Spontaneous Pneumothorax

Causes of spontaneous pneumothorax:

1.      Primary:

·         Rupture of subpleural emphysematous bullae.

·         Rupture of pleural bleb.

·         Rupture of pulmonary end of pleural adhesion.

2.      Secondary:

·         Rupture of subpleural tubercular focus.

·         Staphylococcal lung abscess.

·         Bronchogenic carcinoma.

·         COPD, asthma, pulmonary infraction.

·         All forms of fibrotic and cystic lung disease.

Types of spontaneous pneumothorax:

1.      Closed type.

2.      Open type.

3.      Tension (valvular) type

Pathology:

[A] Closed type: The communication between pleural and lungs seals off as the lung deflates and does not reopen. The air is gradually absorbed and lung re-expands.

[B] Open type: All abnormal communication is made between bronchus and pleural space (broncho-pulmonary fistula) the air pressure in pleural space is equal to atmospheric pressure both on inspiration and expiration, so it does not responds to water seal drainage and the lung cannot re-expand.

[C] Tension (valvular) type: Most dangerous form. Communication between pleural and lung persists but is small and acts as one way valve like action-entry but not escape. Thus pressure within pleural space rapidly increases causes catastrophic collapse of the lung and mediastinal displacement.

Clinical features:

Symptoms:

1.      Sudden sever chest pain usually on the affected side due to stretching of parietal pleural, radites to the tip of shoulder and arm.

2.      Increasing dyspnoea, cyanosis in severe cases:

a)      Closed type: Dysponea is not sever, improves gradually.

b)      Open type: Dysponea is not severe but does not improve.

c)      Tension type: Rapidly progressive severe  dysponoea and accompanied by central cyanosis.

3.      Symptoms of underlying cause.

Signs:

1.      Respiratory rate: Marked increased.

2.      Tachycardia.

3.      There may be hypertension.

4.      Patient may be in shock.

O/E of respiratory system:

Inspection:

·         Patient is dyspnoeic.

·         Movement of chest is restricted to the affected side.

·         Intercostal spaces are full.

Palpation:

·         Trachea is shifted to the opposite side.

·         Apex beat may be shifted to opposite side.

·         Movement of chest diminished on the affected side.

·         Expansion of chest is reduced (on affected side)

·         Vocal fremitus is reduced/absent.

Percussion: Hyper-resonance over the affected area.

Auscultation:

·         Breath sound is vesicular & markedly diminished.

·         Vocal resonance is reduced.

·         No added sound.

Investigation:

1.      X-ray chest P/A view in erect posture (most important)

·         Sharply defined collapsed lung margin.

·         Hypertranslucency without any lung markings in between collapsed lung margin and chest wall.

·         Mediastinal shifting towards opposite side.

2.      Lung function test.

3.      Sputum for AFB stain & Gram stain.

4.      M.T test.

5.      Complete-blood count: TC, DC, ESR, Hb%.

Management:

[A] Conservative treatment:      

1.      Strict bed rest in propped-up position.

2.      Diet- easily digestible.

3.       inhalation (3-4 litre/min continuous)

4.      Ensure easy bowel clearance/movement by laxatives.

5.      Broad spectrum antibiotics.

Then keep the patient under close observation-if the conservative treatment fails then we shall go for- Water seal drainage.

[B] Treatment of underlying cause: depends on type.

1.      Closed type:

·         Small pneumothorax: No active measure, radiographic observation 2 weekly until re-expansion of the lung is complete.

·         Large pneumothorax: (with breathlessness): Water seal drainage (intercostals tube drainage) Radiological observation. Specific chemotherapy if aetiology is TB.

2.      Open type: Surgical measure because such cases are amenable to medical treatment, surgery is the treatment of choice whether it is tuberculous or non-tuberculous.

3.      Tension (valvular) type:

·         Water seal drainage.

·         Radiological observation.

4.      Recurrent spontaneous pneumothorax: Obliteration of at least one pleural space (Pleurodesis) by introducing irritant substance such as tetracycline, Kaolin, bleomycin or by pleurectomy at thoractomy.