Background Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) encompasses autoimmune disorders marked by inflammation and damage to small- and medium-sized blood vessels, alongside the presence of circulating ANCA. Prompt diagnosis and treatment are critical for patient survival, necessitating interventions like hemodynamic support, high-dose corticosteroids, immunosuppressants, and plasmapheresis (PLEX). Case Presentation We report a case of a 65-year-old female with a history of hypertension and Chronic Kidney Disease (CKD) Stage 4, secondary to rapidly progressive glomerulonephritis caused by Microscopic Polyangiitis. She presented to the emergency department with a productive cough, subjective fever, chills, body aches, and generalized weakness. Her initial vitals were stable. Laboratory results indicated normocytic anemia, leukocytosis, and acute kidney injury on CKD. Chest X-ray revealed left multifocal pneumonia. She was treated with intravenous Ceftriaxone and Azithromycin and transfused with one unit of packed red blood cells (PRBC). On the following day, she developed shortness of breath and acute hypoxic respiratory failure, necessitating 6L nasal cannula oxygen. Persistent symptomatic anemia without overt bleeding led to the suspicion of diffuse alveolar hemorrhage (DAH) amidst her rapid progressive glomerulonephritis. A CT scan of the chest, abdomen, and pelvis disclosed extensive multilobar airspace disease. Methylprednisolone 1g IV daily was initiated, followed by prophylactic intubation. Bronchoscopy confirmed DAH. The patient was started on Rituximab and underwent five sessions of PLEX. She was subsequently weaned off mechanical ventilation and discharged to a subacute rehabilitation facility, with instructions to follow up with Nephrology, Rheumatology, and her primary care physician. Discussion The triad of dyspnea, anemia, and lung infiltrates was pivotal in raising suspicion of DAH in this patient. Previous studies have noted a correlation between age at presentation and mortality risk in AAV patients with DAH. Hemoptysis is not always present and may be absent in up to 33% of cases. Prompt and aggressive treatment is essential to prevent complications in ANCA vasculitis patients. The mainstays of remission induction therapy in AAV include corticosteroids and cyclophosphamide or rituximab. PLEX serves as an adjunct to immunosuppressive therapy, effectively removing circulating pathogenic antibodies that contribute to vascular damage.