INTRODUCTION:
Pneumothorax is the presence of air in the pleural space, which can either occur spontaneously, or result from iatrogenic injury or trauma to the lung or chest wall.
Primary spontaneous pneumothorax occurs in patients with no history of lung disease. Smoking, tall stature and the presence of apical subpleural blebs are known risk factors.
Secondary pneumothorax affects patients with pre-existing lung disease, especially COPD, bullous emphysema and asthma. It is most common in older patients and is associated with the highest mortality rates.
CLINICAL FEATURES:
There is sudden-onset unilateral pleuritic chest pain or breathlessness (those with underlying chest disease may have severe breathlessness).
With a small pneumothorax the physical examination may be normal;
A larger pneumothorax (> 15% of the hemithorax) results in decreased or absent breath sounds and a resonant percussion note.
A tension pneumothorax occurs when a small communication acts as a one-way valve, allowing air to enter the pleural space from the lung during inspiration but not to escape on expiration; this causes raised intrapleural pressure, which leads to mediastinal displacement, compression of the opposite lung, impaired systemic venous return and cardiovascular compromise.
INVESTIGATION:
CXR shows the sharply defined edge of the deflated lung with a complete lack of lung markings between this and the chest wall.
CXR also shows any mediastinal displacement and gives information regarding the presence or absence of pleural fluid and underlying pulmonary disease.
Care must be taken to differentiate between a large pre-existing emphysematous bulla and a pneumothorax to avoid misdirected attempts at aspiration; where doubt exists, CT is useful in distinguishing bullae from pleural air.
MANAGEMENT:
Primary pneumothorax, where the lung edge is < 2 cm from the chest wall and the patient is not breathless, normally resolves without intervention.
In young patients presenting with a moderate or large spontaneous primary pneumothorax, an attempt at percutaneous needle aspiration of air should be made in the first instance, with a 60–80% chance of avoiding the need for a chest drain.
Patients with chronic lung disease usually require a chest tube and inpatient observation, as even a small pneumothorax may cause respiratory failure.
Intercostal drains should be inserted in the 4th, 5th or 6th intercostal space in the mid-axillary line, following blunt dissection through to the parietal pleura, or by using a guidewire and dilator (‘Seldinger’ technique).
The tube should be advanced in an apical direction, connected to an underwater seal or one-way Heimlich valve, and secured firmly to the chest wall. Clamping of the drain is potentially dangerous and never indicated.
The drain should be removed 24 hrs after the lung has fully re-inflated and bubbling stopped. Continued bubbling after 5–7 days is an indication forsurgery.
Supplemental oxygen is given, as this accelerates the rate at which air is reabsorbed by the pleura.
Patients with an unresolved pneumothorax should not fly until the pleural air is gone, as the trapped gas expands at altitude.
Patients should be advised to stop smoking and informed about the risks of a recurrent pneumothorax (25% after primary spontaneous pneumothorax).
Recurrent spontaneous pneumothorax:
Surgical pleurodesis, with thoracoscopic pleural abrasion or pleurectomy, is recommended in all patients following a second pneumothorax (even if ipsilateral), and should be considered following the first episode of secondary pneumothorax if low respiratory reserve makes recurrence hazardous.
Patients who plan to continue activities where pneumothorax would be particularly dangerous (e.g. diving) should also undergo definitive treatment after the first episode of a primary spontaneous pneumothorax.
THOSE ABOVE ARE COLLECTED FROM SOME BOOKS AND
WEBSITES..
(DAVIDSON'S ESSENTIAL OF MEDICINE)
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