STEPUP Diseases of the Pulmonary System: Diseases of the Pleura

Question 1

By what mechanisms is a pleural effusion caused?

Answer 1

Caused by one of the following mechanisms:

1) Increased drainage of fluid into pleural space
2) Increased production of fluid by cells in the pleural space
3) Decreased drainage of fluid from the pleural space

Question 2

What are transudative effusions due to?

Answer 2

Pathophysiology is due to either:

1) Elevated capillary pressure in visceral or parenteral pleura (e.g., CHF)
2) Decreased plasma oncotic pressure (e.g., hypoalbuminemia)

Question 3

What are exudative effusions due to?

Answer 3

Pathophysiology: caused by increased permeability of pleural surfaces or decreased lymphatic flow from pleural surface because of damage to pleural membranes or vasculature

Question 4

When are pleural effusions well tolerated? What may a pleural effusion in the presence of lung disease lead to?

Answer 4

1) If the patient has minimal lung compromise, pleural effusions are well tolerated
2) Respiratory failure

Question 5

What are causes of transudative pleural effusions?

Answer 5

1) CHF
2) Cirrhosis
3) PE
4) Nephrotic syndrome
5) Peritoneal dialysis
6) Hypoalbuminemia
7) Atelectasis

Question 6

What are causes of exudative pleural effusions?

Answer 6

1) Bacterial pneumonia, TB
2) Malignancy, metastatic disease
3) Viral infection
4) PE
5) Collagen vascular diseases

Question 7

If an exudative effusion is suspected, what tests should be performed on the pleural fluid?

Answer 7

1) Differential cell count
2) Total protein
3) LDH
4) Glucose
5) pH
6) Amylase
7) Triglycerides
8) Microbiology
9) Cytology

Question 8

What are the Light’s criteria?

Answer 8

Exudative effusions meet at least one of the following of Light’s criteria (transudates have none of these):

1) Protein (pleural)/protein (serum) >0.5
2) LDH (pleural)/LDH (serum) >0.6
3) LDH > two-thirds the upper limit of normal serum LDH

Question 9

What are causes of pleural effusion?

Answer 9

1) CHF is the most common cause
2) Pneumonia (bacterial)
3) Malignancies: lung (36%), breast (25%), lymphoma (10%)
4) Pulmonary embolism (PE)
5) Viral diseases
6) Cirrhosis with ascites

Question 10

What are causes of elevated pleural fluid amylase?

Answer 10

1) Esophageal rupture
2) Pancreatitis
3) Malignancy

Question 11

What is milky, opalescent pleural fluid?

Answer 11

Chylothorax (lymph in the pleural space)

Question 12

What is frankly purulent pleural fluid?

Answer 12

Empyema (pus in the pleural space)

Question 13

What is a bloody pleural effusion?

Answer 13

Malignancy

Question 14

What are exudative pleural effusions that are primarily lymphocytic?

Answer 14

TB

Question 15

What causes a pleural effusion with pH <7.2?

Answer 15

1) Parapneumonic effusion

2) Empyema

Question 16

What should you consider in your differential if pleural fluid glucose level is <60? What are other causes?

Answer 16

1) Rheumatoid arthritis

2) TB, esophageal rupture, malignancy, lupus

Question 17

What are some symptoms of pleural effusion?

Answer 17

1) Often asymptomatic
2) Dyspnea on exertion
3) Peripheral edema
4) Orthopnea, paroxysmal nocturnal dyspnea

Question 18

What are signs of pleural effusion?

Answer 18

1) Dullness to percussion
2) Decreased breath sounds over the effusion
3) Decreased tactile fremitus

Question 19

How can you confirm the presence and evaluate the size of a pleural effusion?

Answer 19

1) CXR (PA and lateral)
2) CT scan - more reliable than CXR for detecting effusions
3) Thoracentesis

Question 20

What will be seen on CXR in a pleural effusion? How much pleural fluid must accumulate before an effusion can be detected? What are lateral decubitus films more reliable than PA and lateral CXRs for detecting?

Answer 20

1) Blunting of costophrenic angle
2) About 250mL
3) Small pleural effusions; can also determine whether fluid is free flowing or loculated

Question 21

When is a thoracentesis useful? Is it therapeutic? What is a complication of thoracentesis and does it require treatment? When should you avoid performing a thoracentesis?

Answer 21

If etiology is not obvious. It provides a diagnosis in 75% of patients, and even when it is not diagnostic it provides important clinical information

2) Yes - drainage provides relief for large effusions
3) Pneumothorax is a complication seen in 10% to 15% of thoracenteses, but it requires treatment with a chest tube in <5% of cases
4) Do not perform thoracentesis if effusion is <10-mm thick on lateral internal decubitus CXR

Question 22

What is the treatment for transudative effusions?

Answer 22

1) Diuretics and sodium restriction

2) Therapeutic thoracentesis - only if massive effusion is causing dyspnea

Question 23

What is the treatment for exudative effusions?

Answer 23

Treat underlying disease

Question 24

What is a parapneumonic effusion?

Answer 24

Pleural effusion in presence of pneumonia (a noninfected pleural effusion secondary to bacterial pneumonia)

Question 25

How do you treat an uncomplicated parapneumonic effusion? How do you treat a complicated parapneumonic effusion?

Answer 25

1) Antibiotics alone (in most cases)
2) a) Chest tube drainage
b) Intrapleural injection of thrombolytic agents (streptokinase or urokinase); may accelerate the drainage
c) Surgical lysis of adhesions may be required

Question 26

What are the criteria for a complicated parapneumonic effusion?

Answer 26

The criteria for a complicated parapneumonic effusion include:

1) The presence of pus
2) Gram stain–positive or culture-positive pleural fluid
3) Pleural fluid pH <7.20
4) Pleural fluid LDH that is greater than three times the upper limit of normal of serum LDH

Question 27

What is an empyema?

Answer 27

A complicated parapneumonic effusion, which means the pleural effusion is infected

Question 28

What can lead to empyema (pus within the pleural space) if left untreated? How do most cases occur?

Answer 28

1) Exudative pleural effusions
2) Most cases occur as a complication of bacterial pneumonia, but other foci of infection can also spread to the pleural space (e.g., mediastinitis, abscess)

Question 29

What are clinical features of empyema?

Answer 29

The clinical features are those of the underlying disease (pneumonia most common)

Question 30

How is the diagnosis of empyema made?

Answer 30

CXR and CT scan of the chest are the recommended tests

Question 31

How is empyema treated? Is the infection easy to rid of and is recurrence common? What does this require? If empyema is severe and persistent, what may be necessary?

Answer 31

1) Treat empyema with aggressive drainage of the pleura (via thoracentesis) and antibiotic therapy
2) The infection is very difficult to eradicate, and recurrence is common, requiring repeated drainage
3) If empyema is severe and persistent, rib resection and open drainage may be necessary