Lecture 22: Pleural Disease Flashcards
(40 cards)
Describe lymph drainage to pleura (parietal and visceral)
Parietal lymphatics drain into internal mammary chain anterioraly and internal intercostal chain posteriorarly; Visceral lymphatics drain to hilar and middle mediastinal lymph nodes
Which pleura is primarily responsible for pleural fluid formation and absorption? What is a compensatory function of this structure?
Parietal pleura –> Parietal pleural lymphatics can increase fluid absorption capacity many-fold
Three ways to get fluid into pleural space
- High osmotic pressure in capillaries (transudate); 2. High oncotic pressure in pleural area (junk in pleura) OR decreased oncotic pressure in capillaries (transudate); 3. Altered permeability of pleural membranes (exudate)
Which layer of pleura contains the lymphatic stomata?
Parietal pleura
What is the difference between exudate and transudate?
Exudate = something is in the fluid; transudate = just fluid
Physical findings of pleural effusions
Decreased breath sounds and fremitus, dullness to percussion
Chest radiographs usually under/over estimate amount of fluid in pleural effusions? What sign do we look for in chest x-ray?
Under –> takes a lot of fluid (~1/2 liter) to blunt the costophrenic angle
What position in chest x-ray detects free-flowing effusions?
Lateral decubitus
How do we clear pleural effusions? Describe procedure
Thoracentesis: guide via CXR or ultrasound one interspace below loss of fremitus/dullness over the rib
What “chemistries” do we perform on pleural fluid? What else?
Protein, LDH, glucose; cell count, pH, gram stain
Light’s criteria
Exudate IF (only need one): pleural fluid/serum protein ratio > 0.5; pleural fluid/serum LDH ratio > 0.6; pleural fluid LDH > 2/3 upper limit of normal
What is a pleural exudate often the result of?
Inflammation or tissue destruction
What kind of things cause transudative effusions? Most common?
Heart failure (most common), renal problems, hypoalbuminemia
These two things can cause EITHER a transudative or exudative effusion
Malignancy, pulmonary emoblism
Three causes of pleural effusion
- Increased hydrostatic pressure (CHF); 2. Decreased plasma oncotic pressure (liver/kidney); 3. Movement of transudative abdominal fluid (ascites)
Describe hepatic hydrothorax. Tx?
Pressure in abdomen is positive, pleura is negative, fluid moves up if there is a connection, source is ascities; more common on right side; treat ascites
Top two causes of exudative effusions?
Infections and malignancy
Some other causes of exudative effusions…
Collagen, PE, Dressler’s, asbestos, pancreatitis…
Three categories of parapneumonic effusion
Simple (relatively small, doesn’t have to be drained); Complicated (must be drained; Empyema (pus in chest, must be chained)
Parapneuomic effusion is exudate or transudate?
Exudate (inflammatory)
What can an undrained empyema lead to?
Fibrothorax or even septic shock
Very low pH or very high LDH in parapneumonic effusion means what?
You could have a complicated paraneumonic effusion…You should drain it!
Describe tuberculous pleuritis. Exudative or transudative? Mechanism?
Subpleural focus of TB ruptures into pleural space 6-12 weeks after primary infection or reactivation of disease; exudative; TB antigen in pleural space causes hypersensitivity reaction
If tuberculous pleuritis is not drained, what can happen?
65% will go onto develop active TB
