What is the appropriate management for an 18-year-old female with right lumbar pain, tenderness on palpation, leukocytosis, and anemia?

Management of Right Lumbar Pain with Leukocytosis and Anemia in an 18-Year-Old Female

This clinical presentation requires urgent imaging with CT or ultrasound to identify the source of infection, followed by appropriate source control and antimicrobial therapy based on the underlying pathology.

Initial Diagnostic Approach

The combination of right lumbar pain, tenderness on palpation, leukocytosis (WBC 13,900), and anemia (Hb 10.1) in a young woman suggests an acute infectious or inflammatory process requiring immediate evaluation.

Essential Laboratory Investigations

Beyond the basic complete blood count already obtained, the following tests are mandatory 1:

• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) - these inflammatory markers are more sensitive than WBC alone for acute abdominal pathology 1
• Comprehensive metabolic panel including electrolytes, liver enzymes, and renal function 1
• Urinalysis with culture - critical given the right-sided location which could represent pyelonephritis 1
• Blood cultures if fever is present 1

The anemia (Hb 10.1) warrants attention but is likely secondary to the acute inflammatory process rather than the primary issue 1.

Imaging Strategy

First-Line Imaging

Ultrasound of the right upper quadrant and flank is the initial imaging of choice for several reasons 1:

• Non-invasive and readily available
• Excellent for evaluating gallbladder pathology (cholecystitis)
• Can assess for hydronephrosis suggesting urinary obstruction
• Can identify fluid collections or abscesses

CT abdomen/pelvis with IV contrast should be obtained if ultrasound is non-diagnostic or if clinical suspicion remains high 1:

• Superior sensitivity for identifying abscesses, perforated viscus, or other intra-abdominal pathology
• Can detect free air, fluid collections, and inflammatory changes
• Essential for surgical planning if intervention is needed

Differential Diagnosis and Management by Pathology

Acute Pyelonephritis/Obstructive Uropathy

If imaging shows hydronephrosis with perinephric stranding and urinalysis confirms infection 1:

• Immediate urinary decompression is lifesaving in obstructive pyelonephritis 1
• Percutaneous nephrostomy (PCN) or retrograde ureteral stenting should be performed emergently if the patient appears septic 1
• Antibiotic therapy with fluoroquinolones (ciprofloxacin 500mg twice daily for 7 days) or third-generation cephalosporins 1, 2
• Critical pitfall: Antibiotics alone are insufficient in obstructive pyelonephritis - decompression is mandatory 1

Acute Cholecystitis

If ultrasound demonstrates gallbladder wall thickening, pericholecystic fluid, and stones 1:

• Early laparoscopic cholecystectomy (within 7 days) is the definitive treatment and results in shorter hospitalization compared to delayed surgery 1
• Laparoscopic approach is safe and preferred when feasible 1
• If source control is complete with cholecystectomy, no postoperative antibiotics are necessary for uncomplicated cases 1

Appendicitis

Though right lumbar pain is atypical, appendicitis can present with variable locations 1:

• Appendectomy should be performed within 24 hours of diagnosis 1
• Laparoscopic approach is preferred 1
• The leukocytosis pattern fits, though CRP elevation is more consistent than WBC elevation alone 1

Intra-abdominal Abscess

If CT reveals a fluid collection 1:

• Percutaneous catheter drainage (PCD) is usually appropriate for collections >3 cm 1
• Broad-spectrum antibiotics covering gram-negative and anaerobic organisms 1
• Source control through drainage is essential - antibiotics alone are inadequate 1

Critical Management Principles

Immediate actions required:

1. Obtain imaging within hours, not days - diagnostic delay significantly worsens outcomes 1
2. Start empiric broad-spectrum antibiotics after blood cultures if sepsis is suspected 1
3. Arrange surgical or interventional radiology consultation based on imaging findings 1
4. Monitor for sepsis - fever, tachycardia, and hypotension require aggressive resuscitation 1

Common pitfalls to avoid:

• Do not rely on WBC count alone - CRP and clinical presentation are equally important 1
• Do not delay imaging for "observation" - this presentation requires anatomic diagnosis 1
• Do not treat obstructive uropathy with antibiotics alone - decompression is mandatory 1
• Do not assume the anemia is unrelated - it may indicate chronic inflammation or bleeding requiring follow-up 1

The anemia should be reassessed after treatment of the acute process, as it may resolve with treatment of the underlying inflammatory condition 1.