How is Renal Trauma Categorized?

Patient Presentation
A 17-year-old female came to the emergency room with a history of being hit on her left side playing soccer. She had some pain in her flank but continued playing. This pain stopped after the playing but her left inner leg began to hurt. About two hours after the hit she had painless gross hematuria. She denied any other trauma, or illnesses. Her last menstrual period was 1 week prior. The family history was negative for kidney disease, autoimmune disease, congenital abnormalities or hearing problems. The review of systems was negative.

The pertinent physical exam showed a healthy teen with some limping of her left leg. Her vital signs were normal including her blood pressure. Her physical examination was notable for pain of the medial upper thigh especially with abduction. Abdominal and genitourinary examination were negative. The diagnosis of presumed renal contusion and muscle strain were made. Because of the risk of renal injury a computed tomography study of the abdomen and pelvis was ordered and was negative. Urinalysis showed grossly bloody urine without clots and no white cells. Complete blood count was normal. The patient’s clinical course at her 3 day followup showed that the gross hematuria cleared around 24 hours after injury. She was sent home with urine dipsticks. On day 8 during a previously scheduled health maintenance examination she reported negative microscopic urine testing since day 5. She still was having some mild pain with active exercise in her leg but was much improved.

Discussion
Gross hematuria has many causes (see here for a differential diagnosis) but in the setting of trauma causes concern. The integrity of the urinary system has been breached and can be anywhere within the system from the kidney itself to urethral opening caused by blunt or cutting forces. Other injuries including to the renal pedicle, and abdomen and pelvis need to be considered, evaluated and treated. Blunt trauma from motor vehicles, bikes, falls, assaults and sports are common causes of gross hematuria in children.

Patients should have a through history and physical examination searching for additional injuries and assessment of hemodynamic stability. Laboratory evaluation should include a urinalysis and complete blood count plus other laboratories depending on clinical circumstances. Imaging usually begins with computed tomography of the abdomen and pelvis also to help identify other potential injuries.

There are different injury scales that are designed to assist in the description, management of different organ systems. A list of various scales can be found here. The American Association for the Surgery of Trauma’s Organ Injury Scale and is one organ system scale . AIS score is the abbreviated injury score. “The AIS provides standardized terminology to describe injuries and ranks injuries by severity.” This is independent of the organ system.

The AIS Scores are:

• 1 = Minor
• 2 = Moderate
• 3 = Serious
• 4 = Severe
• 5 = Critical
• 6 = Unsurvivable

Learning Point
Renal trauma is categorized by the Organ Injury Scale into 5 groups:

• Grade 1 – (AIS 2)
  • Contusion with hematuria (microscopic or gross), normal urological studies
  • Hematoma that is subcapsular without parenchymal laceration and is not expanding
• Grade 2 – (AIS 2)
  • Perirenal hematoma continued to the renal retroperitoneum that is not expanding
  • Laceration of < 1 cm of renal cortex parenchyma without urinary extravasation
• Grade 3 – (AIS 3)
  • Laceration of > 1 cm depth of renal cortex parenchyma with urinary extravasation or collecting system rupture
• Grade 4
  • (AIS 4) Laceration extending through the renal cortex parenchyma, medulla and collecting system, has urinary extravasation
  • (AIS 5) Main renal artery or vein injury with controlled hemorrhage
• Grade 5 – (AIS 5)
  • Completely shattered kidney
  • Hilar avulsion or major renovascular injury with uncontrolled hemorrhage

Note: the AIS classification increases by one level if there are multiple injuries to same organ.

Renal trauma treatment depends on the trauma grade and associated injuries. Many renal injuries can be treated conservatively with rest and close monitoring. Others such as level 5 require emergency exploration for hemodynamic control and possible nephrectomy.

Questions for Further Discussion
1. What is the Organ Injury Scale rating for the patient described?
2. What are indications for imaging for gross hematuria?
3. What are indications for nephrology or urology consultation for hematuria?

Related Cases

Disease: Renal Trauma | Kidney Diseases

Symptom/Presentation: Hematuria | Trauma

Specialty: Emergency Medicine | Nephrology / Urology

Age: Teenager

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Kidney Disease.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Ahn JH, Morey AF, McAninch JW. Workup and management of traumatic hematuria. Emerg Med Clin North Am. 1998 Feb;16(1):145-64.

Santucci RA, Langenburg SE, Zachareas MJ. Traumatic hematuria in children can be evaluated as in adults. J Urol. 2004 Feb;171(2 Pt 1):822-5.

Trauma.org. Organ Injury Scale. Available from the Internet at http://www.trauma.org/archive/scores/ois.html (rev. 2012 cited 6/15/12).

Trauma.org. Abbreviated Injury Scale. Available from the Internet at http://www.trauma.org/archive/scores/ais.html (rev. 2012, cited 6/15/12).

United State Army Military Institute. Pediatric Surgery and Medicine for Hostile Environments. Available from the Internet at http://www.bordeninstitute.army.mil/other_pub/pediatric/21GUTractFinal2.pdf (rev. 3/10/11, cited 6/15/12).

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