Medical Care: Individualize treatment of each patient, depending on the type or stage of parapneumonic effusion.
" Initial treatment
o The initial treatment of a patient with pneumonia and pleural effusion involves 2 major decisions. First, select an appropriate antibiotic. Second, decide whether to initiate tube drainage of the pleural space. The initial antibiotic selection is usually based on whether the pneumonia is community-acquired pneumonia or hospital-acquired pneumonia and the severity of the patient's illness. For a patient with community-acquired pneumonia, the recommended agents are second-generation or third-generation cephalosporins in addition to a macrolide. For patients hospitalized with severe community-acquired pneumonia, initiate treatment with a macrolide plus a third-generation cephalosporin with antipseudomonal activity. Enteric gram-negative bacilli frequently cause pneumonia acquired in institutions (eg, hospitals, nursing homes). Therefore, initial antibiotic coverage should include an antibiotic effective against pseudomonads.
o Base the decision to institute tube drainage on examination of the pleural fluid. Identify patients who need tube drainage as soon as possible because the pleural effusions become loculated if tube thoracostomy is delayed.
o Patients with pleural effusions that have a pleural fluid thickness greater than 10 mm on lateral decubitus radiographs must have a diagnostic thoracentesis. Effusions with pleural fluid thickness less than 10 mm on decubitus chest radiographs almost always resolve with appropriate systemic antibiotics.
o If the diagnostic thoracentesis yields thick pus, the patient has an empyema. Institute tube thoracostomy immediately. If the pleural fluid is not thick pus, then the results of the pleural fluid Gram stain and the pleural fluid glucose, pH, and LDH levels should guide the course of action.
" Uncomplicated parapneumonic effusions
o If the pleural fluid pH is greater than 7.20, the pleural fluid glucose is greater than 40 mg/dL, and the pleural fluid LDH is less than 1000 IU/L, the parapneumonic effusion is in the exudative stage, and no further therapeutic intervention is required. However, if the pleural effusion increases in size or the patient remains or becomes febrile, repeat the thoracentesis.
o Uncomplicated effusions resolve with antibiotics alone.
o Patients with uncomplicated effusions can be monitored with serial radiography or meticulous physical examination to document resolution of effusion.
" Complicated parapneumonic effusions
o If the initial thoracentesis reveals pleural fluid with a pH less than 7.20 or a glucose level greater than 40 mg/dL, immediately perform tube thoracostomy. If the Gram stain of the pleural fluid is positive, tube thoracostomy is recommended.
o Complicated effusions have a variable response to appropriate antibiotic therapy, although some patients can be treated with antibiotics alone. Patients with complicated parapneumonic effusions are treated as though they have thoracic empyema.
" Chest tubes (tube thoracostomy)
o Insert chest tubes immediately after a complicated parapneumonic effusion or empyema is diagnosed because delay leads to formation of loculated pleural effusion. Position the chest tube in a dependent part of the pleural effusion. Although traditionally large-bore (38-32F) tubes are recommended, smaller catheters (8.5-16F) can also be used successfully in draining the pleural space.
o If the patient responds clinically and radiologically to closed tube drainage of the pleural space, leave the chest tubes in place until the volume of the pleural drainage is less than 50 mL/24 h and the drainage fluid becomes clear yellow.
o If the patient has not demonstrated clinical or radiologic improvement, perform ultrasonic examination or CT scanning of the pleural space to detect remaining loculi of pleural fluid and to ensure that the tube is in the proper place. If multiple loculi are identified, administer thrombolytic therapy intrapleurally. Closed chest tube drainage yields satisfactory results in approximately 60% of patients with aerobic infections and 25% of patients with anaerobic infections.
" Intrapleural thrombolytic agents
o Since the 1970s, several studies have reported success of thrombolytic therapy for loculated complicated parapneumonic effusions. The thrombolytic agents appeared to be more effective if they were administered early in the course of parapneumonic effusions. In a randomized trial of patients with multiloculated pleural effusions, those in the urokinase group drained significantly more pleural fluid, required less surgical intervention, and required fewer days in the hospital.
o With fibrinolytic therapy, success rates of 70-90% have been quoted. Streptokinase is used in a dose of 250,000 IU in 100 mL of isotonic sodium chloride solution once or twice a day. Following instillation, the chest tube is clamped for 2-4 hours before draining spontaneously. These agents may be administered daily for as many as 14 days. Both streptokinase and urokinase appear to be equally effective, although streptokinase may lead to sensitization with production of an antibody response and subsequent allergic reaction if employed for systemic thrombolysis. Multiple tubes may be inserted under CT scan guidance for multiloculated pleural space.
o A recent prospective randomized trial of intrapleural fibrinolytic agent streptokinase was conducted in the drainage of infected pleural-fluid collections. In this double-blind trial, 454 patients with pleural infection (either purulent pleural fluid or pleural fluid with a pH <7.2 with signs of infection) received either intrapleural streptokinase (250,000 IU bid for 3 days) or placebo. Among the 427 patients who received streptokinase or placebo, no benefit was reported for streptokinase in terms of mortality, rate of surgery, radiographic outcomes, or length of hospital stay; serious adverse events (chest pain, fever, or allergy) were more common with streptokinase (Maskell, 2005).
o Tokuda et al performed a meta-analysis of all properly randomized trials comparing intrapleural fibrinolytic agents with placebo in adult patients with empyema and complicated parapneumonic effusions. The outcome of primary interest was the reduction of death and surgical intervention. Five trials totaling 575 patients were included. The meta-analysis did not support the routine use of fibrinolytic therapy for all patients who required chest tube drainage for empyema or complicated parapneumonic effusions. However, because of significant heterogeneity of the treatment effects, selected patients might benefit from the treatment (Tokuda, 2006).
Surgical Care: Several surgical procedures are available to treat a patient with empyema. The definite indication for surgical therapy is persistent pleural sepsis despite antibiotics and attempts at pleural drainage with thoracoscopy.
" Thoracoscopy
o Thoracoscopy is an alternate therapy for multiloculated empyema.
o In patients with multiloculated parapneumonic effusion, the loculations in the pleural space can be disrupted with a thoracoscope, and the pleural space can be drained completely.
o If extensive adhesions are present or thick pleural peel entraps the lung, the procedure may be converted to open thoracostomy and decortication.
o Luh et al published their experience in treatment of complicated parapneumonic effusion and pleural empyema by video-assisted thoracoscopic surgery (VATS) in 234 patients (108 women, 126 men). More than 85% (200 patients) received preoperative diagnostic or therapeutic thoracentesis, tube thoracostomy, or fibrinolytics. Out of 234 patients, 202 patients (86.3%) achieved satisfactory results with VATS treatment. Only 40 patients required open decortication or repeat procedures. VATS is safe and effective for treatment; earlier intervention with VATS can produce better clinical results (Luh, 2005).
o Hope et al reviewed outcomes of surgical treatment for parapneumonic empyema. The use of VATS was compared with thoracotomy. Morbidity and mortality rates were similar among all groups. Conversion rate to open thoracotomy was 21%. Based on a shorter postoperative length of stay with similar morbidity and mortality in patients operated on within 11 days of admission, early aggressive surgery treatment for parapneumonic empyema is recommended (Hope, 2005).
" Rib resection and drainage of pleural space
o Open drainage of the pleural space may be employed when closed tube drainage of the pleural infection is inadequate and the patient does not respond to intrapleural thrombolytic agents. This procedure is recommended only when the patient is too ill to tolerate a decortication. The resection of 1-3 ribs overlying the lower part of the empyema cavity is performed, a large-bore chest tube is inserted into the empyema cavity, and the tube is drained into a colostomy bag.
o When a patient is treated by open drainage, expect an open chest wound for a prolonged period. In one series, the median time for healing the drainage site was 142 days. With decortication, the period of convalescence is much shorter, although patients who are markedly debilitated do not tolerate decortication.
" Decortication
o In decortication, all the fibrous tissue is removed from the visceral pleural peel, and all pus is evacuated from the pleural space. Decortication is a major thoracic operation requiring full thoracotomy; therefore, do not perform decortication on patients who are markedly ill.
o Decortication is the procedure of choice for patients in whom pleural sepsis is not controlled by closed tube thoracostomy, intrapleural thrombolytic agents, and possibly, thoracoscopy.
o Mortality rates as high as 10% have been described with this procedure.
o Do not perform decortication just to remove the thickened pleural peel; these thickened peels usually resolve spontaneously over several months. If after 6 months the pleura remains thickened and the patient's pulmonary function is reduced sufficiently to limit activities, consider decortication.
" Postpneumonectomy empyema, an uncommon but life-threatening complication, is associated with bronchopleural fistula. Treatment of bronchopleural fistula depends on several factors, including extent of dehiscence, degree of pleural contamination, and general condition of the patient. Early diagnosis and aggressive therapeutic strategies of controlling infection, closure of fistula, and sterilization of the closed pleural space are mandatory. Repeated debridement, VATS, endoscopic application of tissue glue, and stenting may be additional management strategies (Ng, 2005).