BACKGROUND: The prevalence of acute renal infarction (ARI) in Japan remains unclear. We describe the clinical features and renal prognosis of ARI in Japanese patients. METHODS: This single-center, retrospective, observational study included 33 patients with newly diagnosed ARI (2009-2013). Their clinical features and long-term renal outcomes were evaluated. RESULTS: The prevalence of ARI among emergency room patients was 0.013 %. The incidence of ARI among in-patients was 0.003 % (mean age 71.9 ± 13.4 years; men 63 %). Enhanced computed tomography or renal isotope scans were obtained to diagnose ARI. ARI involved the left kidney in 70 %, right kidney in 18 %, and both kidneys in 12 % of patients. Four cases had splenic infarction, and 70 % of patients had atrial fibrillation. We noted abdominal or flank pain in 66 %, fever (>37.6 °C) in 36 %, and nausea/vomiting in 6 % of patients. The white blood cell count, and levels of lactate dehydrogenase and C-reactive protein peaked at 2-4 days after onset. Acute kidney injury due to ARI occurred in 76 % of patients. The estimated glomerular filtration rate decreased to ~70 % and recovered to ~80 % of the original value after 1 year. The mortality rates were 9 and 15 % at 1 month and 1 year, respectively. CONCLUSIONS: We determined the prevalence of ARI among emergency room patients, its incidence among in-patients, and short-term and long-term mortality. The majority of ARI cases were of cardiac origin, and the others were due to trauma or systemic thrombotic disease. Clinicians should recognize ARI as a fatal arterial thrombotic disease.
BACKGROUND: The prevalence of acute renal infarction (ARI) in Japan remains unclear. We describe the clinical features and renal prognosis of ARI in Japanese patients. METHODS: This single-center, retrospective, observational study included 33 patients with newly diagnosed ARI (2009-2013). Their clinical features and long-term renal outcomes were evaluated. RESULTS: The prevalence of ARI among emergency room patients was 0.013 %. The incidence of ARI among in-patients was 0.003 % (mean age 71.9 ± 13.4 years; men 63 %). Enhanced computed tomography or renal isotope scans were obtained to diagnose ARI. ARI involved the left kidney in 70 %, right kidney in 18 %, and both kidneys in 12 % of patients. Four cases had splenic infarction, and 70 % of patients had atrial fibrillation. We noted abdominal or flank pain in 66 %, fever (>37.6 °C) in 36 %, and nausea/vomiting in 6 % of patients. The white blood cell count, and levels of lactate dehydrogenase and C-reactive protein peaked at 2-4 days after onset. Acute kidney injury due to ARI occurred in 76 % of patients. The estimated glomerular filtration rate decreased to ~70 % and recovered to ~80 % of the original value after 1 year. The mortality rates were 9 and 15 % at 1 month and 1 year, respectively. CONCLUSIONS: We determined the prevalence of ARI among emergency room patients, its incidence among in-patients, and short-term and long-term mortality. The majority of ARI cases were of cardiac origin, and the others were due to trauma or systemic thrombotic disease. Clinicians should recognize ARI as a fatal arterial thrombotic disease.