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Renal Injury, Emergency Medicine

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Renal Injury, Emergency Medicine

Basics

Description

Patients with significant renal injury require hospitalization for definitive laparotomy or observation.

  • Kidneys are located in the retroperitoneal space and are surrounded by adipose tissue and loose areolar connective tissue.
  • Kidneys lie along the lower 2 thoracic vertebrae and 1st 4 lumbar vertebrae.
  • Left kidney is positioned slightly higher than the right.
  • Kidneys are not fixed:Shift with the diaphragm and are supported by the renal arteries, veins, and adipose tissue to the renal (Gerota) fascia
  • Shift with the diaphragm and are supported by the renal arteries, veins, and adipose tissue to the renal (Gerota) fascia

Etiology

  • Most common of all urologic injuries
  • Occurs in ’ ˆ Ό8 " “10% of all abdominal trauma
  • Blunt renal trauma accounts for 80 " “85% of all renal injuries and is 5 times more common than penetrating injury:Mechanisms include motor vehicle accidents, falls, domestic violence, and contact sports.Pathophysiology includes rapid deceleration and displacement mechanisms. ’ ˆ Ό20% of cases are associated with intraperitoneal injury.
  • Mechanisms responsible for significant renal injury almost never affect the kidney alone:Most often disrupt and injure other vital organs that can be responsible for patient mortality
  • Renal injuries are graded by type and severity of injury (Association for the Surgery of Trauma [AAST] criteria)Grade IContusion: Microscopic or gross hematuria, urologic studies normalHematoma: Subcapsular, nonexpanding without parenchymal lacerationGrade II:Hematoma: Nonexpanding, perirenal hematoma confined to retroperitoneumLaceration: <1 cm parenchymal depth of renal cortex without urinary extravasationGrade IIILaceration: >1 cm parenchymal depth of renal cortex without collecting system rupture or urinary extravasationGrade IV:Laceration: Parenchymal laceration extending through renal cortex, medulla, and collecting systemVascular: Main renal artery or vein injury with contained hemorrhageGrade V:Laceration: Completely shattered kidneyVascular: Avulsion of renal hilum, devascularizing the kidney
  • Mechanisms include motor vehicle accidents, falls, domestic violence, and contact sports.
  • Pathophysiology includes rapid deceleration and displacement mechanisms.
  • ’ ˆ Ό20% of cases are associated with intraperitoneal injury.
  • Most often disrupt and injure other vital organs that can be responsible for patient mortality
  • Grade IContusion: Microscopic or gross hematuria, urologic studies normalHematoma: Subcapsular, nonexpanding without parenchymal laceration
  • Grade II:Hematoma: Nonexpanding, perirenal hematoma confined to retroperitoneumLaceration: <1 cm parenchymal depth of renal cortex without urinary extravasation
  • Grade IIILaceration: >1 cm parenchymal depth of renal cortex without collecting system rupture or urinary extravasation
  • Grade IV:Laceration: Parenchymal laceration extending through renal cortex, medulla, and collecting systemVascular: Main renal artery or vein injury with contained hemorrhage
  • Grade V:Laceration: Completely shattered kidneyVascular: Avulsion of renal hilum, devascularizing the kidney
  • Contusion: Microscopic or gross hematuria, urologic studies normal
  • Hematoma: Subcapsular, nonexpanding without parenchymal laceration
  • Hematoma: Nonexpanding, perirenal hematoma confined to retroperitoneum
  • Laceration: <1 cm parenchymal depth of renal cortex without urinary extravasation
  • Laceration: >1 cm parenchymal depth of renal cortex without collecting system rupture or urinary extravasation
  • Laceration: Parenchymal laceration extending through renal cortex, medulla, and collecting system
  • Vascular: Main renal artery or vein injury with contained hemorrhage
  • Laceration: Completely shattered kidney
  • Vascular: Avulsion of renal hilum, devascularizing the kidney
  • The kidney is the organ most commonly damaged by blunt abdominal trauma.
  • Contributing factors:Relatively larger size of kidneys compared with adults10th and 11th ribs are not completely ossified until the 3rd decade of life.
  • Significant abdominal injury occurs in about 5% of nonaccidental trauma cases but is the 2nd most common cause of death after head injury.
  • Relatively larger size of kidneys compared with adults
  • 10th and 11th ribs are not completely ossified until the 3rd decade of life.

Diagnosis

Signs and Symptoms

  • Mechanism of injury and kinematics are important factors.
  • Majority of renal injuries are associated with injury of other abdominal organs.
  • In blunt trauma, note the type and direction (horizontal or vertical) of any deceleration or compressive forces.
  • In penetrating trauma, note the characteristic of the weapon (type and caliber), distance from the weapon, or the type and length of knife or impaling object:Injuries result from a combination of kinetic energy and shear forces of penetrating object.
  • Injuries result from a combination of kinetic energy and shear forces of penetrating object.
  • Hematuria is the best indicator of traumatic urinary system injury:Severity of renal trauma does not correlate with the degree of hematuria.Absence of hematuria does not exclude renal injury
  • Microscopic hematuria with a systolic BP <90 mm Hg
  • Flank mass or ecchymosis
  • Tenderness in the flank, abdomen, or back
  • Fracture of the inferior ribs or spinal transverse processes
  • Nausea and vomiting
  • Severity of renal trauma does not correlate with the degree of hematuria.
  • Absence of hematuria does not exclude renal injury

Essential Workup

  • In 1989, Mee et al. published the hallmark article (10-yr prospective study) that established guidelines for the evaluation and treatment of blunt renal trauma:Major renal lacerations represent significant reparable renal injuries.Adult patients at risk for having sustained major lacerations:Gross hematuria, orMicrohematuria ( ≥3 " “5 RBCs/HPF) with shock (systolic BP ≤90 mm Hg) in the field or on arrival in the ED, orHistory of sudden deceleration without hematuria or shock
  • IV contrast-enhanced CT scan is the procedure of choice in identifying urologic injury.
  • Guidelines are not applicable in cases of penetrating renal trauma or in children.
  • Adults with blunt renal trauma and gross hematuria, or microhematuria in the presence of shock, require renal imaging for further evaluation of renal injury.
  • In adults with penetrating renal trauma, significant injuries to the kidney and ureter can occur without hematuria:Location of penetrating wound in relation to urinary tract is the most important factor in deciding need for radiographic imaging.Penetrating injuries with any degree of hematuria should be imaged.
  • Important to rule out coexisting injuries
  • Major renal lacerations represent significant reparable renal injuries.
  • Adult patients at risk for having sustained major lacerations:Gross hematuria, orMicrohematuria ( ≥3 " “5 RBCs/HPF) with shock (systolic BP ≤90 mm Hg) in the field or on arrival in the ED, orHistory of sudden deceleration without hematuria or shock
  • Gross hematuria, or
  • Microhematuria ( ≥3 " “5 RBCs/HPF) with shock (systolic BP ≤90 mm Hg) in the field or on arrival in the ED, or
  • History of sudden deceleration without hematuria or shock
  • Location of penetrating wound in relation to urinary tract is the most important factor in deciding need for radiographic imaging.
  • Penetrating injuries with any degree of hematuria should be imaged.

Diagnosis Tests & Interpretation

  • Urinalysis: Gross hematuria or >50 RBCs/HPF in adults and >20 RBC/HPF in children is suggestive of renal injury.
  • Baseline lab values including hematocrit and BUN/creatinine should be obtained.
  • Plain abdominal films:May show fractured inferior ribs or transverse processes, a unilateral enlarged kidney shadow, or obscuring of the psoas margin
  • IV pyelogram (IVP):Bolus infusion IVP with nephrotomography study of choice in institutions without 24-hr availability of CTRapid injection of 1.5 " “2 mL of contrast material per kilogram of body weight to a maximum or 150 mL after obtaining a preliminary kidney, ureter, and bladder imagePostinfusion supine film is obtained followed by 1-, 2-, and 3-min supine films.Allows evaluation for renal viability and functionExtravasation reflects injury to the collecting system.Nonvisualization of a kidney may indicate renal pedicle injury or parenchymal shattering.Abnormal findings are often nonspecific and require more definitive studies.
  • Ultrasound:Role in evaluation of renal injury is controversialRoutinely performed at bedside in trauma patients as part of focused assessment with sonography in trauma (FAST)May show size of perirenal hematoma and whether it is expanding or resolvingLow sensitivity for identification of retroperitoneal free fluidOtherwise, exam is nonspecific and does not provide enough information
  • CT scan:An IV contrast-enhanced helical CT scan is the diagnostic procedure of choice.Superior anatomic detail and diagnostic accuracy of 98% for renal injurySensitive indicator of minor extravasation, parenchymal laceration, vascular injury, and nonrenal injuries
  • May show fractured inferior ribs or transverse processes, a unilateral enlarged kidney shadow, or obscuring of the psoas margin
  • Bolus infusion IVP with nephrotomography study of choice in institutions without 24-hr availability of CT
  • Rapid injection of 1.5 " “2 mL of contrast material per kilogram of body weight to a maximum or 150 mL after obtaining a preliminary kidney, ureter, and bladder image
  • Postinfusion supine film is obtained followed by 1-, 2-, and 3-min supine films.Allows evaluation for renal viability and functionExtravasation reflects injury to the collecting system.Nonvisualization of a kidney may indicate renal pedicle injury or parenchymal shattering.Abnormal findings are often nonspecific and require more definitive studies.
  • Allows evaluation for renal viability and function
  • Extravasation reflects injury to the collecting system.
  • Nonvisualization of a kidney may indicate renal pedicle injury or parenchymal shattering.
  • Abnormal findings are often nonspecific and require more definitive studies.
  • Role in evaluation of renal injury is controversial
  • Routinely performed at bedside in trauma patients as part of focused assessment with sonography in trauma (FAST)
  • May show size of perirenal hematoma and whether it is expanding or resolving
  • Low sensitivity for identification of retroperitoneal free fluid
  • Otherwise, exam is nonspecific and does not provide enough information
  • An IV contrast-enhanced helical CT scan is the diagnostic procedure of choice.
  • Superior anatomic detail and diagnostic accuracy of 98% for renal injury
  • Sensitive indicator of minor extravasation, parenchymal laceration, vascular injury, and nonrenal injuries
  • Major blunt renal trauma can occur in the absence of gross hematuria or shock (as children have a high catecholamine output after trauma, which maintains BP until ’ ˆ Ό50% of blood volume has been lost).
  • Meta-analysis has defined 50 RBC/HPF as the microscopic quantity below which imaging can be omitted and no significant injuries missed.
  • CT scan is the imaging modality of choice.
  • Renal parenchymal injury
  • Renal vascular injury
  • Ureteral injury
  • Bladder or urethral injury

Treatment

Pre-Hospital

  • Obtain details of injury from pre-hospital providers.
  • IV access
  • Penetrating wounds or evisceration should be covered with sterile dressings.

Initial Stabilization/Therapy

  • Airway management (including C-spine immobilization)
  • Standard Advanced Trauma Life Support (ATLS) resuscitation measures:Adequate IV access, including central lines and cutdowns, as dictated by the patients hemodynamic statusFluid resuscitation, initially with 2 L of crystalloid (NS or lactated Ringer solution), followed by blood products as needed
  • Rule out potential life-threatening injuries 1st.
  • Adequate IV access, including central lines and cutdowns, as dictated by the patients hemodynamic status
  • Fluid resuscitation, initially with 2 L of crystalloid (NS or lactated Ringer solution), followed by blood products as needed

Ed Treatment/Procedures

  • Immediate laparotomy in the acutely injured patient who is hemodynamically unstable with presumed hemoperitoneum and renal injury
  • Significant injuries (grades II " “V) are found in only 5.4% of renal trauma cases.
  • 98% of blunt renal injuries can be managed nonoperatively.
  • ’ ˆ Ό80 " “90% of renal injuries have major associated organ injury that can affect the choice of renal injury management.
  • Angiography and selective renal embolization has an increasing role and is an alternative treatment to laparotomy in patients not requiring immediate surgery.
  • Penetrating renal trauma:Previously exploratory laparotomy was recommended for all patients with penetrating renal injuries.Nonoperative management has become more accepted for grades I " “III with penetrating renal injuries in the absence of associated intra-abdominal injury or hemodynamic instability
  • Blunt renal trauma:Isolated renal injury without significant associated injuries occurs more commonly from blunt trauma, and in most circumstances, can be managed nonoperatively.Classes I and II: Contusions and minor lacerations with stable vital signs and urographically normal renal function can be managed nonoperatively.Class III: Renal lacerations with urinary extravasation:Controversy between operative vs. nonoperative managementManagement should be based on degree of injury using CT scanning.Classes IV and V: Shattered kidney or renal pedicle injuries and hemodynamically unstable patients require emergent laparotomy.All ureteral injuries require operative repair.
  • Previously exploratory laparotomy was recommended for all patients with penetrating renal injuries.
  • Nonoperative management has become more accepted for grades I " “III with penetrating renal injuries in the absence of associated intra-abdominal injury or hemodynamic instability
  • Isolated renal injury without significant associated injuries occurs more commonly from blunt trauma, and in most circumstances, can be managed nonoperatively.
  • Classes I and II: Contusions and minor lacerations with stable vital signs and urographically normal renal function can be managed nonoperatively.
  • Class III: Renal lacerations with urinary extravasation:Controversy between operative vs. nonoperative managementManagement should be based on degree of injury using CT scanning.
  • Classes IV and V: Shattered kidney or renal pedicle injuries and hemodynamically unstable patients require emergent laparotomy.
  • All ureteral injuries require operative repair.
  • Controversy between operative vs. nonoperative management
  • Management should be based on degree of injury using CT scanning.

Follow-Up

Disposition

  • Adult trauma patients without hematuria, shock, or no renal injury confirmed radiographically
  • Adult blunt trauma patient with microhematuria ( ≥3 " “5 RBCs/HPF) but no shock (systolic BP ≤90 mm Hg)
  • Pediatric blunt trauma patient with ≤50 RBC/HPF and no other coexisting major organ injuries
  • Outpatient referral to urologist should be made for microhematuria to ensure that it does not represent a more serious underlying condition.
  • Urinoma formation is the most common complication (1 " “7%) of patients with renal trauma:Urinary extravasation resolves spontaneously in 76 " “87% of cases
  • Urinary extravasation resolves spontaneously in 76 " “87% of cases

Additional Reading

  • Broghammer ‚ JA, Fisher ‚ MB, Santucci ‚ RA. Conservative management of renal trauma: A review. Urology. 2007;70(4):623 " “629.
  • Mee ‚ SL, McAninch ‚ JW, Robinson ‚ AL, et al. Radiographic assessment of renal trauma: A 10-year prospective study of patient selection. J Urol. 1989;141:1095 " “1098.
  • Santucci ‚ RA, Wessells ‚ H, Bartsch ‚ G, et al. Evaluation and management of renal injuries: Consensus statement of the renal trauma subcommittee. BJU Int. 2004;93(7):937 " “954.
  • Shoobridge ‚ JJ, Corcoran ‚ NM, Martin ‚ KA, et al. Contemporary management of renal trauma. Rev Urol. 2011;13(2):65 " “72.
  • Tinkoff ‚ G, Esposito ‚ TJ, Reed ‚ J, et al. American Association for the Surgery of Trauma Organ Injury Scale I: Spleen, liver, and kidney, validation based on the National Trauma Data Bank. J Am Coll Surg. 2008;207(5):646 " “655.

Codes

ICD9

  • 866.00 Injury to kidney without mention of open wound into cavity, unspecified injury
  • 866.01 Injury to kidney without mention of open wound into cavity, hematoma without rupture of capsule
  • 866.02 Injury to kidney without mention of open wound into cavity, laceration
  • 866.03 Injury to kidney without mention of open wound into cavity, complete disruption of kidney parenchyma
  • 866.0 Injury to kidney without mention of open wound into cavity
  • 866.10 Injury to kidney with open wound into cavity, unspecified injury
  • 866.11 Injury to kidney with open wound into cavity, hematoma without rupture of capsule
  • 866.12 Injury to kidney with open wound into cavity, laceration
  • 866.13 Injury to kidney with open wound into cavity, complete disruption of kidney parenchyma
  • 866.1 Injury to kidney with open wound into cavity

ICD10

  • S37.009A Unspecified injury of unspecified kidney, initial encounter
  • S37.019A Minor contusion of unspecified kidney, initial encounter
  • S37.049A Minor laceration of unspecified kidney, initial encounter
  • S37.069A Major laceration of unspecified kidney, initial encounter
  • S37.001A Unspecified injury of right kidney, initial encounter
  • S37.002A Unspecified injury of left kidney, initial encounter
  • S37.011A Minor contusion of right kidney, initial encounter
  • S37.012A Minor contusion of left kidney, initial encounter
  • S37.021A Major contusion of right kidney, initial encounter
  • S37.022A Major contusion of left kidney, initial encounter
  • S37.029A Major contusion of unspecified kidney, initial encounter
  • S37.031A Laceration of right kidney, unspecified degree, init encntr
  • S37.039A Laceration of unsp kidney, unspecified degree, init encntr
  • S37.041A Minor laceration of right kidney, initial encounter
  • S37.042A Minor laceration of left kidney, initial encounter
  • S37.051A Moderate laceration of right kidney, initial encounter
  • S37.052A Moderate laceration of left kidney, initial encounter
  • S37.059A Moderate laceration of unspecified kidney, initial encounter
  • S37.061A Major laceration of right kidney, initial encounter
  • S37.062A Major laceration of left kidney, initial encounter
  • S37.091A Other injury of right kidney, initial encounter
  • S37.092A Other injury of left kidney, initial encounter
  • S37.099A Other injury of unspecified kidney, initial encounter

SNOMED

  • 40095003 injury of kidney (disorder)
  • 70092007 Contusion of kidney (disorder)
  • 262893009 Laceration of kidney (disorder)
  • 283905005 Avulsion of kidney (disorder)
  • 20341008 Injury of kidney without open wound into abdominal cavity (disorder)
  • 210197003 Closed injury of kidney (disorder)
  • 210811000 Renal blood vessel injury (disorder)
  • 61474001 Injury of kidney with open wound into abdominal cavity (disorder)