Vasculitis affecting the kidney: presentation, histopathology and long-term outcome

Area of Science:

• Nephrology
• Pathology
• Immunology

Background:

• Kidney vasculitis, excluding lupus and Schönlein-Henoch purpura, presents diagnostic and prognostic challenges.
• Microscopic polyarteritis, characterized by segmental necrotizing glomerulitis, is a key manifestation of kidney vasculitis.
• Understanding the clinical and histological spectrum is crucial for managing this severe renal disease.

Purpose of the Study:

• To review clinical and histological features of kidney vasculitis.
• To compare outcomes of vasculitis confined to glomerular capillaries versus those with extra-glomerular lesions.
• To assess prognostic factors and treatment efficacy in patients with kidney vasculitis.

Main Methods:

• Retrospective review of 53 patients diagnosed with kidney vasculitis.
• Exclusion of patients with systemic lupus erythematosus or Schönlein-Henoch purpura.
• Clinical assessment, histological examination (including immunohistochemistry and electron microscopy), and survival analysis.

Main Results:

• Clinical presentation was predominantly extrarenal; renal-only presentation occurred in only two patients.
• Segmental necrotizing glomerulitis ('microscopic polyarteritis') was the most common histological finding (42 patients).
• Poor prognosis observed, with 35 deaths and 1-year, 5-year, and 10-year survival rates of 54%, 38%, and 34% respectively. Oligoanuria and extensive crescent formation were adverse prognostic indicators.

Conclusions:

• Kidney vasculitis, particularly microscopic polyarteritis, has a poor prognosis with high mortality.
• Extrarenal manifestations are common, and renal disease progression can be rapid.
• Current treatment strategies show limited efficacy, necessitating further research into effective therapies.