What is the follow-up workup for a patient with proteinuria and hematuria?

Follow-up Workup for a Patient with Proteinuria and Hematuria

The follow-up workup for a patient with proteinuria and hematuria should include quantification of protein excretion, comprehensive laboratory testing, appropriate imaging studies, and referral to nephrology or urology based on risk stratification. 1

Initial Assessment and Quantification

1. Confirm and quantify proteinuria:

   • For proteinuria of grade 1+ or higher (roughly ≥30 mg/dL), obtain spot urine protein-to-creatinine or albumin-to-creatinine ratio 2
   • This provides information about both type and activity of renal disease

2. Confirm true hematuria:

   • Microscopic examination to confirm ≥3 RBCs per high-power field 1
   • Distinguish between hematuria, hemoglobinuria, and myoglobinuria

3. Rule out benign causes:

   • Recent vigorous exercise
   • Menstruation in women
   • Recent trauma or procedures
   • Current UTI (confirm with urine culture) 1

Laboratory Evaluation

1. Essential laboratory tests:

   • Complete urinalysis with microscopic examination
   • Urine culture to rule out infection
   • Complete blood count
   • Renal function tests (BUN, creatinine)
   • Estimated glomerular filtration rate (eGFR) to stage kidney disease 2, 1

2. Additional serological tests:

   • Hepatitis B and C testing
   • Complement levels
   • Antinuclear antibody testing
   • Cryoglobulin levels
   • Quantitative immunoglobulin testing
   • Serum and urine protein electrophoresis 2
   • Serum glucose 2

Imaging Studies

1. Kidney ultrasound:

   • Provides information on kidney size, presence of stones, and intra/extrarenal lesions
   • Note: Small kidneys (<9 cm in length) may indicate advanced, irreversible kidney disease 2

2. Additional imaging based on risk stratification:

   • For high-risk patients: CT urography (sensitivity 92%, specificity 93%)
   • For patients with renal insufficiency or contrast allergy: MR urography or ultrasound
   • For young, low-risk patients: Renal ultrasound 1

Risk Stratification

Categorize patients into risk groups based on:

1. High-risk factors:

   • Age (women ≥50 years, men ≥40 years)
   • Smoking history >30 pack-years
   • Gross hematuria or >25 RBC/HPF
   • History of pelvic radiation
   • Chronic urinary infections
   • Occupational exposures to dyes or chemicals 1

2. Additional risk factors:

   • African American ethnicity
   • CD4+ cell counts <200 cells/mL (in HIV patients)
   • HIV RNA levels ≥14,000 copies/mL (in HIV patients)
   • Hepatitis C virus coinfection (in HIV patients) 2

Referral Criteria

1. Nephrology referral indicated for:

   • Significant proteinuria (>1g/day)
   • Evidence of glomerular disease
   • Declining renal function
   • Persistent hematuria with proteinuria 1

2. Urology referral indicated for:

   • Gross hematuria
   • High-risk patients with microscopic hematuria
   • Suspected urological malignancy 1

Follow-up Monitoring

1. Short-term follow-up:

   • Repeat urinalysis within 2 weeks to assess persistence of findings 1
   • If infection identified, follow-up urinalysis after antibiotic treatment to confirm resolution

2. Long-term monitoring:

   • Regular monitoring of renal function, electrolytes, and urinalysis
   • Blood pressure control (target ≤125/75 mmHg) for patients with kidney disease 1
   • Annual screening for patients at high risk for kidney disease 2

Common Pitfalls to Avoid

• Assuming a benign cause without complete evaluation in high-risk patients 1
• Using inadequate imaging (e.g., ultrasound alone) in high-risk patients 1
• Dismissing microscopic hematuria in patients with overactive bladder symptoms 1
• Delaying evaluation (>9 months) which can decrease survival in patients with underlying malignancy 1
• Failing to refer patients to specialists based on sex disparities 1

Remember that patients with both hematuria and proteinuria are at higher risk for significant renal pathology compared to those with isolated findings 3. Even patients with seemingly benign initial presentations may develop progressive disease, with studies showing that 21-23% of patients can experience increased proteinuria over time 3.