A 34-year-old woman with a double‑J ureteral stent placed for persistent bilateral hydronephrosis now has marked leukocytosis with neutrophil predominance despite four days of ceftriaxone; what further diagnostic work‑up and management are indicated?

Immediate Diagnostic Work-Up and Management

This patient requires urgent blood and urine cultures, imaging to assess stent position and rule out obstruction or perinephric abscess, and immediate escalation of antibiotic therapy with consideration for percutaneous nephrostomy if sepsis persists despite adequate drainage. 1, 2, 3

Critical Diagnostic Steps

Obtain Cultures Immediately

• Draw blood cultures (at least two sets) before any antibiotic change to identify the causative organism and guide definitive therapy 3
• Collect urine for culture and antibiogram testing—this is mandatory in obstructed, infected systems 3
• The persistent leukocytosis (WBC 23,000) with left shift (89.6% neutrophils) after 4 days of ceftriaxone strongly suggests either resistant organisms, inadequate source control, or a complication 2, 3

Imaging to Assess Stent Function and Complications

• Order CT scan with contrast (CT urogram) to evaluate:

  • Stent position and patency 1, 3
  • Presence of perinephric stranding, abscess formation, or hematoma 1, 4
  • Degree of persistent hydronephrosis despite stenting 1
  • Any evidence of stent-related complications (perforation, malposition) 4

• CT is the gold standard for identifying complications in non-pregnant patients with fever and leukocytosis despite stenting 3

Assess for Specific Complications

• Ceftriaxone-associated urolithiasis: Although rare in adults, prolonged or high-dose ceftriaxone can cause crystalluria and obstructing stones, which would explain treatment failure 5
• Stent malposition or migration: Can lead to inadequate drainage and persistent infection 4, 6
• Perinephric abscess or pyonephrosis: Requires more aggressive drainage than a stent alone can provide 1, 2

Immediate Management Changes

Escalate Antibiotic Coverage

• Switch from ceftriaxone to broader-spectrum coverage pending culture results 3
• Consider combination therapy targeting resistant gram-negatives and enterococci (e.g., piperacillin-tazobactam or carbapenem plus vancomycin if MRSA risk) 3
• Third-generation cephalosporin ceftazidime has shown superiority over fluoroquinolones in urosepsis, but your patient is already failing ceftriaxone, suggesting resistance or inadequate source control 3

Consider Urgent Drainage Upgrade

• If the patient appears septic, hypotensive, or has worsening renal function, percutaneous nephrostomy (PCN) is indicated 1, 2, 3
• PCN provides superior drainage compared to internal stents in pyonephrosis and has been shown to improve early and long-term cure rates in infected obstructed systems 3
• The American College of Radiology specifically recommends PCN for patients with "prolonged history of flank pain, fever, and leukocytosis" who "appear septic" with dilated collecting systems 1

Hemodynamic Support

• Intensive care may be necessary if the patient shows signs of septic shock (hypotension, altered mental status, oliguria) 3
• Aggressive fluid resuscitation and vasopressor support as needed 2, 3

Common Pitfalls to Avoid

Do Not Assume the Stent is Functioning

• A stent in place does not guarantee adequate drainage—malposition, encrustation, or obstruction by debris can occur 4, 6
• Bilateral stents can both fail simultaneously if there is systemic infection or technical issues 6

Do Not Continue Ineffective Antibiotics

• Four days without clinical improvement (persistent high WBC, fever presumed) indicates treatment failure 2, 3
• Waiting for "more time" on ceftriaxone risks progression to septic shock and multiorgan failure 2, 3

Do Not Delay Imaging

• Clinical deterioration or lack of improvement mandates imaging to identify correctable causes 1, 3
• Perinephric abscess, stent malposition, or new obstruction will not resolve with antibiotics alone 1, 4

Algorithm for Decision-Making

1. Obtain blood and urine cultures immediately 3
2. Order CT scan with contrast to assess stent position, hydronephrosis, and complications 1, 3
3. Escalate antibiotics to broader-spectrum coverage (e.g., piperacillin-tazobactam or carbapenem ± vancomycin) 3
4. If CT shows:
   • Adequate stent position with mild hydronephrosis: Continue escalated antibiotics and monitor closely for 24-48 hours 3
   • Stent malposition, severe persistent hydronephrosis, or perinephric abscess: Proceed urgently to bilateral PCN placement 1, 2, 3
   • Ceftriaxone stones: Consider stent exchange and ensure adequate hydration; stones typically resolve after drug discontinuation 5
5. If patient is hemodynamically unstable or appears septic: Proceed directly to PCN without delay, even before imaging if necessary 1, 2, 3

Definitive Management After Stabilization

• Once infection is controlled and cultures finalize, tailor antibiotics to sensitivities 3
• Plan for definitive treatment of the underlying cause of hydronephrosis (stone removal, stricture repair, etc.) once sepsis resolves 2, 3
• Stents should remain in place until the underlying pathology is definitively treated and infection cleared 2, 3
• Monitor for normalization of temperature, WBC count, and inflammatory markers before considering stent removal or further intervention 1, 2