SM 172a - Pleural Diseases Flashcards
Which layer of pleura is thicker?
The visceral pleura is thicker than the parietal pleura
An exudative pleural effusion with low glucose on thoracentesis is most worrisome for…
- Infection
- Malignancy with metastasis to the pleura
- Rheumatoid arthritis
A cardiogenic pleural infusion is [transudative/exudative]
A cardiogenic pleural infusion is transudative
How is pleural effusion diagnosed?
Bedside ultrasound
Confirms findings of chest x-ray and can guide safe drainage
(Chest x-ray may miss a pleural effusion)
What is the treatment for a plerual effusion?
THORACENTESIS
Drain if large and symptomatic or when infected
- If transudative
- Treat HF first, effusion will usually resolve on its own
- If exudative
- Additional testing is necessary
What is the treatment for pneumothorax?
- Small pneumothorax
- May go away on its own
- Large pneumothorax (tension)
- Emergent needle decompression
- Chest tube drainage
- May obliterate pleural space to prevent recurrence
An exudative pleural effusion with low pH on thoracentesis is most worrisome for…
- Infection
- Malignancy w/pleural metastasis
- Esophageal perforation
Must place a CHEST TUBE if pH < 7.2
A patient with a pleural effusion has the following labs:
Pleural fluid LDH = 200 units/L
Serum LDH = 200 units/L
Lymphocytes = 80%
What are the most likely causes of the pleural effusion?
This is an exudative pleural effusion
Pleural LDH / Serum LDH = 1
Lymphocyte-predominance increases the liklihood of:
- Autimmune disorder (ex: connective tissue diesease)
- Cancer/malignancy
- Tuberculosis
- If >5% mesothelial cells, it is not TB
- Fungal infection
How does parapneumonic effusion lead to plerual effusion?
A parapneumonic effusion is caused by inflammation
Inflammation -> increased permeabiltiy of capillaries and pleural lining, leading to fluid leakage into the pleural space
How can a pneumothorax lead to heart failure?
If the pneumothorax is closed, air will build up in the pleural space with every expiration
Intrapleural pressure becomes positive, and puts pressure on the right atirum
This impairs filling fo the heart, leading to circulatory collapse
Describe the presentation of a patient with a pleural effusion
Often asymptomatic and usually nonspecific if symptomatic
- Nonproductive cough
- Chest discomfort
- Pain indicates inflammation of the parietal pleura
- Dyspnea
What is an empyema?
Pus in the pleural space
What determines fluid flow in the pleural space?
Starling forces
A patient with a pleural effusion has the following labs:
Pleural fluid LDH = 200 units/L
Serum LDH = 200 units/L
Neutrophils = 80%
What is the most likely cause of the pleural effusion?
This is an exudative pleural effusion
Pleural LDH / Serum LDH = 1
Neutrophil-predominance increases the liklihood of infection (ex: bacterial pneumonia) as the cause of the pleural effusion
What is the function of pleural fluid?
Lubricates the pleural space, allowing for mechanical coupling of the lung, chest wall, and diaphragm
Where is microfilration pressure highest:
The parietal or visceral pleura?
The microfiltration pressure is higher in the parietal pleura - it drains into the systemic circulation
The visceral pleura drains into the lower-pressure pulmonary veins, so the microfiltration pressure is lower
What is the function of the parietal pleura?
Forms pleural fluid
How does congestive heart failure lead to pleural effusion?
Congestive HF increases microvascular hydrostatic pressure
More fluid will leak out of the microvasculature, leading to pleural effusion
What is the pleura made from?
Collagen + Elastin, covered by a single layer of mesothelium
What is the function of the visceral pleura?
The visceral pleura provides mechanical support for the lung
An exudative pleural effusion with high lymphocytes on thoracentesis is most worrisome for…
- Autimmune disease
- Ex: connective tissue disease
- Malignancy
- Tuberculous infecion (MTB or NTM)
- Fungal infection
What are the 3 most common causes of transudative pleural effusions?
- Congestive heart failure -> Increased capillary hydrostatic P
- Liver cirrhosis -> Decreased capillary oncotic P
- Nephrotic syndrome -> Decreased capillary oncotic P
LDH levels in the pleura correlate with…
Inflammation ino or near the pleural.
LDH in the pleural fluid is increased when the pleura is leaky or inflamed, such as in an exudative pleural effusion
What are the characteristics of a primary, spontaneous pneumothorax?
- No underlying lung pathology
- No inciting event
- Tends to occur in young, thin, tall patients
- High recurrence rates
- May obliterate pleural space to prevent
What are the characterisitcs of a secondary spontaneous pneumothorax?
A spontaneous pneumothorax (no inciting event) in a patient with underlying lung disease
May be caused by anything that causes holes in the lung
- Cystic lung disease
- Infection
- Malignancy
An exudative pleural effusion with cholesterol > 45 mg/dL on thoracentesis is most worrisome for…
Chylothorax - cholesterol in the pleural space
What is the function of the pleural space?
Reservoir for excess lung water
Blood flow in the pleura comes from…
The systemic circulation
What physical exam findings would be worrisome for tension pneumothorax?
Tracheal shift
What lung diseases can predispose a patient to pneumothorax?
Anything that can cause holes in the lung
- Cystic lung disease
- Lymphangioleiomatosis
- Cystic fibrosis
- Infection
- Cavitary pneumonia
- Malignancy
What are lymphatic stroma?
Which layer of pleura has them?
Lymphatic stroma are little vaccumes that drain pleural fluid from the tissue to the lymphatics
They are found in the parietal pleura but not the visceral pleura
Blood supply to the parietal pleura drains into the
_________
Blood supply to the parietal pleura drains into the
systemic circulation
Describe Light’s Criteria for classification of pleural effusion
An effusion is exudative if it meets any of these criteria
- (Plerual fluid total protein) / (serum total protein) > 0.5
- (Pleural fluid LDH) / (serum LDH) > 0.6
- Pleural fluid LDH > 2/3 of the upper normal value of serum LDH
The concentration of protein in the pleural fluid is an estimate of the leakinesss of the pleural membrane to protein
More leaky = more protein in the effusion = exudative
How does nephrotic syndrome lead to pleural effusion?
Nephrotic syndrome -> decreased microvascular oncotic pressure
Less force sucking fluid into the capillaries = more fluid leaking out into the pleural space
In a patient with pleural effusion, what is the cause of the patient’s chest pain?
- Inflammed lung tissue
- Punctured visceral plerua
- Inflammed parietal pleura
- Hypoxia
d. Inflammed parietal pleura
Visceral pleura and lung tissue do not have sensory innervation
Hypoxia may cause pain, but not localized to the chest
An exudative pleural effusion with high neutrophils on thoracentesis is most worrisome for…
Bacterial infection
How can malignancy lead to pleural effusion?
A tumor an cause obstuction to lymphatic drainage.
This increased microcirculatory hydrostatic pressure, casuing fluid to filter into the interstitial space
What is more dangerous:
An open pneumothorax or a closed pneumothorax?
Why?
Closed pneumothorax: Air gets trapped in the pleural space with every expiration, leading to tension pneumothorax
In an open pneumothorax (hole in the chest wall), expiration just pushes the air out
How does a trapped lung lead to plerual effusion?
A trapped lung leads to decreased pleural space pressure
This decreases the hydrostatic pressur of the pleural space, and promotes fluid leakeage from the microvasculatrue into the pleural space
What patient condition might cause a “false positive” for an exudative effusion, based on Light’s Criteria?
Heart failure treated with diuretics
Diuretics increase the protein content of the pleural effusion, even when the cause of the effusion is transudative
What determines the subatmospheric pressure in the pleural space (PiP)?
- Pleural surface pressure
- The lung pulling in and the chest wall pulling out
- Pleural liquid pressure
- Pumping pressure of parietal pleura lymphatic stroma that suck liquid out of the pleural space
Blood supply to the visceral pleura drains into the
_________
Blood supply to the visceral pleura drains into the
low-pressure pulmonary veins
In the most general sense, what causes pleural effusion?
Pleural effusion = fluid in the pleural space
Due to imbalance between
pleural fluid filtration and lymphatic clearance
Describe the clinical presentation and physical exam findings of pneumothorax
Usually symptomatic
- Pleuritic chest pain
- Dyspnea
- Cough
- On the side with the pneumothorax
- Increased volume
- Hyperresonance to percussion
- Decreased breath sounds
- Increased fremitus
