Pyothorax is a medical condition defined by the accumulation of purulent fluid, or pus, within the pleural space. This space is the thin gap situated between the lung’s outer lining and the inner wall of the chest cavity. The presence of pus indicates a severe infection in this normally sterile region. Pyothorax is also referred to as pleural empyema.
How Pyothorax Develops
Pyothorax typically arises as a complication of an existing bacterial infection, most commonly severe pneumonia, where the infection spreads from the lung tissue into the pleural space. The bacteria trigger an inflammatory response, causing fluid, proteins, and white blood cells to move into the pleural cavity. This process creates a thick, infected fluid that the body’s lymphatic drainage system struggles to clear.
The fluid, now pus, creates an environment where bacteria thrive. Inflammation often leads to the formation of fibrin strands, which create pockets, or loculations, that trap the pus and prevent defenses from reaching the infection. Less common routes of infection include direct inoculation from chest trauma, such as a penetrating wound, or complications from chest surgery. A ruptured lung abscess can also seed the pleural space with bacteria, leading to the rapid onset of pyothorax.
Identifying the Symptoms
The accumulation of pus causes a range of clinical signs. A person with pyothorax will often experience a high fever and chills, which are systemic indicators of infection. The expanding fluid volume compresses the lung, leading to shortness of breath, or dyspnea.
Difficulty breathing is often accompanied by a persistent cough. Another symptom is pleuritic chest pain, a sharp, localized pain that intensifies when taking a deep breath, coughing, or sneezing. Patients may also show signs of general illness, including lethargy, weakness, and decreased appetite.
Diagnosing and Treating the Condition
A physician’s initial suspicion of pyothorax is often raised by symptoms and physical examination, but imaging tests are necessary to confirm the presence of fluid. A chest X-ray typically shows a pleural effusion, and a computed tomography (CT) scan provides a more detailed view, often revealing thick, organized fluid or loculations. The definitive diagnosis is established by thoracentesis, where a needle is inserted into the chest wall to aspirate a sample of the pleural fluid.
The fluid is then analyzed and cultured in a laboratory to confirm it is pus, identify the specific bacteria, and determine which antibiotics will be most effective. Treatment aims to control the systemic infection and mechanically drain the purulent fluid. Broad-spectrum antibiotics are started immediately to combat potential bacterial pathogens.
The physical drainage of the pus is accomplished by inserting a chest tube, a procedure known as tube thoracostomy. This tube remains in place for several days, allowing for continuous drainage and sometimes for the instillation of sterile fluid to wash out the pleural space, a process called pleural lavage.
For cases where the pus has formed thick, organized pockets that cannot be fully drained by the chest tube, a more involved intervention may be necessary. These complicated cases often require a procedure such as video-assisted thoracoscopic surgery (VATS). VATS is a minimally invasive surgical technique that allows the surgeon to break up the fibrin strands, fully drain the trapped pus, and remove any thick, inflammatory peel that may be constricting the lung. Long-term antibiotic therapy, often lasting four to six weeks, is then required to ensure the deep-seated infection is completely eradicated and prevent recurrence.