Aneurysmal rupture in microscopic polyangiitis: a case-based review

Area of Science:

• Nephrology
• Rheumatology
• Vascular Surgery

Background:

• Microscopic polyangiitis (MPA) is a small and medium vessel vasculitis that can lead to arterial aneurysms.
• Ruptured aneurysms in MPA are rare, with only 15 reported cases in English literature prior to this study.
• This study investigates a fatal case of MPA with multiple visceral aneurysms and reviews existing literature to understand aneurysmal rupture in MPA.

Purpose of the Study:

• To analyze the clinical features, rupture characteristics, and outcomes of arterial aneurysms in patients with microscopic polyangiitis.
• To identify risk factors and optimal timing for intervention in MPA-associated aneurysms.

Main Methods:

• A comprehensive review of 16 cases of ruptured aneurysms in MPA, including one fatal case experienced by the authors.
• Analysis of organ involvement, aneurysm locations, time to rupture, presenting symptoms, pathological findings, and causes of death.
• Correlation of clinical presentation with pathological findings and treatment outcomes.

Main Results:

• Common organ involvement included glomerulonephritis (100%), pulmonary (25%), and peripheral neuropathy (25%).
• Ruptured aneurysms were most frequently found in the left gastric artery (31.25%), renal and hepatic arteries (18.75% each).
• Rupture occurred median 45 days post-symptom onset and 15 days post-immunosuppressive treatment; mortality rate was 50%.

Conclusions:

• MPA-associated ruptured aneurysms often present initially as renal-limited vasculitis, with abdominal medium-sized arteries being prone to rupture.
• Aneurysms typically develop asymptomatically and rupture within weeks of symptom onset or treatment initiation.
• Early immunosuppressive treatment is crucial for potentially shrinking aneurysms and preventing rupture in MPA patients.