🎧 Pleural Disease: MUST KNOW FACTS
December 4, 2023 | RR Baliga, MD
Dr Baliga's Internal Medicine "MUST KNOW FACTS PODCASTS' for Physicians from a chapter titled "Pleural Disease" authored by Jeremy B Richards & Richards MD M Schwartzstein, MD, Harvard Medical School & Beth Israel Deaconess Medical Center, Boston, MA in Baliga's Textbook of Internal Medicine: An Intensive Board Review with 1480 MCQs | www.MasterMedFacts.com
- The visceral pleura is adherent to the external surface of the lungs, including the fissures between the lobes of the lungs while the parietal pleura lines the chest wall and is in direct apposition with the visceral pleura.
- Disruption in apposition between the visceral and parietal pleural can cause uncoupling of the expanding forces of the chest wall and the collapsing forces of the lungs, resulting in aberrations in respiratory system functioning both locally (at the specific site of pathology) and globally (as respiratory system functioning is affected). Dyspnea may ensue.
- Transudative effusions are due to increases in capillary hydrostatic pressure and/or decreases in capillary oncotic pressure; fluid is characterized by a low protein concentration and a low concentration of inflammatory markers.
- Exudative effusions are caused by increased capillary permeability and leakage of fluid and proteins into the pleural space; fluid is characterized by a high protein concentration and a high concentration of inflammatory markers.
- The absence of tactile fremitus is associated with an increased likelihood of pleural effusion, and dullness to percussion is the most accurate physical exam finding for its diagnosis.
- Pleural pressures should be measured during thoracentesis after every 250 cc to 500 cc is drained, and thoracentesis should be aborted if the pleural pressure is more negative than -20 cm H2O to minimize the risk of re-expansion pulmonary edema.
- “Trapped lung” is a condition in which the visceral pleural has become fibrotic and increasingly stiff, usually due to prior pleural inflammation; associated pleural effusions are transudative. Lung entrapment describes a condition in which the lung does not re-expand when pleural fluid is removed because of decreased pulmonary compliance due to pathology within the lung itself; associated pleural effusions are exudative. In both situations, the lung does not fully expand after fluid is removed. The two conditions can be distinguished by the assessment of pleural pressure during a thoracentesis and the characteristics of the effusion.
- Small pneumothoraces may be monitored clinically while providing high levels of FiO2, while a large pneumothorax with tension physiology requires immediate decompression (with a 14 gauge angiocath and/or immediate chest tube placement).
- Malignant mesothelioma is associated with an average survival of one year after diagnosis; five-year survival is 5%.
- Pleurodesis may be indicated for some patients with pleural effusions who have rapid re-accumulation of pleural fluid and who do not desire, cannot tolerate, or have not responded to indwelling catheter drainage.