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)(2010)(2011)(2012)(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 inpatients, 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 aim of this study was to investigate specific bleeding volume after percutaneous renal biopsy (PRB) and the correlation between bleeding volume and clinical parameters. Methods: A retrospective study of 252 consecutive patients (153 male patients and 99 female patients) who underwent PRB at the Department of Nephrology, Japanese Red Cross Ishinomaki Hospital, between July 2013 and January 2016 was conducted. PRB was performed under ultrasound guidance using an automated spring-loaded biopsy device and a 16-cm, 16-gauge needle. Patients underwent computed tomography (CT) the day after PRB. Bleeding volume after PRB was evaluated using reconstructed CT data. Results: The median bleeding volume after PRB was 38 mL (25th–75th percentile, 18–85 mL), with ≥4 punctures identified as a risk factor for massive bleeding. The incidence rates of macrohematuria, transient hypotension and bladder obstruction were 14.3, 8.7 and 4.7%, respectively. Post-PRB blood transfusion and intervention were required in 4.7 and 0.8% of patients, respectively. Conclusion: Although it is difficult to assess the risk for massive bleeding prior to PRB, we do provide evidence of a specific increased risk with ≥4 puncture attempts, and recommend careful follow-up of these patients.

IntroductionLate referral to a nephrologist, the type of vascular access, nutritional status, and the estimated glomerular filtration rate (eGFR) at the start of hemodialysis (HD) have been reported as independent risk factors of survival for patients who begin HD. The aim of this study was to clarify the influence of the HD-free interval from the time of an eGFR of 10 ml/min per 1.73 m2 (IGFR10-HD) on patient outcome.MethodsWe enrolled 124 patients aged older than 20 years who had HD initiated in a general hospital. The predictive factor was the HD-free IGFR10-HD. The primary outcome was the relationship of the HD-free interval on death or the onset of a cardiovascular event. Survival analysis was performed using the Cox regression model.ResultsThe median IGFR10-HD was 159 days (range: 2–1687 days). The median eGFR at the initiation of HD was 5.48 ml/min per 1.73 m2. Sixty-seven of 124 patients (54.0%) reached the primary outcome. Of these, 29 died and 38 experienced a cardiovascular event. In univariate analysis, older age, a history of cardiovascular disease, nephrologic care for <6 months, higher modified Charlson comorbidity index score, poor performance status, temporary catheter, edema, diabetic retinopathy, and nonuse of erythropoiesis-stimulating agent were statistically related to the primary outcome. The unadjusted hazard ratio per log-transformed IGFR10-HD was 0.393 (95% confidence interval [CI]; 0.244−0.635; P < 0.001) and the hazard ratio adjusted for confounding factors was 0.507 (95% CI: 0.267−0.956; P = 0.036).DiscussionA longer HD-free IGFR10-HD was associated with a lower risk of death or a cardiovascular event. The interval could be considered an independent prognostic factor for outcomes in patients on HD.

Background: Sarcoidosis is a multi-system disorder characterized by noncaseating epitheloid granuloma in multiple organs. However, granulomatous interstitial nephritis in the absence of extrarenal renal lesions is very rare. Case presentation: A 64-year-old male presented with a weight loss of 10 kg and an increase in serum creatinine from 1.1 to 4.8 mg/dl over a 1-year period. At admission, no proteinuria or hematuria was found, although serum creatinine was 5.1 mg/dl and was associated with slight increases in serum angiotensin converting enzyme and calcium levels. Renal biopsy revealed granulomatous interstitial nephritis with noncaseating epitheloid cells. The patient was diagnosed with sarcoidosis, although no extrarenal sarcoid lesion was found. Oral prednisolone was effective, with normalization of serum creatinine levels 2 weeks later. A review of the literature showed that isolated granulomatous renal sarcoidsosis preferentially affected elderly males, and their serum angiotensin converting enzyme levels were normal or mildly increased in many cases. Conclusions: This paper describes a rare case of isolated renal sarcoidosis with acute granulomatous interstitial nephritis. This case and a relevant review of the literature demonstrate that sarcoid granulomatous interstitial nephritis should be considered as one of differential diagnoses in elderly male patients with suspected tubulointerstitial nephritis irrespective of angiotensin converting enzyme levels.