Quick reference algorithm

Renal Injury Management

Blunt renal trauma patients · October 2026 edition

Blunt renal traumaAAST 2018 revised gradingNOM pathwayAAST grades ↓

AAST published a 2025 kidney scale revision; this chart uses the 2018 scale.

Renal Injury Identified on CT

ATLS • CT abdomen/pelvis with IV contrast + delayed images (10 min) for collecting system

Hemodynamically stable?After initial resuscitation

NOUnstable ↓YESStable · NOM ↓

Hemodynamically unstable

Hemodynamically Unstable

Expanding/pulsatile hematoma

Operative Exploration

Operative Options

Renorrhaphy (partial repair)
Nephrectomy (if non-reconstructable)

Confirm contralateral kidney function

YES

Hemodynamically stable · NOM

Hemodynamically Stable

NOM for all hemodynamically stable patients, any grade

Grade I–II

Floor admission

Vital signs q4h
H/H q12h until stable × 2
Serial exams; monitor hematuria
Reduced activity until gross hematuria clears
Repeat CT only for clinical change

Grade III–V

ICU admission ≥ 24 h

Continuous HR; BP q1–2h for the first 24 h
H/H q6h × 24 h → q12h × 24 h → daily; step down only while stable
Serial exams; monitor hematuria (new or worse hematuria → repeat CT)
Type & screen / crossmatch
Mobilize once H/H stable; reduce activity until gross hematuria clears
Urology consult

Selected stable grade III without active bleeding may go to step-down.

Grade III: repeat CT only for clinical changeGrade IV–V: repeat CT with delayed (excretory) images at 48–72 h

No renal guideline sets a vital-sign or hemoglobin frequency, level of care by grade or a minimum length of stay; these tiers and the discharge minimums mirror the WTA spleen (2023) and liver (2024) algorithms. The q12h → daily step-down is institutional practice.

VTE chemoprophylaxis (no active bleeding): grade I–III within 24 h; grade IV–V 24–48 h after injury, once hemodynamically stable with stable H/H

Mechanical prophylaxis (SCDs) for all from admission

Active bleeding: SCDs only, reassess q12h

VTE prophylaxis chart →

Active arterial extravasation?Contained vs. non-contained

YESAngioembolization ↓NOContinue NOM ↓

YES

Angioembolization

IR consult emergently
Selective renal artery embolization
Post-embolization repeat CT at 48–72h

Continue NOM

Pseudoaneurysm or AV fistula: consider angioembolization (EAU, WSES-AAST); otherwise observe
Repeat CT at 48–72h for Grade IV–V
Serial H/H, hematuria monitoring

Collecting System Injury / Urinoma (Grade IV)

Delayed CT images show contrast extravasation from collecting system

Observe initially, with serial imaging
Routine stenting of asymptomatic patients is not needed
Enlarging urinoma, fever, increasing pain, ileus, fistula or infection → drain: ureteral stent first, ± percutaneous drain or nephrostomy (IR/Urology)
Suspected UPJ avulsion (large medial urinoma, no distal ureteral contrast) → prompt intervention

Discharge — Grade I–II

Minimum: ≥ 24 h from injury, stable H/H, tolerating diet
No routine follow-up imaging
Return to sport after microscopic hematuria resolves (typically 2–6 weeks)
Follow-up UA to confirm hematuria resolution

Discharge — Grade III–V

Minimum: ≥ 72 h from injury, stable H/H, tolerating diet
Return to sport after microscopic hematuria resolves: grade III typically 2–6 weeks; IV–V may need 6–12 months
Grade III uncomplicated: no routine follow-up imaging
Follow-up ~3 months: urinalysis, BP, creatinine; imaging individualized
BP checks periodically for 1 year (renovascular hypertension)

AAST 2018 · CT imaging criteria

Kidney injury grades

Any single criterion assigns the grade.

Version note: AAST published a 2025 kidney revision (Keihani et al., J Trauma Acute Care Surg 2025;98(3):448-451) that changes several definitions, including moving collecting-system injury to grade III. This reference and the site's renal algorithm use the 2018 scale.

Vascular injury or active bleeding: where it lands sets the grade (inside the Gerota fascia versus beyond it into the retroperitoneum or peritoneum)

Contained within Gerota fascia

Grade III

Beyond Gerota fascia into the retroperitoneum or peritoneum

Grade IV

Drawing key

Parenchyma and capsule
Renal pelvis, calyces and ureter
Artery
Vein
Gerota fascia
Subcapsular hematoma
Contusion
Perirenal hematoma
Laceration, with depth bracket
Vascular injury (pseudoaneurysm or AV fistula)
Active bleeding, contained within Gerota fascia
Active bleeding, extending beyond Gerota fascia
Urinary extravasation

Labels in the drawings: PSA = pseudoaneurysm. Depth brackets measure a laceration from the capsule inward.

Grade I

AIS 2

Subcapsular hematoma and/or parenchymal contusion without laceration

Grade II

AIS 2

Perirenal hematoma confined to Gerota fascia
Parenchymal laceration ≤ 1 cm depth without urinary extravasation

Grade III

AIS 3

Parenchymal laceration > 1 cm depth without collecting system rupture or urinary extravasation
Any injury with kidney vascular injury or active bleeding contained within Gerota fascia

Grade IV

AIS 4

Laceration extending into the collecting system with urinary extravasation
Renal pelvis laceration and/or complete ureteropelvic disruption
Segmental renal artery or vein injury
Active bleeding beyond Gerota fascia into the retroperitoneum or peritoneum
Segmental or complete kidney infarction from vessel thrombosis without active bleeding

Grade V

AIS 5

Main renal artery or vein laceration or avulsion of the hilum
Devascularized kidney with active bleeding
Shattered kidney with loss of identifiable parenchymal anatomy

All AAST grading scales and definitions →