic pressure created by congestive heart
failure or the hypoproteinemia associated with the
nephrotic syndrome
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Classification of Effusion,
Cont’d
2. Exudates
•
Causes
• They are produced by conditions that directly involve
the membranes of the particular cavity, including
infections and malignancies
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Transudated and Exudates
17
Transudated and Exudates
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Pleural Fluid
1. It is obtained from the pleural cavity, located
between the parietal pleural membrane lining
the chest wall and visceral pleural membrane
covering the lungs
2. Pleural effusions can be transudative or
exudative origin
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Pleural Fluid, Cont’d
3. Procedures are helpful when analyzing pleural
fluid
• For Exudates, if
• Pleural Fluid Cholesterol > 60 mg/dL or
• Pleural Fluid/Serum Cholesterol Ratio > 0.3
• Pleural Fluid/Serum Total Bilirunbin Ratio > 0.6
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Light's Criteria
• If at least one of the following three criteria is
present, the fluid is virtually always an exudate
• If none is present, the fluid is virtually always a
transudate
• Pleural fluid protein/serum protein ratio greater than
0.5.
• Pleural fluid LDH/serum LDH ratio greater than 0.6.
• Pleural fluid LDH greater than two thirds the upper
limits of normal of the serum LDH
21
Physical Properties of Pleural
Fluid
22
Types of Pleural Effusions
23
Evaluation of Pleural Fluid
24
Pleural Fluid Cells
25
Pleural Fluid Cells, Cont’d
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Pleural Fluid Cells, Cont’d
27
Pleural Cells, Cont’d
28
Pleural Cells, Cont’d
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Pleural Cells, Cont’d
30
Pleural Cells, Cont’d
31
Pleural Cells, Cont’d
32
Biochemical Testing of Pleural
Fluid
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Pericardial Fluid
1. Normally, only a small amount (10-50 mL) of
fluid is found between the pericardial serous
membranes
2. Pericardial effusions are result primarily of
changes in the permeability of the membranes
due to infection (pericarditis), malignancy,
trauma, or metabolic disorders as uremia
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Pericardial Fluid, Cont’d
3. Presence of pericardial effusion is expected
when cardiac compression is noted during the
physician’s examination
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Pericardial Cavity
36
Physical Properties of
Pericardial Fluid
37
Pericardial Fluid Cells
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Peritoneal Cavity
39
Peritoneal Dialysis
40
Peritoneal Fluid
1. Accumulations of fluid in the peritoneal fluid
cavity is called ascites, and the fluid is
commonly referred to as ascitic fluid rather
than peritoneal fluid
2. Hepatic disorder, such as cirrhosis, are frequent
causes ascitic transudative fluids
3. Bacterial infections (peritonitis) are most
frequent causes of ascitic exudative fluids
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Ascitic Transudates vs Exudates
1. Differentiation between ascitic fluid transudates
and exudates is more difficult that for pleural and
pericardial effusions
2. Serum/ascites albumin gradient is
recommended over the fluid/serum total protein
and LDH ratios for detection for the transudates
of hepatic origin
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Ascitic Transudates vs Exudates,
Cont’d
3. A difference (gradient) of 1.1 or greater suggests
a transudates effusion of hepatic origin, and
lower gradients are associated with exudative
effusions
43
Ascitic Transudates vs Exudates,
Cont’d
4. Example:
Serum albumin = 3.8 mg/dL
Fluid albumin = 1.2 mg/dL
Gradient 3.8 – 1.2 = 2.6 then indicating hepatic
effusion
44
Physical Properties of Ascitic
Fluid
45
Peritoneal Fluid Cells
46
Peritoneal Fluid Cells
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Peritoneal Fluid Cells
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THE END
Any questions?
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