What are the causes and treatments of hematuria (blood in the urine)?

Causes of Hematuria

Urologic Causes

The most common urologic causes of hematuria include malignancy (bladder, kidney, prostate cancer), urinary tract infection, urolithiasis (kidney/ureteric stones), benign prostatic hyperplasia, and trauma. 1, 2

Malignancy

• Bladder cancer is the most frequently diagnosed malignancy in hematuria cases, accounting for 30-40% of gross hematuria and 2.6-4% of microscopic hematuria 2, 3
• Kidney cancer (renal cell carcinoma) presents with hematuria and requires imaging evaluation 2
• Upper tract urothelial carcinoma affects the renal pelvis and ureters 4
• Risk factors include: male gender, age >35 years, smoking (especially >30 pack-years), and occupational exposure to chemicals/dyes (benzenes, aromatic amines) 1, 2

Infection and Inflammation

• Urinary tract infection is a common cause of both microscopic and macroscopic hematuria, presenting with white cells and micro-organisms in urine 1, 2
• Inflammatory conditions of the bladder and urinary tract 1

Urolithiasis

• Kidney and ureteric stones typically cause painful hematuria with flank pain 1, 2
• Calculus disease is a frequent benign cause requiring imaging evaluation 1

Benign Prostatic Conditions

• Benign prostatic hyperplasia (BPH) is a common cause of hematuria in men 2

Trauma

• Renal trauma with either macroscopic or microscopic hematuria requires imaging to assess extent of injury 1
• Lower urinary tract trauma from instrumentation or external injury 2

Anatomic Abnormalities

• Congenital or acquired structural abnormalities of the urinary tract 1, 2

Renal/Glomerular Causes

Tea-colored urine accompanied by proteinuria (>2+ on dipstick), red blood cell casts, and dysmorphic red blood cells (>80%) strongly suggests glomerular disease. 1, 2

Primary Glomerular Diseases

• IgA nephropathy is a common glomerular cause of hematuria 1, 2
• Post-infectious glomerulonephritis following streptococcal infection 1, 2
• Membranoproliferative glomerulonephritis 1
• Crescentic glomerulonephritis 1

Hereditary Nephropathies

• Alport syndrome presents with hematuria, progressive kidney disease, hearing loss, and ocular abnormalities—audiogram and slit lamp examination indicated if suspected 1, 2
• Thin basement membrane nephropathy is an autosomal dominant condition causing progressive chronic kidney disease 2

Secondary Glomerular Diseases

• Lupus nephritis associated with systemic lupus erythematosus 1, 2
• Vasculitis affecting the kidneys 1, 2
• Glomerular disease associated with hepatitis, endocarditis, and malignancy 1

Interstitial Renal Disease

• Drug-induced interstitial nephritis 1, 2
• Analgesic nephropathy from chronic pain medication use 1, 2

Systemic and Other Causes

Hematologic Disorders

• Coagulopathies including hemophilia cause hematuria due to bleeding disorders 1, 2
• Sickle cell disease causes hematuria through renal papillary necrosis 1, 2
• Anticoagulant and antiplatelet medications may unmask underlying pathology but do not themselves cause hematuria—evaluation should not be deferred 2, 3

Benign Transient Causes

• Vigorous exercise causes transient hematuria that resolves with rest 2, 5
• Menstruation can contaminate urine samples in women—repeat urinalysis 48 hours after cessation of menstruation; if hematuria resolves, no further evaluation needed 2, 5
• Recent urologic procedures 5

Factitious Causes (Not True Hematuria)

• Foods (beets, berries) and medications (rifampin, phenazopyridine) can color urine red without actual red blood cells present 1
• These should be excluded before initiating hematuria workup 1

Age-Specific Considerations

Children

• Glomerulonephritis and congenital anomalies are the most common causes in pediatric patients 1, 2
• History should include: recent strep throat, tropical exposure, family history of sickle cell disease, hemophilia, stone disease, hearing loss, and familial renal disease 1
• Physical examination should assess for: fevers, arthritis, rashes, soft-tissue edema, nephromegaly, abdominal masses, genital/anal bleeding suggesting abuse, deafness, and costovertebral angle tenderness 1

Adults

• Malignancy risk increases significantly with age, particularly over 35-40 years 1, 2
• Men ≥60 years and women ≥60 years are at highest risk for urologic malignancy 2

Critical Clinical Pearls

• Gross hematuria should never be ignored and requires urgent urologic referral even if self-limited, as it carries a 30-40% risk of malignancy 2, 3
• Dipstick positivity must be confirmed with microscopic analysis showing ≥3 RBCs per high-power field before initiating full workup 2, 5
• Anticoagulation is not a reason to forgo evaluation—these medications unmask rather than cause hematuria 2, 3
• Glomerular bleeding is characterized by >80% dysmorphic RBCs, while lower urinary tract bleeding shows >80% normal RBCs 1, 2