Pneumothorax

Question 1

What is the clinical definition of a pneumothorax?

Answer 1

Air within the pleural cavity (pleural cavity is normally just a potential space and should not have anything in it)

Question 2

How does the intraplueral space have negative pressure, and how does this cause lung collapse?

Answer 2

Because it has opposing forces on either side
- the outward force of the chest wall
- the inward force of the lungs
When there is any breach in the pleural space, the elastic lung is then only bearing acted upon by inward forces and collapses

Question 3

What are the three different types of pneumothorax?

Answer 3

Traumatic - e.g. Stabbing or a fractured rib
Iatrogenic - caused by CT guided lung biopsy, TBLB or pleural aspiration
Spontaneous
- primary (young patient with no underlying lung disease)
- secondary (underlying lung disease e.g. COPD, or cystic fibrosis)

Question 4

What is a tension pneumothorax and it’s complications?

Answer 4

A medical emergency when a ‘one way valve’ (tear) leads to increased pressure in the intrapleural cavity
This causes lung collapse, impairment of venous blood return and therefore a fall in cardiac output and blood pressure
- can cause a cardiac arrest

Question 5

What is the immediate management of a tension pneumothorax?

Answer 5

Insert a venflon into the 2nd intercostal space midclavicular line to relieve the pressure

Question 6

What are the risk factors for a spontaneous pneumothorax?

Answer 6

Smoking
Male
Height - the taller you are, the more likely you are to get one

Question 7

What is the likelihood of a recurrence of a spontaneous pneumothorax?

Answer 7

40-50% recurrence after the first episode

Question 8

Describe the pathophysiology of a primary spontaneous pneumothorax.

Answer 8

Development of subpleural blebs and bullae at the lung apex
- increased height cause lower intrapleural pressure at the apex, increasing the risk of bleb development
Spontaneous rupture of these blebs leads to a tear in the visceral pleura and air flows from the airway into the pleural space (pressure gradient)
- elastic lung collapses

Question 9

Describe the pathophysiology of a spontaneous secondary pneumothorax.

Answer 9

The patient will have one of the following risk factors which makes the pleura more likely to rupture

• inherent weakness in lung tissue (e.g. Emphysema)
• increased airway pressure (e.g. Asthma, ventilated patient)
• increased lung elasticity (e.g pulmonary fibrosis)

Question 10

In which spontaneous pneumothorax (primary or secondary) is the prognosis worse?

Answer 10

Secondary

• patient is more symptomatic (due to poor underlying lung function)
• management is more complex
• more likely to require intervention

Question 11

What are the signs and symptoms of a tension pneumothorax?

Answer 11

Pleuritic chest pain
Breathlessness - less if primary 
Respiratory distress - especially in secondary 
Reduced air entry on affected side
Hyper-resonance on percussion 
Reduced vocal resonance

Question 12

What is the sign specific to a tension pneumothorax?

Answer 12

Tracheal deviation away from the affected side

- with or without circulatory collapse

Question 13

What are the differential diagnoses for a pneumothorax?

Answer 13

Pulmonary Thromboembolism
Musculoskeletal pain
Pleurisy
Pneumonia

Question 14

What are the imaging methods for pneumothorax diagnosis?

Answer 14

Chest X-Ray
- easy to miss a small one (check in the apices carefully)
- check the lung edges/pleural edges carefully
CT scanning
- if complicated (to differentiate between pneumothorax and bullae)
Ultrasound
- not used much

Question 15

What would you expect to see on a chest X-Ray if a pneumothorax was present?

Answer 15

Visible visceral pleura edge seen as a very thin, sharp line (no lung markings seen peripheral to this line)
- peripheral space is more radiolucent than the adjacent lung
In a tension pneumothorax- the mediastinum is seen shifting away from the pneumothorax

Question 16

Is the size of the pneumothorax important?

Answer 16

Not as important as the symptoms

• a small pneumothorax may be very symptomatically bad in COPD
• some people can tolerate complete lung collapse if they are very healthy

Question 17

What sizes of pneumothorax are classed as small and large?

Answer 17

Small - less than a 2cm ring of air at the axilla
Large - greater than a 2cm ring of air at the axilla
A 2cm ring of air is equal to about half of the normal volume of a healthy lung

Question 18

How is a primary spontaneous penumothorax handled?

Answer 18

If small or with few symptoms
- Observation with lots of Chest X-Rays
- Can possibly be managed as an outpatient
If large or with concerning symptoms
- aspiration with a small bore catheter in the 2nd intercostal space midclavicular line (air aspirated with syringe or 3 way tap)
- if aspiration doesn’t work, an intercostal drain with an underwater seal is used

Question 19

How is a secondary spontaneous penumothorax handled?

Answer 19

If small or few symptoms
- Aspiration with a small bore catheter in the 2nd intercostal space midclavicular line (air aspirated with a syringe or 3 way tap)
- Intercostal drain with underwater seal (this is done when aspiration hasn’t worked)
- admission with high flow oxygen and observed for 24 hours
If large or with concerning symptoms
- Intercostal drain with underwater seal
- admission

Question 20

Describe the process of inserting and using an intercostal drain.

Answer 20

Generally a small bore tube inserted into the axilla in the ‘triangle of safety’
Attached to a bottle containing water (underwater seal)
Air is expelled through the tube (bubbling in the water) and the lung re-inflates
Drain can be removed when bubbling stops
- if the bubbling doesn’t stop for 5 days it suggests an ongoing air leak (tear hasn’t healed)

Question 21

If an aspiration and a chest drain doesn’t fix the pneumothorax, then what is the treatment?

Answer 21

Video assisted thoracic surgery (VATS)

• Stapling blebs
• talc pleurodesis (causes inflammation of the pleura, causing adhesion and closing up the air space)
• pleural abrasion/stripping

Question 22

When would surgical pleurodesis be considered?

Answer 22

If this is the 2nd pneumothorax the patient has had one the same side, or their first event on the contralateral side the the first pneumothorax