Week 2: Pleural diseases

Question 1

Formation of pleural fluid

Answer 1

• formed and reabsorbed by parietal pleura
• ~10-15mL
• result of hydrostatic and oncotic pressure and lymphatic drainage

Question 2

Mechanisms of pleural fluid accumulation

Answer 2

1. increased venous pressure: CHF
2. Changes in oncotic pressure (hypoalbuminemia)
3. inflammatory processes involving pleura
4. obstruction of lymphatic drainage of pleura
5. peritoneal fluid with movement of fluid through transdiaphragmatic channels

Question 3

Two main types of pleural effusions

Answer 3

1. Transudative
   - produced by disease process not directly involving the pleura or lung
   - CHF, low serum protein
   - think pressure changes
2. Exudative
   - produced by disease process involving pleura
   - trauma, tumor, infection

Question 4

Symptoms associated with pleural effusion

Answer 4

• dyspnea
• chest pain: pleuritic (worse upon inspiration), aching discomfort
• cough
• fever
• singultus (hiccups)
• sputum production, fever, weight loss

Question 5

Signs associated with pleural effusion

Answer 5

• unilateral decrease in breath sounds
• unilateral dullness to percussion
• decreased movement of hemithorax
• tachypnea

Question 6

Radiologic studies of pleural effusion

Answer 6

• PA chest x ray
• lateral decubitus chest x-rays
• ultrasound of chest may be needed in selected cases
• CT scan of the chest

Question 7

Diagnostic procedures in pleural effusion

Answer 7

1. thoracentesis: removing fluid from pleural space
2. studies of pleral fluid
   - protein, LDH, cell count, glucose, amylase, cytology, culture

Question 8

Exudate vs transudate: Light’s criteria

Answer 8

Is exudative if:

1. pleural fluid/serum protein>0.5gm
2. Pleural fluid absolute LDH>2/3 of normal LDH
3. Pleural fluid/serum LDH ratio>0.6

Question 9

Common causes of transudative effusions

Answer 9

1. altered mechanical pressures
   - CHF, SVC obstruction, atelectasis, lymphatic obstruction
2. low oncotic pressures
   - nephrotic syndrome, hypoalbuminemia
3. connection with transudative peritoneal fluid (Ascites)

Question 10

Common causes of exudative effusions

Answer 10

1. neoplasm
   - mostly lung and breast cancer
2. infection
   - TB, parapneumonic, empyema
3. hemothorax
4. autoimmune
5. pancreatitis

Question 11

Treatment of Pleural effusions

Answer 11

1. treat underlying cause
2. thoracostomy (chest tube) to drain pleural space
   - when have respiratory distress
3. recurrent effusions: may use talc
4. surgical drainage rare
5. decortication of lung-surgical removal of visceral pleura-rare

Question 12

Causes of Pneumothorax

Answer 12

• trauma (iatrogenic-line placement)
• ruptured alveolar space: emphysema, cancer, TB, ventilators
• spontanous: young tall men

Question 13

Types of pneumothorax

Answer 13

1. Simple
2. Tension: positive pressure in pleural space during inspiration associated with shift of mediastinum and decreased blood pressure
   - medical emergency

Question 14

Symptoms of pneumothorax

Answer 14

• chest pain, pleuritic
• dyspnea
• cough
• fear

Question 15

Signs of pneumothorax

Answer 15

• decreased breath sounds
• hyperresonant percussion note
• evidence of shift of mediastinum away from pneumothorax: tracheal position, location of cardiac PMI

Question 16

Chest x-ray of pneumothorax

Answer 16

• can be really hard to see
• affected side: no vascular markings, atelectasis of lung, increased haziness of unaffected side due to diversion of entire cardiac output+decreased volume

Question 17

Treatment of pneumothorax

Answer 17

• oxygen
• observation
• needle drainage using one way valve (Heimlich)
• chest tube
• surgery rarely
• if recurrent: pleurodesis (obliteration of pleura space via adhesion)