Blood in urine in young patients, what is DD
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differential diagnosis hematuria young patients causes
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Here is a comprehensive differential diagnosis of hematuria (blood in urine) in young patients, organized by mechanism and supported by authoritative textbook sources:
Differential Diagnosis of Hematuria in Young Patients
The key first step is determining whether the hematuria is glomerular or non-glomerular, and whether it is gross or microscopic. Each category has a distinct DD list.
How to Distinguish Glomerular vs. Non-Glomerular
| Feature | Glomerular | Non-Glomerular |
|---|---|---|
| Urine color | Brown/cola/tea-colored | Bright red or pink |
| Clots | Absent | May be present |
| RBC morphology | Dysmorphic RBCs, acanthocytes | Normal-shaped RBCs |
| RBC casts | Present | Absent |
| Proteinuria | Often present | Usually absent |
| Timing in stream | Throughout | Initial or terminal |
1. GLOMERULAR CAUSES (Nephrology)
Primary Glomerulonephritides
| Condition | Key Features in Young Patients |
|---|---|
| IgA Nephropathy (Berger disease) | Most common glomerular cause; peaks in 2nd decade; episodic macroscopic hematuria within 24 hrs of URTI (synpharyngitic hematuria); brown urine without clots |
| Thin Basement Membrane Disease (TBMD) | Most common cause of isolated microscopic hematuria in young adults; benign course; autosomal dominant (COL4A3/COL4A4 mutations) |
| Alport Syndrome | X-linked hereditary nephritis; hematuria + sensorineural deafness + ocular findings (anterior lenticonus); family history of kidney failure |
| Post-infectious GN | Hematuria 2-3 weeks after strep throat; low C3, anti-streptolysin O titre raised; nephritic syndrome |
| Membranoproliferative GN (MPGN) | Persistent hematuria + proteinuria + low C3 |
Secondary Glomerular Causes
| Condition | Key Features |
|---|---|
| IgA Vasculitis (Henoch-Schonlein Purpura) | Palpable purpura on buttocks/legs + arthritis + abdominal pain + nephritis; most common vasculitis in children |
| Lupus Nephritis (SLE) | Young women; rash, arthralgia, low C3 and C4; anti-dsDNA positive |
| Hemolytic-Uremic Syndrome | Triad: microangiopathic hemolytic anemia + thrombocytopenia + AKI; often post-diarrheal (E. coli O157:H7) |
| Anti-GBM Disease (Goodpasture) | Rare; hematuria + pulmonary hemorrhage; anti-GBM antibodies |
| ANCA Vasculitis | Rapidly progressive GN; systemic features |
2. NON-GLOMERULAR CAUSES (Urology/Other)
Infections
| Condition | Key Features |
|---|---|
| UTI / Cystitis | Most common cause overall, especially in young women; dysuria, frequency, pyuria, bacteriuria |
| Pyelonephritis | Fever, flank pain, CVA tenderness; often E. coli |
| Urethritis | STI-related (Chlamydia, gonorrhea); urethral discharge |
| TB of urinary tract | "Sterile pyuria" + hematuria; in endemic areas |
Structural/Anatomical
| Condition | Key Features |
|---|---|
| Urolithiasis (Kidney stones) | Colicky flank/loin pain radiating to groin; calcium oxalate most common; associated with hypercalciuria |
| Hypercalciuria | ~30% of children with isolated hematuria; no stones yet; "sandy urine"; family history of stones |
| Polycystic Kidney Disease | Autosomal dominant (ADPKD); flank pain, palpable kidneys, family history |
| Medullary Sponge Kidney | Dilated collecting tubules; recurrent stones and hematuria |
| Congenital Urinary Tract Anomalies | Hydronephrosis, UPJ obstruction; incidental findings |
| Nutcracker Syndrome | Left renal vein compression between aorta and SMA; more common in young, thin females; left flank pain + hematuria |
| Renal Arteriovenous Malformation | More common in young women; usually asymptomatic but can cause gross hematuria |
Trauma & Exercise
| Condition | Key Features |
|---|---|
| Trauma | History of impact/sports injury; CT scan diagnostic |
| Exercise-induced hematuria | Transient gross hematuria after vigorous exercise; resolves within 48-72 hrs |
Hematological
| Condition | Key Features |
|---|---|
| Sickle Cell Disease/Trait | Papillary necrosis + hematuria; especially in African-descent populations |
| Coagulopathy / Thrombocytopenia | Bleeding at other sites; PT/aPTT/CBC abnormal |
Neoplastic (Less Common in Young)
| Condition | Key Features |
|---|---|
| Wilms Tumor (Nephroblastoma) | Children <5 years; abdominal mass, hypertension |
| Rhabdomyosarcoma of bladder | Adolescents; rare |
| Renal cell carcinoma | Rare under 40 but occurs |
3. PSEUDOHEMATURIA (Rule Out First)
Urine appears red but no RBCs on microscopy:
- Foods: beetroot, blackberries, rhubarb
- Drugs: rifampicin, phenazopyridine, nitrofurantoin
- Myoglobinuria (rhabdomyolysis)
- Hemoglobinuria (intravascular hemolysis)
- Urate crystals (in neonates - "brick dust" urine)
Approach Summary
- Dipstick positive - confirm with microscopy (>3-5 RBCs/hpf = true hematuria)
- Glomerular pattern (dysmorphic RBCs, casts, proteinuria) - nephrology workup: complement levels, ANCA, ANA, anti-dsDNA, ASO, throat culture, renal biopsy if indicated
- Non-glomerular pattern - urology workup: urine culture, imaging (USS/CT KUB), cystoscopy in older patients
- Family history - think Alport syndrome, TBMD, ADPKD, familial IgA nephropathy
Sources:
- Comprehensive Clinical Nephrology, 7th Edition - IgA nephropathy, TBMD, and hematuria DD
- NKF Primer on Kidney Diseases, 8e - hereditary nephritis and hematuria in young persons
- Campbell-Walsh-Wein Urology - urological causes and evaluation of hematuria
- Textbook of Family Medicine, 9e - microscopic vs. gross hematuria definitions and evaluation
- Hematuria in children: causes and evaluation - pediatric DD including glomerular vs. non-glomerular approach
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