Chapter 10: Recognizing Pneumothorax, Pneumomediastinum, Pneumopericardium, and Subcutaneous Emphysema

Question 1

How do you recognize a pneumothorax?

Answer 1

Visualization of the visceral pleural line

Convex curve of the visceral pleural line paralleling the countour of the chest wall

Absence of lung markings distal to the visceral pleural line

The deep sulcus sign of an inferiority displaced costophrenic angle seen on a supine chest

The presence of an air-fluid interface in the pleural space

Question 2

How large is the pneumothorax?

Answer 2

Size measurement of pneumothorax on X-rays correlate poorly with CT scans of the actual size

There is poor circulation between the size of the pneumothorax and the degree of clinical impairment

Question 3

What is the 2 cm rule and what disease does it correlate with?

Answer 3

Pneumothorax

If the distance between eh lung margin and the chest wall at the apex is <2cm, a chest tube is usually not needed; a distance >2cm usually requires chest tube drainage

Question 4

What is the most important determinant in deciding whether a patient needs a chest tube?

Answer 4

Patient’s clinical status

Question 5

What is a pneumothorax?

Answer 5

Air in the pleural space

Question 6

What must you identify to diagnose a pneumothorax?

Answer 6

The visceral pleural white line

Question 7

What are the pitfalls that resemble a pneumothorax?

Answer 7

Bullae
Skinfolds
Medial border of the scapula

Question 8

What does a simple pneumothorax have?

Answer 8

It doesn’t have a shift of the heart or mobile mediastinal structures

Question 9

What does a tension pneumothorax create?

Answer 9

Produces a shift of the heart and mediastinal structures AWAY from the side of the pneumothorax by virtue of a check-valve mechanism that allows air to enter the visceral pleural space but not leave

Question 10

What do most pneumothoraces have?

Answer 10

Traumatic causes

Question 11

What imaging is better at estimating the size of a pneumothorax?

Answer 11

A CT

Question 12

What are other ways to diagnose a pneumothorax besides an upright CXR?

Answer 12

Expiration exposures
Decubitus views
Delayed images

Question 13

What test detects a small pneumothorax?

Answer 13

CT

Question 14

Why do spontaneous pneumothoraces occur?

Answer 14

They occur as a result of rupture of a small apical, subpleural bleb and they most often occur in younger men

Question 15

How does a pulmonary interstitial emphysema occur and how are they read on an Xray?

Answer 15

Results from an increase in the intraalveolar pressure, which leads to rupture of an alveolus and dissection of air back toward the Hilar along the bronchovascular bundles

It is difficult to see on Xray

Question 16

When does a pneumomediastinum occur?

Answer 16

Occurs when air tracks back to the mediastinum from a ruptured alveolus or from perforation of an air-containing viscus such as the esophagus or trachea

Question 17

What does a pneumomediastinum produce on an X-ray?

Answer 17

Produces a continuous diaphragm sign on a frontal chest xray

Question 18

How does a pneumopericardium form?

Answer 18

Requires direct penetration of the pericardium to occur rather than dissection of air

Question 19

How do you differentiate a pneumopericardium from a pneumomediastinum?

Answer 19

A pneumopericardium does not extend above the roots of teh great vessels, whereas pneumomediastinum does

Question 20

What is subcutaneous emphysema?

Answer 20

Air dissecting into the neck and chest wall