PB2041 UTILITY OF INFLAMMATORY MARKERS IN DISTINGUISHING VARIOUS INFECTIVE ETIOLOGIES OF FEVER IN FEBRILE NEUTROPENIC PATIENTS

Abstract

Background:Febrile neutropenia is a common cause in morbidity and mortality during treatment of hematological neoplasms. This leads to unnecessary use of broad‐spectrum antibiotics adding to the cost of treatment, selection pressure amongst bacteria and side effects of antibiotics.Aims:To study the utility of Procalcitonin and CRP in differentiating various causes of fever in patients with febrile neutropenia.Methods:Subjects included all cases admitted under hematology department with febrile neutropenia from February to June 2018 (age ranged‐1‐60 years). Institutional Ethics Committee clearance was obtained for the conduct of this study.Etiology of febrile episodes classified according to International Immunocompromised Host Society (ICHS) into four groups:• Microbiologically documented infections (MDI)• Clinically documented infections (CDI)• Fever of unexplained origin (FUO)• Invasive fungal infections (IFI)Diagnostic work up for each febrile episode was done including Procalcitonin (PCT) and CRP. PCT and CRP was sent at fever onset 0,24,48hour, day 7 and day 14 or defervescence.Results:A total of 72 patients evaluated out of which 17 patients excluded either due to incomplete data or fever due to non‐ infective causes. Data was analyzed for 52 febrile episodes in 50 patients. At fever onset no significant difference was observed in the PCT & CRP values amongst various etiologies. PCT cut off value at 24 hours of ≤1.2ng/ml had a sensitivity and specificity of 62.5% and 87.5% for discriminating IFI and MDI (p = 0.033). PCT had a negative predictive value of 70% for the diagnosis of IFI as compared to MDI. PCT cut‐off of 0.4ng/ml on day 7 had a sensitivity and specificity of 60.98% and 100% respectively for discriminating IFI and PUO (p = 0.0001). Procalcitonin was significantly higher in the pneumonia group compared to other site infections (median‐11.42; IQR‐6.170 ‐ 13.003; p < 0.05). Patients who developed signs of severe infection like Septic shock, hypoxia were noticed to have significantly high median PCT value at 24 and 48 hours (p value‐ 0.007 for PCT 24 and 0.001 for PCT 48). Patients with only MDI infections had the highest PCT level over the course of febrile episode. CRP cut off >160 mg/dl at 48 hours was suggestive of fever due to fungal infection rather than other causes, with a sensitivity of 100%, specificity of 48%, PPV of 33.3% and NPV of 100%. There was a significant rise from baseline in CRP values at 48 hours in the IFI group when compared to the other groups (median = 33.6; p = 0.045). The CRP values at 24 hours and 48 hours were significantly lower in the PUO (disease fever) group (p = 0.001) when compared to the other groups. There was a significant fall in the level of PCT by day 14(median fall in PCT of 10.8) in the group of patients who had both IFI+ MDI when compared to other groups (p = 0.047).Summary/Conclusion:PCT level at 24 and 48 hours can be a predictor of severity of infection. High PCT level throughout the course of febrile episode were more suggestive of blood culture positive bacterial infection. Regarding CRP, significant rise from baseline at 48 hrs or CRP>160 mg/dl at 48 hrs were significantly indicative of fungal infection rather than bacterial. PCT or CRP may be a useful adjunct to step down or step up antimicrobials.