Microscopic polyangiitis with isolated cardiopulmonary involvement: A case report.

Area of Science:

• Rheumatology
• Pulmonology
• Nephrology

Background:

• Microscopic polyangiitis (MPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis typically affecting the kidneys.
• Atypical presentations of MPA, particularly those without renal involvement, require heightened clinical suspicion.

Purpose of the Study:

• To report a rare case of MPA presenting solely with cardiopulmonary manifestations.
• To emphasize the importance of considering MPA in patients with unexplained interstitial lung disease and pleural effusions.

Main Methods:

• A case study of an 87-year-old female with pre-existing conditions presenting with progressive dyspnea, edema, and fatigue.
• Diagnostic workup included laboratory tests for myeloperoxidase ANCA, high-resolution computed tomography (HRCT) of the chest, and assessment based on 2022 ACR/EULAR criteria.
• Treatment involved high-dose intravenous methylprednisolone followed by oral prednisone and mycophenolate mofetil.

Main Results:

• The patient exhibited elevated myeloperoxidase ANCA levels (122 RU/mL) and HRCT findings consistent with interstitial pneumonia and pleural effusion.
• Renal function remained normal throughout the evaluation.
• The patient responded well to immunosuppressive therapy, with significant improvement in cardiopulmonary symptoms and imaging findings upon discharge and follow-up.

Conclusions:

• MPA can manifest initially with isolated cardiopulmonary disease, mimicking other conditions like pneumonia and heart failure.
• Myeloperoxidase ANCA positivity in the context of refractory interstitial pneumonia and pleural effusion should prompt consideration of MPA.
• Timely initiation of immunosuppressive therapy is crucial for managing MPA and potentially reversing organ damage.