Pneumothorax

Question 1

What is the aetiology and pathophysiology of pneumothorax?

Answer 1

Refers to air in the pleural cavity leading to lung collapse on the affected side

Primary spontaneous forms occur in healthy people

Secondary forms are associated with underlying disease:

• e.g. Rupture of congenital bullae or cyst in COPD; acute exacerbations in asthma
• These are more clinically significant and possibly harder to manage

Traumatic forms follow penetrating chest wall trauma e.g. stab wounds, rib fractures

Iatrogenic forms follow mechanical ventilation, central line placement, lung and liver biopsies etc

Catamenial forms refers to pneumothorax at the time of menstruation:

• 90% in the R lung
• 24hrs pre-72hrs post onset of menstruation
• Caused by thoracic endometriosis leading to necrotic holes in the diaphragm (patients often report long standing recurrent diaphragmatic pain) which let air in from the genital tract once the mucous plug is liquified when menstruating
• Possibly may account for 33% of ‘spontaneous’ forms in women

Tension pneumothorax:

• Life threatening emergency
• Air trapped under increasing positive pressure, leading to CV and resp. compromise

Question 2

What is the epidemiology of pneumothorax?

Answer 2

M>F

• Esp <20yrs and if a tall, skinny guy who might have been doing exercise…
• Then peaks again for both sexes >60yrs

Risk factors:

• Smoking
• Marfans syndrome/habitus
• Women with endometriosis/symptoms of (ask about pleuritic shoulder or upper abdo pain during menses)
• COPD, TB, sarcoid, CF, malignancy, IPF

Question 3

How does pneumothorax present?

Answer 3

May be minimal or absent
- Often greater in secondary forms

Symptoms:

• Sudden onset pain
• Shortness of breath

Signs:

• Possible distress, sweating
• Possible cyanosis
• Tachycardia - >135 suggests tension
• Pulsus paradoxus - opposite to sinus arrhythmia i.e. pulse slows on inspiration = severe pneumothorax
• Hypotension, raised JVP - suggests tension
• Uneven expansion - less on affected side
• Tracheal deviation - away from affected side = tension
• Hyper-resonance to percussion
• Reduced breath sounds
• Progressive deterioration = tension

Signs of cause e.g. trauma, COPD features etc

Question 4

How do you investigate pneumothorax?

Answer 4

IF TENSION SUSPECTED, DO NOT WAIT TO CONFIRM DX, NEEDS TREATING

CXR:
- Standard erect held inspiration

ABG:
- To gauge respiratory compromise/degree of hypoxia

Question 5

How do you mange a pneumothorax?

Answer 5

Sit upright and give 15L O2
- Unless O2 sensitive e.g. COPD retainers

If tension, needs aspiration immediately:

• Grey/orange cannula into 2nd intercostal space, min-clavicular line in the superior border of the rib (to avoid neurovascular bundle) - should expect a hiss; if not, leave cannula in situ and consider 2nd or alternative Dx
• Will also often need a drain placing to avoid re-accumulation

If not tension:

• Send for CXR - if signs of respiratory disease/ age >50 with significant smoking Hx then treat as secondary; if neither then treat as primary
• Rules for aspiration - with needle or drain - depend on size (?>2cm) and whether patient breathless or not

Generally:

• Secondary = admit and drain
• small + asymptomatic primary = consider discharge with safetynet and OP R/V 2-4wks

Question 6

What other treatments might be required for pneumothorax?

Answer 6

Plurodesis:

• If regular recurrence
• With Minocycline

Surgery:
- For more difficult cases i.e. persistent leak

Pregnancy:
- More common during but less invasive Tx i.e. simple observation and aspiration

Catamenial:
- Surgical intervention + hormonal Tx for endo

Confirm resolution with radiology before flying