Approach to hematuria

graph TD
    subgraph "Initial Evaluation"
        A[Child Presents with Hematuria] --> B{Initial Assessment: History & Physical Exam};
        B --> C{Determine Nature of Hematuria};
        C -->|Gross or Persistent Microscopic| D[Initiate Workup];
        C -->|Transient/Isolated Microscopic| E[Monitor & Re-evaluate];
    end

    subgraph "Diagnostic Workup"
        D --> F{Urinalysis & Urine Microscopy};
        F -->|Dysmorphic RBCs, RBC Casts, Proteinuria| G(Glomerular Pathway);
        F -->|Eumorphic RBCs, No Casts| H(Non-Glomerular Pathway);
    end

    subgraph "Glomerular Pathway"
        G --> I{Blood Tests: BUN/Cr, Complements, ASO};
        I --> J[Refer to Pediatric Nephrologist];
        J --> K[Further Workup e.g., Kidney Biopsy & Specific Treatment];
    end

    subgraph "Non-Glomerular Pathway"
        H --> L{Check for Associated Signs};
        L -->|Pyuria/Bacteriuria| M[UTI Workup: Urine Culture --> Treat];
        L -->|Crystals/Pain| N[Stone Workup: Renal Ultrasound, Urine Ca/Cr --> Manage];
        L -->|No Specific Signs| O[Imaging: Renal & Bladder Ultrasound];
        O -->|Abnormal| P[Refer to Urology/Nephrology];
        O -->|Normal| Q[Consider other causes: Trauma, Bleeding Disorder, Nutcracker Syndrome];
    end
    
    subgraph "Monitoring Pathway"
        E --> R{Periodic Urinalysis & Blood Pressure Checks};
        R -->|Remains Normal| S[Continue Observation];
        R -->|Develops Proteinuria, HTN, or Persists| T[--> Initiate Full Workup];
    end

Hematuria, the presence of blood in the urine, is a common finding in children that warrants a systematic and thorough evaluation. The approach involves a detailed history, a comprehensive physical examination, and appropriate laboratory and imaging studies to determine the underlying cause and guide management.

Initial Assessment: History and Physical Examination

A careful history and physical exam are crucial first steps in evaluating a child with hematuria.

History:

• Nature of Hematuria:

  • Gross vs. Microscopic: Is the blood visible to the naked eye (gross hematuria), or was it found on a routine urinalysis (microscopic hematuria)?

  • Color: Bright red or pink urine often suggests a lower urinary tract source (bladder or urethra), while brown, "tea-colored," or "cola-colored" urine is more indicative of a glomerular (kidney) origin.

  • Timing: Blood at the beginning of urination (initial hematuria) may point to a urethral source, while blood at the end (terminal hematuria) often suggests a bladder neck or prostatic urethral issue. Blood throughout urination (total hematuria) can originate from anywhere in the urinary tract.

  • Clots: The presence of blood clots usually indicates a non-glomerular source.

• Associated Symptoms:

  • Pain: Flank or abdominal pain may suggest kidney stones, infection, or obstruction. Pain with urination (dysuria) can indicate a urinary tract infection (UTI).

  • Systemic Symptoms: Fever, rash, joint pain, or recent illness (especially a sore throat or skin infection) can be associated with glomerular diseases like post-streptococcal glomerulonephritis or IgA nephropathy.

  • Edema and Hypertension: Swelling (edema) and high blood pressure can be signs of significant kidney disease.

• Past Medical and Family History:

  • Inquire about previous UTIs, kidney stones, trauma to the abdomen or back, and any known kidney or urological problems.

  • A family history of hematuria, kidney disease, hearing loss, or kidney stones is important, as some causes of hematuria are hereditary (e.g., Alport syndrome, thin basement membrane disease).

• Medications and Diet:

  • Certain medications (e.g., NSAIDs, some antibiotics) and foods (e.g., beets, blackberries) can cause red-colored urine.

Physical Examination:

• Vitals: Measure blood pressure, as hypertension is a key sign of significant renal disease.

• General: Look for signs of swelling (edema) in the face, hands, or feet.

• Abdomen: Palpate for any masses, tenderness in the flanks (costovertebral angle tenderness), or an enlarged bladder.

• Skin: Check for rashes or other skin lesions that might suggest a systemic disease.

• Genitalia: Examine for any external sources of bleeding.

Diagnostic Workup

The diagnostic evaluation is guided by the findings from the history and physical examination.

Urinalysis and Urine Microscopy:

• Confirmation of Hematuria: The first step is to confirm the presence of red blood cells (RBCs) with a microscopic examination of the urine. A urine dipstick can be a screening tool, but it's not specific for RBCs and can be positive with myoglobin or hemoglobin.

• Glomerular vs. Non-Glomerular: Urine microscopy can help differentiate the source of bleeding. The presence of RBC casts (cylindrical structures formed in the kidney tubules) and dysmorphic RBCs (abnormally shaped red blood cells) strongly suggests a glomerular origin.

• Proteinuria: The presence of protein in the urine (proteinuria) along with hematuria is another indicator of glomerular disease.

• Other Findings: The presence of white blood cells and bacteria may indicate a UTI. Crystals in the urine might suggest kidney stones.

Blood Tests:

• Renal Function: A basic metabolic panel, including blood urea nitrogen (BUN) and creatinine, is essential to assess kidney function.

• Complete Blood Count (CBC): This can reveal anemia, which might be present in chronic kidney disease.

• Further Tests: If a glomerular cause is suspected, additional blood tests may be ordered, such as complement levels (C3, C4), antistreptolysin O (ASO) titers (if post-streptococcal glomerulonephritis is suspected), and tests for autoimmune diseases (e.g., ANA).

Imaging Studies:

• Renal and Bladder Ultrasound: This is a non-invasive and safe imaging test that is often the first-line investigation. It can identify structural abnormalities of the kidneys and bladder, kidney stones, cysts, and tumors.

• Other Imaging: In some cases, a CT scan or MRI may be necessary for a more detailed evaluation, particularly if a tumor or complex structural anomaly is suspected.

Common Causes of Hematuria in Children

The causes of hematuria can be broadly categorized as glomerular or non-glomerular.

Glomerular Causes:

• IgA Nephropathy: The most common cause of recurrent gross hematuria in children, often following an upper respiratory or gastrointestinal infection.

• Post-Infectious Glomerulonephritis: Typically occurs after a streptococcal infection of the throat or skin.

• Thin Basement Membrane Disease: A benign inherited condition that causes persistent microscopic hematuria.

• Alport Syndrome: A genetic disorder characterized by hematuria, progressive kidney failure, and often hearing loss and eye abnormalities.

• Henoch-Schönlein Purpura (HSP) Nephritis: A systemic vasculitis that can affect the kidneys.

• Lupus Nephritis: Kidney inflammation caused by systemic lupus erythematosus.

Non-Glomerular Causes:

• Urinary Tract Infection (UTI): A common cause, especially in girls.

• Hypercalciuria: High levels of calcium in the urine, which can cause hematuria even without the formation of kidney stones.

• Kidney Stones (Nephrolithiasis): Can cause significant pain and gross hematuria.

• Trauma: Injury to the kidneys or urinary tract.

• Structural Abnormalities: Such as ureteropelvic junction (UPJ) obstruction.

• Nutcracker Syndrome: Compression of the left renal vein, which can lead to hematuria.

• Sickle Cell Disease or Trait: Can cause damage to the kidneys and lead to hematuria.

• Tumors: Although rare in children, tumors of the kidney (e.g., Wilms' tumor) or bladder can cause hematuria.

When to Refer to a Pediatric Nephrologist

Referral to a pediatric nephrologist is recommended in the following situations:

• Persistent Microscopic Hematuria: Hematuria that is present on three or more consecutive urinalyses over several weeks.

• Gross Hematuria: All cases of visible blood in the urine.

• Signs of Glomerular Disease: Presence of RBC casts, significant proteinuria, or dysmorphic RBCs on urine microscopy.

• Associated Systemic Symptoms: Hypertension, edema, or impaired kidney function.

• Family History: A family history of significant kidney disease, deafness, or inherited kidney disorders.

• Uncertain Diagnosis: When the cause of hematuria remains unclear after the initial evaluation.

A systematic approach to hematuria in children is essential to identify the underlying cause and ensure appropriate management. While many causes are benign and self-limited, some can indicate serious underlying kidney disease that requires prompt diagnosis and treatment.

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