Causes of Hematuria
Primary Classification
Hematuria arises from urologic, glomerular/renal, or systemic causes, with the most critical distinction being between benign conditions and malignancy—gross hematuria carries a 30-40% malignancy risk and demands urgent urologic evaluation regardless of other factors 1, 2.
Urologic Causes (Non-Glomerular)
Malignant Causes
- Bladder cancer is the most frequently diagnosed malignancy in hematuria cases, presenting as painless gross hematuria in 70-80% of patients 1, 3
- Renal cell carcinoma represents upper tract malignancy that can produce hematuria 1
- Prostate cancer may cause lower urinary tract symptoms with hematuria 1
- Risk factors include age >35 years, male gender, smoking >30 pack-years, and occupational exposure to chemicals/dyes 1, 2
Benign Urologic Causes
- Benign prostatic hyperplasia (BPH) is the most common benign urologic cause specifically in men over 50 years old 1, 2, 4
- Urinary tract infection causes both microscopic and macroscopic hematuria with pyuria and bacteriuria 1, 2, 4
- Urolithiasis (kidney and ureteric stones) typically produces painful hematuria with flank pain 1, 2, 4
- Trauma to kidneys or lower urinary tract can cause hematuria 2
Glomerular/Renal Causes
Primary Glomerular Diseases
- IgA nephropathy (Berger disease) is a common cause of persistent isolated microscopic hematuria 2, 4
- Post-infectious glomerulonephritis presents with tea-colored urine, dysmorphic RBCs, and RBC casts 2
- Lupus nephritis and vasculitis can cause hematuria with proteinuria 2
Hereditary Nephropathies
- Thin basement membrane nephropathy is an autosomal dominant condition causing asymptomatic hematuria with generally benign course 2, 4
- Alport syndrome is hereditary nephritis with associated hearing loss 2, 4
Other Renal Causes
- Interstitial renal disease, including drug-induced or analgesic nephropathy 2
- Sickle cell disease causes hematuria through renal papillary necrosis 2
Systemic and Other Causes
Transient/Benign Causes
- Vigorous exercise causes transient hematuria that resolves with rest 2, 4
- Menstruation can contaminate urine samples in women, leading to false-positive results 2
- Recent urologic instrumentation should be considered as potential benign cause 1
Metabolic Causes
- Hypercalciuria and hyperuricosuria are metabolic abnormalities causing microscopic hematuria, potentially leading to nephrolithiasis 2, 4
- Nutcracker syndrome (left renal vein compression) causes hematuria with variable proteinuria 2
Medications and Coagulopathies
- Anticoagulants and antiplatelet agents may unmask underlying pathology but do not themselves cause hematuria—evaluation should never be deferred 2, 4
- Coagulopathies such as hemophilia can cause hematuria due to bleeding disorders 2
Age-Specific Considerations
- In children: glomerulonephritis and congenital anomalies are common causes 2
- In adults over 35 years: malignancy becomes a significant risk factor requiring aggressive exclusion 2
- In men over 50 years: BPH is the predominant benign cause 1
Critical Clinical Pearls
Common pitfalls to avoid:
- Never ignore gross hematuria, even if self-limited—it requires urgent urologic referral due to 30-40% malignancy risk 1, 2
- Anticoagulation is not an explanation for hematuria and should not defer evaluation 2, 4
- Dipstick positivity must be confirmed with microscopic urinalysis showing ≥3 RBCs per high-power field before initiating workup 2
- Tea-colored urine suggests glomerular source, particularly when accompanied by dysmorphic RBCs (>80%), RBC casts, or significant proteinuria 1, 2
- In approximately 80% of cases of asymptomatic microscopic hematuria, no cause is ever found (idiopathic) 4