Horseshoe kidney is one of the most common congenital defects of the urogenital system, having an incidence of 0.25%1. It has an increased risk of trauma to the kidney due to its position anterior to the spinal column2.
In general, renal injury is caused by blunt injury, in particular, motor vehicle accidents and falls from height.
Traumatic renal injury can be graded from 1 though to 5. The grading system is defined as follows3:
- Grade I - Contusion or non-expanding subcapsular haematoma; No laceration
- Grade 2 - Non-expanding perirenal haematoma; Cortical laceration <1cm deep without extravasation
- Grade 3 - Cortical laceration > 1 cm without urinary extravasation
- Grade 4 - Laceration through corticomedullary junction into collecting system OR Vascular segmental renal artery or vein injury with contained haematoma
- Grade 5 - Shattered kidney OR renal pedicle injury or avulsion
Stable patients with grade 1 to 4 lacerations are managed conservatively. Grade 5 injuries, or unstable patients with lesser grade injuries require intervention. Unstable patients may have life-threatening haemorrhage, renal pedicle avulsion or expanding retroperitoneal haematomas.
Management options are either with open surgical exploration or interventional angioembolisation. Typically, nephrectomy is preferred over repair, unless there is a contraindicating factor such as a solitary kidney, or bilateral kidney injury.
This patient has a Grade 4 renal injury due to compromisation of the vascular segmental renal artery, causing hypodense renal parenchyma in the parenchymal phase.
Case contributed by A/Prof Pramit Phal.