ABSTRACT
General comments Whether the incidence of renal injury following blunt abdominal trauma is increased in the pediatric compared with the adult patient population is controversial.1-4 Hypothetically, the pediatric kidney is believed to be more susceptible to trauma due to a decrease in the physical renal protective mechanisms found in childhood: i.e. a slightly lower renal position in the abdomen, an immature thoracic cage, and weaker abdominal musculature. Statistical evaluations to confirm that children have an increased risk of renal injury have revealed mixed results and the question remains unresolved.1-5 What is known, however, is that pre-existing congenital renal abnormalities are found 3-5-fold more commonly in pediatric patients undergoing a screening computed tomography (CT) scan for trauma than the adult population.2-4,6 Classically, patients with a pre-existing genitourinary (GU) abnormality present with a history of hematuria disproportionate to the severity of trauma. In the pediatric population the most common pre-existing GU anomalies found, listed in decreasing frequency, are: ureteropelvic junction (UPJ) obstruction, hydroureteronephrosis secondary to reflux, horseshoe kidney, non-obstructing, non-refluxing hydronephrosis/hydroureteronephrosis, and primary obstructing megaureter.2-4
Traumatic induced hematuria In children, hematuria is unreliable for determining the extent of renal injury; indeed, some studies have failed to find any evidence of either gross or microscopic hematuria in up to 70% of children sustaining grade 2 or higher renal injuries (Table 34.1). In essence, post-traumatic hematuria cannot be used as
the sole determinant in deciding whether or not to screen the child for the presence of a GU injury.7,8
Indications for imaging the genitourinary tract following trauma In the adult, radiographic assessment of the GU tract is recommended following all penetrating trauma, as well as blunt trauma, victims that have one of four criteria:
1 A significant deceleration (motor vehicle accident (MVA), fall from >15 feet) or high-velocity injury (strike to the back or flank with a high-velocity foreign object, i.e. football helmet, baseball bat, etc.).
