A 34-year-old man is brought to the emergency department after a snowmobile accident. The patient was thrown 3 m (9.8 feet) and was dazed for several minutes afterward, although he was wearing a helmet and did not lose consciousness. He now has left mid-back pain. Blood pressure is 130/76 mm Hg and pulse is 98/min. Breath sounds are clear and symmetric. Heart sounds are normal. The abdomen is soft and nontender. There are no areas of spinal tenderness or step-offs. The left costovertebral area is tender to palpation. Focused Assessment with Sonography for Trauma reveals no pericardial or intraperitoneal free fluid, and chest and pelvic x-rays are normal. The patient provides a clear urine sample without pain or difficulty. Urinalysis shows 11-25 erythrocytes/hpf. Complete blood count, serum electrolytes, and creatinine are within normal limits. Which of the following is the best next step in management of this patient?

Question

A 34-year-old man is brought to the emergency department after a snowmobile accident.  The patient was thrown 3 m (9.8 feet) and was dazed for several minutes afterward, although he was wearing a helmet and did not lose consciousness.  He now has left mid-back pain.  Blood pressure is 130/76 mm Hg and pulse is 98/min.  Breath sounds are clear and symmetric.  Heart sounds are normal.  The abdomen is soft and nontender.  There are no areas of spinal tenderness or step-offs.  The left costovertebral area is tender to palpation.  Focused Assessment with Sonography for Trauma reveals no pericardial or intraperitoneal free fluid, and chest and pelvic x-rays are normal.  The patient provides a clear urine sample without pain or difficulty.  Urinalysis shows 11-25 erythrocytes/hpf.  Complete blood count, serum electrolytes, and creatinine are within normal limits.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

This patient with blunt trauma (eg, snowmobile accident) now has left mid-back pain, costovertebral area (CVA) tenderness, and microscopic hematuria (ie, >3 erythrocytes/hpf on urinalysis). This presentation is concerning for renal injury and should prompt imaging of the kidneys via CT scan. The kidneys are the most commonly injured organ of the genitourinary system, typically from blunt trauma (eg, direct blow, compression against paravertebral muscles). Clinical findings vary depending on the degree of injury. Renal contusion, as is likely in this patient, can cause flank (ie, left mid-back) pain, CVA tenderness, and/or hematuria (gross or microscopic). More severe injuries, such as renal laceration or renal vessel injury, can result in retroperitoneal bleeding with flank ecchymosis and/or hemodynamic instability. 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, CVA tenderness) or mechanisms of injury. Hematuria is an additional indication; however, the absence of hematuria does not exclude the need for CT scan because hematuria is absent in up to one-third of renal injuries, including severe injuries. (Choice B) This patient has indications (eg, concerning clinical findings, hematuria) for further imaging to rule out renal injury. Reassurance and analgesics are only appropriate once renal injury has been excluded. (Choices C and E) Retrograde cystourethrogram is used to evaluate for bladder or urethral injuries, which can cause hematuria. However, these injuries typically cause gross, rather than microscopic, hematuria and are accompanied by difficulty urinating, suprapubic pain (bladder injury), or blood at the urethral meatus (urethral injury). Given this patient's mid-back pain and CVA tenderness, renal injury is the more likely cause of hematuria, and a CT scan should be performed first. If the CT scan is negative, retrograde cystourethrogram may be indicated, especially prior to urinary catheter insertion because catheterization can worsen urethral injuries. (Choice D) Selective renal angiography and embolization may be used to evaluate and treat some renal injuries with active bleeding. However, this procedure is typically only undertaken after visualizing the extent of renal injury via CT scan. Educational objective: Blunt trauma can cause renal injury. Concerning clinical findings include flank pain and ecchymosis, costovertebral area tenderness, and hematuria. These findings, or a concerning mechanism of injury, should prompt CT scan of the abdomen and pelvis. References: Renal trauma: the current best practice. (http://www.ncbi.nlm.nih.gov/pubmed/30186367)

A 34-Year-Old Man Is Brought to the Emergency Department After