# Post-renal Biopsy Retroperitoneal Haematoma Accompanied by Decreased Coagulation Factor XIII Levels in Immunoglobulin A Nephropathy

## TL;DR

A teenage boy with IgA nephropathy developed a rare bleeding complication after a kidney biopsy, linked to low levels of a clotting factor not detected in standard tests.

## Contribution

Highlights a case where decreased coagulation factor XIII may contribute to post-biopsy bleeding in IgA nephropathy patients.

## Key findings

- A 14-year-old IgA nephropathy patient developed retroperitoneal haematoma after renal biopsy.
- Decreased coagulation factor XIII was identified as a potential cause of delayed bleeding.
- Mild FXIII deficiency may not be detected in routine pre-biopsy coagulation tests.

## Abstract

Post-biopsy bleeding is the primary complication of renal biopsy. Retroperitoneal haematoma is a rare but severe bleeding complication; it commonly occurs among patients who have risk factors or vascular lesions. The bleeding risks in patients with immunoglobulin A (IgA) nephropathy (IgAN) have been discussed in the literature, but clinical data are lacking. Here, we report a case of a post-biopsy retroperitoneal haematoma accompanied by decreased coagulation factor XIII (FXIII) in a patient with IgAN. A 14-year-old male patient with haematuria and proteinuria but no bleeding or family history of bleeding underwent pre-renal biopsy evaluation that showed no coagulation abnormalities. He underwent percutaneous renal biopsy, and the histopathological diagnosis was IgAN. Five days after the biopsy, he presented with delayed bleeding from a retroperitoneal haematoma. During the workup for undiagnosed haemorrhagic diatheses, a mildly decreased FXIII level was discovered. This result suggested the possibility of bleeding complications associated with decreased FXIII. Some bleeding diatheses, including FXIII deficiency, cannot be evaluated in routine pre-biopsy coagulation tests. Mild FXIII deficiency can increase the risk of post-biopsy bleeding complications. Therefore, physicians should consider unevaluated haemorrhagic diatheses when a patient presents with major bleeding complications or delayed bleeding following renal biopsy without any known risk factors or vascular lesions.