Pyopneumothorax is a pleural disease that develops with the simultaneous entry of pus and air into the pleural fissure from destructive pulmonary foci. Pyopneumothorax is accompanied by sharp chest pain, sudden shortness of breath, cough, apnea, cyanosis, severe hypotension, symptoms of purulent intoxication. The diagnosis of pyopneumothorax is made according to lung radiography, diagnostic pleural puncture. With pyopneumothorax, thoracocentesis with active aspiration drainage, antibiotic therapy, detoxification therapy, if necessary, surgical tactics (thoracostomy, pneumoabsessotomy, lung decortication and thoracoplasty, etc.) are indicated.
Pyopneumothorax is a special form of bacterial destruction of the lungs, characterized by the release of pus and air into the pleural cavity and the formation of a pulmonary pleural fistula. Pyopneumothorax accounts for up to 38% of cases of bacterial lung destruction; every fifth gangrenous abscess is complicated by pyopneumothorax. In pulmonology, pyopneumothorax is considered as a type of pleural empyema. Taking into account the localization, the pyopneumothorax is divided into total (without pleural fusion) and limited (circumscribed, in the presence of pleural adhesions). Total pyopneumothorax can be unstressed (simple) and tense, associated with high pressure in the pleural cavity due to the presence of a valve mechanism in the area of the bronchopleural fistula.
Causes of pyopneumothorax
Pyopneumothorax develops in acute purulent-destructive processes in the lungs, complicating infectious and inflammatory diseases caused by purulent microflora: Staphylococcus, Streptococcus, Pseudomonas aeruginosa; anaerobes (Klebsiella, clostridia), as well as Mycobacterium tuberculosis. The background on which pyopneumothorax occurs may be a congenital suppurated cyst, abscess or gangrene of the lung, cavernous tuberculosis, abscessing pneumonia, acute purulent lobitis.
The most common cause of pyopneumothorax is a breakthrough into the pleural cavity of an intrapulmonary purulent focus communicating with the bronchus, and with a tuberculous lesion – melting and opening of subcortical foci of caseosis. Sometimes pyopneumothorax may be caused by pleural empyema caused by putrefactive anaerobe Clostridium perfringens, the product of which is gas, or communication of the empyema cavity with the external environment through a fistula or wound defect of the chest wall. In children, pyopneumothorax often occurs against the background of septicopyemia as a secondary purulent focus.
The development of pyopneumothorax is caused by increased inflammatory damage to the lungs with the formation of a purulent focus (suppurated cyst, abscess), deep destruction (caverns, necrosis), destruction of lung tissue, cortical layer and visceral pleura and the opening of the abscess into the pleural space. In its course, there are stages of a threatening breakthrough, an open pulmonary-pleural fistula (after perforation of the necrosis focus) and a covered pulmonary-pleural fistula (when gluing the edges of the fistula with the near areas of the pleura).
The intensity of injection of pus and air into the pleural cavity depends on the size of the fistula, abscess and bronchus communicating with them, as well as the rate of resorption of the gas mixture by the pleura. With a rapid intake of pus and air, an intrapleural tension syndrome develops with a sharp increase in pressure inside the pleura, a momentary collapse of the lung, a displacement of the mediastinum, and the onset of pleuropulmonary shock. Preservation of the pleurobronchial fistula supports air access and purulent inflammation of the pleura; covered fistulas may scar or reopen into the pleural fissure.
Symptoms of pyopneumothorax
Pyopneumothorax can occur in acute, mild and erased clinical forms. This is determined by the nature and degree of purulent-destructive lesion of the lung tissue, virulence of the pathogen, the reaction of the pleura to the development of inflammation. The most violent course is acquired by pyopneumothorax, caused by the breakthrough of gangrenous lung abscesses. In the clinic of pyopneumothorax, there are 2 phases – acute respiratory disorders and intense subcompensation, occurring against the background of severe intoxication and temperature reaction.
The acute form of pyopneumothorax begins with a sharp severe pain in the affected half of the chest, a sudden attack of coughing, severe shortness of breath, short-term apnea. There is an increasing pallor and cyanosis of the skin and mucous membranes, cold sticky sweat, sharp hypotension (up to 50-70 mmHg), thready pulse.
The symptoms of simple and limited pyopneumothorax are similar to the manifestations of pleural empyema. In the absence of a valve mechanism, due to compensatory reactions, the patient’s condition gradually stabilizes: the pulse is leveled, pain symptoms are muted. Without evacuation of pus, manifestations of purulent intoxication come to the fore, high fever with “purulent” drops within two degrees, chills, pouring sweat, loss of appetite are possible.
A tense pyopneumothorax is characterized by an extremely severe general condition due to acute respiratory failure. The patient is restless, takes a comfortable forced position – sitting, leaning with his hands on the edge of the bed. Typically, swelling of the cervical veins, increased breathing, a clinic of pseudoabdominal syndrome with tension of the muscles of the anterior abdominal wall may be present. In the presence of a valve mechanism, subcutaneous emphysema of the neck, face, chest wall, mediastinum develops. The stage of subcompensation does not occur. Increasing respiratory and cardiovascular insufficiency in the absence of medical care pose a direct threat to life.
With a mild form of pyopneumothorax, a subcompensated course prevails, with a rapid restriction of the purulent pleural cavity, the chronization of the process occurs. Erased forms of pyopneumothorax can proceed unnoticed with pronounced local and general symptoms of the main purulent-destructive lung disease.
In the diagnosis of pyopneumothorax, the data of the clinical picture, radiography, polypositional X-ray and CT of the lungs, thoracoscopy, transthoracic puncture of the pleural cavity are of decisive importance. With a tense pyopneumothorax, a noticeable lag of the affected half of the chest in the respiratory act is determined, the expansion of intercostal spaces, the sudden appearance of a box sound on the side of the sleeping lung, a weakening of respiratory noises and an amphoric tinge of bronchial respiration.
The radiograph with pyopneumothorax is characterized by a displacement of the mediastinal organs in a healthy direction, the presence of one or more horizontal levels of fluid (pus) in the pleural cavity, over which a sharply prominent air bubble is determined. With an unlimited pyopneumothorax, a partial or complete collapse of the lung is observed, with a limited process – elongated fusiform sealed purulent-air cavities. The separation of the leaves of the visceral and parietal pleura is pathognomonic for pyopneumothorax and is well determined by pleurography after contrast enhancement.
Receiving pus and air during thoracocentesis certifies the diagnosis previously made by a pulmonologist or thoracic surgeon, and also allows for a microbiological examination of the material taken from the pleural cavity. A necessary stage is the differential diagnosis of pyopneumothorax with acute myocardial infarction, PE, bronchial asthma, angina pectoris, perforated ulcer, acute cholecystitis, subpleural gangrenous abscess and suppurated lung cyst.
Treatment of pyopneumothorax is carried out in a surgical hospital and includes local and general measures. In acute and complicated form, an emergency pleural puncture is indicated to evacuate air and relieve tense pneumothorax, then drainage of the pleural cavity with active aspiration of pus. With small closed purulent cavities, a combination of repeated flushing of the pleural cavity with antimicrobial solutions with active aspiration drainage is effective. Prolonged catheterization of the abscess in the lung through the trachea and bronchus with repeated drug irrigation is possible. To remove the patient from shock, infusion therapy, extracorporeal detoxification, as well as oxygen therapy, cardiac glycosides, corticosteroids are administered. Along with antibiotic therapy for pyopneumothorax, passive and active immunization, immunocorrection are used.
In the presence of an open bronchopleural message, cauterization is performed by intrapleural administration of iodolipol and iodinol, temporary closure of the bronchus with a foam sponge during bronchoscopy. Surgical intervention is resorted to when drainage is ineffective for several days. It is permissible to perform thoracostomy, pneumoabsessotomy with suturing of lung tissue, suturing of fistulas. In case of incomplete expansion of the lung after maximum cleansing of the pleural cavity, lung decortication and thoracoplasty are necessary. In the most severe situations, pleurolobectomy, marginal or wedge-shaped resection of the lung is undertaken.
The prognosis of pyopneumothorax is serious and is determined by the severity of lung destruction. In children, especially at an early age, fatal cases can reach 10-20%. With rapid diagnosis and proper treatment, the outcome is generally favorable. In the long term, there is a risk of irreversible changes in lung tissue with the development of chronic nonspecific inflammation.