A 19-year-old man is brought to the emergency department after a hard fall during a skateboarding trick. The patient was attempting a board slide down a metal handrail when he lost his balance, striking his left flank against the rail. He did not hit his head or lose consciousness but felt short of breath for approximately a minute after the impact. The patient now has pain in the left midback. Blood pressure is 132/80 mm Hg and pulse is 106/min. Breath and heart sounds are normal. The abdomen is soft and nontender. The left flank is bruised and tender to palpation. Hematocrit is 44%. Urinalysis is normal. Which of the following is the best next step in management of this patient?
This patient who sustained a direct blow to the flank (eg, handrail impact) now has flank (ie, left midback) pain, ecchymosis, and tenderness to palpation. This presentation is concerning for renal injury and should prompt imaging of the kidneys via CT scan.
Blunt trauma can injure the kidneys by either a direct blow, as in this patient, or by rapid compression of the kidneys against the paravertebral muscles. Clinical findings frequently associated with renal injury include the following:
Hematuria significantly increases suspicion for renal injury; however, its absence (as in this patient) does not exclude the need for further workup. Hematuria is not present in up to one-third of renal injuries, even when they are severe (eg, avulsion of the ureteropelvic junction).
CT scan of the abdomen and pelvis with contrast (typically multiphase: noncontrast, arterial, corticomedullary, excretory) is used to diagnose renal trauma and should be obtained in patients with concerning clinical findings (eg, flank tenderness/ecchymosis) and/or mechanism of injury (eg, direct blow to the flank) (Choice D). In these patients, the advantages of contrast-enhanced CT scan for identifying renal injury generally outweigh the risks (eg, contrast-related complications). Once diagnosed, most blunt renal injuries can be managed nonoperatively.
(Choices A and C) This patient has tachycardia and flank ecchymosis, which may indicate renal injury with bleeding. Management of such an injury may eventually include admission for serial hematocrits (eg, for certain small bleeds expected to tamponade) or surgical intervention (eg, diagnostic laparoscopy). However, imaging is necessary first for visualizing and grading the renal injury, determining the extent of ongoing bleeding, and informing the management strategy.
(Choice E) Retrograde cystourethrography can be used to evaluate for bladder or urethral injury. These injuries typically cause gross hematuria, difficulty urinating, suprapubic pain (bladder injury), or blood at the urethral meatus (urethral injury).
Educational objective:
Blunt trauma (eg, direct blow to the flank) can cause renal injury. Concerning clinical findings (eg, flank pain/ecchymosis) should prompt CT scan of the abdomen and pelvis, regardless of whether hematuria is present.