What are the causes and management of hematuria?

Causes and Management of Hematuria

Hematuria has diverse etiologies ranging from benign conditions to life-threatening malignancies, with gross hematuria carrying up to a 30-40% risk of urinary tract malignancy requiring immediate and thorough evaluation. 1

Classification of Hematuria

• Microscopic hematuria: ≥3 red blood cells per high-power field on microscopic evaluation from two of three properly collected specimens 2
• Gross hematuria: Blood in urine visible to the patient or physician 1

Causes of Hematuria

Nephrogenic (Kidney) Causes

• Glomerular disease: Most common benign nephrogenic cause 1
  • Glomerulonephritis
  • IgA nephropathy (Berger disease)
  • Thin basement membrane nephropathy
  • Alport syndrome
• Renal parenchymal disease:
  • Acute tubular necrosis
  • Acute kidney injury
• Renal tumors:
  • Renal cell carcinoma

Urogenic (Urinary Tract) Causes

• Benign causes:
  • Urolithiasis (kidney/ureteral stones)
  • Urinary tract infections
  • Benign prostatic hyperplasia 1
  • Vigorous exercise
  • Trauma
  • Menstruation (in women)
  • Recent urologic procedures
• Malignant causes:
  • Bladder cancer
  • Ureteral cancer
  • Prostate cancer

Risk Factors for Urinary Tract Malignancy

• Gross hematuria (30-40% risk of malignancy) 1
• Male gender
• Age >35 years (especially >60)
• Smoking history
• Occupational exposure to chemicals
• Analgesic abuse
• History of urologic disease
• Irritative voiding symptoms
• History of pelvic irradiation
• Chronic urinary tract infection
• Exposure to carcinogenic agents or chemotherapy
• Chronic indwelling foreign body 1

Diagnostic Approach

Initial Evaluation

1. Thorough history and physical examination
2. Urinalysis with microscopic examination:
   • Confirm presence of RBCs
   • Look for dysmorphic RBCs (glomerular source)
   • Assess for red cell casts (glomerular disease)
   • Check for proteinuria (suggests glomerular disease)
   • Evaluate for pyuria/bacteriuria (infection) 2
3. Basic laboratory workup:
   • Complete blood count
   • Serum creatinine and BUN
   • Urine culture if infection suspected 2

Risk Stratification

Patients should be categorized as low-, intermediate-, or high-risk for genitourinary malignancy:

• Low risk: 0-0.4% risk
• Intermediate risk: 0.2-3.1% risk
• High risk: 1.3-6.3% risk 2

Imaging Evaluation

• CT Urography: First-line for detecting stones, malignancies, and infections (92% sensitivity, 93% specificity) 2
• MR Urography: Alternative for patients with contrast allergy or renal insufficiency
• Renal Ultrasound: Alternative or for young patients (50% sensitivity, 95% specificity) 2
• Cystoscopy: Indicated for all patients with gross hematuria and high-risk patients with microscopic hematuria 1, 2

Management Approach

Based on Cause

• Urinary tract infections: Appropriate antibiotics based on culture sensitivity
• Urolithiasis: Medical expulsive therapy or surgical intervention
• Benign prostatic hyperplasia: Alpha-blockers or surgical intervention
• Glomerular disease: Nephrology referral and specific therapy based on diagnosis
• Malignancy: Urologic referral for definitive management 2

Special Considerations

• Microhematuria with identified benign cause (exercise, infection, trauma, menstruation, recent urologic procedure): No imaging workup needed 1
• Suspected UTI: Confirm with urine culture before antibiotics 1
• Renal parenchymal disease: Concurrent nephrology evaluation 1
• Anticoagulant therapy: Does not alter the need for urologic evaluation 1

Follow-up Recommendations

• Low-risk patients: Annual urinalysis 2
• Intermediate/high-risk patients: Urine cytology and repeat urinalysis at 6,12,24, and 36 months 2
• High-risk patients with history of gross hematuria: Surveillance with repeat imaging and cystoscopy 2

Common Pitfalls to Avoid

• Relying solely on dipstick testing without microscopic confirmation 2
• Failing to repeat urinalysis after treating a presumed cause 2
• Assuming anticoagulant therapy is the cause of hematuria without further evaluation 1
• Inadequate evaluation of gross hematuria, which carries high malignancy risk 1
• Neglecting to refer patients with persistent hematuria after treatment of presumed cause 2

Special Populations

Children

• Asymptomatic microscopic hematuria without proteinuria in children rarely indicates significant renal disease 1
• Family history screening may identify benign familial hematuria 1
• Imaging not indicated for isolated microscopic hematuria without proteinuria in children 1
• Consider causes specific to children: post-streptococcal glomerulonephritis, Henoch-Schönlein purpura, and congenital anomalies 1, 3