What is the spectrum of nephrological involvement in Hepatitis B (HBV)?

Spectrum of Nephrological Involvement in Hepatitis B Virus (HBV) Infection

The most common nephrological manifestation of HBV infection is membranous nephropathy, occurring in approximately 80% of HBV-related renal disease cases, followed by membranoproliferative glomerulonephritis and polyarteritis nodosa. 1

Pathophysiological Mechanisms

HBV-related renal disease primarily develops through:

• Immune complex-mediated injury with deposition in glomeruli
• Direct viral antigen deposition in renal tissue
• Cryoglobulinemia (less common than in HCV)
• Vasculitic mechanisms (particularly in polyarteritis nodosa)

Specific Renal Manifestations and Their Prevalence

1. Membranous Nephropathy (MN)

• Most common form (80% of HBV-related nephropathy cases) 1
• Clinical presentation:
  • Nephrotic syndrome (heavy proteinuria >3g/24h) in most cases
  • Microscopic hematuria (74% of cases) 2
  • Renal insufficiency (47% of cases) 2
  • Low complement C3 and C4 levels compared to idiopathic MN 2
• Pathology: Subepithelial immune deposits with HBeAg deposition

2. Membranoproliferative Glomerulonephritis (MPGN)

• Second most common form
• Often associated with mixed cryoglobulinemia
• Clinical features:
  • Proteinuria (variable range)
  • Microscopic hematuria
  • Hypertension
  • Renal insufficiency

3. Polyarteritis Nodosa (PAN)

• Occurs in 1-5% of chronic HBV carriers
• Characterized by necrotizing vasculitis of medium-sized vessels
• May present with:
  • Rapidly progressive glomerulonephritis
  • Hypertension
  • Renal infarction

4. Other Less Common Forms

• IgA nephropathy
• Focal segmental glomerulosclerosis
• Mesangioproliferative glomerulonephritis

Clinical Presentation Patterns

The clinical manifestations of HBV-related nephropathy include:

• Isolated proteinuria (<3g/24h) with microscopic hematuria (30%) 3
• Nephrotic syndrome (20%) 3
• Acute nephritic syndrome (15%) 3
• Macroscopic hematuria (10%) 3
• Chronic renal insufficiency (10%) 3
• Acute renal failure (10%) 3
• Oligoanuria (5%) 3

Natural History and Prognosis

The natural course of HBV-related nephropathy varies significantly:

• In children: Higher spontaneous remission rates (64% at 4 years, 84% at 10 years) 4
• In adults: More progressive course with:
  • Persistent proteinuria in untreated patients
  • Progressive renal failure in 29% of cases
  • End-stage renal disease requiring dialysis in 10% of cases 5
• Remission often correlates with HBeAg clearance 4

HBV in Dialysis Patients

• Prevalence has decreased significantly to 0.1-1.4% (from 3-7.8% in 1976) 3
• Higher prevalence in hemodialysis (1.6%) than peritoneal dialysis (0.9%) 3
• Seroconversion rate of 10-20% with 80% developing chronic infection 3
• Risk of reactivation post-transplant even in previously HBsAg-negative patients (2-10%) 3

Treatment Considerations

• Antiviral therapy is the cornerstone of management for HBV-related nephropathy 3
• Nucleoside/nucleotide analogues are preferred over interferon in patients with renal disease 3
• Dose adjustment required for all antivirals in renal impairment 3
• Immunosuppression should generally be avoided except in rapidly progressive GN or vasculitis 3
• Rituximab requires careful monitoring due to risk of HBV reactivation 3

Key Differences from HCV-Related Nephropathy

While HBV primarily causes membranous nephropathy, HCV more commonly causes:

• Type 1 membranoproliferative glomerulonephritis (most frequent)
• Cryoglobulinemic glomerulonephritis (18-40% of cases) 3
• Mixed cryoglobulinemia with renal involvement 3

This spectrum of nephrological involvement in HBV infection highlights the importance of screening for renal manifestations in HBV-infected patients and considering HBV in the differential diagnosis of glomerular diseases, particularly membranous nephropathy.