Abstract Introduction Human metapneumovirus (hMPV) is a paramyxovirus responsible for respiratory tract infections, ranging from mild upper respiratory symptoms in healthy individuals to severe pneumonia and acute respiratory distress syndrome (ARDS) in immunocompromised host 1. Patients receiving rituximab and prolonged high-dose corticosteroids for conditions like p-ANCA-vasculitis face significantly elevated risk due to impaired B-cell and T-cell immunity 2. This case illustrates the challenges in managing hMPV in such a vulnerable population. Case Presentation A 76 -year-old female with past medical history of hypothyroidism, CKD stage 4, and recent diagnosis of P-ANCA Vasculitis (for which she was on Prednisone 40mg for 3 months and had one infusion of rituximab) presented to the ED with dyspnea and dry cough lasting 3 days. She was placed on high-flow-nasal-canula (HFNC) requiring 70% FiO2 on admission. She endorsed dyspnea, nonproductive cough, malaise, and pleuritic chest pain with deep inspiration. Chest X-ray showed bilateral perihilar interstitial infiltrates. CT chest showed pronounced ground-glass opacities with an upper lobe predominance. Home prednisone was immediately held. Patient was started on azithromycin and piperacillin-tazobactam empirically for suspected community acquired pneumonia. 2D ECHO showed EF of 50-55%; blood cultures were negative. Bronchoscopy with bronchoalveolar-lavage (BAL) was performed to evaluate for infection or alveolar hemorrhage in the setting of active vasculitis; DAH was ruled out. The BAL fluid was lymphocyte-predominant, and cultures grew candida, which was thought to be colonized. Respiratory viral panel returned positive for hMPV. Serum Fungi-tell was markedly elevated (500 pg/mL), raising concern for invasive fungal infection; however, specific testing for blastomycosis and histoplasmosis was negative. ID recommended discontinuing antibiotics and not initiating ribavirin due to lack of severe progression and renal concerns and initiating steroids per ARDS protocol to address inflammatory lung injury. Over 3 days, oxygen requirements decreased from HFNC to 3L NC. The patient was discharged on gradual prednisone taper with outpatient follow-up. Discussion This case underscores hMPV as a serious pathogen in patients on dual immunosuppression, often mimicking bacterial or fungal infections on imaging 1. Fungitell likely reflected false positivity on cross reactivity as clinical improvement occurred without antifungal therapy. Escalating steroids, paradoxical to infection, were critical given the virus-driven inflammatory component 2. Avoidance of ribavirin reduced potential nephrotoxicity. Conclusion Early Viral diagnostics are essential in immunocompromised hosts with respiratory failure. Careful use of antibiotics, judicious interpretation of fungal markers, and strategic steroid management can lead to favorable outcomes in hMPV pneumonia without antiviral therapy. This abstract is funded by: None
Whittaker et al. (Fri,) studied this question.