Pleural Effusion and Pneumothorax Flashcards
Under normal circumstances, what is the volume of the pleural space?
1-20cc
Describe pleural fluid
clear, odorless with some nucleated cells whose function is lubrication of the pleural surface
What is the cellular composition of pleural fluid?
less than 1.5l/ul
70-80% macrophages
10% lymphocytes
2% PMNs
Normal protein conc in the pleural space?
1-1.5g/dL
What factors contribute to the development of pleural effusion?
- hydrostatic pressure
- lymphatic drainage
- colloid oncotic pressure
- tissue pressure
airway pressure does not
T or F. The parietal pleura has a low hydrostatic pressure
F. It is high which promotes movement of fluid into the pleural space through junctions (100ml/hr)
T or F. The visceral pleura has a low hydrostatic pressure
T. So it functions to move fluid out (300ml/hr)
What is the difference between a transudate or an exudate?
In a pleural effusion, different fluids can enter the pleural cavity. Transudate is fluid pushed through the capillary due to high pressure within the capillary (i.e. low proteins). Exudate is fluid that leaks around the cells of the capillaries caused by inflammation.
What are the pressure-based causes of pleural effusion?
- increased hydrostatic pressure
- decreased pleural pressure
- increased OR decreased oncotic pressure
When are hydrostatic pressures increased?
heart failure (transudate)
When are pleural pressures decreased?
atelectasis (transudate)
When are oncotic pressures increased?
inflammation (exudate)
When are oncotic pressures decreased?
low albumin (transudate)
T or F. In pleural effusion due to CHF, both the parietal and visceral pleura are adding fluid into the space
T. Oncotic pressure gradient not affected
Characteristics of CHF pleural effusion
- frequently bilateral
- cardiomegaly
The quantity of effusion related to CHF is based on what?
proportional to elevation in pulmonary artery capillary wedge pressure (24+ mm Hg)
What are some pathologies that might promote an exudative pleural effusion?
- infection
- inflammation
- cancer
What happens to the oncotic pressure gradient in exudate rich pleural effusions?
it decreases. Hydrostatic pressures not affected
T or F. In pleural effusion due to inflammation, both the parietal and visceral pleura are adding fluid into the space
T.
Physical findings of pleural effusion?
- dullness to percussion
- decreased vocal fremitus
What happens to RR in pleural effusion?
increased more as more fluid enters
What happens to breath sounds in pleural effusion?
they decrease and become more vesicular and then bronchovesicular as more fluid enters and then become absent
The fluid associated with malignancy is most likely ____
exudate
What pleural:serum protein ratio suggests transudate effusion?
less than 0.5
What pleural:serum LDH ratio suggests transudate effusion?
less than 0.6
What serum LDH level suggests transudate?
less than 200U/L
A single criteria is enough to call it an exudate
What are some common causes of transudates?
- CHF
- Nephrotic syndrome
- Cirrhosis with ascites
What are some common causes of exudates?
- Peritoneal dialysis
- viral infection
- malignancy
- pancreatitis
- atelectasis
- pulmonary embolism
Determining cause of effusion based on cell count. Less than 1000/ul suggests what?
transudate
Determining cause of effusion based on cell count. Greater than 5000/ul suggests what?
chronic exudate (lymphocytes)- TB or malignancy
Determining cause of effusion based on cell count. Greater than 10,000/ul suggests what?
substantial inflammation (neutrophils)
- parapneumonic
- pancreatitis
- pulmonary infarction
Determining cause of effusion based on cell count. Greater than 50,000/ul suggests what?
parapneumonic effusions ONLY
High neutrophils equals what?
acute inflammation
85-95% lymphocytes in pleural fluid suggests what?
TB, lymphoma, sarcoidosis, R.A.
50+% lymphocytes in pleural fluid suggests what?
in 2/3 of carcinomatous effusions
If mesothelial cells are greater than 5%, what does it suggest?
excludes tuberculous pleurisy
What is the first thing that should be done when a pleural effusion is seen?
assess size- size (less than 10mm thick on lateral decubitus or asymptomatic does not need treatment)
What id the PE is large?
order LDH, protein, cholesterol, cell count and differential
T or F. Negative AFB on pleural fluid does not rule out TB
T.
What is primary spontaneous pneumothorax?
patients without identifiable lung diseases but have SUBPLEURAL BLEBS that can rupture and trap air (ball-valve mechanism)
How does primary spontaneous pneumothorax present?
- young previously healthy (tall and thin) patient with acute onset of pleuritic chest pain and dyspnea
4: 1 male:female
What is the first thing that should be done in a tension pneumothorax?
needle decompression in the 2nd ICS anteriorly (16-18 gauge needle)
How does tension pneumothorax present?
- hypotension
- hypoxemia
Which way does the mediastinum shift with a tension pneumothorax? Triad?
away
Triad: Lung collapse, contralateral mediastinum shift, and depression of diaphragm
What kind of probe is used for lung ultrasound?
low frequency probe (or high frequency in thin patients)
What has to happen for lung sliding to occur?
there has to be apposition between the visceral and parietal pleura (there cannot be air)
Lung sliding rules out (100%) ____ at the interspace being imaged
pneumothorax
Pneumothorax
- Absent lung sliding
- Barcode sign on M mode
- Absent B lines
- may or may not have A lines
-Lung point
What is a lung point?
the point where it goes from lung sliding to no lung sliding (dynamic sign)
100% specific for pneumothorax
What does a B line indicate?
thickened interlobular septae or early filling of alveoli
When are/can B lines seen?
- Pulmonary edema
- Interstitial edema
- Interstitial fibrosis
How big must a pleural effusion be for a CXR to detect it?
150cc (ultrasound can detect 5 cc)
