Abdominal, Thoracic, and Pericadial Effusions Flashcards
A small amount of free peritoneal fluid is normal in what species?
fluid can be collected from the peritoneal cavities in clinically healthy horses, cattle, and camelids and the judgment as to whether there is an abnormal or excessive amount of fluid within the cavity is best made clinically.
The main mechanisms by which transudation can occur: (3)
This is due to altered hydrodynamic forces within the vessels serving or draining capillary beds or the interstitium (lymphatics).
- Increased plasma hydrodynamic pressure, this is usually from increased venous pressure (e.g. venous hypertension) but can be from increased blood delivery to capillary beds (arterial hypertension or dilation), although the latter is less common.
- Decreased lymphatic drainage (increases tissue hydrostatic pressure).
- Decreased plasma oncotic pressure (hypoalbuminemia)
The main mechanisms by which an exudate can occur:
This is due to increased capillary permeability and is mediated by vasoactive mediators, usually as a consequence of inflammation.
This may or may not be accompanied by chemotaxis of leukocytes in response to inflammatory cytokines.
Body cavity fluids should be collected into an
EDTA-anticoagulant (purple top) tube. This tube is preferred because cell features are better maintained and bacterial proliferation is inhibited.
Concurrent collection of fluid into a non-anticoagulant (red top) tube is always useful with bloody fluids (to observe clotting) or in case additional testing is desired, e.g. creatinine, total bilirubin or bacteriology.
At the minimum, what should be done with a collected body cavity fluid?
At the minimum, a direct smear (from unconcentrated fluid) should be made from the fluid, however if the sample is poorly cellular, there will be insufficient cells to examine.
With a poorly cellular sample, it is worthwhile making smears of concentrated fluids (after centrifugation), using only a portion (and not all) of the fluid.
Direct smears should suffice for a flocculent or non-opaque fluid.
Fluid analysis begins during
collection of the sample, with observation for blood contamination, ease of collection, and how much fluid is present in the animal.
if the fluid is white and opaque it will most likely be
chylous in nature
if the fluid is from a cat and is yellow and highly viscous (perhaps with a fibrin clot], what should be considered
infection with feline infectious peritonitis virus should be considered
body cavity Fluid analysis should include (4)
gross evaluation
cell counts (nucleated and RBCs)
protein content
cytologic eval.
how to do a cell count for a body cavity effusion?
Nucleated and RBC counts are performed by automated methods (lasercyte/procyte) but can be done using manual methods (hemacytometer).
Note, nucleated cells include leukocytes and mesothelial or cancer cells. It also can include non-nucleated cells, such as bacteria and intestinal contents (so never rely on counts – always look at a smear).
how to measure protein content of a body cavity effusion?
This is estimated on a supernatant of the fluid (if cloudy or turbid) using a refractometer. (often is the left side scale, NOT the s.g. scale on the right)
A more accurate protein can be obtained on automated chemistry analyzer, however this is more expensive and not typically done.
how to: cytologic eval. of a body cavity effusion?
microscopic examination of a Wright’s or Diff-Quik-stained smear.
Fluids with very high nucleated cell counts (>20-30,000/uL) can be prepared without concentration of the cells (direct smear), while concentration techniques such as sediment smears can be used for lower cell count effusions.
The following cells are normally present in cavity fluids: (5)
macrophages: are present in all types of effusions.
neutrophils: These are non-degenerate.
lymphocytes: These are mostly small cells and are present in low numbers.
eosinophils and mast cells: Low numbers may be present.
mesothial cells: These are the lining cells of serosal cavities. Spontaneously exfoliated mesothelial cells are round cells with round, central nuclei.
describe transudates with low protein content
usually colorless to light yellow, and transparent
TP <2.5
cell count x10^3/ul <1.5 (pure transudate) but also <5.0
Pleural fluid: Increased venous or lymphatic hypertension (non-exfoliating neoplasia, lung lobe torsion, etc).
Peritoneal fluid: Portal hypertension (liver disease), severe hypoalbuminemia (< 1.5 g/dL, an uncommon cause of effusion by itself, often combined with portal hypertension), non-exfoliating neoplasia.
describe transudates with high protein content
TP >2.5
cell count x10^3/ul <5.0
Fluid is usually light to moderate yellow, may be blood-tinged and transparent to slightly cloudy (from WBC and RBC).
describe Chylous effusion
Usually TP >2.5
cell count Variable, usually >3.0
Fluid is grossly white to pink (if concurrent hemorrhage), opaque, and may form a cream layer on standing due to chylomicrons with opaque supernatant.
High triglycerides, usually > 100 mg/dL in fluid and usually >2x serum, unless animal is inappetent.
describe Exudate
TP Usually >2.5, often > 4.0 g/dL
cell count uusually >5.0
Cells sediment on centrifugation, yielding clear supernatant (unless concurrently chylous).
pericardial effusion in cats is often secondary to
congestive heart failure or feline infectious peritonitis but may be caused by cardiac neoplasia such as lymphoma.
most common causes of pericardial effusion in dogs include (2)
cardiac neoplasia and idiopathic pericardial effusion.
cardiac neoplasias likely to be
hemangiosarcoma most commonly
but can also be lymphoma, chemodectoma, thyroid carcinoma
pericardial effusion clinical signs (5)
weakness
lethargy
exercise intol.
collapse
coughing
thoracocentesis needle insertion point
2/3rds of the way down the chest, near the costochondral junction at the 7th or 8th intercostal space.
insert needle next to cranial surface of rib to avoid vessels that are found at caudal edge of previous rib.
abdominocentesis needle insertion point
ventral midline of abdomen, 1-2 cm caudal to the umbilicus
if scar present on abdo, insert 1,5 cm away from it in case viscera has ahdered to teh area
pericardiocentesis needle insertion point
from the RIGHT hemithorax, puncture between 4th-5th intercostal spaces at the costochondral junction.
minimum values for total protein content &
total nucleated cell count for transudates
< 2.5 g/dl protein
< 1500 nucleated cells/microliter
minimum values for total protein content &
total nucleated cell count for modified transudates
2.5- 7.5 g/dl protein
1000- 7000 nucleated cells/microliter
minimum values for total protein content &
total nucleated cell count for exudates
> 3.0 g/dl protein
7000 nucleated cells/microliter
How to diagnose gallbladder rupture?
effusion color may be green tinged to yellow-orange
Analyse bilirubin/ TBIL. If the fluid bilirubin is at least 2 to 3 times higher than the serum bilirubin level, it strongly indicates bile peritonitis caused by gallbladder rupture.
TP >2.0 g/dL
How to diagnose uroabdomen? (4)
A fluid-to-serum creatinine ratio >2:1 is highly suggestive of uroabdomen.
A fluid-to-serum potassium ratio >1.4:1 is another diagnostic indicator of uroabdomen.
cell counts typically < 6k cells micro/L
TP generally <3g/dL
What findings in effusion can be seen in septic peritonitis? (6)
Usually cloudy or turbid effusion.
Total protein (measured by e.g. refractometer) should be over (>3.0 g/dL).
Lactate can be elevated due to anaerobic bacterial metabolism.
Low GLU compared to that of the serum, due to bacterial consumption of glucose.
High WBC count, especially neutrophils.
Presence of bacteria
pyogranulomatous effusion means
effusions that consist primarily of neutrophils but with lesser numbers of macrophages
FIP effusions are often (4)
straw colored, odorless
may contain lfecks or fibrin strands
>4 g/dL
call count 2k-6k cells/microL
Bile in the peritoneal cavity causes what type of peritonitis?
chemical peritonitis that is typically exudative
Rupture of a biliary mucocele may cause
atypical bile peritonitis with yellow or red effusion fluid (instead of green or orange).
classic description of a chylous effusion
milky fluid that does not clear after centrifugation and cytologically consists primarily of small lymphocytes.
When blood enters a body cavity (as an effusion), what do the platelets do?
the platelets quickly aggregate, degranulate and disappear.
thus the presence of platelets in an effusion indicate peracute hemorrhage or iatrogenic blood contamination in the effusion.
