1. Chapter 16 Serous Fluid Professor A. S. Alhomida
King Saud University
College of Science
Department of Biochemistry
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Chapter 16 Serous Fluid Professor A. S. Alhomida

2. Closed Cavities of the Body
Pleural Cavity
Pericardial Cavity
Peritoneal Cavity

3. Closed Cavities of the Body, Cont’d
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)
Fluid between the membranes is called serous fluid

4. Function of Serous Fluid
Provide lubrication as the surfaces move against each other
Normally, only small amount of serous fluid is present, because production and reabsorption take place at a constant rate

5. 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:
Hydrostatic pressure
Colloid pressure

6. Formation of Pleural Fluid

7. Formation of Pleural Fluid

8. Pleural Cavity

9. 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

10. Effusion of Serous Fluid, Cont’d
Causes:
Increased Hydrostatic Pressure
Congestive heart failure pressure
Decreased Colloid Pressure
Hypoproteinemia
Increased capillary permeability (inflammation and infection)
Lymphatic obstruction (tumors)

11. Collection of Serous Fluid
Fluid is collected by needle aspiration (100 mL) from the respective cavities
Thoracentesis for pleural cavity
Pericardiocentesis for pericardial cavity
Paracentesis for peritoneal cavity

12. Thoracentesis

13. Pericardiocentesis

14. Paracentesis

15. Classification of Effusion
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

16. Classification of Effusion, Cont’d
Exudates
Causes
They are produced by conditions that directly involve the membranes of the particular cavity, including infections and malignancies

17. Transudated and Exudates

18. Transudated and Exudates

19. Pleural Fluid
It is obtained from the pleural cavity, located between the parietal pleural membrane lining the chest wall and visceral pleural membrane covering the lungs
Pleural effusions can be transudative or exudative origin

20. Pleural Fluid, Cont’d
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

21. 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

22. Physical Properties of Pleural Fluid

23. Types of Pleural Effusions

24. Evaluation of Pleural Fluid

25. Pleural Fluid Cells

26. Pleural Fluid Cells, Cont’d

27. Pleural Fluid Cells, Cont’d

28. Pleural Cells, Cont’d

29. Pleural Cells, Cont’d

30. Pleural Cells, Cont’d

31. Pleural Cells, Cont’d

32. Pleural Cells, Cont’d

33. Biochemical Testing of Pleural Fluid

34. Pericardial Fluid
Normally, only a small amount (10-50 mL) of fluid is found between the pericardial serous membranes
Pericardial effusions are result primarily of changes in the permeability of the membranes due to infection (pericarditis), malignancy, trauma, or metabolic disorders as uremia

35. Pericardial Fluid, Cont’d
Presence of pericardial effusion is expected when cardiac compression is noted during the physician’s examination

36. Pericardial Cavity

37. Physical Properties of Pericardial Fluid

38. Pericardial Fluid Cells

39. Peritoneal Cavity

40. Peritoneal Dialysis

41. Peritoneal Fluid
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
Hepatic disorder, such as cirrhosis, are frequent causes ascitic transudative fluids
Bacterial infections (peritonitis) are most frequent causes of ascitic exudative fluids

42. Ascitic Transudates vs Exudates
Differentiation between ascitic fluid transudates and exudates is more difficult that for pleural and pericardial effusions
Serum/ascites albumin gradient is recommended over the fluid/serum total protein and LDH ratios for detection for the transudates of hepatic origin

43. Ascitic Transudates vs Exudates, Cont’d
A difference (gradient) of 1.1 or greater suggests a transudates effusion of hepatic origin, and lower gradients are associated with exudative effusions

44. Ascitic Transudates vs Exudates, Cont’d
Example:
Serum albumin = 3.8 mg/dL
Fluid albumin = 1.2 mg/dL
Gradient 3.8 – 1.2 = 2.6 then indicating hepatic effusion

45. Physical Properties of Ascitic Fluid

46. Peritoneal Fluid Cells

47. Peritoneal Fluid Cells

48. Peritoneal Fluid Cells

49. THE END
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