Microbial Aetiology and Clinical Course of Pleural Space Infections in a Tertiary Care Hospital- A Cohort Study

Abstract

Introduction: Infection of pleural space that arises due to complicated parapneumonic effusion and empyema is a common worldwide problem that is known since very ancient times. The microbial aetiology of pleural space infections has changed since introduction of antibiotics. Gram positive organisms are slowly and steadily losing their foothold in the pleural space to the more resilient and resistance gram negative bacteria. Incidence of these infections are increasing and delayed treatment causes significant morbidity and mortality. Aim: To study the age-sex profile, symptoms, microbiological findings, aetiology, management and treatment outcome of pleural space infections. Materials and Methods: This cohort study was conducted at Veer Surendra Sai Institute of Medical Sciences and Research, Burla, Odisha, India, from November 2016 to October 2017 on 48 consecutive patients. Each patient was followed-up for a minimum period of two months. The demographic data, clinical presentation, microbiological findings, aetiology, clinical course and management information were collected in a predesigned proforma and analysed. Results: The study population comprised of 33 (68.8%) male, 15 (31.2%) female patients. The mean age of the study population was 46±14 years. The most common presenting complaints were fever {43 (89.5%)}, shortness of breath {42 (87.5%)}, chest pain {38 (79.1%)} and cough {36 (75%)}. Pneumonia was diagnosed in 30 (62.5%) cases as the major cause of pleural space infection. Common organisms isolated were Streptococcus pneumoniae 11 (23%), Streptococcus pyogenes 9 (18.7%), Staphylococcus aureus 7 (14.5%) and Escherichia coli 7 (14.5%). The treatment was with Intravenous (i.v.) antibiotics followed by oral antibiotics. Most cases 46 (95.8%) required both thoracocentesis and Intercostal Tube Drainage (ICTD). Follow-up chest X-ray after two weeks showed complete lung expansion in 25 (52%) cases. Pleural thickening of 2 cm found in 26 (54.2%) cases. At the end of one month of discharge 35 (73%) patient had complete resolution, 8 (16.7%) patients had persistent infection, 3 (6.2%) died and 2 (4.1%) patients were loss to followup. Out of the eight patients with persistent infection one patient had empyema necessitans and seven patients had bronchopleural fistula. On follow up after 2nd month out of the 8 (16.6%) persistence cases, 5 (10.4%) cases were cured and remaining 3 (6.2%) cases the infection persisted (pus) and ICTD was kept in-situ. Conclusion: Pneumonia is the most common cause of pleural space infections. Most common pathogen isolated was gram positive organism Streptococcus pneumoniae. In significant number of cases gram negative organism Escherichia coli was isolated. Most cases required both thoracocentesis and ICTD for resolution. The key to successful management of pleural infection remains to be early diagnosis, initiation of empirical broad spectrum antibiotics, followed by specific antimicrobial therapy after microbial identification and drug sensitivity testing.

Keywords

• empyema
• lung abscess
• parapneumonic effusion