What question did this study set out to answer?

To illustrate the diagnostic challenges of ANCA-associated vasculitis that may mimic pneumonia in adolescents.

May 20, 2026

C41-13 Atypical Presentation of ANCA-associated Vasculitis in an 18-year-old Male Initially Treated as Community-acquired Pneumonia

Key Points

To illustrate the diagnostic challenges of ANCA-associated vasculitis that may mimic pneumonia in adolescents.
Case report of an 18-year-old male with progressive respiratory symptoms and initial misdiagnosis of pneumonia.
Treatment included antibiotics for pneumonia and later immunosuppressive therapy for GPA upon re-evaluation.
Diagnostic procedures included bronchoscopy and bronchoalveolar lavage to confirm conditions.
Initial treatment with antibiotics was ineffective, leading to worsening symptoms and additional testing.
Bronchoalveolar lavage confirmed diffuse alveolar hemorrhage associated with granulomatosis with polyangiitis.
The patient improved significantly after initiation of methylprednisolone and rituximab treatment.

Abstract

Abstract Introduction Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) encompasses a group of small-vessel vasculitides characterized by necrotizing inflammation affecting the respiratory tract, kidneys, and other organs. Granulomatosis with polyangiitis (GPA) typically presents with upper and lower respiratory involvement and renal disease, but early manifestations can mimic infections, leading to diagnostic delays. This report presents a rare case of severe pulmonary-renal syndrome in an adolescent male, initially misdiagnosed as viral and bacterial pneumonia. Case Presentation An 18-year-old male college student with no significant past medical history presented with one week of progressive shortness of breath, dry cough, sore throat, and palpitations. He denied fever, chills, or hemoptysis at presentation. Initial labs showed Parainfluenza virus type 4, hemoglobin 9.4 g/dL (normocytic, normochromic), mild leukocytosis, and negative urinalysis. Chest x-ray showed diffuse bilateral airspace opacities. The patient was suspected of having viral pneumonia with superimposed community-acquired pneumonia. He was treated with ceftriaxone and azithromycin. Despite antibiotic treatment, the patient continued to have worsening hypoxemia requiring a high-flow nasal cannula. He developed hemoptysis with worsening anemia over the course of four days, with Hgb at 6.9, requiring transfusions. Repeat urinalysis revealed hematuria and proteinuria. CT Chest showed diffuse ground-glass opacities with concerns for diffuse alveolar hemorrhage (DAH). The patient was intubated and had a bronchoscopy with bronchoalveolar lavage (BAL) that was consistent with DAH. Further workup revealed a positive C-ANCA (titer 1:160), confirming GPA. BAL cultures grew Staphylococcus aureus, Granulicatella adiacens, and Candida albicans, prompting the initiation of empiric treatment with vancomycin, meropenem, and fluconazole. For his GPA, he was treated with IV methylprednisolone 1 g daily × 3 days with tapering to methylprednisolone 60 mg IV daily and Rituximab 375 mg/m² weekly × 4 doses. The patient had a gradual improvement in oxygenation and resolution of hemoptysis over subsequent days, where he was now eventually on room air. He was discharged on oral prednisone taper, rituximab infusions, and bactrim prophylaxis for Pneumocystis jiroveci pneumonia. Discussion This case illustrates the diagnostic challenge of ANCA-associated vasculitis mimicking community-acquired pneumonia, particularly in young adults without comorbidities. The presence of diffuse pulmonary infiltrates, hemoptysis, and anemia unresponsive to antibiotics should prompt consideration of diffuse alveolar hemorrhage and its etiology, such as vasculitis. Early recognition and initiation of immunosuppressive therapy are critical to prevent irreversible organ damage. This abstract is funded by: NONE

Mark Helpful

Bookmark

Relay