Chapter 25 Pleural Diseases Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc

Chapter 25

Pleural Diseases

Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.

Learning Objectives

Describe important anatomic features and physiologic function of the visceral and parietal pleural membranes.

Describe how pleural effusions occur and the difference between transudative and exudative effusions.

Identify common causes of transudative and exudative pleural effusions.

Write definitions of “chylothorax,” “hemothorax,” and “pneumothorax.”

2Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.

3

Learning Objectives (cont.)

Describe the impact of moderate to large pleural effusions on lung function.

State the role of the chest radiograph in recognizing pleural effusions.

State the purpose of thoracentesis and the potential complications.


4

Learning Objectives (cont.)

Identify the definitions of spontaneous, secondary, and tension pneumothorax.

Describe the diagnosis and treatment of pneumothorax.


5

The Pleural Space

Overview & definitions Visceral pleura cover each lung, while parietal

pleura covers outer structures that bound lungs


6

The Pleural Space (cont.)

Overview & definitions (cont.) Pleural fluid about 10 to 20 mm thick separates

visceral from parietal pleura• ~8 mL of fluid per hemithorax

• Pleural fluid is very similar to interstitial fluid

• Fluid minimizes friction caused by expanding lungs in thorax during inspiration

Pleural pressure is typically negative due to outward thoracic recoil & inward recoil of lung


The Pleural Space (cont.)



The greatest negative pressure in the pleural space can be found at the level of:

A. The mediastinum

B. The lung bases

C. Apex of the Lung

D. The heart

9

Pleural Effusions

Any abnormal accumulation of fluid in pleura is considered pleural effusion

Fluid enters pleural space from visceral & parietal pleurae, particularly in light of increased pressure Stomata connecting to lymphatic system remove

fluid from this space Either increased fluid production or blockage of

drainage can result in pleural effusions


Pleural Effusions (cont.)


11


Transudative effusions Effusions forming while pleural space is

undamaged will have [protein] <50% of serum level & LDH <60% of serum level

Specific causes of transudative effusions: CHF: high hydrostatic pressure increases pleura

fluid production, most common cause of effusions Nephrotic syndrome: protein loss in urine results in

low capillary oncotic pressure & fluid third spacing


12


Specific causes of transudative effusions (cont.): Hypoalbuminemia: different cause but mimics

CHF & nephrotic syndrome Liver disease: ascites fluid moves through small

holes in diaphragm, almost always on right side Atelectasis: cause pleural pressures to become

more negative resulting in small effusions Lymphatic obstruction: blockage prevents

drainage & results in accumulation



Which of the following are the primary causes of a transudative pleural effusion?

1. rupture of the pleural space

2. abnormal hydrostatic pressure

3. increased plasma protein concentration

4. abnormal oncotic pressure

A. 1, 2 and 3 only

B. 1, 3 and 4 only

C. 1, 2, 3, and 4

D. 2 and 4 only

14


Exudative effusions Occur due to inflammation of lung or pleura &

have higher protein & inflammatory cell content Account for 70% of all pleural effusions Thoracentesis may be performed to determine

type Specific causes of exudative effusions

Parapneumonic: secondary to lung inflammation associated with pneumonia

• Complicated if clots form & loculate fluid• Persistent fever may signal an empyema - must be

drained for recovery



Specific causes of exudative effusions (cont.) Viral pleurisy: presents with pleural inflammation

(pleurisy) & pleural pain (pleurodynia)• Pain may result in atelectasis & hypoxemia

Tuberculous pleurisy: occurs when caseous granulomas rupture viscera pleura & drain into pleural space

• Patients need to be isolated Malignancy: most common cause of large

unilateral effusions, most require pleurodesis to treat



Specific causes of exudative effusions (cont.) Postoperative: common following abdominal or

thoracic surgery Chylothorax: caused by rupture of thoracic duct,

50% malignant, 20% surgical• Fluid may be white or yellow, sometimes bloody

Hemothorax: trauma or blood vessel hemorrhage into pleura space

• Hematocrit > 50% of serum level



Complications from a parapneumonic pleural effusion may often lead to the formation of:

A. empyema

B. lung access

C. pulmonary solitary nodules

D. ascites

Physiological Importance of Pleural Effusions

Mechanics of ventilation Effusions cause atelectasis due to limited thoracic

space resulting in restrictive pattern on PFTs

Patients commonly dyspneic, even with small effusions

Rarely cause fibrothorax with true restrictive impairment

Hypoxemia Most effusions cause increased P(A – a)O2 - may

worsen following thoracentesis


19

Diagnostic Tests for Pleural Effusions

Chest radiography Most common method of detecting effusions Upright PA & lateral decubitus are useful

• 1-cm meniscus lung to rib allows for thoracentesis


20

Diagnostic Tests for Pleural Effusions (cont.)

Ultrasonography & computed tomography Ultrasound is very sensitive to pleural effusions

• May use to localize & direct for thoracentesis Contrast-enhanced CT is most sensitive study for

effusions


21


Thoracentesis Percutaneous needle aspiration of effusion sample Drainage for lung reexpansion involves placement

of chest tube Risks include:

• Artery laceration• Infection• Pneumothorax


22




Which of the following is considered the most sensitive procedure to assess size and location of a pleural effusion?

A. thoracentesis

B. CT scanning of the chest

C. ultrasonography

D. Chest x-ray

24


Thoracoscopy (video-assisted) Ideally designed for diagnostic & therapeutic

pleural procedures

Allows visualization of surfaces, drainage of effusion, biopsy, & pleurodesis if needed

Perform under local anesthesia & conscious sedation


25

Management for Pleural Effusions

Pleurodesis Process fusing parietal & visceral pleurae - prevents

further formation of effusions

Can be performed by surgical abrasion or introduction of chemical irritant, most commonly talc

Not recommended for non-malignant pleural effusions


26

Management for Pleural Effusions (cont.)

Pleuroperitoneal shunt & Pleurex catheter For effusions refractory to all other treatment

options

Small pump moves fluid from pleura to peritoneal cavity

Pleurex catheter connects to suction at home to drain persistent effusions


27

Management for Pleural Effusions (cont.)

Chest thoracotomy tubes Designed for tight fit in tissues to avoid leaks & allow

drainage of effusion & subsequent lung reexpansion Tube is attached to chest drainage unit



A lab report shows a pleura effusion protein level of 10 g/dL together with the presence of malignant cells on the cytology report. You would classify this effusion as a:

A. transudate

B. chylothorax

C. exudate

D. normal

29

Pneumothorax

Defined as air in pleural space - can occur through number of mechanisms

Chest pain is typically sharp & abrupt Palpation of & chest wall does not worsen

pain Dyspnea occurs in 2/3rd of patients May decrease vital capacity & PaO2

Hypoxemia may persist after evacuation of pneumothorax


Pneumothorax (cont.)

Traumatic pneumothorax Penetrating chest trauma

• Common secondary to bullet or knife penetration• Chest tube is usually adequate to treat• May require surgery if bleeding is severe

Blunt trauma• Broken ribs puncture lung with air escape into pleura• Chest tube is all that is generally required


Documents

Chapter 25 Pleural Diseases Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc