9/24- Pleural & Mediastinal Disease Flashcards
What are the parietal and visceral pleura?
- Blood supply
Parietal pleura
- Systemic circulation
- Adjacent to chest wall
Visceral pleura
- Bronchial circulation
- Adjacent to lung
How much fluid is normally in the pleural space?
Normal ~15 mL
What causes increased pleural fluid formation? (broad mechanisms and examples)
Increased pleural fluid formation
- Hydrostatic changes: transudative
- CHF (s)
- Atelectasis
- Oncotic changes: transudative (s)
- Altered pleura with increased permeability: exudative (l)
Decreased lymphatic drainage: exudative (l)
Combination of above
(s) = systemic factor; treat systemic condition
(l) = local factor; more serious
What are the symptoms and signs of pleural effusion?
- Shortness of breath
- Sudden onset if cause is air
- More slow/progressive if due to CHF transudate
- Cough
- Less common
- Pleuritic chest pain
- more early; not so much later when pleura is spread wide apart by large effusion
- Decreased breath sounds
- Dullness to percussion
- Decreased tactile fremitus
- Distinguishes this from pneumonia
- Decreased chest wall expansion
- Tracheal shift (massive effusions)
How to distinguish between pleural effusion and pneumonia on physical exam?
Tactile fremitus
- Decreased breath sounds in pleural effusion
What is seen in radiology of pleural effusion?
- Blunting of costophrenic angle on PA CXR (at 100 mL)
- Larger amts: characteristic lower lung field homogeneous density that forms a concave meniscus
- Lateral decubitus film: fluid will “layer” if in significant amount
What is seen here?
Pleural effusion
- Fluid “layers” and somewhat clears lung field
What is seen here?
Large effusion- concave mensicus and shift of mediastinum to the right
When is it safe to do a thoracentesis (how much pleural fluid)?
If you can see ~1 cm of layering
Describe thoracentesis
Removal of pleural fluid transthoracically to diagnosis etiology of effusion and/or treat (remove fluid to reduce symptoms)
- Ultrasound-guided
What is seen here?
Can see diaphragm and overlying fluid (and a little collapsed lung)
What are complications of thoracentesis?
- Pneumothorax (11%, 2% require chest tube; down to 3% know with ultrasound guidance)
- Vasovagal reaction
- Infection (2% of pleural infections)
- Hemothorax
- Splenic/hepatic laceration
- Seeding of tumor (mesothelioma)
- Adverse RX to local anesthesia
- HIV/Hepatitis B (like any needle procedure)
- Re-expansion pulmonary edema
- Depends on rapidity [and a little quantity] of fluid removal due to induced negative P in lung
- Only remove 1-2L at a time, max
- Can measure pleural pressure (nl ~ 5); with pleural effusion P will be 0 -> (+). Keep drawing fluid until too negative (~ - 20)
Should needle be entered right above the lower rib or right below the upper rib?
Just above lower rib
- Vascular bundle located just under ribs, so avoid that
What is seen here?
Patient with large pleural effusion (see meniscus sign on left; right lung)
Same pt following chest tube for fluid removal of his pleural effusion. What is this?
Re-expansion pulmonary edema following rapid removal of pleural effusion fluid
What is the first decision point in evaluation of effusions?
- How is this done/what criteria?
Transudative vs. Exudative effusion
- Based on the results of evaluation of pleural fluid
- Differentiation based on Light’s criteria
What is Light’s criteria?
Exudate has at least 1 criteria, a transudate has none:
- Pleural/serum protein > 0.5
- Pleural/serum LDH > 0.6
- (pleural) LDH > 2/3 upper limit
If you can only do 1 test, want LDH (determines 2 criteria)
What are some causes of transudative effusions?
- Congestive heart failure
- Cirrhosis
- Nephrotic syndrome
- Ascites
- Peritoneal dialysis
- Hypoalbuminemia
What are some causes of exudative effusions?
- Infections (i.e., parapneumonic, TB)
- Malignant disorders(lung CA, mets, mesothelioma)
- Collagen vascular diseases
- Pulmonary embolism
- Gastrointestinal disease
- Pancreatitis and pancreatic pseudocyst (high amylase)
- Esophageal rupture (high amylase)
- Abdominal or retroperitoneal abscess
Are transudative or exudative effusions more common?
Transudative
- Due to commonality of CHF (no.1)
What are the most common causes of effusions (either transudative or exudative)?
- CHF
- Infections (parapneumonic)
- Primary lung malignancy
What is seen here?
Complicated parapneumonic effusion:
- Loculated pleural effusion
- Thickened pleura
What is seen here?
Pneumothorax
What is the prognosis of primary pneumothorax (PTX)?
- 20-30% recur within 5 years
- Those with 1st PTX are more likely to have subsequent PTX
To prevent recurrence:
- Thoracotomy with over sewing of apical blebs if present and pleural abrasion
- Versus initial attempt at chest tube and chemical pleurodesis (irritate pleura and cause adhesion… to?)
What is a tension pneumothorax?
- Cause
- Signs/symptoms
- Trachea movement?
- Treatment
- Most often occurs during mechanical ventilation or resuscitation
Signs/symptoms:
- Cyanosis and hypotension
- Absence of breath sounds on affected side
- Shift of trachea away from affected side
Treat: large bore catheter to rapidly remove gas followed by chest tube placement
How can the mediastinum be divided?
- Anterior-lying forward and superior to the heart shadow and extending to the anterior vertebrae
- Middle-triangular shaped, extending from the heart shadow to the anterior vertebral border
- Posterior-occupies the space within the margins of the vertebra
What are symptoms of medisatinal masses?
“Terrible Ts”
- Thymoma
- Teratoma
- Thyroid
- Tumor, especially lymphoma
What is seen here?
Thymoma
- No retrosternal air space
What is the most common germ cell tumor?
- Characteristics
- Pt age
- Malignant vs. benign
- Treatment
Teratoma
- Masses are made up of tissue foreign to the area and are predominately of ectodermal derivatives (may contain hair, teeth, etc.)
- Tumor may be cystic or solid
- 80% are benign
- Usually occurs in young adults
- Treatment: surgical resection
What is seen here?
Bronchogenic Cyst
