Research Day
DELAYED ANCA POSITIVITY: A CHALLENGING CASE OF MULTISYSTEM EGPA
Document Type
Abstract
Date
2021
Abstract
Introduction: Vasculitides are often are misdiagnosed until the disease process is advanced. Testing for antineutrophil cytoplasmic antibodies (ANCA) reactivity is a common practice, though only 30 to 60 percent of patients with eosinophilic granulomatosis with polyangiitis (EGPA) are ANCA positive which can lead to diagnostic delay. We report a case of EGPA with multi-system involvement in a patient with an initially negative ANCA.
Case Description: A 56-year-old female with a medical history of hypertension, epilepsy, asthma, chronic hepatitis C, and nasal polyps initially presented to the emergency department (ED) for dysuria and shortness of breath. Urine cultures and ANCA were negative, she followed up with nephrology outpatient who recommended renal biopsy due to increasing hematuria and proteinuria. She returned to the ED one month later with weight loss, arthralgias, diarrhea, hemoptysis, elevated troponins, and oliguria. She was discharged with steroids and her hydralazine was discontinued due to concern for drug-induced lupus. Her repeat ANCA came back positive, she returned to the hospital. She was anemic requiring transfusion, in hypertensive urgency with severe acute kidney injury, requiring oxygen, and had likely diffuse alveolar hemorrhage on imaging. Renal biopsy supported a diagnosis of EGPA.
Discussion: ANCA positivity is a hallmark of EGPA. Unfortunately, some cases of EGPA present with a negative ANCA which can be falsely reassuring of disease absence. Awareness of this irregularity allows the clinician to keep EGPA on the differential despite a negative ANCA. To overcome this, early biopsy permits prompt therapy and potential reduction of morbidity and mortality.