STEPUP Diseases of the Pulmonary System: Diseases of the Pleura Flashcards
By what mechanisms is a pleural effusion caused?
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
What are transudative effusions due to?
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)
What are exudative effusions due to?
Pathophysiology: caused by increased permeability of pleural surfaces or decreased lymphatic flow from pleural surface because of damage to pleural membranes or vasculature
When are pleural effusions well tolerated? What may a pleural effusion in the presence of lung disease lead to?
1) If the patient has minimal lung compromise, pleural effusions are well tolerated
2) Respiratory failure
What are causes of transudative pleural effusions?
1) CHF
2) Cirrhosis
3) PE
4) Nephrotic syndrome
5) Peritoneal dialysis
6) Hypoalbuminemia
7) Atelectasis
What are causes of exudative pleural effusions?
1) Bacterial pneumonia, TB
2) Malignancy, metastatic disease
3) Viral infection
4) PE
5) Collagen vascular diseases
If an exudative effusion is suspected, what tests should be performed on the pleural fluid?
1) Differential cell count
2) Total protein
3) LDH
4) Glucose
5) pH
6) Amylase
7) Triglycerides
8) Microbiology
9) Cytology
What are the Light’s criteria?
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
What are causes of pleural effusion?
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
What are causes of elevated pleural fluid amylase?
1) Esophageal rupture
2) Pancreatitis
3) Malignancy
What is milky, opalescent pleural fluid?
Chylothorax (lymph in the pleural space)
What is frankly purulent pleural fluid?
Empyema (pus in the pleural space)
What is a bloody pleural effusion?
Malignancy
What are exudative pleural effusions that are primarily lymphocytic?
TB
What causes a pleural effusion with pH <7.2?
1) Parapneumonic effusion
2) Empyema
What should you consider in your differential if pleural fluid glucose level is <60? What are other causes?
1) Rheumatoid arthritis
2) TB, esophageal rupture, malignancy, lupus
What are some symptoms of pleural effusion?
1) Often asymptomatic
2) Dyspnea on exertion
3) Peripheral edema
4) Orthopnea, paroxysmal nocturnal dyspnea
What are signs of pleural effusion?
1) Dullness to percussion
2) Decreased breath sounds over the effusion
3) Decreased tactile fremitus
How can you confirm the presence and evaluate the size of a pleural effusion?
1) CXR (PA and lateral)
2) CT scan - more reliable than CXR for detecting effusions
3) Thoracentesis
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?
1) Blunting of costophrenic angle
2) About 250mL
3) Small pleural effusions; can also determine whether fluid is free flowing or loculated
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?
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
What is the treatment for transudative effusions?
1) Diuretics and sodium restriction
2) Therapeutic thoracentesis - only if massive effusion is causing dyspnea
What is the treatment for exudative effusions?
Treat underlying disease
What is a parapneumonic effusion?
Pleural effusion in presence of pneumonia (a noninfected pleural effusion secondary to bacterial pneumonia)
How do you treat an uncomplicated parapneumonic effusion? How do you treat a complicated parapneumonic effusion?
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
What are the criteria for a complicated parapneumonic effusion?
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
What is an empyema?
A complicated parapneumonic effusion, which means the pleural effusion is infected
What can lead to empyema (pus within the pleural space) if left untreated? How do most cases occur?
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)
What are clinical features of empyema?
The clinical features are those of the underlying disease (pneumonia most common)
How is the diagnosis of empyema made?
CXR and CT scan of the chest are the recommended tests
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?
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
