Introduction: Cytomegalovirus (CMV)-related infections are commonly seen in immunocompromised patients. However, hemorrhagic cystitis (HC) is an exceptionally rare associated manifestation [1]. Late-onset cytomegalovirus-related HC in kidney transplant has been reported [2], while CMV-related HC in early post-renal transplant has not been reported.
Methods: We reported a child with CMV-related HC in early post-renal transplant and analyzed his clinical manifestations, diagnostic points, and treatment.
Results: A 10-year-old boy manifested acute painful macrohematuria with the white purulent flocculent deposit on day 18 after kidney transplantation. Cystoscopy revealed features of HC with clots in the bladder and mucosa biopsy pathology revealed suspicious nuclear pseudoinclusion. But the immunohistochemistry staining showed CMV-negative. His metagenomic next-generation sequencing of blood, urine and bladder tissue indicated the presence of CMV and Torque teno virus. Computed tomographic scan indicated bladder wall thickening and graft kidney hydronephrosis. Due to the adjustment of immunosuppressive protocol and antiviral drugs regimen, CMV viral load declined.

On 87 days after kidney transplant, his symptoms generally disappeared. Follow-up examinations indicated that the bladder wall had chronic inflammation changes, but it became better in re-examination. In addition, transplanted kidney effusion was also relieved.

On 98 days after discharge, he underwent balloon angioplasty of the transplanted renal artery due to the transplant renal artery stenosis.
Conclusion: This case appears to be the first report of CMV-related HC in early post-renal transplantation. We recommend that the diagnosis of CMV cystitis demands a combination of next-generation sequencing. Bladder biopsy has a low positive rate for CMV-related HC. Therefore, biopsy tissue needs to be taken from the deep muscular layer [3]. Besides manifesting as urinary tract symptoms such as painful hematuria, CMV-related HC may also manifest as systemic symptoms of CMV infection. In addition, it may also lead to graft kidney hydronephrosis. Timely adjustment of immunosuppressive regimens including tacrolimus to cyclosporine and antiviral therapy is essential to the successful treatment of CMV-related HC.