What are the possible causes of hematuria in different age groups?

Causes of Hematuria Across Age Groups

Hematuria arises from distinct etiologies that vary significantly by age, with malignancy (particularly bladder cancer) being the dominant concern in adults over 35 years, while glomerulonephritis and congenital anomalies predominate in children.

Pediatric Population (Children and Adolescents)

Glomerular Causes

• Post-infectious glomerulonephritis following streptococcal infection is a common cause, presenting with tea-colored urine, proteinuria, and red blood cell casts 1
• IgA nephropathy (Berger disease) represents a frequent glomerular cause requiring renal biopsy for definitive diagnosis 1
• Alport syndrome presents with hematuria accompanied by progressive kidney disease, hearing loss, and ocular abnormalities, warranting audiogram and slit lamp examination when suspected 1
• Thin basement membrane nephropathy is an autosomal dominant condition and the most common cause of benign familial hematuria in children 1
• Henoch-Schönlein purpura can be diagnosed clinically based on characteristic rash, arthritis, and abdominal symptoms 1

Non-Glomerular Causes

• Urinary tract infection is identified by white cells and micro-organisms in urine 1
• Hypercalciuria detected by spot urine calcium-to-creatinine ratio can cause microscopic hematuria and predispose to stone formation 1
• Trauma with macroscopic hematuria requires imaging to assess extent of renal or urinary tract injury 1
• Sickle cell disease causes hematuria through renal papillary necrosis 1
• Coagulopathies including hemophilia produce hematuria due to bleeding disorders 1

Factitious Causes

• Food substances or medicines can color urine without actual red blood cells present, requiring microscopic confirmation 1

Critical pediatric consideration: Isolated microscopic hematuria without proteinuria or dysmorphic red blood cells in children is unlikely to represent clinically significant renal disease and requires no imaging 1

Adult Population (Ages 35-60 Years)

Urologic Malignancies (Highest Priority)

• Bladder cancer accounts for 30-40% of gross hematuria cases and 2.6-4% of microscopic hematuria cases 2, 3
• Renal cell carcinoma requires multiphasic CT urography for detection 2, 3
• Transitional cell carcinoma of the upper urinary tract is detected through CT urography and cystoscopy 2, 3

Benign Urologic Causes

• Urinary tract infection remains common, presenting with dysuria, frequency, and pyuria 2, 3
• Urolithiasis (kidney and ureteric stones) typically causes painful hematuria with flank pain 2, 3
• Benign prostatic hyperplasia in men can cause hematuria but does not exclude concurrent malignancy 2, 3

Glomerular Causes

• IgA nephropathy is a common glomerular cause in adults 2
• Lupus nephritis and vasculitis require advanced serologic testing including ANA and ANCA 2

Medication-Related

• Anticoagulants and antiplatelet agents may unmask underlying pathology but do not themselves cause hematuria—evaluation must proceed regardless 2, 3

Critical adult consideration: Risk factors including male gender, age >35 years, smoking history (especially >30 pack-years), and occupational exposure to benzenes or aromatic amines mandate complete urologic evaluation with cystoscopy and CT urography 2, 3

Elderly Population (Over 60 Years)

Malignancy (Predominant Concern)

• Bladder cancer risk increases dramatically, with gross hematuria carrying a 30-40% malignancy risk requiring urgent urologic referral even if self-limited 2, 3, 4
• Males ≥60 years are automatically classified as high-risk and require cystoscopy and CT urography regardless of other factors 2
• Urothelial carcinoma risk is elevated by smoking history and occupational chemical exposure 2, 3

Benign Causes

• Benign prostatic hyperplasia is extremely common in elderly men but must be proven as the source through appropriate evaluation 2, 3
• Urinary tract infection with recurrent infections potentially masking malignancy 2
• Urolithiasis remains a consideration 5, 6

Systemic Causes

• Renal parenchymal disease with chronic kidney disease becomes more prevalent 2
• Anticoagulation therapy is common in elderly patients but should never defer evaluation, as medications may unmask underlying malignancy 2, 3

Critical elderly consideration: In patients >60 years with gross hematuria, the prevalence of asymptomatic microscopic hematuria can reach 21%, with significantly higher risk for urologic malignancy requiring mandatory cystoscopy and upper tract imaging 2, 3

Age-Independent Causes

Trauma-Related

• Blunt or penetrating renal trauma with macroscopic hematuria requires contrast-enhanced CT imaging 1, 3
• Pelvic fractures with blood at urethral meatus require retrograde urethrography before catheter placement 3

Exercise-Induced

• Vigorous exercise can cause transient hematuria that resolves with rest 3

Contamination

• Menstruation in women can contaminate urine samples leading to false-positive results 3

Key Diagnostic Distinctions

Glomerular vs. Non-Glomerular Bleeding

• Glomerular bleeding: Tea-colored urine, >80% dysmorphic RBCs, red blood cell casts (pathognomonic), proteinuria >2+ on dipstick 1, 2
• Non-glomerular bleeding: Bright red blood, >80% normal RBCs, absence of casts, minimal proteinuria 2

Common pitfall: Dipstick positivity has only 65-99% specificity and must be confirmed with microscopic urinalysis showing ≥3 RBCs per high-power field on at least two of three properly collected specimens before initiating extensive workup 2, 3