Approach Considerations
Treatment of lung abscesses or empyema is performed in-hospital, with consultations involving internists, pulmonologists, thoracic surgeons, and/or interventional radiologists.
All patients should undergo pulse oximetry and evaluation of their respiratory status. If respiratory failure is found or likely to occur, intubation and mechanical ventilation is necessary. Supplemental oxygen should be started for any patient who is acutely short of breath or who is hypoxic based on pulse oximetric findings.
Once the diagnosis of a lung abscess is made, parenteral antibiotics should be started. Ideally, sputum and blood culture findings should be obtained prior to the initiation of antibiotics.
After the diagnosis of empyema is made, prompt drainage by means of tube thoracostomy with use of parenteral antibiotics should be initiated.
Inpatient care is mandatory for the management and assistance of the patient's respiratory status, continuation of intravenous antibiotics, and drainage of the lung abscess or empyema as needed. Antimicrobial therapy should be continued empirically until therapy can be guided with culture results.
Transfer is usually not indicated unless advanced respiratory management or surgical drainage is not available without transfer. Patients should be transferred only after stabilization of their respiratory status and administration of intravenous antibiotics.
Medical Care
Lung abscesses are treated with a prolonged course of parenteral antibiotics that target organisms found in aspiration pneumonia. [3] The initial choice of antibiotics frequently is empiric, beginning with clindamycin, cefoxitin, ticarcillin, or piperacillin/tazobactam, although penicillin has been very effective when the organism is sensitive. Some authors advocate adding coverage for Klebsiella as well. Subsequent therapy should be based on sputum or blood culture results.
An empyema is treated with parenteral antibiotics and prompt surgical drainage. Empiric therapy, including anaerobic coverage, for an empyema frequently includes clindamycin, carbapenems, or beta-lactam plus beta-lactamase inhibitors like piperacillin/tazobactam until a definitive organism is identified on pleural fluid cultures and sensitivities are obtained. For an empyema secondary to aspiration pneumonia or a parapneumonic process, choose antibiotics that are active against mouth flora, S aureus, and Streptococcus species. For an empyema secondary to penetrating chest trauma, administer antibiotics that have coverage for skin flora. There should be a strong consideration to cover with vancomycin given the increasing incidence of empyema caused by MRSA. Pleural fluids or sputum specimens that are obtained should be cultured for M tuberculosis as well.
Many clinicians advocate the administration of intrapleural fibrinolytics in patients with empyemas. Intrapleural fibrinolytics assist in the breakdown of fibrin bands that can cause loculation of the empyema and allow for better chest tube drainage of the infected material. A meta-analysis that included 761 patients showed that intrapleural fibrinolytic therapy confers significant benefit in reducing the requirement for surgical intervention for patients. [23] However, some randomized clinical trials have reported opposite results, with these studies suggesting no benefit in outcomes with fibrinolytic therapy. [24]
Surgical Care
Lung abscesses typically respond well to antibiotic therapy, but when that therapy is unsuccessful, the consulting clinician might consider percutaneous catheter drainage or endoscopic surgical resection of the involved area of the lung (see Lung Abscess Surgery). Surgery is required in 11-21% of cases [25] and is often indicated for complications, including severe hemoptysis or development of bronchopleural fistula or empyema, and abscesses larger than 6 cm, associated with obstructing neoplasms, or secondary to Pseudomonal infections. [26]
Interventional radiographic management has become a well-established treatment and is becoming an increasingly safe and effective means of treating lung abscesses. The success rate of CT-guided drainage of a lung abscess is up to 90% and is associated with fewer complications, less pain, and shorter hospital stays. [27]
The overall success rate of percutaneous tube drainage (PTD) has been reported in one study as 84% with a complication rate of 16%. PTD is associated with less morbidity and mortality than surgical resection. [28]
Complicated parapneumonic effusions or empyemas require drainage in addition to medical therapy to ensure a good prognosis. Traditionally, a large caliber, chest thoracostomy tube has been placed to drain the fluid in an effort to avoid further surgical intervention. More recently, CT- or US-guided pigtail drainage catheters, smaller than 14F, have been used with comparable results but with much less pain. [27]
If chest tube or pigtail catheter drainage and fibrinolytic treatment are unsuccessful, many authors recommend video-assisted thoracic surgery (VATS) next rather than the more traditional open thoracotomy. VATS is less invasive and well tolerated, with outcomes that compare favorably with open thoracotomy. [29]
Prevention
Prevention of aspiration is important to minimize the subsequent risk of lung abscess. The risk of aspiration can be reduced by cessation of alcohol and drug abuse, good dental hygiene, good nutrition, and management of gastroesophageal reflux disease. Early intubation should be performed in patients who do not have a gag reflex or are in the process of respiratory failure.
The 13-valent pneumococcal conjugate vaccine (PCV13) has been found to reduced parapneumonic empyema among US children under the age of 18 years. [30] In addition, the hospitalization rate for all types of empyema reached a historic low among children younger than 2 years in the two year period following the introduction of PCV13 in both the US and the UK. [30, 31]
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Histology of a lung abscess shows dense inflammatory reaction (low power).
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A thick-walled lung abscess.
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Pneumococcal pneumonia complicated by lung necrosis and abscess formation.
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A lateral chest radiograph shows air-fluid level characteristic of lung abscess.
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A 54-year-old patient developed cough with foul-smelling sputum production. A chest radiograph shows lung abscess in the left lower lobe, superior segment.
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A 42-year-old man developed fever and production of foul-smelling sputum. He had a history of heavy alcohol use, and poor dentition was obvious on physical examination. Chest radiograph shows lung abscess in the posterior segment of the right upper lobe.
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A 42-year-old man developed fever and production of foul-smelling sputum. He had a history of heavy alcohol use, and poor dentition was obvious on physical examination. Lung abscess in the posterior segment of the right upper lobe was demonstrated on chest radiograph. CT scan shows a thin-walled cavity with surrounding consolidation.
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Chest radiograph of a patient who had foul-smelling and bad-tasting sputum, an almost diagnostic feature of anaerobic lung abscess.
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Histology of a lung abscess shows dense inflammatory reaction (high power).
