What is the best course of action for an adult patient with a history of kidney stones, presenting with complicated pyelonephritis, leukocytosis with a predominance of neutrophils, and having received initial treatment with fluids, Fentanyl (for pain), and Zofran (ondansetron, for nausea)?

Management of Complicated Pyelonephritis with Leukocytosis and History of Kidney Stones

This patient requires immediate IV antibiotic therapy with ceftriaxone 1-2g daily, urgent imaging with ultrasound to rule out obstruction, and close monitoring for sepsis given the complicated presentation with kidney stone history and marked leukocytosis. 1, 2

Immediate Next Steps

Antibiotic Therapy

• Initiate IV ceftriaxone 1-2g once daily immediately as the first-line parenteral agent for hospitalized patients with complicated pyelonephritis 1, 2
• Alternative IV options include ciprofloxacin 400mg twice daily, levofloxacin 750mg once daily, cefotaxime 2g three times daily, or cefepime 1-2g twice daily 1
• The patient has already received appropriate initial supportive care with IV fluids, pain control (Fentanyl), and antiemetic therapy (Zofran) 1

Urgent Diagnostic Workup

• Obtain urine culture and antimicrobial susceptibility testing immediately before starting antibiotics, as this is mandatory in all cases of pyelonephritis 1, 2
• Perform urgent ultrasound of the upper urinary tract to rule out urinary obstruction or kidney stones, which is specifically indicated given this patient's history of urolithiasis 1
• Obtain blood cultures given the leukocytosis (WBC 10.96) with neutrophil predominance (80.8%), which suggests possible bacteremia 2

Critical Risk Assessment

Sepsis Monitoring

• This patient is at substantially elevated risk for progression to sepsis (occurs in 26-28% of hospitalized patients with complicated pyelonephritis), particularly given the kidney stone history and marked neutrophilia 2
• The combination of kidney stones and pyelonephritis creates risk for obstructive pyelonephritis, which is a urologic emergency that can rapidly progress to sepsis and death 3
• Monitor closely for signs of clinical deterioration including persistent fever, hypotension, altered mental status, or worsening renal function 2

Obstruction Concerns

• If obstruction is identified on imaging, it must be relieved within 12 hours to prevent progression to urosepsis 2
• Kidney stones obstructing the urinary tract causing pyelonephritis represent a urologic emergency requiring urgent intervention 3

Treatment Duration and Monitoring

Antibiotic Course

• Plan for total treatment duration of 7-14 days for complicated pyelonephritis 1, 2
• Once the patient can tolerate oral intake and shows clinical improvement, transition to oral therapy based on culture and susceptibility results 2
• Oral options after IV therapy include ciprofloxacin 500-750mg twice daily for 7 days or levofloxacin 750mg once daily for 5 days (if susceptible) 1, 2

Clinical Response Expectations

• 95% of patients with uncomplicated pyelonephritis become afebrile within 48 hours of appropriate antibiotic therapy, and nearly 100% within 72 hours 1, 2
• If the patient remains febrile after 72 hours of appropriate treatment, obtain CT imaging to evaluate for complications such as renal abscess, perinephric abscess, or emphysematous pyelonephritis 1, 2

Common Pitfalls to Avoid

• Do not delay imaging in a patient with kidney stone history and pyelonephritis - obstruction must be ruled out urgently 1
• Do not use oral β-lactams or nitrofurantoin for pyelonephritis - these agents have insufficient efficacy for upper urinary tract infections 2
• Do not wait for culture results to start antibiotics - empiric IV therapy must begin immediately while awaiting susceptibility data 2
• Do not discharge the patient until obstruction is definitively ruled out and clinical improvement is documented 1, 3

Special Considerations for Stone Disease

• Patients with chronic kidney stone disease and pyelonephritis are at risk for rare but serious complications including xanthogranulomatous pyelonephritis and emphysematous pyelonephritis 4
• Complete stone removal is ultimately the mainstay of treatment for infection stones, though this is addressed after acute infection control 3
• The patient will require long-term stone prevention strategies after resolution of acute infection, including increased fluid intake to achieve at least 2L of urine per day 5