BODY CAVITY EFFUSIONS (ABDOMINAL, THORACIC, PERICARDIAL)

46 BODY CAVITY EFFUSIONS (ABDOMINAL, THORACIC, PERICARDIAL)



Rick L. Cowell, Theresa E. Rizzi, James H. Meinkoth



1 List the three major classifications of effusions.



a. Transudates

b. Modified transudates

c. Exudates


2 What is a transudate?


Transudates are clear, colorless effusions of low protein concentration (<2.5 g/dl) and low total nucleated cell counts (<1500 cells/μl; some use 1000 cells/μl as the cutoff point). These effusions are often referred to as pure transudates.



3 How are transudates or pure transudates formed?


Generally, transudates are formed by leakage of protein-poor fluids from small vessels as a result of increased hydrostatic vascular pressure or low plasma oncotic pressure. In the early stages of uroabdomen, the fluid may be in the transudate range since urine is typically low in protein concentration and has a low cell count.



4 What are some causes of pure transudates?


Since plasma albumin concentration is the dominant factor in control of plasma oncotic pressure, severe hypoalbuminemia is a common cause of pure transudates. Other causes include hypertension, early myocardial insufficiency, hepatic insufficiency, and portosystemic shunts.



5 What is a modified transudate?


Modified transudates are transudates that are modified by higher total protein concentrations and cell counts. Reference numbers for modified transudates vary slightly among authors. In general, modified transudates have total protein concentrations greater than 2.5 g/dl and nucleated cell counts between 1000 and 7000/μl in dogs and cats (some use range of 1000-5000 cells/μl). Cell counts in horses are often allowed to be higher and are generally from 1000 to 10,000 nucleated cells/μl. Some overlap between pure transudates and modified transudates exists. In general, if the protein is greater than 2.5 g/dl, the fluid is classified as a modified transudate even if the cell count is in the transudate range.



6 How are modified transudates formed?


Modified transudates are formed by leakage of fluid from small vessels caused by increased vascular permeability and increased hydrostatic pressure within local vascular beds.



7 List common causes of modified transudates.



a. Congestive heart failure (increased hepatic and splanchnic blood pressure)

b. Nonseptic inflammation (e.g., pancreatitis, hepatitis, splenitis)

c. Sterile irritants (e.g., uroabdomen)

d. Vascular insults (e.g., pulmonary thrombosis)

e. Feline infectious peritonitis (FIP)

f. Neoplasia (exfoliative or nonexfoliative)


8 What is an exudate?


Exudates are effusions of high total protein concentration and high nucleated cell count. Again, actual numbers vary among authors. Generally, total protein concentration is greater than 3 g/dl and nucleated cell count greater than 7000 cells/μl in dogs and cats (some use >5000/μl). In horses, nucleated cell count is typically greater than 10,000 cells/μl.



9 How are exudates formed?


Exudates are formed by leakage (exudation) of protein-rich fluid through highly permeable vessels and migration of leukocytes into the cavities in response to chemotactic factors.



10 What are some causes of exudates?


Exudates have both septic causes (e.g., bacterial, fungal, protozoal, viral) and nonseptic causes (e.g., bile peritonitis, pancreatitis, steatitis, abscesses, inflammation associated with neoplasia).

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Aug 26, 2016 | Posted by in INTERNAL MEDICINE | Comments Off on BODY CAVITY EFFUSIONS (ABDOMINAL, THORACIC, PERICARDIAL)

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