Characterization of renal damage in Wilson's disease-Detailed analysis of 20 Chinese cases.

Objective: Copper metabolism disorder disease is thought to contribute to renal symptoms in Wilson's disease (WD). Nonetheless, there remains limited knowledge regarding the precise characteristics of renal damage in individuals with Wilson's disease, encompassing clinical presentations, biochemical indicators, imaging findings, and renal histopathological alterations.
Methods: In this study, 20 patients diagnosed with Wilson's disease and renal involvement were enrolled in our hospital. These patients met the validated European criteria for Wilson's disease, and those with primary kidney disease or secondary renal damage caused by other underlying conditions were excluded. The baseline data of patients were collected. Various biochemical and hematological parameters were monitored. Biochemical examinations were measured using an automatic biochemistry analyzer, blood routines were tested by flow cytometry analysis, 24-h urine copper was tested by atomic absorption spectrophotometer. Besides, CER was measured by turbidimetric immunoassay with a Hitachi 7020 automatic biochemical analyzer (the intraplate and interplate coefficients of variation were 2.7% and 5.13% respectively). Copper oxidase was tested by colorimetric method using p-phenylenediamine hydrochloride (the intraplate and interplate coefficients of variation were both <10%). Diagnostic criteria for Wilson's disease and kidney damage were established based on the European Association for the Study of the Liver (EASL) and CKD Epidemiology Collaboration guidelines, respectively. Statistical analysis was carried out using t-tests and χ ² tests in SPSS 22.0 software. Significant differences were considered when P<0.05.
Results: In those patients with Wilson's disease-related renal damage, edema, gross hematuria, oliguria, and lumbar pain were present in most patients. Microscopic haematuria and proteinuria were also observed in 19 patients. Compared to patients without renal involvement, those with renal complications exhibited a significant increase in white blood cell (WBC) and neutrophil counts (P<0.05). Additionally, patients with renal damage showed a noteworthy rise in both diastolic and systolic blood pressure, along with a significant reduction in hemoglobin levels (P<0.05). Color Doppler ultrasound results revealed diffuse lesions in both kidneys in 12 patients, renal cysts were identified in 5 patients, and 2 patients exhibited abnormal renal blood flow signals. Meanwhile, varying degrees of IgA, IgM, IgG-based immunoglobulins, complement C3 and C1q deposition in the glomerular mesangial area were detected by immunofluorescence. Furthermore, renal puncture biopsy results revealed a spectrum of findings, including minimal change nephrosis in 1 case, IgA nephropathy in 3 cases, atypical membranous proliferative nephropathy in 2 cases, and focal segmental glomerulosclerosis in 1 case.
Conclusion: This study comprehensively elucidates the distinct attributes of renal damage related to Wilson's disease, while also speculating that renal dysfunction in Wilson's disease could be linked to immune complex deposition. Depending on the underlying pathogenesis, kidney injury associated with Wilson's disease can be classified as primary or secondary. To slow down the progression of renal impairment, it is essential to undergo a renal biopsy pathological examination as early as possible to clarify the type of impairment and take the appropriate treatment.
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