Pleural effusion Flashcards
pleural effusion also known as
hydrothorax
Presence of fluid in pleural cavity.
Is Not an independent illness, but a symptom!
Several etiologically different diseases
cause pleural effusion.
Broad physical causes of pleural effusion (not ddx) (3)
Presence of fluid in pleural cavity due to:
- Increased production
- Increased hydrostatic pressure,
- increased vascular permeability,
- decreased oncotic pressure - Decreased absorption
Several etiologically different diseases
cause pleural effusion.
(4 observations)
▪ diaphragmatic and cardiac silhouettes obscured.
▪Retraction of lung margins from thoracic wall.
▪Rounding of lung margins at costophrenic angles (so the angle formed at the caudal thorax by diaphragm and last ribs).
▪Lungs appear floating in the fluid.
Pleural effusion – signs and clinical findings
Symptoms depend on the cause of effusion, volume of fluid and rate of fluid accumulation.
Signs:
▪ Cough, respiratory distress, lethargy, exercise intolerance, reluctance to lay down, anorexia, weight loss. Asynchronous breathing pattern (when thorax out- abdo in).
Clinical findings
▪ Dyspnea, tachypnea, cyanosis, shallow breathing
▪ Muffled lung and heart sounds
e.g. Ventral vs. dorsal (gravity dependent fluid muffles sounds ventrally)
Left sided heart failure does NOT cause
pleural effusion in dogs.
Right sided cardiac failure causes pleural effusion and ascites in dogs.
Which sided heart failure causes pleural effusion in dogs?
Right sided cardiac failure causes pleural effusion and ascites in dogs. NOT left sided.
When to do Thoracocentesis?
▪ Suspicion of pleural disease is enough!
▪ Therapeutic and diagnostic, potentially life-saving!
▪ Usually no sedation or local anesthesia is needed.
Puncture site
▪ 7th-9th intercostal space
▪ Upper part of the lower 1/3 of the chest
▪ Cranial to the rib - nerves and vessels run caudally to every rib.
Puncture site for thoracocentesis.
▪ 7th-9th intercostal space
▪ Upper part of the lower 1/3 of the chest
▪ Cranial to the rib - nerves and vessels run caudally to every rib.
drug therapy for FIP treatment (2)
remdesivir IV, SC
GS-441524 nucleoside analog PO
(is the main plasma metabolite of the antiviral prodrug remdesivir)
Describe Thoracocentesis procedure.
▪ Clip hair, scrub skin, use sterile gloves
▪ Butterfly needle, three-way stopcock, syringe
▪ Direct the needle bevel toward the lung
▪ Insert the needle perpendicular to chest wall and advance until pleura is penetrated.
▪ Then angle the needle parallel to chest wall, direct the tip ventrally.
▪ Aspirate as much fluid as you can
Analysis of pleural effusion
▪ Measure protein concentration with a refractometer
▪ Perform aerobic and anaerobic bacterial cultures
▪ Calculate the amount of cells by hand with a Bürker counting chamber or automatically with a hematology machine.
Other analyses when indicated:
▪ Cytological analysis of the smears, Gram-staining
▪ Triglycerides and cholesterol (incase of chylothorax)
▪ pH, glucose (in case of pyothorax both are low)
What should you do first when presented with a dyspneic cat?
thoracocentesis
(do NOT give furosemide first thing, it’ll only help if its a cardiogenic pulmonary edema)
Main effusion types. (3+4)
▪ Transudate
▪ Modified transudate
▪ Exudate
Which can be Nonseptic, septic, chylous, hemorrhagic.
Describe transudates.
▪ Clear, colourless fluid
▪ Low protein (< 25 g/l) and low cellularity (< 1500 cells/µl) (Mononuclear cells)
Causes of transudates:
▪ Hypoalbuminemia (Liver failure, glomerulonephropathy, protein-losing
enteropathy)
▪ Cardiac failure
Treat the underlying disease.
Describe modified transudates.
▪ Hazy or turbid, yellowish, pink, red
▪ Moderate cellularity (< 7000 cells/µl) and
protein concentration (25-40 g/l) (remember: “modified for moderate”)
Causes:
▪ Right-sided cardiac failure in cats and dogs (e.g. tricuspidal regurgitation,
pericardial effusion,
pulmonary hypertension,
cardiomyopathy),
left-sided cardiac failure in cats,
lung lobe torsion,
diaphragmatic hernia,
neoplasia
Treat the underlying disease.
Describe Nonseptic exudatess.
Is an Inflammatory effusion.
Non-septic = no bacterial infection present.
▪ High protein (> 30 g/l) and cellularity (> 5000 cells/µl)
(Both mononuclear cells and neutrophils)
▪ e.g. due to FIP, neoplasia, chronic chylothorax, chronic lung lobe torsion, fungal effusion
▪ Chronic effusions turn more inflammatory over time!
Treat the underlying disease.
Describe Septic exudates.
= pyothorax
▪ Bacterial infection of the pleural cavity.
▪ Lots of cells ( > 7000 cells/µl, usually > 30 000 cells/µl), predominantly neutrophils, intracellular bacteria,
degenerated neutrophils.
▪ Bad smell in anaerobic and mixed
infections.
▪ Low pH (≤ 6.9), low glucose
Describe Chylothorax
= chyle in pleural cavity
▪ Milky white, pink, opaque
▪ Cellularity and protein as in modified transudate or non-septic exudate. Mainly lymphocytes, neutrophils increase if chronic.
If Triglycerides in effusion > triglycerides in blood, is diagnostic for chyle.
If Cholesterol in effusion ≤ cholesterol in blood, its chylous because chyle is dominated by triglyceride-rich chylomicrons rather than cholesterol-rich lipoproteins.
Can be caused by Cardiac disease (cardiomyopathy, pericardial effusion,
congestive heart failure),
lung lobe torsion,
diaphragmatic hernia,
rupture or obstruction of thoracic duct, mediastinal mass,
other neoplasia etc.
Often Cause is not identified
= Idiopatic chylothorax
▪ Afghan, shiba inu, oriental cats
Chest drain (chest tube) indications (2)
repeated thoracocentesis,
lavage of pleural cavity
Describe chest tube placement.
▪ MILA International Inc® Fenestrated small-bore wire-guided chest tube
▪ Aseptic preparation, local skin block with lidocaine, sedation if necessary
▪ 7th to 9th intercostal space
▪ Do not tunnel under skin
▪ Suture tube into place
