A 42-year-old female patient is evaluated in the outpatient surgical clinic on her third p… — USMLE Step 2 CK

A 42-year-old female patient is evaluated in the outpatient surgical clinic on her third postoperative day. She reports new-onset, right-sided lower back pain accompanied by subjective fevers. Three days prior, she underwent an uncomplicated laparoscopic hysterectomy to treat symptomatic, large uterine leiomyomas. Her past medical history is notable only for mild asthma. Her current temperature is 38.3°C (100.9°F), blood pressure is 122/76 mm Hg, and heart rate is 94/min. Physical examination demonstrates marked tenderness to percussion over the right costovertebral angle. Her abdomen is soft and non-distended, with well-healing laparoscopic port sites without erythema or induration. Urinalysis reveals 1 to 2 leukocytes per high-power field, negative nitrites, and no red blood cells. Which of the following is the most appropriate next step in the management of this patient?

Computed tomography urographyAnswer
B
Broad-spectrum antimicrobial administration
C
Duplex ultrasound of the deep veins
D
Plain radiography of the thorax
E
Urgent surgical re-exploration

Answer

Computed tomography urography

The correct answer is computed tomography urography. This patient is presenting with a new-onset fever, right-sided flank pain, and costovertebral angle tenderness on postoperative day 3 following a laparoscopic hysterectomy. This constellation of symptoms is highly suspicious for an iatrogenic ureteral injury. During a hysterectomy, the ureter is particularly vulnerable to transection, accidental ligation, or thermal damage at the level of the cardinal ligament (where the uterine artery crosses over the ureter) and at the pelvic brim (during ligation of the infundibulopelvic ligament). Although acute pyelonephritis can present similarly, this patient's completely benign urinalysis effectively rules out an infectious etiology. The underlying mechanism is likely a ureteral obstruction or leak causing urinary pooling and subsequent renal capsular distension. Computed tomography urography with intravenous contrast is the preferred initial diagnostic modality because it can rapidly and accurately identify hydronephrosis, exact sites of ureteral obstruction, or intraperitoneal/retroperitoneal contrast extravasation.

Step-by-Step Solution

Analyze the patient's postoperative presentation and vital signs.

The patient exhibits fever and marked right-sided costovertebral angle tenderness on postoperative day 3, while remaining hemodynamically stable.

Characterizing the exact timing and specific physical findings is essential for differentiating the etiology of a postoperative complication.

Correlate the physical findings with the surgical history and laboratory results.

The recent laparoscopic hysterectomy places the ureters at risk of injury. The normal urinalysis makes an infectious etiology (pyelonephritis) unlikely, pointing instead to a structural or obstructive issue.

Costovertebral angle tenderness indicates renal pathology; in the absence of infection, an iatrogenic obstruction (such as a ligated or thermally injured ureter) must be suspected.

Determine the optimal diagnostic imaging modality.

Computed tomography urography is the most appropriate next step.

It visualizes the urinary tract using contrast, allowing clinicians to accurately identify hydronephrosis, ureteral stricture, or contrast extravasation into the pelvis.

Key Concept

Diagnosis of postoperative ureteral injury following pelvic surgery

Estimated Time:1m 15s

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