OBJECTIVETo study the value of serum Cystatin C (Cyst C) in the evaluation of glomerular filtration function in children with viral encephalitis.

METHODSSerum levels of Cyst C, urea nitrogen (BUN) and creatinine (Cr) were measured in 92 children with viral encephalitis and in 50 healthy children as a control group. According to glomerular filtration rate (GFR), the encephalitis group was subdivided into normal renal function, renal insufficiency in the compensatory or decompensatory stage, and renal failure /end-stage groups.

RESULTSSerum levels of Cyst C, BUN and Cr in the encephalitis group increased and GFR decreased significantly compared with those in the control group (P<0.01). With the decline of renal function, GFR decreased and serum levels of Cyst C, BUN and Cr increased gradually. Serum levels of Cyst C and GFR were significantly different among the encephaitis subgroups (P<0.01). For serum levels of BUN and Cr, there were significant differences among the subgroups except between the normal renal function and the compensatory renal insufficiency groups. Serum Cyst C level was positively correlated with serum BUN and Cr levels, and negatively correlated with GFR.

CONCLUSIONSThe children with viral encephalitis have different degrees of renal impairments. Cyst C appears to be superior to BUN and Cr as a marker for the evaluation of glomerular filtration function. Measurement of serum Cyst C levels is very valuable in renal function monitoring in children with viral encephalitis.