Approach to Pediatric Nephrology: Hematuria, Proteinuria, and Edema c associated disease Post-streptococcal glomerulonephritis (PSGN), Nephrotic Syndrome, and Henoch-Schönlein Purpura (HSP)

Hematuria

Initial Assessment:

• Differentiate red urine from true hematuria using a urine dipstick.
  • Microscopic hematuria: Confirmed by microscopy. Positive dipstick results with RBCs in urine sediment.

Determining the Cause:

• History:
  • Pain: Indicates stones or infections.
  • Urinary symptoms: Dysuria, frequency.
  • Recent infections: e.g., post-streptococcal glomerulonephritis.
  • Family history: Renal diseases such as Alport syndrome.
• Physical Examination:
  • Rash: Suggests systemic vasculitis (e.g., Henoch-Schönlein purpura).
  • Edema, hypertension: Suggests glomerular disease.
• Laboratory Investigations:
  • Urine Analysis: RBC morphology (dysmorphic suggests glomerular origin).
  • Blood Tests: Renal function tests, complement levels (C3, C4), ASO titer, ANA, ANCA.
  • Imaging: Ultrasound if extraglomerular causes are suspected.

Glomerular vs. Extraglomerular Causes:

• Glomerular: Dysmorphic RBCs, significant proteinuria.
  • Additional Tests: Complement levels, serological tests (ASO, ANA, ANCA, anti-GBM).
  • Kidney Biopsy: If indicated (persistent hematuria with proteinuria, declining renal function).
• Extraglomerular: Eumorphic RBCs, minimal proteinuria.
  • Additional Tests: Imaging (e.g., ultrasound), urine culture.

Diagnostic Criteria for Hematuria:

1. Microscopic Hematuria:
   • 5 RBCs per high-power field (HPF) in a centrifuged urine sample on at least two occasions.
2. Macroscopic Hematuria:
   • Visible red or brown urine, confirmed by the presence of RBCs on microscopy.

Management:

• Glomerular Hematuria:
  • Treat underlying glomerular disease (e.g., corticosteroids for nephritis).
• Extraglomerular Hematuria:
  • Treat specific causes (e.g., antibiotics for UTI).

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Proteinuria

Classification:

• Transient Proteinuria: Temporary factors like fever, exercise.
• Orthostatic Proteinuria: Positional, common in adolescents.
• Persistent Proteinuria: Underlying kidney disease.

Assessment:

• Urine Dipstick: Initial screening.
• Quantitative Tests: Urine protein/creatinine ratio (UPCR), 24-hour urine protein.

Persistent Proteinuria:

• History and Physical Examination: Systemic signs of kidney disease (edema, hypertension).
• Laboratory Investigations:
  • Urine analysis, and renal function tests.
  • Imaging if structural abnormalities are suspected.
  • Blood tests: Serum albumin, complement levels.

Diagnostic Criteria for Proteinuria:

1. Significant Proteinuria:
   • UPCR > 0.2 g/g or 24-hour urine protein > 150 mg in children.
2. Nephrotic Range Proteinuria:
   • UPCR > 2 g/g or 24-hour urine protein > 1 g/m² in children.

Management:

• Transient/Orthostatic: Usually benign, follow-up.
• Persistent:
  • Glomerular Causes: Treat underlying condition (e.g., ACE inhibitors for nephrotic syndrome).
  • Tubular Causes: Correct underlying metabolic disorders (e.g., hypokalemia).
  • Overflow: Treat underlying cause (e.g., multiple myeloma).
  • Secretory: Treat underlying malignancy if present.

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Edema

Pathophysiology:

• Increased capillary hydrostatic pressure.
• Decreased plasma oncotic pressure.
• Increased capillary permeability. (In the test it will be the answer to the pathophysiology of burn)

Clinical Evaluation:

• History: Duration, progression, associated symptoms (e.g., shortness of breath, ascites).
• Physical Examination: Distribution (localized vs. generalized), character (pitting vs. non-pitting), severity.

Investigations:

• Urine Analysis: To assess proteinuria.
• Blood Tests: Renal function, liver function, serum albumin.
• Imaging Studies: Ultrasound, and echocardiogram if the cardiac cause is suspected.

Diagnostic Criteria for Edema:

1. Pitting Edema:
   • Visible indentation remains after applying pressure.
2. Non-pitting Edema:
   • Swelling without indentation.

Management:

• Treat Underlying Cause:
  • Renal Causes: Diuretics (e.g., furosemide), salt and fluid restriction.
  • Cardiac Causes: Manage heart failure (e.g., ACE inhibitors, beta-blockers).
  • Liver Causes: Manage cirrhosis (e.g., diuretics, paracentesis).
• Supportive Treatment: Elevation of affected limbs, compression stockings for venous insufficiency.

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Detailed Disease Discussion

Post-streptococcal glomerulonephritis (PSGN)

• Presentation: Often follows a streptococcal throat or skin infection.
  • Symptoms: Hematuria (cola-colored urine), edema, hypertension, proteinuria.
• Diagnosis: Elevated ASO titer, decreased C3, normal C4, hematuria with dysmorphic RBCs.
• Management:
  • Supportive care (fluid and salt restriction, antihypertensives).
  • Antibiotics to eradicate streptococcal infection.

Nephrotic Syndrome

• Presentation: Massive proteinuria (>3.5 g/day), hypoalbuminemia, edema, hyperlipidemia.
• Diagnosis: Urine dipstick (3+ or 4+ protein), serum albumin <2.5 g/dL, lipid profile.
• Management:
  • Corticosteroids as first-line therapy.
  • ACE inhibitors or ARBs to reduce proteinuria.
  • Diuretics for edema management.
  • Monitor for complications (e.g., infections, thromboembolism).

Henoch-Schönlein Purpura (HSP)

• Presentation: Palpable purpura, arthralgia, abdominal pain, renal involvement (hematuria, proteinuria).
• Diagnosis: Clinical findings, skin biopsy (IgA deposition).
• Management:
  • Supportive care (hydration, pain management).
  • Corticosteroids for severe abdominal pain or nephritis.
  • Monitor renal function and urinalysis.

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Conclusion

A thorough and systematic approach to pediatric nephrology cases is essential for accurate diagnosis and effective management. By understanding the detailed pathophysiology, clinical presentation, diagnostic criteria, and management strategies for conditions like hematuria, proteinuria, and edema, healthcare providers can ensure optimal care and improve outcomes for pediatric patients with kidney diseases.