Pneumothorax Definition

The presence of air within the pleural cavity is called as Pneumothorax.

Pneumothorax Classification

1) Spontaneous Pneumothorax

• Primary Pneumothorax
• Secondary Pneumothorax

2) Traumatic Pneumothorax

• Non-iatrogenic Pneumothorax
• Iatrogenic Pneumothorax

Spontaneous Pneumothorax

Pneumothorax occurring in the absence of trauma may be described as spontaneous. 

Presents in 3 ways: 

• Open Pneumothorax- air moves freely in & out of pleural space during breathing. 
• Closed pneumothorax- no movement of air from the pleural space due to the closure of the communication, air slowly gets absorbed & the lung re-expands.
• Tension pneumothorax- a check – valve mechanism is produced; this allows air to enter the pleura & accumulate to raise the intrapleural pressure above the atmospheric pressure and leads to compression on the lung & shifting of mediastinum to the opposite side.

1) Primary spontaneous pneumothorax

• Commonly occurs in healthy subjects with no h/o of pre-existing lung disease.
• The disease of young adults.

2) Secondary spontaneous pneumothorax

• Coexisting structural or functional abnormality in the lung.
• Stature.

Causes of Pneumothorax

Primary spontaneous

• Apical Blebs (90%)
• Stature

Secondary spontaneous – less common

• Chronic bronchitis & emphysema, (35%).
• Asthma (0.8).
• Suppurative pneumonia-like Staphylococci, Klebsiella, HIV (2-4%).
• TB of lungs.

Traumatic Iatrogenic

• Paracentesis thoracic (28%).
• Central venous cannulation (22%).
• Barotrauma (mechanical ventilation).
• Tracheostomy.

Traumatic Non-Iatrogenic Pneumothorax

• Open & closed chest injury, (road traffic accident).
• Stab or gunshot wounds.
• Rib fractures.

Pneumothorax Symptoms

1. Small pneumothorax is asymptomatic.
2. Chest pain – Sharp unilateral associated with shortness of breath is the commonest presentation.
3. Sharp & stabbing Chest pain exacerbated by deep inspiration & postural change.
4. Anxious, restless, tachypnoeic, struggling for breath, rapid low volume pulse & hypotension.
5. May large pneumothorax produce respiratory distress, signs of shock.
6. Closed pneumothorax –usually does not produce severe symptoms.
7. Tension pneumothorax – a medical emergency.

Pneumothorax Physical signs 

• Small pneumothorax – Difficult to detect on physical examination.
• Absence or diminished breath sounds on the affected side.
• Chest movement diminished on the affected side
• Decreased vocal fremitus.
• Hyper resonant percussion notes.
• Ipsilateral enlargement of the chest due to decrease elastic recoil of the collapsed lung.
• The shift of mediastinum on the opposite side.
• Increased JVP.
• Respiratory distress.
• Diaphoresis
• Cyanosis.
• Hypotension.
• Crepitus is seen if there is associated subcutaneous emphysema.

Pneumothorax Diagnosis

1. ECG – Diminished anterior QRS amplitude.Radiographic appearances.
2. X-ray chest – sharply defined lung edge convex outwards separated from chest wall by translucency with no lung markings & mediastinal displacement depending upon the extent of pneumothorax.

Pneumothorax Differential diagnosis

• Transmural myocardial infarction-ECG changes & left-sided pneumothorax changes resolve once re-expansions.
• Emphysema confused with pneumothorax but an x-ray is the main diagnostic tool.
• Massive emphysematous bulla or congenital cyst, when ruptures may be confused with pneumothorax but the previous x-ray, lateral decubitus view is helpful in differentiating upper lobe bulla/cyst.

Pneumothorax Complications

• Recurrence,
• Haemopneumothorax,
• Pyopneumothorax, 
• Respiratory failure – when tension pneumothorax present.

Pneumothorax Treatment

Treatment depends on cause, size, degree of physiological derangement. A primary pneumothorax-smaller without pleural air leak may resolve spontaneously.

• If pneumothorax small but the patient mild symptomatic, admit the patient & administer high–flow oxygen, resulting in nitrogen gradient will speed resorption.
• If pneumothorax larger than 15% to 20% or more than mildly symptomatic, insert a thoracostomy tube.
• Secondary pneumothorax – Patients are symptomatic & require lung re-expansion.
• Often bronchopleural fistula persists & larger thoracostomy tube & suction are required.
• Iatrogenic pneumothorax – Due to barotrauma from mechanical ventilation always persistent air leak & should be managed with a chest tube & suction.
• Tension pneumothorax – decompress the affected hemithorax immediately with a 14-gauge needle attached to a fluid-filled syringe, release of air with clinical improvement confirms the diagnosis. Seal chest wound with an occlusive dressing & arrange the placement of a thoracostomy tube.