[Lung abscess and thoracic empyema: retrospective analysis in an internal medicine department]

Lung abscess is a collection of necrotic and suppurated tissue located at the pulmonary parenchyma. Empyema is defined as the presence of pus in the pleural space.

To study the clinical and microbiological characteristics, treatment and prognosis of patients with lung abscess and/or empyema admitted to an Internal Medicine ward.

A retrospective analysis of medical records was performed, including all patients admitted to an Internal Medicine ward for lung abscess or empyema, between 2000 and 2008.

Thirty patients were included (22 males/ eight females), accounting for 0.18% of all patients admitted in this ward in the same period. Three patients had pulmonary abscess, 18 empyema, and nine both diseases. The average age was 68.5 years (31 to 90). The most frequent complaints were dyspnoea (90%), fever (73.3%), cough (66.7%), weight loss (60%) and chest pain (53.3%). The most frequent associated disorders were stroke associated disability (46.7%), heart failure (43.3%) and arterial hypertension (33.3%). Thoracentesis was performed in all patients with empyema. In one patient with lung abscess an anaerobic microorganism was identified. In patients with empyema, cultures were positive in 61.1% of cases, with a slight predominance of methicillin-resistant Staphylococcus aureus (27.3%) and Prevotella intermedia (18.2%). In patients with both abscess and empyema, cultures of the abscess were positive in 44.4% and of the pleural fluid in 33.3%, with no predominant microorganism. Empiric antimicrobial therapy was started in all patients and later adapted to the antibiotic sensitivity test results. Surgery was performed in three patients. Seven patients (23.3%) died during admission. The average age of the patients who died was 81.3 years and of those who survived was 64.5 years.

Lung abscess and empyema are infrequent diseases in an Internal Medicine ward, affect mostly males and have unspecific clinical manifestations. The chest X-ray, computed tomography (CT) and thoracentesis were the main diagnostic tests. Most cultures were negative. Medical treatment was the most frequent choice, with surgery being used in 10% of cases. Older age and multiple associated conditions were associated with a worse prognosis.