Microscopic Polyangiitis Presenting With Diffuse Alveolar Hemorrhage In A Patient With Chronic Kidney Disease.

Abstract

Background:
Diffuse alveolar hemorrhage (DAH) is a rare, life-threatening manifestation of pulmonary–renal syndrome and may occur in microscopic polyangiitis (MPA), a myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-associated small-vessel vasculitis. Early diagnosis is particularly challenging in patients with pre-existing chronic kidney disease (CKD), in whom worsening renal function and pulmonary infiltrates may be misattributed to progression of CKD, infection, or fluid overload.
Case Report:
A 60-year-old man with type 2 diabetes mellitus, hypertension, and stage 4 CKD presented with fever, haemoptysis, weakness, oliguria, and hypoxemia. Investigations revealed severe anemia (hemoglobin 5.5 g/dL), leukocytosis, and acute-on-chronic kidney injury with serum creatinine rising from a baseline of 3.8 mg/dL to 6.4 mg/dL. Chest radiograph showed bilateral patchy consolidations. High resolution computed tomography (HRCT) chest demonstrated diffuse ground-glass opacities with septal thickening, suggestive of DAH. Despite empiric broad-spectrum antibiotics, oxygen therapy, blood transfusions, and renal replacement therapy, hypoxemia and haemoptysis persisted. Flexible bronchoscopy on day 3 showed progressively bloodier bronchoalveolar lavage aliquots, confirming
DAH. Serology revealed MPO-ANCA positivity, and a diagnosis of MPA presenting as pulmonary–renal syndrome was established. The patient received high-dose intravenous methylprednisolone, six sessions of plasma exchange, and two doses of rituximab. He showed
progressive clinical improvement with resolution of haemoptysis, stabilization of hemoglobin, improved oxygenation, and recovery of renal parameters, and was discharged in stable condition on day 24.
Conclusion:
MPA should be considered in patients with CKD who develop haemoptysis, anemia, bilateral pulmonary infiltrates, and acute worsening of renal function. Early recognition of DAH using imaging, bronchoscopy, and serology, followed by prompt immunosuppressive therapy, can be lifesaving.