What is the best course of treatment for a female patient with a history of kidney stones, presenting with severe low back and side pain, fever, tachycardia, and urinalysis results indicating a urinary tract infection, including leukocytes, nitrites, and bacteria, after initial discharge with a diagnosis of muscle strain?

Acute Pyelonephritis with Sepsis: Immediate Management Required

This patient requires immediate hospitalization with intravenous antibiotics for acute pyelonephritis with systemic inflammatory response syndrome (SIRS), not discharge with oral therapy. The initial discharge diagnosis of muscle strain was a critical error given the classic presentation of nephrolithiasis-associated pyelonephritis.

Critical Clinical Indicators Missed on First Visit

The initial presentation screamed kidney stone with developing infection, not musculoskeletal strain:

• Excruciating flank pain radiating to the side requiring 75mcg fentanyl is pathognomonic for renal colic, not muscle strain 1
• History of kidney stones makes nephrolithiasis the leading differential diagnosis 2
• Pain so severe the patient couldn't find a comfortable position is classic for ureteral obstruction 1
• Severe nausea without ability to achieve pain relief indicates visceral pain from urinary tract pathology 2

The absence of fever and urinary symptoms on initial presentation does not rule out developing pyelonephritis—fever often develops 24-48 hours after obstruction begins 1.

Current Presentation: Obstructive Pyelonephritis

The patient now meets criteria for complicated pyelonephritis with sepsis:

Systemic Inflammatory Response (SIRS criteria met):

• Temperature 99.3°F (was 101.6°F at home) 1
• Heart rate 117 (tachycardia) 1
• WBC 10.96 with 80.8% neutrophils (left shift with absolute neutrophilia of 8.870) 3

Urinalysis confirms severe infection:

• Positive nitrites and 500/uL leukocytes indicate gram-negative bacterial infection 2
• TNTC (too numerous to count) WBCs and RBCs with many WBC clumps 2
• Many bacteria with turbid urine 2
• 250 Ery/uL blood suggests stone-related trauma or infection 4

Red flags for complicated infection:

• Fever, chills, and rigors developing after initial presentation 2, 1
• Altered mental status (hallucinations) suggests sepsis 1
• Inability to tolerate oral intake (nothing eaten since discharge) 1
• Persistent severe pain despite Flexeril and fentanyl 1

Immediate Management Protocol

1. Hospitalization and Monitoring (Mandatory)

• Admit to hospital immediately—this is obstructive pyelonephritis until proven otherwise 1, 4
• Vital signs every 4 hours including temperature, blood pressure, heart rate, respiratory rate, oxygen saturation 3
• Strict intake/output monitoring given reduced oral intake and hematuria 3
• Daily weights to assess fluid status 3

2. Urgent Diagnostic Studies (Within 2-4 Hours)

Blood work:

• Blood cultures × 2 before antibiotics (patient appears systemically ill with high fever) 1, 3
• Repeat CBC with differential to establish baseline 3
• Comprehensive metabolic panel including creatinine to assess renal function 1
• C-reactive protein or procalcitonin to assess severity 3

Urine studies:

• Urine culture and antimicrobial susceptibility testing (mandatory before antibiotics) 2, 1
• The urinalysis already performed confirms infection 2

Imaging (URGENT—within 24 hours, sooner if clinical deterioration):

• Renal and bladder ultrasound immediately to rule out urinary obstruction, stones, or abscess 2, 1, 3
• If ultrasound shows hydronephrosis or is inconclusive, proceed immediately to contrast-enhanced CT abdomen/pelvis 2, 1
• Given history of kidney stones and hematuria, imaging cannot be delayed 2, 4

3. Intravenous Antibiotic Therapy (Start Immediately)

First-line empirical regimen:

Ceftriaxone 1-2 grams IV once daily is the preferred initial agent for hospitalized patients with pyelonephritis 2, 1, 3

Alternative if ceftriaxone unavailable:

• Cefepime 2 grams IV every 12 hours 3
• Levofloxacin 750 mg IV once daily (only if local fluoroquinolone resistance <10%) 2, 1, 5

Do NOT use oral antibiotics initially—this patient requires parenteral therapy given systemic toxicity, inability to tolerate oral intake, and potential obstruction 2, 1

Total duration: 7-14 days with transition to oral therapy based on culture sensitivities once afebrile for 24-48 hours 2, 1, 3

4. Aggressive Supportive Care

Fluid resuscitation:

• Continue IV normal saline—patient received 1000mL bolus, now needs maintenance at 125-150 mL/hour adjusted for clinical status 3
• Patient has had nothing to eat since discharge and is likely significantly volume depleted 3

Symptom management:

• Continue fentanyl or transition to scheduled ketorolac 15-30mg IV every 6 hours for flank pain 3
• Ondansetron 4-8mg IV every 8 hours as needed for nausea 3
• Acetaminophen 650-1000mg every 6 hours for fever 3

Critical pitfall: The patient was given Flexeril (cyclobenzaprine) and told to take it with alcohol (implied by "[DRINK]")—this is dangerous as both are CNS depressants and may explain the hallucinations 1. Discontinue Flexeril immediately.

Monitoring for Treatment Response

48-72 hour assessment:

• Repeat CBC and inflammatory markers to confirm response 3
• If fever persists beyond 72 hours of appropriate antibiotics, obtain contrast-enhanced CT immediately to evaluate for complications (abscess, emphysematous pyelonephritis, persistent obstruction) 2, 1

Transition to oral therapy when:

• Afebrile for 24-48 hours 1
• Tolerating oral intake 1
• Clinical improvement in pain and systemic symptoms 1
• Culture sensitivities available to guide narrow-spectrum oral agent 2, 1

Oral options for transition (based on sensitivities):

• Ciprofloxacin 500mg PO twice daily 2, 1, 6
• Levofloxacin 750mg PO once daily 2, 1, 5
• Trimethoprim-sulfamethoxazole 160/800mg PO twice daily (only if susceptible) 2, 1

Urological Consultation

Immediate urology consult if imaging shows:

• Hydronephrosis or ureteral obstruction 4
• Obstructing stone requiring intervention 4
• Perinephric or renal abscess 1

Obstructive pyelonephritis is a urologic emergency—if obstruction is confirmed, the patient requires urgent decompression via percutaneous nephrostomy or ureteral stent placement 4.

Follow-Up After Discharge

• Repeat urine culture 1-2 weeks after completing antibiotics to document clearance 3
• Urology follow-up for stone management and metabolic evaluation 4
• If recurrent UTIs develop, consider prophylaxis strategies per guidelines 2

Key Pitfalls to Avoid

1. Never discharge a patient with suspected pyelonephritis who cannot tolerate oral intake or has systemic toxicity 1
2. Never delay imaging in patients with history of kidney stones presenting with flank pain and fever—obstruction must be ruled out urgently 2, 1, 4
3. Never prescribe muscle relaxants for renal colic—they provide no benefit and add CNS depression 1
4. Never assume absence of urinary symptoms rules out UTI—pyelonephritis can present without dysuria, especially with obstruction 2, 1
5. Never use fluoroquinolones empirically without considering local resistance patterns—if resistance exceeds 10%, use ceftriaxone instead 2, 1