Serum Procalcitonin for diagnosing and monitoring response in pleural infection

Aim: To assess the value of procalcitonin (PCT) in the diagnosis of pleural infection and monitoring response to treatment. Methods: All patients presenting to our unit with pleural infection had PCT as well as C-reactive protein (CRP) measured. Data was collected prospectively for all patients presenting with a clinical picture consistent with pleural infection and either acidic pleural fluid (pH Results: 53 patients presented to our unit with pleural infection in the 28 months from Sept. 2016. Graphs A&B display inflammatory marker trends during the first week of treatment. CRP was elevated in all cases whilst PCT was raised in 38 out of 41 patients with acute infection and in only 5 of 12 patients with chronic symptoms (more than three weeks duration). In patients with elevated PCT, levels appeared to drop consistently in response to appropriate treatment and matched the patients’ reported wellbeing. In contrast, CRP did not show a consistent decline in all patients. In a subgroup of the seven most challenging patients (Graph C, D) with features suggestive of persisting sepsis (fever and elevated CRP), PCT trends indicated a steady improvement in systemic bacterial infection. Conclusion: In patients with pleural infection, PCT appears to be a more specific marker of response to treatment. Further studies are required to confirm this.