1222 - A Rare Presentation of Small Vessel Vasculitis Leading to Acute Inpatient Rehabilitation

Case Diagnosis: Granulomatosis with Polyangiitis (GPA)

Case Description: A 77-year-old woman with peripheral vascular disease, hypertension, and substance use disorder presented with altered mental status, purulent nasal drainage, and a chronic non-healing leg ulcer. Imaging showed severe sinonasal destruction; biopsy revealed fungal hyphae in necroinflammatory debris, initially concerning for invasive fungal sinusitis. She was admitted to the ICU for hypercalcemic crisis and treated with broad-spectrum antibiotics, antifungals, and surgical debridement. Her hospital course was complicated by acute kidney injury with proteinuria, hypocomplementemia, anemia, thrombocytosis, and multiple cerebral infarcts noted on MRI. Serology was positive for PR3-ANCA, and renal biopsy confirmed granulomatosis with polyangiitis (GPA). She received high-dose corticosteroids and rituximab induction therapy, then transitioned to acute inpatient rehabilitation.

Discussions: On admission, she required moderate to maximal assistance for mobility and daily activities due to profound debility and cognitive deficits. With multidisciplinary therapy, she progressed from dependent to supervision with ambulation (10 to 50 feet), toileting, showering, and transfers. Cognition and dysphonia improved with speech therapy, and she was discharged with home health and family support.

GPA is a systemic small-vessel vasculitis that primarily affects the respiratory tract and kidneys. Classic sinonasal findings include mucosal thickening (87.7%), bony destruction (59.9%), and septal erosion (59.4%). Extensive necrosis with fungal colonization is rare and may mimic invasive fungal sinusitis, delaying diagnosis and treatment. Untreated GPA has a one-year survival rate of less than 20%, but immunosuppressive advances have improved outcomes to 8–9 years in greater than 80% of patients.

Conclusions: This case highlights a rare GPA presentation with destructive sinonasal necrosis mimicking fungal infection. It underscores the importance of broad differential diagnosis, early biopsy, and intensive rehabilitation in restoring functional independence.