Pulmonary bulla is a large alveolar change that occurs when the walls of the alveoli rupture and fuse with each other due to increased pressure in the alveoli. Etiology and pathology Pulmonary bulla is usually secondary to inflammatory lesions of the small bronchi, such as pneumonia, tuberculosis or emphysema. Clinically, they often coexist with emphysema. The inflammatory lesions of the small bronchi cause edema and narrowing, resulting in partial obstruction of the lumen, which produces a live-gate effect, allowing air to enter the alveoli but not easily expelled, resulting in increased pressure in the alveoli. Inflammation causes damage to the lung tissue, and the alveolar septum gradually ruptures due to increased intra-alveolar pressure. If air enters the dirty subpleural space after the alveoli rupture, a subpleural blister is formed. There are single or multiple pulmonary blisters. Those secondary to pneumonia or tuberculosis are often solitary or have only a few blisters, and there is no obvious emphysema present at the same time; those secondary to emphysema are often multiple, showing several large blisters with multiple small blisters, and the lung parenchyma around the blisters is often accompanied by obstructive lung lesions and emphysema. Pulmonary blisters are most often located in the apical region of the lung and at the margins of the upper lobe. The walls of the blisters are very thin and vary in size and number. It can present as a wide basal seat. They may also appear as large, narrow-necked blisters. Microscopically, the walls of the blisters are visible as alveolar flat epithelial cells, sometimes with only fibrous membranes or fibrous connective tissue present. Large pulmonary blisters can compress the surrounding lung tissue, resulting in incomplete expansion of the remaining lung and affecting gas exchange. This is usually caused by a sudden rise in intrapulmonary pressure due to violent coughing, breath-holding or exercise, resulting in the sudden rupture of the large scar and the formation of a spontaneous pneumothorax. In other cases, the herpes may be adhered to the apex of the chest to form a wither strip, which is torn off when a sudden pneumothorax occurs, causing bleeding and resulting in a hemopneumothorax. Clinical manifestations The patient’s symptoms are closely related to the number and size of the blisters and the presence of chronic diffuse obstructive lung disease. Smaller, simple pulmonary blisters may be asymptomatic and are sometimes detected only occasionally on X-ray or during dissection for other diseases. Large or multiple pulmonary blisters may have symptoms such as chest tightness and shortness of breath. When a patient with pulmonary maculoplasm suddenly develops shortness of breath, cough, dyspnea, or chest pain similar to angina; cyanosis on physical examination, displacement of trachea to the healthy side, drum sound on percussion on the affected side, and disappearance of breath sounds on auscultation, rupture of maculoplasm and formation of spontaneous pneumothorax should be suspected. The main complication is spontaneous pneumothorax or hemopneumothorax. Diagnosis Chest X-ray is the main method to diagnose pulmonary herpes. The presentation is characterized by increased lung translucency and thin-walled cavities of varying size and number. The cavities are sparsely textured or have only striated shadows and are surrounded by compressed dense lung tissue. Large pulmonary blisters can look similar to a pneumothorax and are difficult to distinguish. However, the latter has higher translucency, no lung texture visible at all, and the lung tissue is compressed in the direction of the hilum with an arc opposite to that of the pulmonary macula. CT is an effective differential diagnosis that can reduce the overlapping shadow of the pulmonary macula in the stereoscopic position, can show the extent of the macula, and also helps in the differential diagnosis of the pneumothorax. When distinguishing pneumothorax from giant pulmonary blister, making chest puncture should be taken with caution. If pulmonary herpes is mistaken for pneumothorax and chest puncture is performed, it can lead to large scar leakage and cause medically induced pneumothorax or even become tension pneumothorax. If it is not possible to distinguish between pulmonary herpes or tension pneumothorax and the patient is in high respiratory distress, puncture or drainage and decompression can be performed temporarily to save life in an emergency, but at the same time, preparations for further dissection need to be made. Treatment Small-sized pulmonary cannons, especially patients aged >60 years, with chronic obstructive pulmonary disease and low respiratory function, should not be operated. Treatment is mostly non-surgical, such as smoking ban, exercise of lung function, control of respiratory tract infection, etc. In addition to the above, surgical treatment should be considered for large pulmonary scars of large size, especially for recurrent complications such as spontaneous pneumothorax or secondary infection. 1.Lung maculoplasty The main point of surgery is to carefully suture the air leakage area after cutting the lung maculoplasty. Partial excision of the excess wall of the herpes, suture the edges. For smaller pulmonary maculoplasty can be sutured or ligated. For bilateral pulmonary maculoplasty a split-sided resection or bilateral open-heart surgery can be done bilaterally at one time depending on the patient’s condition. Some people make wall pleurodesis or apply other methods to make lung and chest wall adhesions to promote withering and prevent recurrence of spontaneous pneumothorax after removing large lung scars. Pulmonary maculoplasty can be performed via TV thoracoscopy if available. If there is no normal lung tissue after resection of pulmonary blister, lobectomy can also be considered according to the patient’s respiratory function. 2.External drainage of pulmonary herpes is used as a temporary or long-term treatment for patients with large pulmonary scars that are at great risk of open chest. A 2.5 cm section of rib is excised at the closest part of the chest wall, and sutures are placed through both the wall pleura and the wall of the herpes as purse-string sutures with the wall pleura intact. A flexible tube with a balloon is inserted. After filling the balloon and pulling the drainage tube so that the wall of the herpes is tightly attached to the chest wall, the drainage tube is properly secured. If there is a pneumothorax, a closed chest drainage tube should be placed at the same time. Intensive antibiotic therapy is also indicated. The need for drainage is much longer than after pulmonary canal resection. Infection usually occurs more or less severely, and infection sometimes contributes to the closure of the macula.