Biopsy-proven dengue virus-associated IgA nephropathy and interstitial nephritis with viral RNA detected in kidney tissue.

BACKGROUND: Dengue virus infection can cause kidney involvement, but biopsy-confirmed cases with both glomerular and tubulointerstitial lesions and molecular evidence of viral presence are rare. CASE PRESENTATION: A previously healthy 34-year-old man developed fever and dark urine after returning from Vietnam. He presented with acute kidney injury, nephrotic-range proteinuria, hematuria, and elevated aminotransferases. Kidney biopsy revealed IgA nephropathy (Oxford M1E0S0T0C0) with acute interstitial nephritis and granulomatous inflammation. Dengue virus serotype 2 RNA was detected in blood and renal tissue by tNGS. With supportive treatment, renal function, proteinuria, and hematuria completely resolved within one month. CONCLUSION: Dengue infection may trigger concurrent glomerular and tubulointerstitial immune-mediated kidney injury. Molecular detection of viral RNA in renal tissue provides evidence of renal involvement.