Definição e significado de Pleural_empyema

Pleural empyema (also known as a pyothorax^[1] or purulent pleuritis) is an accumulation of pus in the pleural cavity. Most pleural empyemas arise from a bacterial infection within the lung (pneumonia), often associated with parapneumonic effusions. There are three stages: exudative, fibrinopurulent and organizing. In the exudative stage, the pus accumulates. This is followed by the fibrinopurulent stage in which there is loculation of the pleural fluid (the creation of pus pockets). In the final organizing stage, scarring of the pleural space may lead to lung entrapment.^[2]

  Symptoms

  CT chest showing large right sided hydro-pneumothorax from pleural empyema. Arrows A: air, B: fluid

  Encasement of the left lung by thick purulent exudate which is characteristic of pleural empyema.

Symptoms of pleural empyema may vary in severity. Typical symptoms include: cough, fever, chest pain, sweating and shortness of breath.^[2]

Clubbing may be present in cases of a chronic nature. There is a dull percussion note and reduced breath sounds on the affected side of the chest. Other diagnostic tools include a blood white cell count, chest x-ray, CT scan, and ultrasonography.^[2]

  Progression to empyema over 2 weeks period.

  Diagnosis

Diagnosis is confirmed by thoracentesis; frank pus or merely cloudy fluid may be aspirated from the pleural space. The pleural fluid typically has a leukocytosis, low pH (<7.20), low glucose (<60 mg/dL), a high LDH (lactate dehydrogenase), elevated protein and may contain infectious organisms.^[2]

  Treatment

  World War I photo showing removal of several ribs as described.

Definitive treatment for pleural empyema entails drainage of the infected pleural fluid or pus. A chest tube may be inserted, often using ultrasound guidance. Intravenous antibiotics are given.

Chest tubes in the setting of pleural empyema have a tendency to be clogged by the thick pus. To combat this problem, surgeons will often place one or more large bore chest tubes. Insufficient drainage of the pleural empyema, particularly in loculated empyema, can lead to re accumulation of pus and infected material, a worsening clinical picture, organ failure and even death. Thus managing chest tube function is particularly important in the treatment of a pleural empyema.^[2] To improve the chest tube drainage, fibrinolytics and DNA enzyme can be given intrapleurally through the chest tube to break the fibrinous septation and to reduce the pus viscosity. Although these adjunct treatments are proven effective, its administration may cause rare but life-threatening intrapleural hemorrhage and hypersensitivity reaction.^[3]

If this is insufficient, surgical debridement of the pleural space may be required. This is frequently done using video-assisted thoracoscopic techniques but if the disease is chronic, a limited thoracotomy may be necessary to fully drain the pus and remove the fibrinopurulent exudate from the lung and from the chest wall.^[2] Occasionally, a full thoracotomy, formal decortication and pleurectomy are required. Rarely, portions of the lung have to be resected.

An earlier form of treatment involved surgical removal of most of the ribs on the infected side of the thorax, causing a permanent collapse of the lung and obliteration of the infected pleural space. This would leave the patient with a large portion of the upper chest removed, giving the impression that the shoulder had been detached from the body. Rarely performed today, the surgery was common during World War I. ^[4]

  References

  External links

• Empyema, Pleuropulmonary at eMedicine
• Images of Pleural Empyema from MedPix