A 62-year-old woman is brought to the emergency department by her family due to a 2-day hi… — USMLE Step 2 CK

A 62-year-old woman is brought to the emergency department by her family due to a 2-day history of severe left flank pain, high fevers, and worsening confusion. She has a medical history of type 2 diabetes mellitus and hypertension. Her temperature is $39.4^\circ\text{C}$ ( $102.9^\circ\text{F}$ ), pulse is $124/\text{min}$ , blood pressure is $84/52\text{ mmHg}$ , and respirations are $24/\text{min}$ . Physical examination reveals a lethargic patient with dry mucous membranes and marked left costovertebral angle tenderness. Laboratory studies show a leukocyte count of $24,000/\text{mm}^3$ , serum creatinine of $2.3\text{ mg/dL}$ (baseline $0.9\text{ mg/dL}$ ), blood urea nitrogen of $48\text{ mg/dL}$ , and serum lactate of $4.5\text{ mmol/L}$ . Urinalysis is positive for leukocyte esterase, nitrites, and numerous bacteria. A non-contrast computed tomography scan of the abdomen and pelvis reveals a $9\text{-mm}$ radiopaque calculus in the left proximal ureter with severe hydroureteronephrosis and extensive perinephric fat stranding. Aggressive intravenous fluid resuscitation and broad-spectrum antibiotics are initiated, but her blood pressure remains $86/54\text{ mmHg}$ . Which of the following is the most appropriate next step in management?

Percutaneous nephrostomy tube placementAnswer
B
Retrograde ureteroscopy with laser lithotripsy
C
Continued medical management with targeted antibiotics
D
Extracorporeal shock wave lithotripsy
E
Intravenous sodium bicarbonate administration

Answer

Percutaneous nephrostomy tube placement

The correct intervention is percutaneous nephrostomy tube placement. This patient is in septic shock secondary to an obstructing ureteral calculus complicated by infection (pyonephrosis). In this scenario, the infected collecting system becomes a closed, high-pressure abscess. Antibiotics cannot effectively penetrate the obstructed kidney. Immediate source control via urgent decompression is lifesaving. Decompression can be achieved with either a percutaneous nephrostomy tube (placed by interventional radiology) or a retrograde ureteral stent (placed by urology).

Step-by-Step Solution

Analyze the patient's clinical presentation and vital signs.

The patient has a fever, tachycardia, hypotension unresponsive to fluids, altered mental status, and lactic acidosis, indicating septic shock.

Identifying hemodynamic instability is the first step in prioritizing emergent interventions over definitive or elective procedures.

Evaluate the imaging and laboratory data to identify the source of sepsis.

CT shows a 9-mm obstructing proximal ureteral stone with severe hydronephrosis and perinephric stranding, alongside a profoundly infected urinalysis.

This confirms the diagnosis of an infected, obstructed kidney (pyonephrosis), which is the source of the systemic infection.

Determine the management algorithm for an obstructed, infected kidney.

The algorithm requires immediate decompression of the collecting system to allow purulent fluid to drain, achieved either by a percutaneous nephrostomy tube or a retrograde ureteral stent.

Definitive stone removal (e.g., ureteroscopy, ESWL) is contraindicated during active sepsis due to the risk of exacerbating systemic infection via pressurized irrigation.

Key Concept

Emergent decompression of an obstructed, infected collecting system

Estimated Time:1m 30s

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