Background Systemic autoimmune disease children presents with fever during disease flare and systemic infection. It is very difficult for clinician to decide the diagnosis clinically, acute phase reactants helps in this situation. Hence we decided to determine the diagnostic value of procalcitonin to differentiate bacterial infection and non infectious inflammation.
Objectives To determine the clinical value of procalcitonin (PCT) in differentiating bacterial infection from disease activity in children with systemic autoimmune disease.
Methods This was a cross-sectional study of children with systemic autoimmune disease presented with fever recruited over 9 months. Baseline demographic variables were recorded and measurements of PCT, CRP, ESR and blood cultures were done. The disease activity for SLE was determined by SLEDAI score and for JIA by Wallace criteria. During the study period, 24 children with systemic autoimmune disease were recruited and analysed. Children were divided in 2 groups: Fever due to disease flare and due to infections.
Results Out of 24 children recruited as per inclusion criteria, 16 had SLE (11 in disease flare group and 5 in infection group) and 8 had disease flare of Systemic JIA. 2 children in SLE infection group died. As for infections, serum PCT concentration (cut-off value >1.2 ng/ml) gave a sensitivity of 83% (95% CI 43.6 - 0.97), a specificity of 72% (95% CI 49.1–87.5), a positive predictive value of 50% (95% CI 23.6- 76.3) and a negative predictive value of 93% (95% CI 68.5 - 98.7).To achieve the same sensitivity (as of PCT) of 83%, the cut off value for CRP was 34 mg/dl and ESR was 76 mm/hr. Mean PCT was 92.2 ng/ml in SLE infectious group and 3.50 ng/ml in SLE flare group which was statistically significant (p=0.009). But mean CRP was 98 mg/dl in SLE infectious group and 52 mg/dl in SLE flare group which was not statistically significant (p=0.25). Similarly mean ESR level (38 mm/hr) in SLE infectious group and in SLE flare group (66 mm/hr) was not statistically significant (p=0.35).
Conclusions Our results suggested that the procalcitonin level was the most discriminatory parameter, followed by CRP in children with SLE presenting with fever between disease flare and infection. Procalcitonin levels>1.2 ng/ml in febrile SLE patients should point to bacterial infection, whereas procalcitonin levels less than <1.2 ng/ml might indicate non-infectious inflammation that could reduce unnecessary antibiotic use.
Disclosure of Interest None declared