Cavitary Effusion Flashcards
What are cavities line by?
Mesothelial cells
What does the small amounts of clear serous fluid in animals do?
Acts as lubricant and medium of transport for electrolytes and other substances
What is serous fluid removed by?
Lymphatic system
What is the composition of fluid in health determined by?
Permeability of capillaries
What is serous fluid permeable to?
H2O Electrolytes Glucose Urea Creatinine
What is the cellular composition of serous fluid?
No erythrocytes
Low numbers of nucleated cells
What does it mean if pleural and peritoneal fluid is collected?
There is an effusion
What is accumulation of fluid or the fluid that is accumulated??
Effusion
What is fluid accumulated in the cavity, typically peritoneal?
Ascites
What is the passage of fluid or solute through a membrane due to changes in hydraulic or oncotic pressure gradients?
Transudation
What is effusion produced by changes in mechanical factors?
Transudate
What is pressure of a fluid at rest?
Hydrostatic pressure
What is pressure of a fluid in motion?
Hydraulic pressure
What is exuding or oozing out through pores?
Exudation
What is effusion produced by increase vascular permeability to plasma proteins?
Exudate
What is the escape/loss of blood?
Hemorrhage
What is the escape/loss of lymph from lymph vessels?
Lymphorrhage
What is a transudate that has been modified by addition of protein and/or cells?
Modified transudate
What makes up the colloidal particles concentration?
Mainly albumin and other proteins
What does colloidal osmotic pressure vary by?
Tissue: 30% of the plasma in muscle interstitium, 70% of the plasma in lungs
What is Starling’s law?
Capillaries - intersitium forces
Pressure gradient = Δhydraulic - Δoncotic
What is arterial pressure?
Hydraulic difference > oncotic
Fluid leaves the vessel
What is venous pressure?
Hydraulic difference < oncotic
Fluid enters the vessel
How does fluid that enters the intersitium return?
Via permeabl venous capillaries
When does effusion accumulate?
Increased fluid into cavity
Decreased removal of fluid from cavity
What does the composition of fluid provide?
Evidence for the type of pathologic process
What causes transudates?
Excess diffusion of water from the vascular space
Pleural effusion
Portal hypertension
What can transudation from the liver create?
Protein rich fluid
What is pleural effusion primarily caused by?
Increased hydraulic pressure in alveolar capillaries
What does pleural effusion mostly remain?
Lungs
When do protein-poor transudates tend to form?
When there is marked hypoproteinemia
What are the most common causes of protein-poor transudates in dogs?
Hepatic cirrhosis
PLN
What are the 2 major factors of protein-poor transudates?
Decreased plasma oncotic pressure
Increased hydraulic pressure
What causes protein-rich transudates?
Increased plasma hydraulic pressure in liver or lungs because of venous congestion
What are the most common disorders that cause protein-rich transudates?
Congestive heart failure
Portal venous hypertension
What causes exudates?
Infectious or noninfectious agents
Septic (bacterial, fungal, viral, or protozoal)
Noninfectious Inflammation: increased vascular permeability
What is the most common cells in most exudates?
Neutrophils
What kind of exudate is associated with FIP?
High [protein] exudates
Protein types are very similar to the plasma
When is effusion considered hemorrhagic effusion?
When the primary reason for effusion is hemorrhage
What is the decision threshold for hemorrhagic classification?
Many factors affecting hematocrit
Sometimes there are hemorrhage and other processes
If effusion’s Hct >3%, hemorrhage is contributing to the effusion
What are the pathologic states associated with lymphorrhagic effusions?
Traumatic: physical damage
Nontraumatic: lymph stasis, lymphatic hypertension, defective lymphatic valve function, increased permeability of lymphatic vessels
What are many chylous pleural effusions caused by?
Obstruction of thoracic duct or cranial vena cava
What is a cause of lymphorrhagic effusions?
Blockage of lymphatic vessels by neoplastic cells
What are the 2 major groups lymphorrhagic effusions are classified into?
Chylous (chylomicron-rich)
Nonchylous
What causes chylous effusions?
Chylomicron-rich lymph leaks from vessels and enters the cavity
What does chylous effusion indicate?
Damage to the lymphatic vessels between the SI and thoracic vena cava
What is chylothorax common in?
Cats
What disorders can cause chylous effusions?
Neoplasms Cardiomyopathy Heart failure Lung lobe torsion Infections
What do almost all chylous effusions look like?
Milky-white to pink-white fluids
What are pseudochylous effusions?
Grossly similar appearance to chylous effusions
Have a high cholesterol content due to degeneration of cell membranes in the body cavity
What is uroperitoneum?
Leakage of urine from bladder, ureter, urethra, or kidney
What does uroperitoneum initiate?
Inflammatory response
What is the nucleated cell count like with uroperitoneum?
Low because of the relatively large amount of urine entering the body
What will the leakage of bile cause?
Low-moderate grade inflammation –> exudate
What does the leakage of gastric/intestinal contents cause?
Inflammation and exudate
What can causes cavitary effusions to accumulate?
Abdominal neoplasia
Heart failure
Urine or bile
What samples should be collected for pleural and peritoneal fluids?
EDTA to inhibit fibrin clot formation
Sterile for microbiologic testing
What does it mean if fluid is clear/hazy?
Cellularity probably low, concentration method is needed
What does it mean if fluid is cloudy/opaque?
Concentration method is probably not needed
What will fluid look like if it’s supernatant contains bilirubin?
Yellow-orange
What will fluid looks like if it’s supernatant contains Hgb?
Pink-red-brown
What will fluid look like if it’s supernatant contains stercobilinogen?
Brown
What will fluid look like if it’s supernatant contains chorophyll?
Green
What will fluid look like if it’s supernatant contains lipoproteins/chylomicrons?
White/creamy
What does it mean if the supernatant has color?
Pigment solutes in the fluid
What does it mean if the sediment has color?
Pigments in the cells or particles
What physical analysis is used for pleural and peritoneal effusion?
Refractometric estimates of [total protein]
Refractometric estimates of specific gravity
What does total nucleated cell concentration measure?
Fluids that contain leukocytes, mesothelial cells, potentially other cells
What kind of fluid is present if TNCC is at its lowest values (<1,000/ul)?
Protein-poor transudates
What kind of fluid is present if TNCC is at its greatest values (>100,000/ul)?
Exudates and neoplastic lymphoid effusions
What is the most important part of the fluid analysis if the fluid is not clear and colorless?
Microscopic exam
What are the major aspects of microscopic exams?
Percentages of each nucleated cell
Diagnostic features of cells
Nucleated cell differential count
Extracellular structures
What cells are routinely identified on microscopic exams of fluid?
Neutrophils Lymphocytes Mesothelial cells Macrophages Mononuclear cells Erythrocytes Platelets
What does increased neutrophils usually indicate?
Exudation
What can degenerate appearing neutrophils occur without?
Sepsis
What may nondegenerate neutrophils occur with?
Sepsis
What should you look for if degenerate neutrophils are present?
Organisms
What may lymphocytes of fluid have features of when stimualted?
Reactive lymphocytes, plasmacytoid lymphocyte, or plasma cells
What is the structural function of mesothelial cells?
Involved in inflammatory response
What becomes more prominent the longer blood is in the cavity?
Erythophages, siderophages, and other macrophages
What happens when there is recurring or persistent low-grade hemorrhage (neoplasm)?
Properties of both acute (high Hct) and chronic (siderophages) hemorrhagic effusion are present
What does the presence of platelets suggest?
Ongoing or very recent hemorrhage or blood contamination
What does the presence of clots in the sample indicate?
Fibrinogen was in the sample and could be because of exudation, hemorrhage, or blood contamination
What will the analysis should if there is a suspicion that they effusion is chylous?
TG will be higher in fluid than in the serum
Cholesterol:TG ratio will be low
TG >100 mg/dL
What will urea and creatinine be like if there is recent urine in the cavity?
They will be greater than in plasma
What electrolytes are freely diffusible through most capillary walls?
Na, Cl, K
Where are the concentrations of Na, Cl, and K nearly the same?
In plasma, interstitial fluids, and most effusions
What is the exception to the concentrations of Na, Cl, and K?
Uroperitoneum has low Na and Cl and high K compared to plasma
What is L-lactate a product of?
Anaerobic glycolysis, which is increased in hypoxia
What is L-lactate increased in?
Peritoneal fludis
Is glucose lower in dogs and cats with bacterial effusions of nonbacterial effusions?
Bacterial effusions
What do protein concentrations in effusions represent?
Proteins that leaked through the capillary wall
What does increased lipase in fluid indicate?
Acute pancreatitis
When is septic used to describe exudates?
When bacteria was found in the microscopic exam of an exudate
What is bacterial exudate like?
Few to numerous leukocytes, often degenerate, TP >2 g/dL
What is intestinal content like?
Not many neutrophils
What are effusions with neoplastic lymphocytes like?
> 10um nuclei, high cellular activity
What may carcinomas and adenocarcinomas do?
Exfoliate cells into effusion
Do metastatic sarcomas exfoliate or cause effusions?
Not typically
True or False: metastatic mast cell neoplasias may exfoliate cells into fluid
True
Will have hemangioma or hemangiosarcome have neoplastic cells in effusions?
Rarely
Will metastatic melanomas exfoliate neoplastic cells?
Yes
What can mesotheliomas produce?
Effusions with numerous anaplastic cells
What are the most common causes of lymphocyte rich effusions?
Lymphoid neoplasia
Accumulation of lymph
What are pericardial effusions associated with?
Neoplasia and infection, often idiopathic
What do pericardial effusions frequently have features of?
Hemorrhagic effusion
What is amniotic fluid like?
Clear and watery
What are the cells present in amniotic fluid?
Numerous nucleated or anucleate cornified squamous epithelial cells
