Renal trauma: a practical guide to evaluation and management.

Abstract

1. Blunt trauma and gross hematuria. Gross hematuria is the most reliable indicator for serious urological injury. The degree of hematuria, however, does not correlate with the degree of injury. In fact, renal pedicle avulsion or acute thrombosis of segmental renal arteries can occur in the absence of hematuria while renal contusions can present with gross hematuria. 2. Blunt trauma, microscopic hematuria and shock. Significant microscopic hematuria is >5 RBC/HPF in the first voided or catheterized specimen. Shock is any presence of systolic blood pressure <90 during transport or upon arrival in the emergency room. Blunt trauma patients with microhematuria and no shock have minor renal injuries in nearly all cases. Miller and McAninch, based on findings in over 2000 blunt renal trauma injuries determined that in <0.2% of cases will a grade 2 or more severe renal injury be missed. These patients are the victims of multiple trauma and thus during the evaluation of other intra-abdominal injuries, most of the missed major renal injuries will be detected. When patients who were imaged for associated intra-abdominal injuries are included only 0.03% of significant renal injuries were not identified. 3-5 3. Major deceleration injury. The kidney primarily floats free in a bed of fat contained within the envelope of Gerota's fascia. The kidney is fixed at only two points, the ureter and the vascular pedicle. Because of poor fixation, the kidney can be easily dislocated by sudden acceleration or deceleration. Kidney dislocation can result in tearing of the collecting system at the ureteropelvic junction (UPJ) or tearing of renal artery intima, resulting in partial to complete vessel occlusion. Such injuries can occur with major deceleration, as in head-on motor vehicle accidents (MVA) or