Collapsed Lung

Fig 1: Chest x-ray showing collapsed left lung.

What do you think the doctors meant by "endobronchial lesion" in the following diagnosis?

She was diagnosed and treated as a case of pneumonia, later on, after few weeks she had a second attack of hemoptysis for which a CT- scan of the chest was performed that revealed an endobronchial lesion obstructing the left main stem bronchus (Fig 2).




COLLAPSED LUNG

From the pages of Wikipedia

Note: a collapsed lung can be the result of disease; we were curious specifically regarding bullet wounds - regarded here as a tension pneumothorax

Mechanism

CT scan of the chest showing a pneumothorax on the patient's left side (right side on the image). A chest tube is in place (small black mark on the right side of the image), the air-filled pleural cavity (black) and ribs (white) can be seen. The heart can be seen in the center.The thoracic cavity is the hollow space that contains the lungs. The lungs are physically connected at the hila, where the airways and blood vessels enter the lung. They remain inflated inside the thoracic cavity because the pressure inside the pleural space (the space between the chest wall and the lung) is almost consistently negative throughout the respiratory cycle, effectively sucking the lung to the chest wall. Both the lung and the chest wall are covered by a layer of cells known as the pleura (visceral and parietal pleura, respectively), and a small amount of serous fluid is typically present. The negative pressure normally does not allow air to enter the pleural space because there are no natural connections to air-containing space, and the pressure of gases in the bloodstream is too low for them to be released into the pleural space. Pneumothorax can therefore only develop if air is allowed to enter, either through damage in the chest wall, or damage to the lung itself, or occasionally because microorganisms in the space produce gas.[2]

The chest wall defect is usually evident in cases of injury to the chest wall, such as bullet wounds ("open pneumothorax"). In secondary spontaneous pneumothorax, vulnerabilities in the lung tissue are caused by a variety of disease processes, such as bullae (large air-containing lesions) in emphysema. Areas of necrosis (tissue death) may precipitate pneumothorax episodes, although the exact mechanism is unclear.[1] Primary spontaneous pneumothorax has for many years been thought to be caused by "blebs", small lesions just under the pleural surface, which were presumed to be more common in those classically at risk of pneumothorax (tall males) due to mechanical factors. Various lines of evidence suggest that this hypothesis may not be correct, such as the fact that pneumothorax may recur even after surgical treatment of blebs, and that blebs occur in 15% of healthy people. It has therefore been suggested that PSP is instead caused by areas of disruption (porosity) in the pleural layer, which are prone to rupture.[1][2] Smoking may lead to inflammation and obstruction of small airways, accounting for the markedly increased risk of PSP in smokers.[4] Once air has stopped entering the pleural cavity, it is gradually resorbed spontaneously. Estimated rates of resorption are between 1.25% and 2.2% the volume of the cavity per day. This would mean that even a completely collapsed lung would spontaneously reinflate over a period of about 6 weeks.[4]

Tension pneumothorax occurs because the opening that allows air to enter the pleural space functions like a valve, and with every breath more air enters and cannot escape. Severe hypoxia follows, with a resultant drop in blood pressure and level of consciousness. A previously uttered theory that the collapsed lung compresses large blood vessels such as the aorta is probably incorrect.[3]


Treatment
Schematic drawing of a person with a chest tube in the left thoracic cavity. It is connected to a water seal.The treatment of pneumothorax depends on a number of factors, and may vary from discharge with early follow-up to immediate needle decompression or insertion of a chest tube. Treatment is determined by the severity of symptoms and indicators of acute illness, the presence of underlying lung disease, the estimated size of the pneumothorax on X-ray, and in some instances also on the personal preference of the person involved. In spontaneous pneumothorax, air travel is discouraged until it has completely resolved.[4]

In traumatic pneumothorax, chest tubes are usually inserted (unless iatrogenic, see below). It is not yet clear if there is a subgroup of patients with small pneumothoraces who do not require tube treatment and could be managed conservatively. If mechanical ventilation is required, the insertion of a chest tube is mandatory as it would increase the risk of tension pneumothorax.[2][12]

Tension pneumothorax is usually treated with urgent needle decompression. This may need to happen before transport to hospital, and can be performed by an emergency medical technician or other trained professional. The needle or cannula is left in place until a chest tube can be inserted.[3][13] Any open chest wound is covered, as it carries a high risk of leading to tension pneumothorax, ideally with a dressing called the Asherman seal, which appears to be more effective than standard "three-sided" dressing. The Asherman seal is a specially designed device that adheres to the chest wall and allows air to escape but not to enter the chest through a valve-like mechanism.[13]