Causes of Benign Chronic Hematuria
The most common causes of benign chronic hematuria include renal parenchymal disease, urinary tract infection, urolithiasis, benign prostatic hyperplasia, thin basement membrane nephropathy, and exercise-induced hematuria. 1
Glomerular Causes
- Thin Basement Membrane Nephropathy: An autosomal dominant condition that has been reported to be the most common cause of progressive chronic kidney disease presenting with asymptomatic hematuria and usually has a benign course 2
- IgA Nephropathy (Berger Disease): A common cause of persistent isolated microscopic hematuria that may require renal biopsy for diagnosis 2, 3
- Alport Syndrome: A hereditary nephritis with associated hearing loss that can cause benign chronic hematuria, requiring audiogram and slit lamp examinations for diagnosis 2, 1
- Post-infectious Glomerulonephritis: Can present with hematuria and is a frequent cause of increased renal cortical echogenicity in childhood 2
Urologic Causes
- Urinary Tract Infection: A common cause of both microscopic and macroscopic hematuria that should be confirmed with urine cultures, preferably before antibiotic therapy 2, 1
- Benign Prostatic Hyperplasia (BPH): A common benign cause of hematuria in men 1, 4
- Urolithiasis: Kidney and ureteric stones can cause hematuria, sometimes associated with hypercalciuria and hyperuricosuria 2, 1
- Interstitial Cystitis: Should be considered particularly in women with chronic pelvic pain along with microhematuria 2, 1
Systemic/Other Causes
- Exercise-Induced Hematuria: Vigorous exercise can cause transient hematuria that resolves with rest 1, 5
- Hypercalciuria and Hyperuricosuria: Can be associated with microscopic hematuria and may require evaluation for renal calculi 2
- Nutcracker Syndrome: An anatomic abnormality that can cause persistent unexplained microhematuria 2
- Sickle Cell Disease: Can cause hematuria due to renal papillary necrosis 1
- Coagulopathies: Bleeding disorders such as hemophilia can cause hematuria 1
Benign Familial Hematuria
- Familial Hematuria: Screening family members' urine may be useful in the setting of persistent unexplained microhematuria 2
- The term "benign familial hematuria" is considered a misnomer by some experts, who recommend abandoning it as it prompts loss to follow-up 3
- Instead, annual/biennial follow-up assessment is recommended, including measurement of blood pressure, urinalysis, and kidney function tests 3
Diagnostic Approach
- Determine if hematuria is glomerular or non-glomerular by examining urinary sediment for dysmorphic RBCs 1
- Check for proteinuria, as significant proteinuria suggests renal parenchymal disease 2, 1
- Evaluate for hypercalciuria (such as a spot urine calcium-to-creatinine ratio) 2
- Consider renal ultrasound to evaluate for structural abnormalities, though the yield is low in isolated microscopic hematuria 2
Important Clinical Considerations
- In most patients with asymptomatic microscopic hematuria, a cause is never found (idiopathic microscopic hematuria accounts for approximately 80% of cases) 2, 6
- Patients without risk factors and with an identified benign cause of microhematuria may not require extensive imaging workup 2, 1
- Persistent isolated microscopic hematuria confers a risk for future chronic kidney disease, which is dependent on disease context, underlying genetics, environment interactions, and treatment 3
- Microscopic hematuria most commonly has benign causes, with a malignancy risk of only 2.6-4% 2, 7
Follow-up Recommendations
- For patients with negative initial evaluation but persistent hematuria, repeat urinalysis at 6,12,24, and 36 months 5, 4
- Monitor blood pressure and consider nephrology referral if hematuria persists with development of hypertension, proteinuria, or evidence of glomerular bleeding 5, 4
Remember that while these causes are considered "benign," some conditions like thin basement membrane nephropathy and IgA nephropathy may still progress to chronic kidney disease over time and require monitoring 3.