P1_69 Interstitial Lung Disease as a Possible Etiology of ANCA-associated Vasculitis: A Case Report

Abstract

A 72-year-old woman was admitted for rapidly progressive glomerulonephritis. Three years previously, she was diagnosed with interstitial lung disease at another hospital. At that time, a dipstick test showed hematuria (1+) and proteinuria (-), but she tested negative for myeloperoxidase anti-neutrophilic cytoplasmic antibodies (MPO-ANCA)( < 1.0 U/mL; normal, < 3.5 U/mL). As respiratory symptoms were absent, she was followed-up with chest radiography. Ten months previously, she developed polyarthralgia and was diagnosed with rheumatoid arthritis following a positive result for rheumatoid factor. Testing for MPO-ANCA was again ordered, and showed positive conversion at 9.0 U/mL. Therapy with tacrolimus and celecoxib alleviated her symptoms. Her medical history included cholecystectomy and lumbar compression fracture, and her medication regime comprised tacrolimus, celecoxib, famotidine, and sulfamethoxazole/trimethoprim. Laboratory tests indicated acute renal failure with active urinary sediment: BUN, 42.2 mg/dL; creatinine, 4.23 mg/dL; urinary protein, 2+; and urinary erythrocytes, > 300/high-power field. The level of MPO-ANCA was highly elevated at 71.2 U/mL. Renal biopsy showed necrotizing crescentic glomerulonephritis. Our experience indicates that interstitial lung disease may be a cause, rather than a result, of ANCA-associated vasculitis.