Pleural Disease

Question 1

Pleural Anatomy

Answer 1

• 2 layers made of mesothelial cells
  
  • Visceral pleura ⇒ lines lungs
  • Parietal pleura ⇒ lings chest wall
• Normal pleural fluid production ~ 16.8 nl/day for 70 kg adult
• Fluid flows from visceral to parietal pleura
• Lymphatic drainage ~ 470 cc/day
  
  • 28x more than production
  • No fluid in pleural space normally

Question 2

Pleural Effusion

Definition

Answer 2

Accumulation of fluid in the pleural space.

Question 3

Pleural Effusions

Pathophysiology

Answer 3

• ↑ fluid accumulation
  Entry of fluids into pleural space:
  
  • ↑ systemic venous pressure
  • ↑ pulmonary venous pressure
  • ↑ permeability of pleural vessels
  • ↓ pleural pressure
  • ↓ microvascular oncotic pressure
• ↓ fluid removal
  Blockage of lymphatics:
  
  • Central lymphatic obstruction
  • Obstruction of lymphatic channels at pleural surface by tumor

Question 4

Transudates

Characteristics

Answer 4

Light’s Criteria

Question 5

Exudates

Characteristics

Answer 5

Light’s Criteria

Question 6

Transudates

Etiologies

Answer 6

Question 7

Exudates

Etiologies

Answer 7

Question 8

Pleural Fluid

Analysis

Answer 8

• Cell count and differential
• Chemistry
  
  • Proteins, LDH, albumin, amylase, pH, glucose
  • Obtain concurrent serum values
• Gram strain and culture
• Cytology
• Other tests as indicated
  
  • Lipids, fungal culture, triglycerides, Ig

Question 9

Pleural Effusion

History

Answer 9

• Asymptomatic
• Dyspnea ⇒ d/t compression of underlying lung
• Pleuritic CP ⇒ see w/ some exudative effusions

Question 10

Pleural Effusion

Physical Exam

Answer 10

• ↓ tactile fremitus
• Dullness to percussion
• ↓ or absent breath sounds
• Tracheal shift to contralateral side w/ very large effusion
• Tubular breath sounds, egophany (E to A changes)

Question 11

CHF Related

Pleural Effusions

Answer 11

• Most common cause of transudates
• D/t ↑ pulmonary venous pressures from LV dysfunciton
• Usually bilateral, R > L
• Thoracentesis often not needed
  
  • Unless atypical or fail to resolve w/ medical treatment

Question 12

Image 1

Answer 12

Left-sided Massive Pleural Effusion

With contralateral shift of mediastinum and trachea.

Most common cause of non-traumatic massive pleural is cancer.

Question 13

Parapneumonic Effusions

Definition

Answer 13

Exudative effusions in setting of bacterial PNA or lung abscess.

• Often very high WBCs and LDH levels
• Effusion on same side as PNA

Question 14

Uncomplicated Paraneumonic Effusion

Characteristics

Answer 14

• Negative gram stain and culture
• pH > 7.30
• Glucose > 40
• Resolves w/ simple abx treatment of PNA

Question 15

Complicated Parapneumonic Effusion

Answer 15

• pH < 7.20
• Glucose < 40
• Requires chest tube or surgical drainage for resolution

Question 16

Empyema

Answer 16

“Pus” in the pleural space.

• Will usually have a positive gram stain or culture
• Treatment same as complicated parapneumonic effusion

Question 17

RA

Pleural Effusions

Answer 17

• Pleural glucose < 30
• P/S ratio < 0.5
• pH < 7.3
• High LDL level > 700

Question 18

TB

Pleural Effusion

Answer 18

• Exudative effusiosn d/t hypersensitivity rxn
• Usually neg. AFB smear
• Lymphocytic predominance
• Culture neg. for AFB
• Adenosine deaminanse in fluid consistent w/ TB

Question 19

Malignant Pleural Effusion

Answer 19

• 2nd most common cause of exudative effusion
• Malignant cells seen in 60% of 1st thoracentesis
  
  • Yield inc. by 20% on second tap
• Common etiologies
  
  • Lung Ca
  • Breast Ca
  • Lymphoma
  • Ovarian Ca

Question 20

Chylothorax

Answer 20

Disruption or obstruction of thoracic duct ⇒ leakage of chyle fluid.

• High TAG
• Milky appearance
• Lymphocytic predominance
• Pleural triglyceride > 110 mg/dL ⇒ 85% of pts
• Etiologies ⇒ trauma, surgery, malignancy (lymphoma)

Question 21

Cholesterol Effusion

Answer 21

“Pseudochylothorax”

• High cholesterol ⇒ milky appearance
• Chronic inflammatory process such as TB or RA
• Pleural cholesterol > 200 mg/dL ⇒ 75% of pts
• Cholesterol crystals in fluid

Question 22

Nephrotic Syndrome

Pleural Effusions

Answer 22

Caused by PE and renal vein thrombosis

Question 23

Pleural Effusion

Management

Answer 23

• Treat underlying cause of effusion
• Thoracentesis
  
  • Can remove up to 1,500 ml to relieve dyspnea
  • Removing more inc. risk of re-expansion pulmonary edema
• Chest tube
  
  • Drain complicated parapneumonic effusion/empyema
  • Palliate SOB d/t recurrent large pleural effusion e.g malignancy
  • Perform chemical pleurodesis to obliterate pleural space & prevent reaccumulation of fluid ⇒ rarely done
• Surgery ⇒ thoracoscopy or thoracotomy
  
  • If interventions via chest tube fails

Question 24

Pneumothorax

Definition

Answer 24

Air in the pleural space.

Question 25

Image 2

Answer 25

**Hydropneumothorax** Pneumothorax ⇒ collapsed lung As lung deflated, injured some vessels. Also see blood in the pleural cavity ⇒ air fluid line

Question 26

Pneumothorax History

Answer 26

* Asymptomatic * Dyspnea * Ipsilateral pleuritic chest pain

Question 27

Pneumothorax Physical Exam

Answer 27

* ↓ tactile fremitus * Hyperresonant to percussion * ↓ breath sounds * If tension PTX ⇒ ± tracheal shift, tachycardia, hypotension

Question 28

Pneumothorax Etiologies

Answer 28

* **Traumatic PTX** ⇒ from penetrating or non-penetrating chest trauma * **Iatrogenic PTX** ⇒ result of a dx or therapeutic medical procedure * **Spontaneous PTX** * _Primary_ * In absence of known lung disease * Men \> Women * Associated w/ cigarette smoking * Cocaine use is a risk factor * _Secondary_ * In presence of known lung disease * COPD most common but there are others

Question 29

Pneumothorax Treatment

Answer 29

* Observation ⇒ if small and pt stable * Rim of air \< 2 cm on CXR * Simple aspiration ⇒ pneumocentesis * Primary spontaneous PTX * Emergently in tension PTX ⇒ temporizing * Chest tube ⇒ with or without pleurodesis * Surgery ⇒ recommended after 2nd PTX

Question 30

Tension Pneumothorax

Answer 30

**PTX w/ progressive build-up of air in pleural space d/t inability of air to escape.** * 1-2% of spontaneous PTX * **More common w/ trauma and positive-pressure ventilation** * Clinical features: * **Severe respiratory distress, cyanosis, tachycardia, hypotension** * Radiographic changes: * **Mediastinal shift** * **Treatment is immediate decompression** * Large-bore needle, 2nd anterior intercostal space * Ventilator + PTX = automatic chest tube

Question 31

Malignant Mesothelioma

Answer 31

* **Occurs after asbestos exposure** * Latency 30-40 years * Symptoms non-specific ⇒ **CP, SOB, cough, weight loss** * **Most have pleural effusion** * Need biopsy to confirm * Therapy very limited ⇒ prognosis poor

Question 32

Benign Fibrous Mesothelioma

Answer 32

* Less common * No asbestos association * Both dx and tx is surgical ⇒ good prognosis