When to get a follow-up CT scan in a patient with a grade V renal injury?

Follow-up CT Imaging in Grade V Renal Injury

For patients with grade V renal injuries, a contrast-enhanced CT scan with excretory phase is recommended within the first 48 hours after trauma, with subsequent imaging guided by clinical status and potential complications.

Initial Follow-up Imaging

• Contrast-enhanced CT scan with excretory phase should be performed within the first 48 hours after admission for all grade V renal injuries, as urinary leak may be missed on the initial CT scan in up to 1% of high-grade renal injuries 1
• This early follow-up imaging is crucial as grade V injuries are prone to developing troublesome complications such as urinoma or hemorrhage 1
• The timing of this initial follow-up CT (within 48 hours) is based on the high risk of complications in these severe injuries 1

Subsequent Follow-up Imaging

• After the initial 48-hour follow-up CT, additional imaging should be driven by the patient's clinical condition rather than routine scheduling 1
• Indications for further imaging include:
  • Fever
  • Worsening flank pain
  • Ongoing blood loss
  • Abdominal distention
  • Hematuria (particularly if recurrent or worsening) 1

Monitoring for Specific Complications

• Secondary hemorrhage deserves particular attention as it occurs in up to 25% of severe renal injuries, typically within 2 weeks of the injury 1
• Hematuria is the most common sign suggesting vascular complications such as pseudoaneurysm or arteriovenous fistula formation 1
• If hematuria develops, prompt contrast-enhanced CT scan is indicated 1

Alternative Imaging Modalities

• In settings where CT is not readily available, Doppler ultrasound (DUS) or contrast-enhanced ultrasound (CEUS) may be considered as alternatives for follow-up, as these techniques have shown similar reliability in detecting vascular complications 1
• For pediatric patients with grade V injuries, ultrasound and contrast-enhanced US should be the first choice in follow-up, with MRI preferred if cross-sectional imaging is required 1

Long-term Follow-up Considerations

• Monitor blood pressure for up to one year after injury to detect possible renovascular hypertension, which occurs in 0-6.6% of cases 1
• Long-term renal function in preserved grade V kidneys is typically poor, with studies showing approximately 0-11% relative renal function at 6 months post-injury 2, 3
• No specific timeframe exists for return to normal activity after grade V renal trauma, but severe injuries may require 6-12 months before return to sports activities 1

Management of Detected Complications

• If follow-up imaging reveals complications such as enlarging urinoma, urinary drainage should be performed 1
• Drainage options include ureteral stent placement, possibly augmented by percutaneous urinoma drain or percutaneous nephrostomy 1
• For detected vascular complications such as pseudoaneurysms or arteriovenous fistulas, angiography with super-selective angioembolization is indicated 4

Common Pitfalls to Avoid

• Failing to perform the initial 48-hour follow-up CT for grade V injuries, which have high complication rates 1, 4
• Relying solely on clinical symptoms without appropriate imaging follow-up, as some complications may develop silently 1
• Not monitoring for renovascular hypertension, which can develop as a late complication 1, 4
• Attempting arterial repair in severely damaged kidneys with prolonged warm ischemia time (>240 minutes), which has poor outcomes 4