• Pneumothorax

    by  • 07/06/2013 • Respiratory

    Pneumothorax

    Definition

    Pneumothorax: Collection of air or gas in pleural cavity.

    Tension pneumothorax: life-threatening condition that results from a progressive deterioration and worsening of a simple pneumothorax, associated with the formation of a one-way valve at the point of a rupture in the lung

    Epidemiology

    1. Young, tall, slim male – marfanoid habitus
    2. Lung cancer
    3. COPD patient with ruptured bullae

     

    Presenting complaint

    1. Decreased or absent breath sounds on the affected side
    2. Tracheal deviation towards unaffected side – pushed over by hyperinflated pathological side
    3. Hyperresonance on percussion on pathological side
    4. Unequal chest rise
    5. Dyspnoea
    6. Tachypnoea
    7. Tachycardia
    8. Hypotension due to cardiogenic shock (heart being compressed)
    9. Hypoxia
    10. Cyanosis
    11. Subcutaneous emphysema (air trapped beneath the skin)
    12. Jugular venous distension (enlarged jugular veins; late sign)

     

    If untreated, hypoxia may lead to hypercapnia (RF-T2), leading to respiratory acidosis, and loss of consciousness. In a tension pneumothorax, shifting of the mediastinum away from the site of the injury can obstruct the superior and inferior vena cava resulting in reduced venous return. This in turn decreases cardiac preload and cardiac output.

    Diagnostic tools/investigations

    1. Clinical suspicion: combination of signs as above
    2. CXR if time. If a TP – decompress IMMEDIATELY!

     

    Aetiology

    1. Spontaneous pneumothorax has been reported in young people with a marfanoid habitus

     

    It most commonly arises:

    1. Spontaneously (more commonly in tall slim young males and in Marfan syndrome
    2. Following a penetrating chest wound
    3. Following barotrauma to the lungs = SCUBA/altitude…

     

    It may also be due to:

    1. Chronic lung pathologies including COPD (emphysema), asthma
    2. Acute infections: pneumonia
    3. Chronic infections, such as TB
    4. Lung damage caused by CF
    5. Lung Cancer
    1. Rare diseases that are unique to women such as Catamenial pneumothorax (due to endometriosis in the chest cavity) and lymphangioleiomyomatosis (LAM) = muscle tissue growing into bronchi, lymphatics, alveolar seta causing airway obstruction, cysts, and pneumothorax. Women, 20-40yo.
    2. Interstitial lung disease

     

    Spontaneous Pneumothorax can be classified as primary spontaneous pneumothorax and secondary spontaneous pneumothorax

    1. In primary spontaneous pneumothorax, it is usually characterized by a rupture of a bleb in the lung while secondary spontaneous pneumothorax mostly occurs due to collapse of an emphysematous bullae as seen in COPD

     

    Pathophysiology

    Pneumothorax: gradual accumulation of air to the degree that it begins to put pressure on the mediastinum, compressing the heart and decreasing cardiac output due to the reduced amount of diastolic filling of the ventricles, and also putting pressure against the trachea, causing it to move away from the midline. Because of the increased thoracic pressure, venous return to the heart is decreased, causing a backup of blood into the venous system, as evidenced by distended jugular veins

    No vascular markings, tracheal shift, L-heart border compressed. L-sided pneumothorax.

    Treatment and management (conservative/medical/surgical)

    1. Conservative = anticoagulate and wait
    2. Needle decompression – IMMEDIATELY in TP
    3. Chest tube and one way valve
    4. Video assisted thorascopic surgery (VATS),
    5. Recurrent pneumothorax may require further corrective and/or preventive measures such as pleurodesis (fusion of pleura via microtrauma to cause knitting together and avoidance of future entrapment of air/blood/infection).

     

    Prognosis

    Can be fatal, good survival if managed in time 

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