The presence of air within the pleural cavity is called as Pneumothorax.
1) Spontaneous Pneumothorax
- Primary Pneumothorax
- Secondary Pneumothorax
2) Traumatic Pneumothorax
- Non-iatrogenic Pneumothorax
- Iatrogenic 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.
Causes of Pneumothorax
- Apical Blebs (90%)
Secondary spontaneous – less common
- Chronic bronchitis & emphysema, (35%).
- Asthma (0.8).
- Suppurative pneumonia-like Staphylococci, Klebsiella, HIV (2-4%).
- TB of lungs.
- Paracentesis thoracic (28%).
- Central venous cannulation (22%).
- Barotrauma (mechanical ventilation).
Traumatic Non-Iatrogenic Pneumothorax
- Open & closed chest injury, (road traffic accident).
- Stab or gunshot wounds.
- Rib fractures.
- Small pneumothorax is asymptomatic.
- Chest pain – Sharp unilateral associated with shortness of breath is the commonest presentation.
- Sharp & stabbing Chest pain exacerbated by deep inspiration & postural change.
- Anxious, restless, tachypnoeic, struggling for breath, rapid low volume pulse & hypotension.
- May large pneumothorax produce respiratory distress, signs of shock.
- Closed pneumothorax –usually does not produce severe symptoms.
- 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.
- Crepitus is seen if there is associated subcutaneous emphysema.
- ECG – Diminished anterior QRS amplitude.Radiographic appearances.
- 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.
- Respiratory failure – when tension pneumothorax present.
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.