Delayed Haemorrhage from a Lower-Pole Renal Artery Pseudoaneurysm Complicating Grade III Blunt Renal Trauma in a Solitary Kidney: A Case Report

Abstract Background: Blunt renal trauma in children with a solitary kidney poses a distinct management challenge, as the imperative for nephron preservation must be balanced against the risk of delayed vascular complications. Renal artery pseudoaneurysm is an uncommon but potentially life-threatening sequela of blunt renal injury and may present days after the index event, once the patient has been de-escalated from intensive monitoring. Case presentation: A 9-year-old boy with a congenital solitary right kidney sustained a grade III right renal injury with retroperitoneal haematoma following a road traffic accident. He was resuscitated for compensated haemorrhagic shock (lactate 4.8 mmol/L) and managed initially with blood transfusion and non-operative care, with a two-day period of intensive care unit monitoring before transfer to the ward. On day five of admission he developed gross haematuria with a pelvic blood clot on ultrasound, managed with tranexamic acid and transfusion. This progressed to acute urinary retention from bladder clot obstruction requiring suprapubic catheterisation, accompanied by a rising serum creatinine. Computed tomography angiography, performed as part of nephrology-directed work-up for the deteriorating renal function, demonstrated a lower-pole arterial pseudoaneurysm with active bleeding. Following further transfusion requirements and a peak creatinine of approximately 600 µmol/L, a multidisciplinary decision was made to proceed with digital subtraction angiography and coil embolisation. The immediate post-procedural course was complicated by anuric acute kidney injury requiring 72 hours of haemodialysis, with recovery of urine output on the fourth post-procedural day and normalisation of renal function by post-operative day twelve. Follow-up ultrasound at two weeks showed parenchymal changes in the solitary kidney. The child was discharged on the fifteenth post-procedural day with planned surgical and nephrology follow-up. Conclusions: Children with a solitary kidney and moderate-to-severe blunt renal trauma remain at risk of delayed haemorrhagic complications, including pseudoaneurysm formation, even after apparent early stabilisation. A high index of suspicion for delayed bleeding, low threshold for repeat imaging when haematuria recurs, and early angiographic intervention are essential to achieve nephron-sparing haemostasis. Superselective embolisation is effective but may be followed by transient acute kidney injury in a solitary kidney, for which close nephrological support and dialysis readiness are required.