Systemic inflammatory response and time from onset to hospital admission in severe pneumococcal pneumonia

Abstract number: 1733_690

Calbo E., Alsina M., Ródriguez-Carballeira M., Cuchi E., Xercavins M., Garau J., Network the Spanish Pneumococcal Infection Study

Introduction: The inflammatory response triggered by the presence of invading bacteria is a dynamic process changing over time, and many factors can influence the magnitude of this response. The aim of our study was to analyse the impact of time from onset of symptoms to hospital admission on the systemic plasmatic cytokine concentrations in patients with severe pneumococcal pneumonia (SPP).

Material and Methods: Consecutive adults with pneumonia classes III–V of the Pneumonia Severity Index (PSI) developed by the Pneumonia Outcome Research Team and with a confirmed pneumococcal aetiology were included. At admission, demographics, smoking and alcohol habits, comorbidities (Charlson score), immunosuppressive conditions, previous or current therapy with statins, use of non-steroidal or steroidal anti-inflammatory drugs, and prognosis measured by PSI and APACHE II scores were prospectively recorded. Special attention was paid to record time between pneumonia onset and hospital admission, collection of initial blood samples and the initiation of antimicrobial therapy. Vital signs, haematological and biochemical parameters were also assessed. Circulating levels of CRP, serum amyloid A (SAA), C3a, C5a and cytokines TNF-a, IL-1b, IL-6, IL-8, IL-10, and IL-1ra were measured at inclusion.

Results: 32 patients with SPP were included; 13 patients were seen and included within the first 48 h and the other 19 patients after 48 h from onset of symptoms. Both groups were homogeneous in terms of demographics, clinical characteristics, presence of comorbidities, bacteraemia, previous use of statins, severity of disease at presentation and radiological involvement. The group with a longer time of evolution at entry presented higher plasmatic levels of TNF-a (19.1[SD8.5] vs. 35.5[SD26] pg/mL; p = 0.035), fibrinogen (6[SD1.8] vs. 9[SD2]; p = 0.001); CRP (130[SD85] vs. 327[SD131]; p = 0.000), SAA (678[SD509] vs. 678[SD391]; p = 0.025) and lower albumin concentrations (40[SD5] vs. 35[SD4]; p = 0.043).

Conclusions: In pneumococcal pneumonia, the sustained release over time of pneumococcal antigens strongly correlates with a higher pro-inflammatory pattern and a higher expression of acute phase protein synthesis.