What is the best course of action for a patient with a history of West Nile virus infection, currently hospitalized with flaccid paralysis, who presents with brown urine, significant hematuria (blood in urine), and proteinuria (excess protein in urine)?

Management of Brown Urine in a Hospitalized Patient with Flaccid Paralysis Due to West Nile Virus

The patient with brown urine showing 3+ blood, 2+ protein, 1+ leukocyte esterase, and 1+ bilirubin requires immediate urologic and nephrologic evaluation, as these findings suggest significant underlying pathology that could worsen morbidity and mortality.

Immediate Assessment and Management

1. Rule out infection first:

   • Obtain urine culture to rule out urinary tract infection as a benign cause of hematuria 1
   • Check for systemic symptoms (fever, chills) that might indicate complicated UTI

2. Evaluate for rhabdomyolysis:

   • Order serum creatine kinase (CK) levels immediately
   • Rhabdomyolysis has been reported in patients with West Nile virus infection with flaccid paralysis 2
   • Brown urine with positive blood on dipstick may represent myoglobinuria rather than true hematuria

3. Assess renal function:

   • Check BUN, creatinine, and electrolytes to evaluate for acute kidney injury
   • Calculate estimated GFR
   • Monitor fluid status and urine output

Further Diagnostic Workup

1. Urologic evaluation:

   • Complete urologic evaluation including cystoscopy and upper tract imaging is indicated due to significant hematuria (3+) 1
   • Consider CT urography as the preferred imaging modality (sensitivity 92%, specificity 93%) 1
   • If renal insufficiency or contrast allergy is present, consider MR urography or ultrasound 1

2. Nephrologic evaluation:

   • Quantify proteinuria with urine protein-to-creatinine ratio (normal ratio <0.2 g/g) 3
   • 2+ proteinuria warrants nephrology referral for consideration of renal biopsy 3, 1
   • Additional testing: complement levels (C3, C4), antinuclear antibody, hepatitis serologies 3

3. Evaluate for other causes of brown urine:

   • Check liver function tests to evaluate bilirubin elevation
   • Consider hemolysis workup (LDH, haptoglobin, peripheral smear)

Special Considerations in West Nile Virus Patients

• Patients with West Nile virus neuroinvasive disease, especially those with flaccid paralysis, are at risk for complications:

  • Rhabdomyolysis with CK values that can exceed 45,000 U/L 2
  • Immobility-related complications including UTIs and kidney stones
  • Long-term sequelae affecting multiple organ systems 4

• Indwelling Foley catheter considerations:

  • Evaluate catheter for obstruction or trauma
  • Consider catheter change if infection is suspected
  • Ensure proper catheter care to prevent further complications

Management Algorithm

1. If rhabdomyolysis is confirmed:

   • Aggressive IV hydration to maintain urine output >100 mL/hour
   • Monitor electrolytes (especially potassium) and renal function
   • Consider alkalinization of urine if severe

2. If UTI is confirmed:

   • Initiate appropriate antibiotics based on culture and sensitivity
   • Consider catheter change or removal if possible

3. If glomerular disease is suspected:

   • Nephrology consultation for possible renal biopsy
   • Management based on underlying pathology

4. Follow-up monitoring:

   • Daily urinalysis to track resolution of hematuria
   • Serial renal function tests
   • If hematuria persists after negative workup, yearly urinalyses should be conducted 1

Pitfalls and Caveats

• Don't assume hematuria is simply due to the Foley catheter - the presence of proteinuria and bilirubin suggests a more complex process
• Avoid attributing all findings to West Nile virus without ruling out other serious conditions
• Be aware that dipstick "blood" positivity may represent myoglobinuria rather than true hematuria in the setting of rhabdomyolysis
• Delays in evaluation of hematuria can be associated with decreased survival 1
• Patients with prolonged immobility due to flaccid paralysis are at higher risk for urinary complications and require vigilant monitoring