To study the differences in demographic characteristics, presentation,treatment and overall outcomes between empyema caused by either Gram positive or Gram negative organisms.
A retrospective analysis of the clinical records of patients with a diagnosis of thoracic Empyema seen at our institution during a 10-year period (1996 to 2006) were evaluated.
122 patients were diagnosed with Empyema.46 were excluded. 66 patients were classified to the gram positive group and 13 to the gram negative group. There was no statistical difference between the age, sex and co-morbid conditions( Smoking History, Malignancy, COPD, Diabetes) between the two groups. Gram Positive orgamisms were implicated more often in healthy patients. (42.4% vs 23.1 %, p value 0.014) There was no difference in the biochemical profile of the pleural fluid,the presenting symptoms, which included dyspnea, hemoptysis, cough, fever, weight loss and chest pain or the underlying etiology of empyema in the gram positive or the gram negative group. Among the gram positive group Streptococcus pneumoniae and other streptococci [n-39 (59%], MSSA [n-10(15.1%)] and MRSA [n-7(10.6%)] were the most commonly isolated organisms. Among the gram negative group Prevotella [n-3(27.2%] Hemophilus influenza [n-3(27.2], Klebsiella [n-2(18.1%)], Pseudomonas [n-2(18.1%)] and Escherechia coli [n-1(9%0] were identified. A higher number of Gram negative empyemas required surgical decortication. (61.5% versus 39.4%, p value 0.33) There was no statistical difference in the length of stay and the overall discharge status of patients in either group.
Gram Positive organisms remain a more prevalent cause of empyema. Gram negative organisms are seen more in debilitated pateints, and require more invasive surgical interventions. Overall there are no differences in the demographic characteristics, clincial features and outcomes in Gram positive empyema as compared to Gram negative empyema.
Further studies need to look at the prevalence of Gram negative organisms as a cause of empyema in sick patients. We also need to look at the need for surgical interventions in this population as compared to empyema caused by gram positive organisms.
Abhijit Duggal, No Financial Disclosure Information; No Product/Research Disclosure Information