Abstract
A 69-year-old Japanese man developed abdominal pain, purpura, proteinuria, and hematuria while receiving treatment for pulmonary tuberculosis. A skin biopsy revealed IgA-positive leukocytoclastic vasculitis, and a renal biopsy showed IgA-positive mesangial proliferative glomerulonephritis with crescent formation. Based on these findings, we diagnosed IgA vasculitis with nephritis (IgAVN) and initiated treatment. The patient's abdominal symptoms improved following factor XIII supplementation and corticosteroids. Corticosteroids were administered, and after 5 months, the proteinuria was in complete remission. Although IgAVN often follows a prior infection, it is rarely complicated by tuberculosis. In this case, staining for galactose-deficient IgA1, which is specifically positive in IgA nephropathy and IgAVN, was positive. Nephritis-associated plasmin receptor staining was also positive, suggesting some involvement of infectious glomerulonephritis. Therefore, the patient was considered to have IgAVN associated with pulmonary tuberculosis. In adult-onset cases, IgAVN is often severe. This patient was presented with adult-onset nephrosis and International Study of Kidney Disease in Children grade IIIb IgAVN, suggesting a poor prognosis. Therefore, we immediately initiated treatment with corticosteroids, factor XIII supplementation, a renin-aldosterone-system inhibitor, and a sodium-glucose cotransporter 2 inhibitor. The patient recovered uneventfully with no worsening of tuberculosis.