Pleural Effusions Flashcards
What lines the surface of both parietal and visceral pleura?
mesothelial cells
Does visceral pleura have stomata and sensory fibers?
NO!!! (think about when get pleuritic pain - when the parietal pleura is irritated!!!) visceral pleura does NOT have sensory fibers, parietal pleura does!!!
What are three things that happens when there is abnormal accumulation of stuff in the pleural space?
bad news bears!!
- mechanical uncoupling of lung and chest wall
- reduction in FRC (restrictive physio)
- atelactasis and impaired gas exchange (shunt - i.e. lack of ventilation)
How much pleural fluid is normally in each hemithorax?
8-10 cc
How does a clinically significant effusion happen?
increased pleural fluid production and/or impaired lymphatic resorbtion (ie. either make too much and/or trouble getting rid of it)
Where does pleural fluid come from?
PLEURAL CAPILLARIES
- parietal: intercostal and internal mammary arteries (major contributor)
- visceral: bronchial arteries (minor - not pulling much weight :P)
What takes pleural fluid away (i.e. clears it away)?
- parietal lymphatics (major contributor)
- pulmonary capillaries (minor
(looks like the parietal does most of the work with pleural fluid - bring it AND taking it away)
Causes of pleural effusion
- increased driving pressure –> transudative pleural effusion (more watery)
- altered permeability –> exudative pleural effusion (more proteinaceous)
examples of increased driving pressure
- incr intravascular P (Pcap_
- decr Ppl
- decr plasma protein (decr COPcap)
- incr gradient for flow from peritoneal to pleural space (Ppr >Ppl)
TRANSUDATES!!!!!
examples of altered permeability
- incr permeability
- decr lymphatic clearance via stomata
- structural disruption
EXUDATES!!!!
transudate v. exudate
transudate - watery
exudate - high protein content
How much pleural fluid usu needs to acculumate before sx?
> 300-500cc!
often a-sx before that, keep in mind normal is 8-10 cc per hemithorax
Sx of pleura effusion
- dyspnea (>50%),
- cough (40%),
- pleuritic chest pain - inflammation of the parietal pleura
- fever - more common in infectious/inflamm disease
Physical findings
- dullness to percussion
- decr breath sounds
- egophony at UPPER border (compressive actelectasis)
- pleural friction rub
egophony
- increased resonance of voice sounds[1] heard when auscultating the lungs, often caused by lung consolidation and fibrosis
- E to A transition
thoracentesis
removal of xs pleural fluid
indication for thoracentesis
- fluid of unknown etio, esp important for
- unilateral effusion (esp Lft side)
- bilateral effusions of unequal size
- normal cardiac silhouette on CXR
- febrile patient
- clinical evidence of pleurisy
- concern for undiagnosed malignancy
- relief of dyspnea
Where does the needle go for thoracentesis and why?
ABOVE the rib
b/c the nerves and vessels that feed the rib run along the inferior aspect of that rib
Light’s Criteria for exudate
exudate if ANY one of following present:
- pleural fluid:serum protein ratio of >0.5
- pleural fluid: serum LDH ratio of >0.6
- pleural fluid LDH >2/3 upper limits of normal serum value
Is the pleural usually intact in transudative pleural effusion?
YES!
- normal ability to restrict movement of protein and other large molecules (normal permeability)
- can think of transudative effusion as the more watery effusion
What disease states most commonly lead to transudative effusion?
CHD, nephrotic syndrome, cirrhosis complicated by ascites
Rare causes of pleural effusion include . . .
- Pulmonary embolism
- peritoneal dialysis
- pericardial disease
- hypoalbuminemia (<1.5)
- sarcoidosis
- SVC syndrome
- urinothorax
- myxedema
What are some diseases that productive exudative effusion?
infectious, inflamm, and malignant disease --> exudative effusion (proteinaceous) these include: - parapneumonic effusion/empyema - malignant effusion - TB - PE (infarct) - connective tissue disease (SLE, RA) - absestos exposure - pancreatitis, esophageal perforation
chylothorax
a rare cause of exudative effusion w/ incr lipid content that results from obstruction or disruption of thoracic duct
