Case Presentation: Pulmonary renal syndrome is a condition characterized by diffuse alveolar hemorrhage and rapidly progressive glomerulonephritis. It is often associated with vasculitides, but rarely Type I cryoglobulinemic vasculitis. When presenting in the setting of rare comorbidities, it can be confused with pneumonia and acute kidney injury. This patient was a 66-year-old male with a history of multiple myeloma with prior vascular complications who had previously undergone bone marrow transplant several years ago as well as CAR-T therapy one year prior to admission, after which he was thought to be in remission. He presented to the emergency department with progressive fatigue, dyspnea on exertion and easy bleeding and bruising, including nosebleeds and cough with bloody sputum, of several weeks’ duration.Upon arrival at the emergency department, he was hemodynamically stable and breathing room air. Initial laboratory evaluation revealed acute kidney injury with a creatinine of 4.27, urinalysis with proteinuria and microscopic hematuria, anemia with a hemoglobin of 10.0, and a low C4. Chest x-ray revealed multifocal opacities. CT angiogram was notable for ground glass opacities.He was initially admitted for multifocal pneumonia due to these imaging findings, and acute kidney injury, which was thought to be pre-renal and related to his infection and dehydration.Due to the patient’s presentation with hemoptysis, hypoxia, and acute kidney injury, the admitting team was concerned for pulmonary hemorrhage and pulmonary renal syndrome, most specifically with relation to possible cryoglobulinemic vasculitis given his history of multiple myeloma. Plasmapheresis was initiated for concerns of cryoglobulinemic vasculitis causing pulmonary renal syndrome. Nephrology was consulted and his initial workup was notable for positive cryoglobulin, with immunofixation showing monoclonal IgG Kappa, consistent with Type I cryoglobulinemia. He also had elevated IgG with low IgA and IgM. Serum protein electrophoresis revealed two monoclonal proteins in the gamma globulin regions. He underwent a bone marrow biopsy, which revealed persistent plasma cell myeloma, consistent with recurrence of his known multiple myeloma. He was treated with a four-day course of high dose dexamethasone per hematology recommendations. Following this hospitalization, he was started on Talquetamab for multiple myeloma in the outpatient setting.
Discussion: This case demonstrates a rare and severe manifestation of type I cryoglobulinemic vasculitis. Although type I cryoglobulinemic vasculitis secondary to multiple myeloma is an exceedingly rare cause of pulmonary renal syndrome, due to the life-threatening nature of this condition, it is important to maintain a broad differential diagnosis when evaluating patients with pulmonary infiltrates and acute kidney injury, especially in patients with a history or concern for plasma cell disorders like multiple myeloma. For patients with conditions in remission, it is also important to monitor for complications indicative of recurrence. Pulmonary renal syndrome is one such clue of recurrence. Treatment often includes glucocorticoids and plasma exchange.
Conclusions: Since pulmonary renal syndrome is a life-threatening but treatable condition, prompt recognition is of utmost importance.