An internal medicine physician is urgently called to the medical admission unit to evaluat… — USMLE Step 3

An internal medicine physician is urgently called to the medical admission unit to evaluate a patient with acute right-sided flank pain and rigors. The patient, a 64-year-old female, reports that her symptoms started abruptly yesterday. Initial vitals demonstrate a temperature of $39.4^\circ\text{C}$ ( $102.9^\circ\text{F}$ ), blood pressure of $86/54\text{ mm Hg}$ , heart rate of $122/\text{min}$ , and respiratory rate of $22/\text{min}$ . On examination, exquisite tenderness is elicited over the right costovertebral angle. Laboratory analysis reveals a leukocytosis of $18,500/\text{mm}^3$ and a serum creatinine of $1.8\text{ mg/dL}$ (baseline $0.9\text{ mg/dL}$ ). A catheterized urine specimen yields positive results for leukocyte esterase, nitrites, and abundant bacteria. Intravenous fluid resuscitation with 2 liters of crystalloid is immediately administered, yielding a blood pressure improvement to $110/70\text{ mm Hg}$ . Clinical suspicion is high for an infected obstructing ureteral calculus.

Arrange the following management steps in the most appropriate chronological sequence for this patient.

1Intravenous fluid resuscitation and administration of broad-spectrum antibiotics
2Diagnostic imaging with non-contrast computed tomography (CT) of the abdomen and pelvis
3Emergent urinary tract decompression via percutaneous nephrostomy or ureteral stent
4Definitive stone extraction via ureteroscopy or shock wave lithotripsy

Answer

The correct sequence is to first stabilize the patient with fluids and antibiotics, confirm the diagnosis with a CT scan, perform emergent decompression of the obstructed kidney, and finally defer definitive stone extraction until the infection has cleared.

The correct sequence for managing an infected, obstructing kidney stone (obstructive pyelonephritis) follows the principles of trauma and sepsis resuscitation: stabilize first, define the anatomy, achieve source control, and defer definitive repair. The patient must first receive intravenous fluids and broad-spectrum antibiotics to treat the septic shock. Once the patient is stabilized (blood pressure improves), a non-contrast CT scan is obtained to accurately identify the stone's location and size. Subsequently, emergent decompression of the collecting system via a ureteral stent or percutaneous nephrostomy tube is performed to drain the infected urine. Finally, definitive stone extraction is deferred for several weeks until the infection has completely resolved, as acute extraction carries a profound risk of fatal septic shock.

Step-by-Step Solution

Prioritize hemodynamic stabilization and source control initiation.

Intravenous fluids and antibiotics are administered first.

The patient presents with septic shock (hypotension, fever, leukocytosis). The ABCs of resuscitation require immediate volume expansion and early antimicrobial therapy.

Confirm the anatomical diagnosis.

A non-contrast CT of the abdomen and pelvis is performed.

Following stabilization, precise imaging is needed to confirm the level of obstruction and rule out other complications (like a perinephric abscess) before attempting invasive procedures.

Relieve the obstruction to achieve definitive source control.

A percutaneous nephrostomy tube or ureteral stent is placed.

An obstructed, infected kidney is a surgical emergency. Decompression allows the purulent urine to drain, which is necessary to cure the infection.

Plan for long-term resolution.

Definitive stone extraction is scheduled for a later date.

Attempting to break or pull out the stone during an active infection significantly increases intrarenal pressure, which can cause massive bacteremia and fatal shock. It must be delayed.

Key Concept

Management sequence for obstructive pyelonephritis

Estimated Time:1m 30s

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic