Serum cystatin C and microalbuminuria in children with immune thrombocytopenia under short course of corticosteroids

BackgroundCorticosteroids are the universally accepted first line therapy for moderate and severe immune thrombocytopenia (ITP).ObjectivesWe investigated the effect of a short course prednisolone on serum cystatin C and the appearance of microalbuminuria as markers for renal injury in a group of ITP children.MethodsThe study involved 33 (19 males, 14 females) newly diagnosed ITP children divided into two groups; group I included 15 children with no or mild bleeding treated according to “watch and wait” policy; group II included 18 children of moderate or severe bleeding treated by oral prednisolone. Fifteen healthy, age and sex matched children were enrolled as a control group. Blood urea, serum creatinine, estimated glomerular filtration rate (eGFR) by Schwartz formula, serum cystatin C (by ELISA) and urinary albumin concentration (by immunoturbidimetric assay) were determined.ResultsThe baseline investigations were comparable in the three groups and were within the reference ranges. Corticosteroids of 12 mg/kg cumulative dose had induced significant increments in serum creatinine [from 0.62 ± 0.16 to 0.84 ± 0.12 mg/dL, p < 0.0001] cystatin C [from 750.83 ± 108.1 to 2300.55 ± 991.94 ng/ml, p < 0.0001] and decreased eGFR [from 116.69 ± 40.87 to 79.76 ± 24.48 ml/min/1.73 m2, p = 0.001] without change in urinary albumin concentration or induction of microalbuminuria in paired analysis.ConclusionAlthough not accompanied by microalbuminuria, steroid induced cystatin C elevation could be attributed in part to impaired GFR. Large population follow up studies are recommended to investigate the reversibility of this effect.