Lecture 15 10/29/24 Flashcards
What is oncotic pressure?
water following solids
What is hydraulic pressure?
force of flow when fluid encounters resistance
Which system in the body drains fluid from body cavities?
lymphatic system
What are the characteristics of fluid formed by plasma exiting the arterial capillary bed?
-low protein conc.
-low cellularity
-normal fluid in body cavity
What is the cycle for normal body cavity fluid?
-fluid moves out of capillaries
-fluid lubricates organs
-fluid is drained by lymphatics
-fluid goes back into the vascular space
What is an effusion?
pathological fluid accumulation
What are the mechanisms of pathologic fluid accumulation?
-disturbances in fluid circulation
-inflammation in a body cavity
-organ rupture
-neoplasia
What is the clinical presentation of abdominal/peritoneal effusions?
-distended abdomen
-exercise intolerance
-possible respiratory difficulty
What is the clinical presentation of thoracic/pleural effusions?
-increased resp. rate
-difficulty breathing
-exercise intolerance/weakness
What is the clinical presentation of pericardial effusions?
-exercise intolerance/weakness/collapse
-respiratory difficulty
-muffled heart sounds
-weak pulses
-jugular distension
-ECG abnormalities
-abdominal effusion possible
What is a purple top tube/EDTA tube used for when collecting effusion samples?
-total protein
-total nucleated cell count
-cytology
What is a green top tube/heparin tube used for when collecting effusion samples?
-K+
-creatinine
-bilirubin
-triglycerides
-glucose
-lactate
What is a red top tube/non-additive tube used for when collecting effusion samples?
bacterial culture and susceptibility
How should smear samples be shipped?
-should include direct smear of fresh fluid +/- stained smear
-slide shipped in room temp. slide holder
How should tube samples be shipped?
-refrigerated EDTA tube +/- additional heparin and additive free tubes
-shipped overnight on cool pack
How does a fluid analysis differ from a cytology (UTCVM specific)?
-fluid analysis looks at total protein refractometry, total nucleated cell count, and microscopic eval.
-cytology only looks at microscopic eval.
What type of effusion is typically seen with disturbances in fluid circulation?
transudate
What are the mechanisms of transudate production?
-decreased oncotic pressure
-increased hydraulic pressure
-altered lymphatic drainage
What is a clinical example of decreased oncotic pressure?
protein losing nephropathy
What is a clinical example of increased hydraulic pressure?
right-sided heart failure
What is a clinical example of lymphatic obstruction?
space-occupying mass
What is a transudate?
fluid with low cellularity and variable protein concentration
What difference determines if a transudate will have high or low protein?
-transudates that come from vessels with small fenestrations will have low protein
-transudates that come from vessels with large fenestrations will have high protein
What is the pathophysiology of exudates?
-sterile or infectious inflammatory stimulus
-inflammation leads to increased vascular permeability
-leaky vessels allows for exudation of fluid, protein, and cells
-chemokines attract inflammatory cells
What is an exudate?
fluid with high cellularity and high protein
What are the characteristics of a sterile exudate?
-high protein
-high cellularity
-non-degenerate neutrophils
-submitted for bact. culture as a precaution
What is sepsis?
systemic inflammation due to bacterial infection
What are the two meanings of septic?
-“a patient that has sepsis”
-“containing bacteria,” but not having the clinical syndrome of sepsis
What are the characteristics of a septic effusion?
-high protein
-high cellularity
-degenerate neutrophils
-bacteria phagocytized by neutrophils and/or macrophages
-positive bact. culture is gold standard for diagnosis
What are the characteristics of glucose as an effusion biochemical marker?
-helps ID septic effusion
-fluid glucose is typically less than plasma glucose
What are the characteristics of lactate as an effusion biochemical marker?
-helps ID septic effusion or strangulating obstruction
-fluid lactate is typically greater than plasma lactate
What are the characteristics of a low-protein transudate?
-colorless and clear
-total protein less than 2.5
-total nucleated cell count less than 5000
-mononuclear cells predominate
What are the characteristics of a high-protein transudate?
-light yellow and clear
-total protein greater than 2.5
-total nucleated cell count less than 5000
-mononuclear cells predominate
What are the characteristics of an exudate?
-variable color
-turbid/cloudy/opaque
-total protein greater than 2.5
-total nucleated cell count greater than 5000
-neutrophils predominate
What type of effusion is typically seen with inflammation in a body cavity?
exudate
Which types of effusion are typically seen with organ rupture?
-exudate
-hemorrhage
What are the characteristics of effusions due to GI rupture?
-variable appearance
-find mixed bacteria and debris
-can perform glucose and lactate testing
-caused by linear foreign body or necrosis from neoplasia
What are the characteristics of uroabdomen?
-variable appearance
-looks like a transudate early on
-looks like an exudate later on
-crystals that are typically found in urine may be seen
-can test creatinine and potassium conc.; confirmatory if 2x greater than plasma conc.
-caused by urinary tract rupture
What are the characteristics of chylous effusion?
-white, milky, lactescent
-highly vacuolated light purple background with many small lymphocytes
-triglyceride conc. greater than 100mg/dL is confirmatory
-caused by lymphatic duct rupture or leakage
What are the characteristics of bile peritonitis?
-exudate appearance
-presence of bile in background and within macrophages
-bilirubin conc. 2x greater than plasma bilirubin is confirmatory
-caused by biliary tract rupture
What are the characteristics of hemorrhagic effusion?
-grossly bloody
-looks like a blood smear, but minus platelets
-may see erythrophagocytosis and/or presence of hemosiderin
-PCV >3% suggests hemorrhagic component
-caused by organ rupture or coagulopathy
What are the characteristics of neoplastic effusion?
-variable appearance
-will see cells with malignancy features
-flow cytometry, PARR, and special stains help to confirm
-caused by tumor rupture or exfoliation
What are the characteristics of pericardial effusion?
-often hemorrhagic but can appear like a transudate
-typically appears like a hemorrhagic effusion +/- mesothelial cells
-can be caused by idiopathic pericarditis, neoplastic rupture, or atrial rupture
