A case of renal vein thrombosis associated with autoimmune hemolytic anemia and eosinophilic granulomatous polyangiitis

Only a few cases of renal vein thrombosis (RVT) occurring in patients with vasculitis have been reported. RVT associated with vasculitis and hemolytic anemia has not been reported yet. We describe here a patient with RVT complicated by pulmonary embolism, autoimmune hemolytic anemia, and eosinophilic granulomatous polyangiitis. A 69-year-old Japanese man who had been treated with corticosteroids was referred to our department for severe proteinuria (4.32 g/gCr). Abdominal ultrasonography showed bilateral RVT, and contrast-enhanced computed tomography showed bilateral pulmonary embolism. Therefore, the patient was diagnosed with RVT complicated by pulmonary embolism. Anticoagulation therapy with heparin followed by apixaban was started. Thereafter, the D-dimer concentration decreased from 8.3 to 1.2 μg/mL, and urinary protein excretion improved to 0.62 g/gCr. Renal function was unchanged with an estimated glomerular filtration rate of 68.8 mL/minute/1.73 m(2). The thrombi in both renal veins and pulmonary arteries gradually regressed. Clinicians should be aware of this complication when worsening proteinuria is observed during steroid therapy in patients with autoimmune hemolytic anemia and eosinophilic granulomatous polyangiitis.