Yoo Jin Lee

This report presents radiologic changes after clinical improvement in a patient with acute interstitial nephritis (AIN). A 45-year-old female patient was referred for decreased renal function. Eight months prior, she had undergone hysterectomy and received chemotherapy. At the start of chemotherapy, her baseline creatinine level was 0.55 mg/dL, which rose to 1.46 mg/dL. Multiple imaging modalities performed when decreased renal function was observed revealed bilateral renal enlargement with increased cortical attenuation on computed tomography (CT), cortical hyperechogenicity on ultrasonography, and diffusion restriction in the renal cortices on magnetic resonance imaging. A renal biopsy was performed, and AIN was diagnosed. Follow-up laboratory tests showed that kidney function had improved to normal levels, and CT at that time showed a reduction in the size of both kidneys. Radiologic changes can serve as clues for the diagnosis of AIN. This is the first report to confirm radiological changes after the clinical improvement of AIN, thereby providing novel information about the course of AIN.

Background: This study aimed to investigate differences in intrinsic prefrontal functional connectivity according to the presence of cognitive impairment in patients with end-stage renal disease (ESRD) using functional near-infrared spectroscopy (fNIRS). Methods: We prospectively enrolled 37 patients with ESRD who had been undergoing hemodialysis for more than 6 months and had no history of neurological or psychiatric disorders. All patients with ESRD underwent the Korean version of the Montreal Cognitive Assessment (MoCA-K) to assess cognitive function. The NIRSIT Lite device (OBELAB Inc.) was used to acquire fNIRS data, and the NIRSIT Lite Analysis Tool program was used to process the data and generate a functional connectivity matrix. We obtained functional connectivity measures by applying graph theory to the connectivity matrix using the BRAPH (brain analysis using graph theory) program. Results: Of the 37 patients with ESRD, 23 had cognitive impairment, whereas 14 patients showed no cognitive impairment. Intrinsic prefrontal functional connectivity was significantly different between groups. Network measures of strength, global efficiency, and mean clustering coefficient were lower in ESRD patients with cognitive impairment than in those without cognitive impairment (4.458 vs. 5.129, p = 0.02; 0.397 vs. 0.437, p = 0.03; and 0.316 vs. 0.421, p = 0.003; respectively). There were no significant correlations between MoCA-K scores and clinical characteristics. Conclusion: We demonstrated a significant association between cognitive function and intrinsic prefrontal functional connectivity in patients with ESRD. ESRD patients with cognitive impairment have reduced connectivity and segregation in the prefrontal brain network compared to those without cognitive impairment.

End-stage kidney disease (ESKD) patients undergoing hemodialysis experience diverse neurological complications. This study investigated prefrontal cerebral blood volume (CBV) and cerebral blood flow (CBF) during hemodialysis using functional near-infrared spectroscopy (fNIRS) to analyze cerebral hemodynamic changes. ESKD patients undergoing maintenance hemodialysis without a history of neurological disorders were enrolled prospectively. The fNIRS data were collected using a NIRSIT Lite device. The fNIRS values were recorded three times for each patient: before the start of hemodialysis (pre-HD), 1 h after the start of hemodialysis (mid-HD), and after the end of hemodialysis (post-HD). The average changes in oxy-hemoglobin (HbO₂), deoxy-hemoglobin (HbR), total hemoglobin (HbT, calculated as HbO₂ + HbR) concentrations, and in hemoglobin concentration difference (HbD, calculated as HbO₂ - HbR) were analyzed. We then compared the differences in changes in HbO₂, HbR, HbT, and HbD according to the hemodialysis period. Thirty hemodialysis patients were analyzed. The change in HbO₂, HbT, and HbD levels showed significant differences according to the hemodialysis period. Between the pre-HD and post-HD periods, there were significant differences in changes in HbO₂ (0.005 ± 0.001 µM vs. 0.015 ± 0.004 µM, p = .046) and HbT (0.006 ± 0.001 µM vs. 0.016 ± 0.008 µM, p = .029). Additionally, between pre-HD and post-HD periods, HbD tended to increase (0.005 ± 0.001 µM vs. 0.014 ± 0.004 µM, p = .094). We demonstrated that during one hemodialysis session, the relative change in prefrontal CBV increased post-HD compared with pre-HD. These results are expected to help understanding the mechanisms underlying the effects of hemodialysis on brain function.

Patients undergoing maintenance dialysis have a higher mortality rate associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and response rates to vaccination against SARS-CoV-2 vary from 29.6% to 96.4% in such patients. This study aimed to assess the immunogenicity of SARS-CoV-2 vaccination in Korean patients undergoing dialysis. We enrolled 70 SARS-CoV-2-vaccinated patients undergoing dialysis, with 11 healthcare workers serving as healthy control subjects. Thirty-two patients had received a third vaccination, whereas 38 had received 2 vaccinations. The healthy control subjects completed the second vaccination. Immunoglobulin G (IgG) antibodies targeting the receptor-binding domain of the S1 subunit of the SARS-CoV-2 spike protein were measured The vaccination responder rates were 86% (37/43), 96% (26/27), and 91% (10/11) in the patients undergoing hemodialysis and peritoneal dialysis and healthy controls, respectively. IgG antibody levels were significantly higher when a third dose was administered, independent of the type of vaccine or the time interval between vaccination and the subsequent blood sampling date. When a third dose of vaccine was administered, there was no difference in IgG antibody levels between those receiving cross-vaccination or a single vaccine. There was no significant difference in IgG antibodies between healthy controls and patients undergoing dialysis. Patients on dialysis exhibited a sufficient antibody-related response to vaccination against SARS-CoV-2, even in those receiving cross-vaccination, and the antibody titer was higher after a third vaccination. Therefore, it is necessary to administer a third vaccine dose to Korean patients undergoing dialysis.

Posterior reversible encephalopathy syndrome (PRES) is a rare condition manifested by inflammation in certain areas of the brain. Rhabdomyolysis with acute kidney injury (AKI) complicated by PRES is rarely reported. A 26-year-old female presented with neurological symptoms, high blood pressure, and AKI. Her symptoms improved with blood pressure control, anticonvulsant drug medications, and renal replacement therapy. This case demonstrates that PRES should be considered in the differential diagnosis of patients who have rhabdomyolysis with AKI accompanied by neurological symptoms, including headaches and convulsions.

Background: Copeptin is the carboxyl-terminal part of the vasopressin precursor protein, and its concentration is an independent predictor of the onset of chronic kidney disease and a rapid decline in the glomerular filtration rate. The glomerular filtration rate is regarded as the best indicator of kidney transplant function and is a predictor of graft and patient survival. We investigated the clinical significance of copeptin as an early predictor of renal graft dysfunction in renal transplant recipients.Methods: We measured serum creatinine, cystatin C, and copeptin concentrations in renal transplant recipients on the day of their operation, as well as on postoperative days 3, 7, 30, and 365. Acute rejection was defined as a sudden decrease in renal function accompanied by histological changes.Results: Eight renal transplant recipients were enrolled in the study from July 2018 to December 2019. Four patients experienced histologically confirmed transplant rejection. All four cases involved acute T-cell rejection. No significant correlation was found between the copeptin level and the presence or absence of rejection at any time point. In subgroup analyses, changes in creatinine, the estimated glomerular filtration rate, cystatin, and copeptin did not show statistical significance.Conclusions: We anticipated that copeptin would be useful to identify individuals at high risk of transplant rejection; however, our study failed to show an association. Further research will be needed to overcome the limitations of this study.

Background: Postoperative acute kidney injury (AKI), which increases the risk of postoperative morbidity and mortality, poses a major concern to surgeons. We conducted this study to analyze the risk factors associated with the occurrence of AKI after orthopedic surgery. Methods: This was a retrospective study that included 351 patients who underwent total hip or knee replacement surgery at Inje University Haeundae Paik Hospital between January 2012 and December 2016. Results: AKI occurred in 13 (3.7%) of the 351 patients. The patients' preoperative estimated glomerular filtration rate (eGFR) was 66.66 ± 34.02 mL/min/1.73 m 2 in the AKI group and 78.07 ±21.23 mL/min/1.73 m 2 in the non-AKI group. The hemoglobin levels were 11.21 ±1.65 g/ dL in the AKI group and 12.39 ±1.52 g/dL in the non-AKI group. Hemoglobin level was related to increased risk of AKI (odds ratio [OR], 0.13; 95% confidence interval [CI], 0.02-0.68; p= 0.016). Administration of crystalloid or colloid fluid alone and the perioperative amount of fluid did not show any significant relationship with AKI. Further analysis of the changes in eGFR was performed using a cutoff value of 7.54. The changes in eGFR were significantly related to decreased risk of AKI (OR, 0.74; 95% CI, 0.61-0.89; p= 0.002). Conclusion: Renal function should be monitored closely after orthopedic surgery if patients have chronic kidney disease and low hemoglobin level. Predicting the likelihood of AKI occurrence, early treatment of high-risk patients, and monitoring perioperative laboratory test results, including eGFR, will help improve patient prognosis.

Our previous study demonstrated that patients with end-stage renal disease had decreased structural and functional brain connectivity, and there was a significant association between brain connectivity and cognitive function. The aim of this study was to evaluate the alterations of structural and functional connectivity using graph theoretical analysis in neurologically asymptomatic patients with relatively early-stage chronic kidney disease (CKD). We enrolled 18 neurologically asymptomatic patients with early CKD and 28 healthy controls. All the subjects underwent diffusion-tension imaging and resting functional magnetic resonance imaging. We calculated structural and functional connectivity based on diffusion-tension imaging and resting functional magnetic resonance imaging using a graph theoretical analysis. Then, we investigated differences of structural and functional connectivity between the CKD patients and the healthy controls. All the measures of structural connectivity were significantly different between the patients with CKD and healthy controls. The global efficiency, local efficiency, mean clustering coefficient, and small-worldness index were decreased, whereas the characteristic path length was increased in the patients with CKD compared with healthy controls. The structural betweenness centrality of the left calcarine and right posterior cingulum was also significantly different from that in healthy participants. However, all the measures of global functional connectivity in patients with CKD were not different from those in healthy controls. In patients with CKD, the functional betweenness centrality of the right insular cortex, right occipital pole, and right thalamus was significantly different from that in healthy participants. There are significant alterations of the global structural connectivity between the patients with CKD and the healthy subjects, whereas the global functional connectivity of the brain network is preserved. We find that the efficiency of the structural brain network is decreased in the patients with CKD.

Park BS, et al. J Clin Neurol. 2020 Jul;16(3):390-400. https://doi.org/10.3988/jcn.2020.16.3.390

Objective: We evaluated global topology and organization of regional hubs in the brain networks and microstructural abnormalities in the white matter of patients with reflex syncope.Methods: Twenty patients with reflex syncope and thirty healthy subjects were recruited, and they underwent diffusion tensor imaging (DTI) scans. Graph theory was applied to obtain network measures based on extracted DTI data, using DSI Studio. We then investigated differences in the network measures between the patients with reflex syncope and the healthy subjects. We also analyzed microstructural abnormalities of white matter using tract‐based spatial statistics analysis (TBSS).Results: Measures of global topology were not different between patients with reflex syncope and healthy subjects. However, in reflex syncope patients, the strength measures of the right angular, left inferior frontal, left middle orbitofrontal, left superior medial frontal, and left middle temporal gyrus were lower than in healthy subjects. The betweenness centrality measures of the left middle orbitofrontal, left fusiform, and left lingual gyrus in patients were lower than those in healthy subjects. The PageRank centrality measures of the right angular, left middle orbitofrontal, and left superior medial frontal gyrus in patients were lower than those in healthy subjects. Regarding the analysis of the white matter microstructure, there were no differences in the fractional anisotropy and mean diffusivity values between the two groups.Conclusions: We have identified a reorganization of network hubs in the brain network of patients with reflex syncope. These alterations in brain network may play a role in the pathophysiologic mechanism underlying reflex syncope.