Neurological complications in chronic kidney disease patients

Depression Symptoms Do Not Worsen over Time in a Cohort of Patients with CKD: The Brain in Kidney Disease Study

Key Points

In a cohort of individuals with CKD and a high prevalence of depression and antidepressant use, depression symptoms did not worsen over time. This finding was consistent across all levels of eGFR impairment, including those who initiated dialysis. There were no differences in changes in depressive symptoms over time between individuals with CKD of any stage and those without CKD.

Background

The prevalence of depression is high in the CKD (20%–40%) and dialysis (30%–50%) populations. Less is known about how depressive symptoms change over time in patients with CKD.

Methods

Participants in the Brain in Kidney Disease cohort study completed a depressive symptom questionnaire (Patient Health Questionnaire-9 [PHQ-9]) and serum creatinine testing annually. We used linear mixed-effects models to examine changes in PHQ-9 scores over time and compared rates of change between participants with different ranges of eGFR impairment and those with normal eGFR.

Results

At baseline, 147 participants had normal eGFR, 424 had impaired eGFR without dialysis dependence, and 31% reported a diagnosis of depression, with a mean baseline PHQ-9 score of 4.3. Participants were followed for up to 5 years. After adjustment for factors associated with depression, mean PHQ-9 scores decreased (improved) by 0.25 points per year (95% confidence interval [CI], 0.07 to 0.42) among participants with normal eGFR (>60 ml/min per 1.73 m2) and by 0.35 points (95% CI, 0.14 to 0.56), 0.30 points (95% CI, 0.13 to 0.46), and 0.42 points (95% CI, 0.06 to 0.77) among participants with eGFR 45–59 ml/min per 1.73 m2, with eGFR 30–44 ml/min per 1.73 m2, and who developed dialysis dependence, respectively. PHQ-9 scores among participants with eGFR <30 ml/min per 1.73 m2 did not change significantly. We did not observe any statistically significant differences in mean change in PHQ-9 scores between participants with any degree of eGFR impairment and those with normal eGFR, nor between participants with dialysis dependence and those with eGFR of ≤15 ml/min per 1.73 m2. Participants with a PHQ-9 score ≥5 had 80% greater odds of immediate study attrition than participants with a PHQ-9 score of 0–4.

Conclusions

The mean PHQ-9 scores of participants were largely stable over time, and we observed no differences in change in PHQ-9 scores between those with impaired eGFR and those with normal eGFR.

Cognitive impairment in chronic kidney disease: role of brain imaging, functional imaging, electroencephalography, cerebrospinal fluid biomarkers and sensors

Chronic kidney disease is associated with cognitive impairment although the underlying mechanisms are still not fully understood. Characterization and efficient monitoring of the cognitive impact of kidney disease and ensuing therapies are critical for the accurate clinical management of patients. A vast array of imaging modalities, biomarkers, and sensors have shown relevance for the assessment of cognitive impairment. Knowing the potential and limitations of these paraclinical techniques is a necessary condition to improve the understanding of this phenomenon and to design monitoring protocols and guidelines applicable to this clinical population. The goal of this review is to provide an overview of current imaging modalities and biomarker sources available to the community, for the benefit of the research and clinical community.

Research progress on the kidney-gut-brain axis in brain dysfunction in maintenance hemodialysis patients

Maintenance hemodialysis (MHD) has become the primary renal replacement therapy for patients with end-stage renal disease. The kidney-gut-brain axis represents a communication network connecting the kidney, intestine and brain. In MHD patients, factors such as uremic toxins, hemodynamic changes, vascular damage, inflammation, oxidative stress, and intestinal dysbiosis in MHD patients refers to a range of clinical syndromes, including brain injury, and is manifested by conditions such as white matter disease, brain atrophy, cerebrovascular disease, cognitive impairment, depression, anxiety, and other behavioral or consciousness abnormalities. Numerous studies have demonstrated the prevalence of these brain disorders in MHD patients. Understanding the mechanisms of brain disorders in MHD patients, particularly through the lens of kidney-gut-brain axis dysfunction, offers valuable insights for future research and the development of targeted therapies. This article reviews the brain dysfunction associated with MHD, the impact of the kidney-brain axis, intestinal barrier damage, gut microbiota dysbiosis caused by MHD, and the role of the gut-brain axis in brain dysfunction.

Differences in microorganism profile in periprosthetic joint infections of the hip in patients affected by chronic kidney disease

BACKGROUND

Patients affected by chronic kidney disease (CKD) are at increased risk of periprosthetic joint infection (PJI) after total hip arthroplasty (THA). This patient population has a higher risk of recurrent infections and hospitalization. The aim of this study is to compare the profile of microorganisms in patients with CKD and PJI of the hip versus controls and to individuate potentially unusual and drug-resistant microorganisms among the causative bacteria.

MATERIALS AND METHODS

A total of 4261 patients affected by PJI of the hip were retrospectively studied. Patients affected by CKD in this population were identified and compared with a control group of patients with PJI but without CKD. Data on patient characteristics and comorbidities were collected. The microorganisms responsible for PJI were identified and compared between both groups.

RESULTS

The CKD group included 409 patients, 54.3% male, mean age of 73.8 ± 8.9 years, a higher body mass index (BMI) than the general population (29.88 ± 5.90 kg/m2), and higher age-adjusted CCI of 6.15 ± 2.35. Overall, 70 different isolates of microorganisms were identified, including 52 Gram-positive spp., 28 Gram-negative spp., 3 fungi, and 1 mycobacterium. Polymicrobial infections were more common in CKD group than controls (47.9% versus 30.9%; p < 0.0001). Staphylococcus spp. were the most common bacteria in both groups, followed by Gram-negative Enterobacteriaceae and Streptococcus spp. CKD group showed a higher risk of developing infections caused by Staphylococcus aureus (p = 0.003), Gram-negative bacteria, and Candida (p = 0.035).

CONCLUSIONS

Renal failure exposes patients who undergo THA to PJI caused by microorganisms that are potentially more drug resistant, leading to a higher risk of treatment failure. Knowing in advance the different microorganism profiles could help to plan a different surgical strategy.

Regulation of the blood-brain barrier function by peripheral cues in health and disease

The blood-brain barrier (BBB) is formed by microvascular endothelial cells which are ensembled with pericytes, astrocytes, microglia and neurons in the neurovascular unit (NVU) that is crucial for neuronal function. Given that the NVU and the BBB are highly dynamic and regulated structures, their integrity is continuously challenged by intrinsic and extrinsic factors. Herein, factors from peripheral organs such as gonadal and adrenal hormones may influence vascular function also in CNS endothelial cells in a sex- and age-dependent manner. The communication between the periphery and the CNS likely takes place in specific areas of the brain among which the circumventricular organs have a central position due to their neurosensory or neurosecretory function, owing to physiologically leaky blood vessels. In acute and chronic pathological conditions like liver, kidney, pulmonary disease, toxins and metabolites are generated that reach the brain via the circulation and may directly or indirectly affect BBB functionality via the activation of the immunes system. For example, chronic kidney disease (CKD) currently affects more than 840 million people worldwide and is likely to increase along with western world comorbidities of the cardio-vascular system in continuously ageing societies. Toxins leading to the uremic syndrome, may further lead to neurological complications such as cognitive impairment and uremic encephalopathy. Here we summarize the effects of hormones, toxins and inflammatory reactions on the brain vasculature, highlighting the urgent demand for mechanistically exploring the communication between the periphery and the CNS, focusing on the BBB as a last line of defense for brain protection.

Combinatorial lipidomics and proteomics underscore erythrocyte lipid membrane aberrations in the development of adverse cardio-cerebrovascular complications in maintenance hemodialysis patients

Patients on maintenance hemodialysis exhibit a notably higher risk of cardio-cerebrovascular complications that constitute the major cause of death. Preceding studies have reported conflicting associations between traditional lipid measures and clinical outcome in dialysis patients. In this prospective longitudinal study, we utilized quantitative lipidomics to elucidate, at molecular resolution, changes in lipidome profiles of erythrocyte and plasma samples collected from maintenance hemodialysis patients followed up for 86 months (≈7 years). Primary outcome was defined as cardiovascular-related deaths or new-onset cardio-cerebrovascular events. Cox regression model uncovered plasma/erythrocyte lipids associated with incident cardio-cerebrovascular events in the erythrocyte cohort (n = 117 patients, 37 events) and plasma cohort (n = 45 patients, 11 events), respectively. Both the erythrocyte lipid panel [PA 40:5, PI 34:2, PC 42:6, AUC = 0.83] and plasma lipid panel [PC O-34:1, GM3 18:1; O2/25:0, TG 44:1(16:1_28:0), AUC = 0.94] significantly improved the prediction of cardio-cerebrovascular-related outcome compared to the base model comprising age, sex and dialysis vintage alone. Our findings underscore the pathophysiological significance of anionic phospholipid accretion in erythrocytes in the development of cardio-cerebrovascular complications in dialysis patients. In particular, distorted membrane lipid asymmetry leads to compromised membrane deformability, aberrant cell-cell interactions and altered glutathione metabolism in the erythrocytes of high-risk individuals even at relatively early stage of hemodialysis. Our findings thus underscore the importance of maintaining the RBC pool to lower the risk of cardio-cerebrovascular complications in dialysis patients.

Hypocalcemia-induced seizures in a peritoneal dialysis (PD) patient: A case report

Key Clinical Message

A thorough evaluation is necessary for seizures caused by hypocalcemia, both during the patient's presentation and following their recovery from the postictal seizure episode. This is because the underlying cause of hypocalcemia must be ruled out in order to ensure the best possible clinical outcome from calcium and vitamin D therapy.

Abstract

Patients with multiple systemic issues, including neurological involvement and seizure development, are not uncommon among nephrologists. Both the central and peripheral neural systems can be impacted by kidney disease. The main symptoms are myopathy, cranial or peripheral neuropathy, cognitive impairment, and seizures. A 22-year-old female with an unusual medical history who had been known to have end-stage kidney disease (ESKD) for a year and regularly had CAPD (continuous ambulatory peritoneal dialysis) suffered from two episodes of tonic-colonic seizures 2 weeks apart. On physical examination, symptoms of tongue biting, decreased vision in the left eye, and mild bilateral pulmonary air entry were notable. Upon examination, there was evidence of severe hypocalcemia, hyponatremia, a high renal profile (urea and creatinine), anemia, and a severe vitamin D deficiency. Her peritoneal dialysis (PD) prescription was reviewed, her seizures ceased, and she was released from the hospital after the hypocalcemia was treated with intravenous calcium and high doses of vitamin D. The issue of hypocalcemic seizures should be carefully evaluated both at the presentation and after the patient recovers from the postictal stage. By following this, seizure episodes can be prevented with good success if patients strictly adhere to the medication for which they are responsible.

Beyond Numbers: How Biochemical Parameters Can Predict Outcomes in Chronic Kidney Disease Patients on Maintenance Hemodialysis

Introduction The treatment and management of patients undergoing maintenance hemodialysis (MHD) requires constant evaluation through the assessment of biochemical markers. This is necessary for treatment, to prevent progression to complications such as mineral bone disease, and to improve quality of life. We aimed to study the biochemical profile of patients with chronic kidney disease (CKD) grades 4 and 5 on MHD, identify markers altered due to different etiologies, duration of illness, and duration of hemodialysis, and create a panel of markers that can be useful in planning better management. Methods All consecutive patients attending the dialysis unit of ESIC Super Speciality Hospital with CKD grade 4 or grade 5 on MHD between 2019 and 2020 were recruited. A detailed clinical history and demographic profile were taken, and blood samples were collected from the patients during follow-up visits in plain and EDTA (ethylenediamine tetraacetic acid) tubes for analysis. Results A total of 312 patients (22.1% females and 77.9% males.) with a mean age of 49.74 ± 11.49 years were recruited. In the study population, diabetic nephropathy (DN) (17%) and hypertensive nephropathy (48.7%) were the two most prevalent causes of CKD. The majority (64%) of the patients were on MHD three times a week. The range of estimated glomerular filtration rate (eGFR) (ml/min/1.73 m2) at the time of initiation of MHD was 2.9-26.8 according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. The mean duration of MHD was 51.58 months, with a mortality rate of 5.9% during the follow-up period (3-108 months). Conclusion Optimal selection and combination of biochemical tests will help in ascertaining the adequacy of management, progress of disease, or complications in MHD patients. This in turn will help guide the clinicians in effectively using these markers in their day-to-day practice.

Prevention of Chronic Kidney Disease and Its Complications in Older Adults

In an era marked by a global demographic shift towards an aging society, there is a heightened prevalence of chronic kidney disease (CKD) among older adults. The burden of CKD spans from kidney-related complications to impacting psychological well-being, giving rise to depressive symptoms and caregiver burnout. This article delves into CKD prevention strategies within the context of aging, contributing to the discourse by exploring its multifaceted aspects. The prevention of CKD in the older adults necessitates a comprehensive approach. Primary prevention is centered on the modification of risk factors, acknowledging the intricate interplay of various comorbidities. Secondary prevention focuses on early CKD identification. Tertiary prevention aims to address factors contributing to CKD progression and complications, emphasizing the importance of timely interventions. This comprehensive strategy aims to enhance the quality of life for individuals affected by CKD, decelerating the deterioration of functional status. By addressing CKD at multiple levels, this approach seeks to effectively and compassionately care for the aging population.

A new approach for cognitive impairment pattern in chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is associated with an elevated risk of neurocognitive disorders (NCDs). It remains unclear whether CKD-related NCDs have a specific cognitive pattern or are earlier-onset phenotypes of the main NCDs (vascular NCDs and Alzheimer's disease).

METHODS

We used the Mini Mental State Examination score (MMSE) to assess cognitive patterns in 3003 CKD patients (stage 3-4) followed up over 5 years in the Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort. After normalizing MMSE scores to a 0-to-100 scale, the associations between the baseline estimated glomerular filtration rate (eGFR, using the Chronic Kidney Disease Epidemiology Collaboration creatinine formula) and changes in each MMSE domain score were assessed in linear mixed models.

RESULTS

Patients (age: 67 ± 13 years old; males: 65%, mean eGFR: 33± 12 mL/min/1.73 m2) had a good baseline cognitive functions: the mean MMSE score was 26.9/30 ± 2.9. After adjustment for age, sex, educational level, depression (past or present), cardiovascular risk factors and cerebrovascular disease, a lower baseline eGFR (per 10 mL/min/1.73 m2) was associated with a 0.53-point decrement [P < .001; 95% confidence interval (CI) (-0.98, -0.08)] for orientation, a 1.04-point decrement [P = .03; 95% CI (-1.96, -0.13)] for attention and calculation, a 0.78-point decrement [P = .003; 95% CI (-1.30, -0.27)] for language, and a 0.94-point decrement [P = .02; 95% CI (-1.75, -0.13)] for praxis. Baseline eGFR was not, however, associated with significant changes over time in MMSE domain scores.

CONCLUSION

A lower eGFR in CKD patients was associated with early impairments in certain cognitive domains: praxis, language and attention domains before an obvious cognitive decline. Early detection of NCD in CKD patients must be performed before clinically cognitive decline using preferably tests assessing executive, attentional functions and language, rather than memory tests. This early cognitive screening could lead to a better management of cognitive impairment and their consequences on CKD management.

Associations between Chronic Kidney Disease and Migraine Incidence: Findings from a Korean Longitudinal Big Data Study

While headaches frequently occur in individuals with chronic kidney disease (CKD), there are few statistical evaluations of their connection to migraines in population-based studies. In this nationwide longitudinal follow-up study of Korean health examination data (2002-2019), a total of 15,443 participants with CKD and 61,772 matched controls were enrolled. We applied overlap-weighted Cox proportional hazard regression models to assess hazard ratios, examining the correlation between CKD and the development of migraines. After accounting for various factors, we observed a modest reduction of approximately 11% in the likelihood of migraine occurrence among CKD patients (95% confidence intervals = 0.81-0.97) during the 16-year monitoring period. Subgroup analysis revealed a significant association among specific demographic and health conditions, including individuals aged 70 or older, females, overweight individuals, nonsmokers, and those without hypertension or diabetes. Our research may indicate a potential relationship between CKD and the onset of migraines in Korean adults, suggesting a slight reduction in the probability of the occurrence of migraines among those with CKD. These findings emphasize the need for attentive follow-up and preventive management in individuals without the identified protective factors, particularly in male CKD patients under the age of 70 with hypertension.

Association between cognitive function and skeletal muscle in patients undergoing maintenance hemodialysis

Background

Patients on hemodialysis have a higher burden of cognitive impairment than individuals of the same age in the general population. Studies have found a link between cognition and skeletal muscle function. However, few studies have investigated these associations and the underlying mechanisms in patients on hemodialysis.

Methods

A total of 166 patients on hemodialysis were enrolled in this longitudinal study. Cognitive function was assessed by Montreal Cognitive Assessment (MoCA) scores. Skeletal muscle indicators were evaluated using Inbody S10. Plasma brain-derived neurotrophic factor (BDNF) concentrations were measured by enzyme-linked immunosorbent assay. The primary outcome was a change in the MoCA scores. A mediation analysis was performed to examine the indirect effect of skeletal muscle on cognitive decline through BDNF.

Results

Among the 166 patients, the average age was 49.9 ± 11.2 years. Of these patients with a median follow-up of 1,136 days, 133 participated in the study. We defined MoCA scores decreased by ≥2 points at 3 years from the baseline measurement as cognitive decline (CD). Compared to the cognitively unchanged group, patients with CD had significantly lower fat-free mass, soft lean mass, skeletal muscle mass, and skeletal muscle index (all P<0.05). After adjusting for potential confounders, skeletal muscle indicators were protective predictors of CD. A significant increase in plasma BDNF levels was observed in the CD group. Mediation analysis suggested that BDNF played a mediating role of 20-35% between cognitive impairment and skeletal muscle.

Conclusion

Skeletal muscle is a protective predictor of CD in patients undergoing dialysis. BDNF mediates the relationship between cognitive impairment and skeletal muscle function.

Methodological challenges and biases in the field of cognitive function among patients with chronic kidney disease

Chronic kidney disease (CKD) affects approximately 850 million people globally and is associated with an increased risk of cognitive impairment. The prevalence of cognitive impairment among CKD patients ranges from 30 to 60%, and the link between CKD and cognitive impairment is partially understood. Methodological challenges and biases in studying cognitive function in CKD patients need to be addressed to improve diagnosis, treatment, and management of cognitive impairment in this population. Here, we review the methodological challenges and study design issues, including observational studies' limitations, internal validity, and different types of bias that can impact the validity of research findings. Understanding the unique challenges and biases associated with studying cognitive function in CKD patients can help to identify potential sources of error and improve the quality of future research, leading to more accurate diagnoses and better treatment plans for CKD patients.

The need for prophylactic hemodialysis to protect against nephrogenic systemic fibrosis in patients with end-stage renal disease receiving gadolinium-based contrast agents

BACKGROUND

The risk of gadolinium (Gd)-based contrast agent (GBCA)-induced nephrogenic systemic fibrosis (NSF) in patients with end-stage renal disease (ESRD) and the efficacy of prophylactic hemodialysis (HD) for protection against NSF are not well understood or summarized in the literature.

PURPOSE

To determine the risk for NSF related to frequency and time per dialysis session after Gd-magnetic resonance imaging (MRI) by emphasizing the safety of Gd-MRI in patients with ESRD.

MATERIAL AND METHODS

This retrospective observational study identified all GBCA injections for MRI examinations performed at two tertiary referral hospitals between 2005 and 2020. All clinical data, including dialysis records and medical history, were investigated for each patient through 2021. The end of follow-up coincided with the last hospital visit.

RESULTS

Overall, 1129 patients with ESRD underwent 1461 Gd-MRI scans (41.5% gadoterate, 39.4% gadobutrol, and 7.7% gadoxetate); a total of 958 patients with 1229 (84.1%) examinations underwent HD on the day of the MRI study, within 2.1 ± 2.0 h (range = 0.2-15.7 h) immediately after Gd exposure. In 53.4% of scans, frequent HD had been performed urgently and then twice more on consecutive days to prophylactically avoid NSF. No cases of NSF were identified during the follow-up period (mean = 81.7 ± 50.5 months) regardless of dose of HD.

CONCLUSION

No cases of NSF were reported in 1461 Gd-MRI examinations of 1129 inpatients with ESRD on HD. Our findings support the lack of benefit of frequent prophylactic HD being performed urgently within 4 h of the receipt of GBCA.

Renal and Electrolyte Disorders and the Nervous System

OBJECTIVE

Neurologic complications are a major contributor to death and disability in patients with renal disease. Oxidative stress, endothelial dysfunction, accelerated arteriosclerosis, and uremic inflammatory milieu affect both the central and peripheral nervous systems. This article reviews the unique contributions of renal impairment to neurologic disorders and their common clinical manifestations as the prevalence of renal disease increases in a globally aging population.

LATEST DEVELOPMENT

Advances in the understanding of the pathophysiologic interplay between the kidneys and brain, also referred to as the kidney-brain axis, have led to more widespread recognition of associated changes in neurovascular dynamics, central nervous system acidification, and uremia-associated endothelial dysfunction and inflammation in the central and peripheral nervous systems. Acute kidney injury increases mortality in acute brain injury to nearly 5 times that seen in matched controls. Renal impairment and its associated increased risks of intracerebral hemorrhage and accelerated cognitive decline are developing fields. Dialysis-associated neurovascular injury is increasingly recognized in both continuous and intermittent forms of renal replacement therapy, and treatment strategies for its prevention are evolving.

ESSENTIAL POINTS

This article summarizes the effects of renal impairment on the central and peripheral nervous systems with special considerations in acute kidney injury, patients requiring dialysis, and conditions that affect both the renal and nervous systems.

Baclofen and the Risk of Encephalopathy: A Real-World, Active-Comparator Cohort Study

OBJECTIVE

To quantify the risk of encephalopathy associated with oral baclofen compared with other muscle relaxants-tizanidine or cyclobenzaprine.

PATIENTS AND METHODS

We conducted a new-user, active-comparator study of 2 pairwise cohorts using tertiary health system data from Geisinger Health in Pennsylvania (January 1, 2005, through December 31, 2018). Adults (aged ≥18 years) newly treated with baclofen or tizanidine were included in cohort 1. Adults newly treated with baclofen or cyclobenzaprine were included in cohort 2. Propensity score-based inverse probability of treatment weighting (IPTW) was used to balance the respective cohorts on 45 patient characteristics. Fine-Gray competing risk regression was used to estimate the risk of encephalopathy.

RESULTS

Cohort 1 included 16,192 new baclofen users and 9782 new tizanidine users. The 30-day risk of encephalopathy was higher in patients treated with baclofen vs tizanidine (IPTW incidence rate, 64.7 vs 28.3 per 1000 person-years) with an IPTW subdistribution hazard ratio (SHR) of 2.29 (95% CI, 1.43 to 3.67). This risk persisted through 1 year (SHR, 1.32 [95% CI, 1.07 to 1.64]). Similarly in cohort 2, baclofen vs cyclobenzaprine was associated with a greater risk of encephalopathy at 30 days (SHR, 2.35 [95% CI, 1.59 to 3.48]) that persisted through the first year of treatment (SHR, 1.94 [95% CI, 1.56 to 2.40]).

CONCLUSION

The risk of encephalopathy was greater with baclofen vs tizanidine or cyclobenzaprine use. The elevated risk was apparent as early as 30 days and persisted through the first year of treatment. Our findings from routine care settings may inform shared treatment decisions between patients and prescribers.

Blood–Brain Barrier Biomarkers before and after Kidney Transplantation

Kidney transplantation (KT) may improve the neurological status of chronic kidney disease (CKD) patients, reflected by the altered levels of circulating BBB-specific biomarkers. This study compares the levels of neuron specific enolase (NSE), brain-derived neurotrophic factor (BDNF), neurofilament light chain (NfL), and circulating plasma extracellular vesicles (EVs) in kidney-failure patients before KT and at a two-year follow up. Using ELISA, NSE, BDNF, and NfL levels were measured in the plasma of 74 living-donor KT patients. Plasma EVs were isolated with ultracentrifugation, and characterized for concentration/size and surface protein expression using flow cytometry from a subset of 25 patients. Lower NSE levels, and higher BDNF and NfL were observed at the two-year follow-up compared to the baseline (p < 0.05). Male patients had significantly higher BDNF levels compared to those of females. BBB biomarkers correlated with the baseline lipid profile and with glucose, vitamin D, and inflammation markers after KT. BBB surrogate marker changes in the microcirculation of early vascular aging phenotype patients with calcification and/or fibrosis were observed only in NSE and BDNF. CD31+ microparticles from endothelial cells expressing inflammatory markers such as CD40 and integrins were significantly reduced after KT. KT may, thus, improve the neurological status of CKD patients, as reflected by changes in BBB-specific biomarkers.

Seizures in patients with kidney diseases: a neglected problem?

Nephrologists may encounter many systemic problems in their patients, including involvement of the neurological system and the development of seizures. Seizures are defined as abnormal neurological functions that cause overstimulation of neurons in the cerebral cortex or limbic system. Seizures may be focal or generalized depending on their origin and may have tonic, clonic, tonic-clonic or myoclonic character depending on the level of involvement of the motor movements. Patients with kidney disease may develop seizures due to etiologies seen in the general population (such as intracranial bleeding, cerebrovascular events, tumors, infections and intoxications) or due to kidney-related etiologies (such as uremic encephalopathy, dialysis disequilibrium syndrome and hyponatremia). Management of seizures in kidney patients is challenging for proper determination of the type and dosage of antiepileptic drugs due to varying renal clearances. This review covers the major causes of new-onset seizures in patients with acute kidney injury, electrolyte imbalances, chronic kidney disease, dialysis, renal transplantation or hypertension, and the available management approaches.

Narrative review of migraine management in patients with renal or hepatic disease

OBJECTIVES/BACKGROUND

Treatment of migraine in the setting of either renal or hepatic disease can be daunting for clinicians. Not only does the method of metabolism have to be considered, but also the method of elimination/excretion of the parent drug and any active or toxic metabolites. Furthermore, it is difficult to think about liver or kidney disease in isolation, as liver disease can sometimes contribute to impaired renal function and renal disease can sometimes impair hepatic metabolism, through the cytochrome P450 system.

METHODS

A detailed search for terms related to liver disease, renal disease, and migraine management was performed in PubMed, Ovid Medline, Embase, and the Cochrane Library.For each medication, product labels were retrieved and reviewed using the US FDA website, with additional review of IBM Micromedex, LiverTox, and the Renal Drug Handbook.

RESULTS

This manuscript provides an overview of migraine drug metabolism and how it can be affected by liver and renal impairment. It reviews the standard terminology recommended by the US Food and Drug Administration for the different stages of hepatic and renal failure. The available evidence regarding the use of abortive and preventative medicines in the setting of organ failure is discussed in detail, including more recent therapies such as lasmiditan, gepants, and calcitonin gene-related peptide antibodies.

CONCLUSIONS

For acute therapy, the use of NSAIDS should be limited, as these carry risk for both severe hepatic and renal disease. Triptans can be selectively used, often with dose guideline adjustments. Ubrogepant may be used in severe hepatic disease with dose adjustment and lasmiditan can be used in end stage renal disease. Though non-medicine strategies may be the most reasonable initial approach, many preventative medications can be used in the setting of hepatic and renal disease, often with dose adjustment. This review provides tables of guidelines, including reduced dosing recommendations, for the use of abortive and preventative migraine medications in hepatic and renal failure.

The extrapyramidal syndromes of chronic kidney disease and dialysis (EPS-CKDD): diagnostic criteria, risk factors and prognosis

BACKGROUND

Acute extrapyramidal movement disorders in dialysis patients are rare, inconsistently defined and have uncertain aetiology and prognosis.

AIM

Define diagnostic criteria, prognosis and risk factors.

DESIGN AND METHODS

Retrospective case series review of 20 patients (14 female, mean age 62 years) receiving dialysis for a median of 15 (interquartile range 4-35) months who presented with acute parkinsonism (AP = 11) or chorea/athetosis (CA = 9).

RESULTS

All patients had type 2 diabetes (HbA1c 6.8 ± 1.0) and had received metformin. Lactic acidosis was present in 2 patients at presentation and serum lactate was elevated in 7/15 patients tested. No patient had abnormal copper or thyroid metabolism and 5/8 patients tested returned marginal abnormalities in heavy metal screening. Magnetic resonance imaging (MRI) revealed characteristic bilateral symmetric T2 hyperintensity of the basal ganglia (BG), predominantly putamen and globus pallidus (the lentiform nucleus) and more extensive involvement of the external and internal capsules in patients with AP presentation. Post-mortem demonstrated cytotoxic necrosis of the BG. Therapy included thiamine, intensive dialysis and cessation of metformin. Two patients died acutely, nine recovered and nine had residual symptoms. Median survival did not differ by presentation: AP 24 [95% confidence interval (CI) 21-27] and CA 33 (95% CI 32-35) months, P = 0.21.

CONCLUSIONS

There are two distinct clinical extrapyramidal movement disorders associated with specific diagnostic MRI imaging that support the diagnosis of the extrapyramidal syndromes of chronic kidney disease and dialysis. The associations with diabetes, metformin and metabolic acidosis suggest a common pathogenic mechanism but require additional study. Early recognition and treatment may improve outcomes.

Cross-sectional assessment of mild cognitive impairment in pre-dialysis chronic kidney disease and its association with inflammation and changes seen on MRI: what the eyes cannot see

Introduction:

Mild cognitive impairment (MCI) is a prevalent and underdiagnosed condition in chronic kidney disease (CKD), that shares common pathophysiological factors such as chronic inflammation.

Objective:

To evaluate the association of MCI in CKD stages 1-5 using inflammatory markers and changes by magnetic resonance imaging (MRI).

Patients and Methods:

Cross-sectional study in adult patients with pre-dialysis CKD. MCI was assessed by the Montreal Cognitive Assessment (MoCA) and the estimated glomerular filtration rate (eGFR) by the Chronic Kidney Disease Epidemiology Collaboration equation. Sociodemographic and clinical data were collected from medical records. The cytokines IL-4, IL-6, IL-17, TNF-α and hs-CRP were determined. Brain MRI was performed in a 1.5 Tesla device, without paramagnetic contrast. A descriptive analysis followed by a comparison of abnormal versus normal MoCA scores among all studied variables. A linear regression analysis was performed using MoCA as a dependent variable, adjusted for confounding factors.

Results:

Of 111 invited patients, eighty completed the neuropsychological assessment and 56 underwent MRI, and were included in the study. Mean age was 56.3 ± 8.3 years and 51.8% (n = 29) had altered MoCA. When compared to the group with normal MoCA, the group with altered MoCA had higher levels of IL-6 and IL-17. There was no correlation between altered MoCA with eGFR or with MRI abnormalities.

Conclusão:

MCI assessed by MoCA was prevalent in patients with pre-dialysis CKD, it was associated with inflammation and showed no correlation with MRI changes.

Chronic kidney disease and neurological disorders: are uraemic toxins the missing piece of the puzzle?

Chronic kidney disease (CKD) perturbs the crosstalk with others organs, with the interaction between the kidneys and the heart having been studied most intensively. However, a growing body of data indicates that there is an association between kidney dysfunction and disorders of the central nervous system. In epidemiological studies, CKD is associated with a high prevalence of neurological complications, such as cerebrovascular disorders, movement disorders, cognitive impairment and depression. Along with traditional cardiovascular risk factors (such as diabetes, inflammation, hypertension and dyslipidaemia), non-traditional risk factors related to kidney damage (such as uraemic toxins) may predispose patients with CKD to neurological disorders. There is increasing evidence to show that uraemic toxins, for example indoxyl sulphate, have a neurotoxic effect. A better understanding of factors responsible for the elevated prevalence of neurological disorders among patients with CKD might facilitate the development of novel treatments. Here, we review (i) the potential clinical impact of CKD on cerebrovascular and neurological complications, (ii) the mechanisms underlying the uraemic toxins' putative action (based on pre-clinical and clinical research) and (iii) the potential impact of these findings on patient care.

Background Activity Findings in End-Stage Renal Disease With and Without Comorbid Diabetes: An Electroencephalogram Study

Renal failure and diabetes can induce cerebral complications, including encephalopathy, for which attentional and cognitive impairment are common symptoms. It is possible that renal failure with comorbid diabetes may induce more severe encephalopathy due to multiple pathogenic mechanisms. This concept was supported by the main findings of this study, which showed that EEG background activity between end-stage renal disease with and without comorbid diabetes was significantly different in relative power of delta in the eyes-open condition in frontoparietal regions; theta in the eyes-closed condition in all regions; beta in the parieto-occipital regions in both eye conditions; the delta/theta ratio in both eye conditions in frontoparietal regions; and the theta/beta ratio in all regions in the eyes-closed condition. These findings may increase awareness of comorbid cerebral complications in clinical practice. Moreover, the delta/theta ratio is recommended as an optimal feature to possibly determine the severity of encephalopathy.

Neuropathy - Exponent of Accelerated Involution in Uremia: The Role of Carbamylation

Premature loss of functional integrity of the nervous system in chronic renal failure (CRF) as a consequence of persistent biological activities of the general uremic milieu is almost identical to its structural and functional involution during the process of physiological ageing, but disproportionate and independent of chronological age. In the hyperuremic status of CRF (urea - carbamide), forced carbamylation, as a non-enzymatic post-translational modification (NEPTM) of proteins and amino acids, by changing their biological properties and decreasing proteolysis capacity, represents pathogenetic potential of intensified molecular ageing and accelerated, pathological involution. Physiological predisposition and the exposure of neuropathy before complications of other organs and organ systems in CRF, due to the simultaneous and mutually pathogenetically related uremic lesion and the tissue and vascular segment of the nervous system, direct interest towards proteomic analytical techniques of quantification of carbamylated products as biomarkers of uremic neurotoxicity. Hypothetically, identical to the already established applications of other NEPTM products in practice, they have the potential of clinical methodology in the evaluation of uremic neuropathy and its contribution to the general prediction, but also to the change of the conventional CRF classification. In addition, the identification and therapeutic control of the substrate of accelerated involution, responsible for the amplification of not only neurological but also general degenerative processes in CRF, is attractive in the context of the well-known attitude towards aging.

Atherosclerotic Vascular Disease Associated with Chronic Kidney Disease

Cardiovascular risk increases as glomerular filtration rate (GFR) declines in progressive renal disease and is maximal in patients with end-stage renal disease requiring maintenance dialysis. Atherosclerotic vascular disease, for which hyperlipidemia is the main risk factor and lipid-lowering therapy is the key intervention, is common. However, the pattern of dyslipidemia changes with low GFR and the association with vascular events becomes less clear. While the pathophysiology and management of patients with early chronic kidney disease (CKD) is similar to the general population, advanced and end-stage CKD is characterized by a disproportionate increase in fatal events, ineffectiveness of statin therapy, and greatly increased risk associated with coronary interventions. The most effective strategies to reduce atherosclerotic cardiovascular disease in CKD are to slow the decline in renal function or to restore renal function by transplantation.

Abnormal degree centrality in end-stage renal disease (ESRD) patients with cognitive impairment: a resting-state functional MRI study

To investigate functional connectivity (FC) changes in end-stage renal disease (ESRD) patients with and without cognitive impairment (CI) by using resting-state functional magnetic resonance imaging (rs-fMRI). Twenty-three ESRD patients with CI, 22 ESRD patients with non-CI (NCI) and 23 matched healthy controls (HC) were included. Rs-fMRI scans were performed in all subjects. Full-range, long-range, and short-range FC defined voxel-wise based degree centrality (DC) and seed based FC were computed and contrasted among the groups. Compared with HC, the DC value of short functional connectivity (SFC), in ESRD patients have increased on the left supramarginal gyrus, while it reduced on the left insula and right postcentral gyrus in CI and decreased on the right precentral gyrus in NCI. Compared with NCI, the DC value of LFC in CI increased on the left fusiform gyrus, while the DC value of short functional connectivity (SFC) increased on the left middle orbital gyrus. In the seed-based FC analyses, the CI showed significantly decreased FC between the left insula and bilateral middle temporal gyrus, between the left fusiform gyrus and the right hippocampus, and between the left postcentral gyrus and the right parahippocampus compared to HC; the CI showed significantly increased FC between the left precuneus and the left fusiform gyrus, between the left postcentral gyrus and the right precuneus compared with NCI. Positive correlations were found between DC values on the right superior frontal gyrus and LDL and BDST, and between MoCA and the DC values on the left insula and the left postcentral gyrus. The altered degree centrality may serve as early biomarkers for CI in ESRD patients.

Evaluation of cerebral dysfunction in patients with chronic kidney disease using neuropsychometric and neurophysiological tests

Background

Uremic encephalopathy is defined as cerebral dysfunction due to toxin accumulation in patients with chronic kidney disease (CKD). This condition is characterized by subtle to florid symptoms, and its clinical course is always progressive when untreated but partially reversible with renal replacement therapy. While no test exists to measure subclinical uremic encephalopathy, two tests have been validated to measure minimal hepatic encephalopathy: the critical flicker frequency (CFF) test and the psychometric hepatic encephalopathy score (PHES).

Objective

To use CFF and PHES to measure the prevalence of cerebral dysfunction in individuals with CKD.

Methods

This cross-sectional study included a total of 69 patients with stage-5 CKD. Cutoff points for minimal encephalopathy were established using existing clinical guidelines: ≤39 Hz for CFF and < −4 for PHES. All participants were also screened for cognitive function and depression.

Results

Eighteen cases (26.1%) of cerebral dysfunction linked to uremic encephalopathy were detected with CFF, while twelve (17.4%) were detected by PHES; only six cases (8.7%) were diagnosed by both methods. Half of the cases (50%) had diabetes, and 61% were on hemodialysis. Cognitive function scores did not differ significantly between those receiving dialysis, hemodialysis, or no renal replacement therapy.

Conclusions

It is essential to identify cerebral dysfunction when uremic encephalopathy is in early subclinical stages to reduce preventable events as traffic and work accidents.

Neuropathologic Findings in Chronic Kidney Disease (CKD)

Studying the neuropathologic autopsy findings in subjects with chronic kidney disease (CKD) or chronic renal failure (CRF) is difficult for several reasons: etiology of the CKD may be heterogeneous, affected patients may have one or more major co-morbidities that themselves can cause significant neurologic disease, and agonal events may result in significant findings that were of minimal significance earlier in a patient's life. We studied the constellation of neuropathologic abnormalities in 40 autopsy brains originating from subjects of ages 34-95 years (no children in the study). The most common pathologic change was that of ischemic infarcts (cystic, lacunar and/or microinfarcts), which were seen in over half of subjects. These were associated with both large artery atherosclerosis and arteriolosclerosis (A/S), the latter finding being present in 29/40 subjects. Charcot-Bouchard microaneurysms were present in the brains of three subjects, in one case associated with severe amyloid angiopathy. Microvascular calcinosis (medial sclerosis in the case of arterioles) was seen in the basal ganglia (n=8) and/or endplate region of the hippocampus (n=7) and occasional ischemic infarcts in one brain showed severe calcification. Sequelae of cerebrovascular disease (especially A/S or microvascular disease) are a common neuropathologic substrate for neurologic disability and brain lesions in this complex group of patients. Regulation of calcium metabolism within brain microvessel walls may be worthy of further research in both human brain specimens and animal models.

Clinical features of ischemic complications after unruptured middle cerebral artery aneurysm clipping: patients and radiologically related factors

Postoperative ischemic complication results in neurological sequelae and longer hospitalization after unruptured middle cerebral artery (MCA) aneurysm clipping surgery. We evaluated the radiological and patient-related factors associated with ischemic complications after unruptured MCA aneurysm clipping surgery. Patient demographics, radiological findings, and intraoperative factors were compared between patients with and without postoperative ischemic complications. The clinical courses and outcomes of postoperative ischemic complications were compared according to the types of ischemic complication. Forty-two out of 2227 patients (1.9%) developed postoperative ischemic complications after MCA aneurysm clipping. Multivariate analysis revealed that diabetes mellitus (DM) was a patient-related factor. Intraarterial (IA) calcification of the distal internal carotid artery (ICA), preoperative M1 stenosis, and M1 aneurysm were radiological factors that increased the risk of postoperative ischemic complications. DM was significantly associated with divisional branch territory infarction (P = 0.04). The time to first presentation of ischemic complication was significantly longer in divisional branch territory infarction than perforator territory infarction (67.8 ± 75.9 h vs. 22 ± 20.7, P = 0.023). Twelve out of 42 patients with ischemic complications (28.6%) had unfavorable outcome (mRS > 3). Perforator territory infarction was significantly associated with an unfavorable outcome (mRS > 3, P = 0.019). IA calcification of the distal ICA, M1 stenosis and aneurysms, and DM were significantly associated with postoperative ischemic complications after unruptured MCA aneurysm clipping. Patients with DM should be closely monitored postoperatively to detect delayed occurrence of divisional branch infarction. Trial registration number: 2019-1002, Date of registration: January 1, 2005, "retrospectively registered".

Renal-Cerebral Pathophysiology: The Interplay Between Chronic Kidney Disease and Cerebrovascular Disease

OBJECTIVES

Cerebrovascular disease has increasingly been linked to overall vascular health. Pathologic conditions like diabetes, hypertension, and kidney disease have been shown to affect brain health and cerebrovascular and nervous systems. Acute kidney injury (AKI) and chronic Kidney Disease (CKD) represent a variety of vascular insults that can adversely affect cerebral health. Hypertension, fluctuations in blood pressure, and diabetic vasculopathy are known risk factors for cerebrovascular disease associated with CKD. Other emerging areas of interest include endothelial dysfunction, vascular calcification due to calcium and phosphorus metabolism dysregulation, and uremic neuropathy present the next frontier of investigation in CKD and cerebrovascular health.

METHODS

It has become apparent that the interrelation of AKI and CKD with vascular health, chemical homeostasis, and hormonal regulation upset many aspects of cerebral health and functioning. Stroke is an obvious connection, with CKD patients demonstrating a higher proclivity for cerebrovascular accidents. Cerebral bleeding risk, uremic neuropathies, sodium dysregulation with impacts on nervous system, vascular calcification, and endothelial dysfunction are the next salient areas of research that are likely to reveal key breakthroughs in renal-cerebral pathophysiology.

RESULTS

In this review nephrological definition are discussed in a neuro-centric manner, and the areas of key overlap between CKD and cerebrovascular pathology are discussed. The multifaceted effects of renal function on the health of the brain are also examined.

CONCLUSION

This review article aims to create the background for ongoing and future neurological-nephrological collaboration on understanding the special challenges in caring for patients with cerebrovascular disease who also have CKD.

Cerebrovascular Disease and Cognition in Chronic Kidney Disease Patients

Chronic kidney disease (CKD) affects both brain structure and function. Patients with CKD have a higher risk of both ischemic and hemorrhagic strokes. Age, prior disease history, hypertension, diabetes, atrial fibrillation, smoking, diet, obesity, and sedimentary lifestyle are most common risk factors. Renal-specific pathophysiologic derangements, such as oxidative stress, chronic inflammation, endothelial dysfunction, vascular calcification, anemia, gut dysbiosis, and uremic toxins are important mediators. Dialysis initiation constitutes the highest stroke risk period. CKD significantly worsens stroke outcomes. It is essential to understand the risks and benefits of established stroke therapeutics in patients with CKD, especially in those on dialysis. Subclinical cerebrovascular disease, such as of silent brain infarction, white matter lesions, cerebral microbleeds, and cerebral atrophy are more prevalent with declining renal function. This may lead to functional brain damage manifesting as cognitive impairment. Cognitive dysfunction has been linked to poor compliance with medications, and is associated with greater morbidity and mortality. Thus, understanding the interaction between renal impairment and brain is important in to minimize the risk of neurologic injury in patients with CKD. This article reviews the link between chronic kidney disease and brain abnormalities associated with CKD in detail.

Mechanisms of cognitive dysfunction in CKD

Cognitive impairment is an increasingly recognized major cause of chronic disability and is commonly found in patients with chronic kidney disease (CKD). Knowledge of the relationship between kidney dysfunction and impaired cognition may improve our understanding of other forms of cognitive dysfunction. Patients with CKD are at an increased risk (compared with the general population) of both dementia and its prodrome, mild cognitive impairment (MCI), which are characterized by deficits in executive functions, memory and attention. Brain imaging in patients with CKD has revealed damage to white matter in the prefrontal cortex and, in animal models, in the subcortical monoaminergic and cholinergic systems, accompanied by widespread macrovascular and microvascular damage. Unfortunately, current interventions that target cardiovascular risk factors (such as anti-hypertensive drugs, anti-platelet agents and statins) seem to have little or no effect on CKD-associated MCI, suggesting that the accumulation of uraemic neurotoxins may be more important than disturbed haemodynamic factors or lipid metabolism in MCI pathogenesis. Experimental models show that the brain monoaminergic system is susceptible to uraemic neurotoxins and that this system is responsible for the altered sleep pattern commonly observed in patients with CKD. Neural progenitor cells and the glymphatic system, which are important in Alzheimer disease pathogenesis, may also be involved in CKD-associated MCI. More detailed study of CKD-associated MCI is needed to fully understand its clinical relevance, underlying pathophysiology, possible means of early diagnosis and prevention, and whether there may be novel approaches and potential therapies with wider application to this and other forms of cognitive decline.

The association of kidney function and cognitive decline in older patients at risk of cardiovascular disease: a longitudinal data analysis

BACKGROUND

Chronic kidney disease (CKD) has been identified as a significant direct marker for cognitive decline, but controversy exists regarding the magnitude of the association of kidney function with cognitive decline across the different CKD stages. Therefore, the aim of this study was to investigate the association of kidney function with cognitive decline in older patients at high risk of cardiovascular disease, using data from the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER).

METHODS

Data of 5796 patients of PROSPER were used. Strata were made according to clinical stages of CKD based on estimated glomerular filtration rate; < 30 ml/min/1.73m² (stage 4), 30-45 ml/min/1.73m² (stage 3b), 45-60 ml/min/1.73m² (stage 3a) and ≥ 60 ml/min/1.73m² (stage 1-2). Cognitive function and functional status was assessed at six different time points and means were compared at baseline and over time, adjusted for multiple prespecified variables. Stratified analyses for history of vascular disease were executed.

RESULTS

Mean age was 75.3 years and 48.3% participants were male. Mean follow-up was 3.2 years. For all cognitive function tests CKD stage 4 compared to the other stages had the worst outcome at baseline and a trend for faster cognitive decline over time. When comparing stage 4 versus stage 1-2 over time the estimates (95% CI) were 2.23 (0.60-3.85; p = 0.009) for the Stroop-Colour-Word test, - 0.33 (- 0.66-0.001; p = 0.051) for the Letter-Digit-Coding test, 0.08 (- 0.06-0.21; p = 0.275) for the Picture-Word-Learning test with immediate recall and - 0.07 (- 0.02-0.05; p = 0.509) for delayed recall. This association was most present in patients with a history of vascular disease. No differences were found in functional status.

CONCLUSION

In older people with vascular burden, only severe kidney disease (CKD stage 4), but not mild to modest kidney disease (CKD stage 3a and b), seem to be associated with cognitive impairment at baseline and cognitive decline over time. The association of severe kidney failure with cognitive impairment and decline over time was more outspoken in patients with a history of vascular disease, possibly due to a higher probability of polyvascular damage, in both kidney and brain, in patients with proven cardiovascular disease.

Microalbuminuria: a sentinel of neurocognitive impairment in HIV-infected individuals?

Background

According to population-based studies, microalbuminuria is associated with subsequent cognitive decline over a 4–6-year period, because of cerebral small-vessel disease (CSVD). This prospective cross-sectional study (NCT02852772) was designed to evaluate whether a history of microalbuminuria is associated with subsequent cognitive decline in combined antiretroviral therapy (cART)-treated persons living with human immunodeficiency virus (PLHIVs).

Methods

From our computerized medical database, we identified 30 PLHIVs (median age 52 years), immunovirologically controlled on cART, who had microalbuminuria in 2008 and had undergone, between 2013 and 2015, a comprehensive neuropsychological assessment (NPA) including seven domains (cases): information-processing speed, motor skills, executive functions, attention/working memory, learning/memory, reasoning and verbal fluency. Forty-nine PLHIVs matched for age (median age 48 years; p = 0.19), sex, and year of first HIV-seropositivity without microalbuminuria in 2008 were identified and underwent the same NPA between 2013 and 2015 (controls).

Results

Cases performed less well than controls for information-processing speed (p = 0.01) and motor skills (p = 0.02), but no differences were found for the other cognitive domains and global z-scores. A multivariable linear-regression model adjusted for confounding factors confirmed the microalbuminuria effect for the information-processing-speed z score.

Conclusion

cART-treated PLHIVs with a history of microalbuminuria subsequently had worse cognitive performances for the information-processing-speed domain, possibly because of CSVD. Our observations should be considered preliminary findings of a temporal link between microalbuminuria, CSVD, and subsequent cognitive impairment.

Pharmacotherapeutic Management of Neuropathic Pain in End-Stage Renal Disease

Background

Chronic noncancer pain is pervasive throughout the general patient population, transcending all chronic disease states. Patients with end-stage renal disease (ESRD) present a complicated population for which medication management requires careful consideration of the pathogenesis of ESRD and intimate knowledge of pharmacology. The origin of pain must also guide treatment options. As such, the presentation of neuropathic pain in ESRD can present a challenging case. The authors aim to provide a review of available classes of medications and considerations for the treatment of neuropathic pain in ESRD.

Summary

In this narrative review, the authors discuss important strategies and considerations for the treatment of neuropathic pain in ESRD, including the pathogenesis of neuropathic pain, physiological changes for consideration in ESRD patients, and disease-specific consideration for medication selection. Pharmacotherapeutic classes discussed include: anticonvulsants, antiarrhythmics, antidepressants, topicals, and opioids.

Key Message

Pain management in ESRD patients requires careful assessment of drug-specific properties, accumulation, metabolism (presence of active/toxic metabolites), extraction by dialysis, and presence of drug - drug interactions. In the absence of pharmacokinetic data in ESRD patients, therapeutic window and potential risks should be factored in the decision making along with continued monitoring throughout therapy.

Protein-bound uremic toxins are associated with cognitive function among patients undergoing maintenance hemodialysis

Patients with chronic kidney disease have a greater risk of cognitive impairment. Cerebral uremic solute accumulation causes uremic encephalopathy; however, the association of protein-bound uremic toxins on cognitive function remains unclear. The present study aimed to investigate the association of two protein-bound uremic toxins, namely indoxyl sulfate (IS) and p-cresyl sulfate (PCS), on cognitive function in patients receiving hemodialysis (HD) for at least 90 days. Circulating free form IS and PCS were quantified by liquid chromatography/mass spectrometry. Mini-Mental State Examination (MMSE) and Cognitive Abilities Screening Instrument (CASI) were used to evaluate cognitive function. In total, 260 HD patients were recruited with a mean age of 58.1 ± 11.3 years, of which, 53.8% were men, 40% had diabetes, and 75.4% had hypertension. The analysis revealed that both free IS and free PCS were negatively associated with the CASI score and MMSE. After controlling for confounders, circulating free IS levels persisted to be negatively associated with MMSE scores [β = −0.62, 95% confidence interval (CI): −1.16 to −0.08] and CASI scores (β = −1.97, 95% CI: −3.78 to −0.16), mainly in the CASI domains of long-term memory, mental manipulation, language ability, and spatial construction. However, there was no correlation between free PCS and total MMSE or total CASI scores after controlling for confounders. In conclusion, circulating free form IS, but not PCS is associated with lower cognitive function test scores in HD patients. Thus, a further study is needed to evaluate whether a decrease in free IS levels can slow down cognitive decline in HD patients.

Elevated parathyroid hormone levels and cognitive function: A systematic review

OBJECTIVE

To systematically estimate the association between elevated parathyroid hormone (PTH) levels and cognitive function.

METHODS

This review was conducted on ten papers identified through database searches from inception to 31 October 2018. The quality of studies was assessed using the Downs and Black checklist.

RESULTS

There is a low volume of data reporting on the impact of elevated PTH levels on cognitive impairment. The quality of the identified studies ranged from poor (37 %) to good (76 %). Although the results from studies were mixed, one cross-sectional study and one prospective study suggested a link between elevated PTH levels and a decrease in the Mini-Mental State Examination (MMSE) score. Three cross-sectional studies that assessed other cognitive domain in specific domains, such as language, memory and executive function provided mixed results for an association between elevated PTH levels and cognitive function. Two studies showed mixed evidence for a link between elevated PTH levels and poor executive function. One prospective study, one cross-sectional study and three case-control studies provide mixed evidence for an association between higher PTH levels and Alzheimer´s disease (AD). Two studies showed limited evidence for an association between elevated PTH levels and vascular dementia.

CONCLUSION

This review presented that the level of evidence available to support an association between elevated PTH levels and cognitive function was generally weak and inconsistent. Future studies with more better methodological quality are needed.

A Low Ankle-Brachial Index and High Brachial-Ankle Pulse Wave Velocity Are Associated with Poor Cognitive Function in Patients Undergoing Hemodialysis

Patients with end-stage renal disease (ESRD) have an increased risk of both impaired cognitive function and peripheral artery disease (PAD) than the general population. The association between PAD and dementia is recognized, but there are limited studies in patients with ESRD. The aim of this study was to evaluate the relationship between ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) and cognitive impairment in patients receiving hemodialysis (HD). We enrolled 136 prevalent HD patients (mean age 59.3 ± 10.5 years, 55.9% male). Cognitive performance was measured using the Montreal Cognitive Assessment (MoCA) and Cognitive Abilities Screening Instrument (CASI) by trained psychiatrists. Associations between the cognitive function and ABI and baPWV were assessed using multiple linear regression analysis. Compared with HD patients with ABI ≥ 0.9, patients with ABI < 0.9 had lower MoCA score (p = 0.027) and lower CASI score but did not achieve significant level (p = 0.056). In the multivariate stepwise linear regression analysis, ABI (per 0.1) was independently positively associated with the MoCA score (β coefficient = 0.62, p = 0.011) and the CASI score (β coefficient = 1.43, p = 0.026). There is a negative association between baPWV (per 100 cm/s) and CASI (β coefficient = −0.70, p = 0.009). In conclusion, a low ABI or high baPWV was associated with a lower cognitive function in HD patients.

[Correlations between parameters of central hemodynamics and cytokine profile in chronic kidney disease in combination with cerebrovascular diseases]

AIM

To study the relationship between central hemodynamics and arterial stiffness indicators with cystatin C, tumor necrosis factor-alpha (TNF-alpha) and interleukin-(IL)-10 in patients with chronic kidney disease (CKD) in combination with cerebrovascular diseases (CEV).

MATERIAL AND METHODS

One hundred and twenty patients, aged from 19 to 81 years, with signs of chronic renal dysfunction, including 73 with CKD (1st group) and 47 with CKD in combination with CEH (group 2), were examined. 'AngioScan' (Russia) was used to study indices of arterial rigidity. Blood plasma concentrations of TNF-alpha, IL-10 and cystatin C were determined by the enzyme immunoassay.

RESULTS

There is a significant increase (p<0.05) in the systolic, diastolic, central levels of arterial pressure, augmentation index, the index of increase at a pulse rate of 75 per min, the age index, the age of the vascular system and cystatin C content in the patients with CKD in combination with CEV compared to the patients with CKD without accompanying CEH. In the group of patients with CKD in combination with CEV, a correlation was found between the level of TNF-alpha and arterial stiffness index on one side (r=0.318; p<0.05) and the augmentation index on the other (r=0.299; p<0.05).

CONCLUSION

The results confirm the fact that there is a significant increase in the level of plasma cystatin C and a decrease in GFR in patients with CKD in combination with CEV. Correlations were found between the level of TNF-alpha, augmentation index and deterioration of parameters of central hemodynamics and arterial stiffness in CKD in combination with CEH.

The role of pericytes in brain disorders: from the periphery to the brain

It is becoming increasingly apparent that disorders of the brain microvasculature contribute to many neurological disorders. In recent years it has become clear that a major player in these events is the capillary pericyte which, in the brain, is now known to control the blood-brain barrier, regulate blood flow, influence immune cell entry and be crucial for angiogenesis. In this review we consider the under-explored possibility that peripheral diseases which affect the microvasculature, such as hypertension, kidney disease and diabetes, produce central nervous system (CNS) dysfunction by mechanisms affecting capillary pericytes within the CNS. We highlight how cellular messengers produced peripherally can act via signalling pathways within CNS pericytes to reshape blood vessels, restrict blood flow or compromise blood-brain barrier function, thus causing neuronal dysfunction. Increased understanding of how renin-angiotensin, Rho-kinase and PDGFRβ signalling affect CNS pericytes may suggest novel therapeutic approaches to reducing the CNS effects of peripheral disorders.

Indole-3 acetic acid increased risk of impaired cognitive function in patients receiving hemodialysis

Patients receiving hemodialysis (HD) have a higher risk of cognitive impairment and dementia than the general population. The accumulation of uremic toxins in the brain causes uremic encephalopathy, however, limited data exists to elucidate the effect of protein-bound uremic toxins on cognitive function. Here we investigate the effect of indole-3 acetic acid (IAA) and hippuric acid (HA), two different protein-bound uremic toxins from amino acid derivatives, on cognitive function by Silico and in a clinical study. Prevalent HD patients were enrolled in two independent hospitals. Serum IAA and HA were measured using mass spectrometry. Cognitive performance was measured using Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Cognitive Abilities Screening Instrument (CASI) by trained psychologists. Using silico data to predict the effect of blood-brain barrier penetration was performed. The silico data demonstrated that IAA and HA had positive blood-brain barrier penetration ability. Amongst the 230 HD patients, serum IAA was associated with poor MMSE score (β= -0.90, 95% CI -1.61 to -0.19) and poor CASI score (β= -3.29, 95% CI -5.69 to -0.88) in stepwise multiple linear regression analysis. In logistic regression model, Serum IAA was also associated with cognitive impairment based on MMSE definition (OR, 1.96, 95% CI 1.10, 3.5) and CASI definition (OR, 2.09, 95% CI 1.21, 3.61). There was no correlation between Serum HA levels and cognitive function status. In conclusion, IAA, not HA, was associated with cognitive impairment in HD patients. Further large scale and prospective studies are needed to confirm our findings.

Ameliorative effects of hydrogen sulfide (NaHS) on chronic kidney disease-induced brain dysfunction in rats: implication on role of nitric oxide (NO) signaling

Chronic kidney disease (CKD) is a major public health problem worldwide and is associated with spatial learning deficits. The aim of the present study was to evaluate the protective effects of hydrogen sulfide (H2S) on CKD-mediated behavioral deficits with emphasis to the role of nitric oxide (NO) in these effects. Fifty rats were randomly allocated to five experimental groups including: sham, Five-sixth (5/6) nephrectomy (Nx), 5/6Nx + NaHS, 5/6Nx + NaHS+L-nitroarginine methyl ester (L-NAME), and 5/6Nx + NaHS+aminoguanidine (AMG). Twelve weeks after 5/6Nx, we evaluated proteinuria, creatinine clearance (CrCl), oxidative/antioxidant status, and hippocampus neuro-inflammation and NO synthase genes in all groups. Furthermore, training trials of all animals were conducted in the Morris water maze (MWM) task one day before animal euthanizing. As predicted, 5/6Nx induced several injuries, including enhancement of proteinuria and reduction of CCr, oxidant/antioxidant imbalance and up-regulation of TNF-α and IL-1β gene expressions in the hippocampus tissues. As predicted, 5/6Nx resulted in learning and memory impairments, and increased escape latency during acquisition trials in the MWM task. Interestingly, NaHS (H2S donor) improved behavioral deficits, renal dysfunction, accelerated anti-oxidant/anti-inflammatory responses and increased eNOS and decreased iNOS. Moreover, these effects of NaHS were prevented by L-NAME but not AMG co-administration. In conclusion, H2S ameliorates CKD-mediated brain dysfunctions, through interaction with NO signaling in the hippocampus.

Work of being an adult patient with chronic kidney disease: a systematic review of qualitative studies

INTRODUCTION

Chronic kidney disease (CKD) requires patients and caregivers to invest in self-care and self-management of their disease. We aimed to describe the work for adult patients that follows from these investments and develop an understanding of burden of treatment (BoT).

METHODS

Systematic review of qualitative primary studies that builds on EXPERTS1 Protocol, PROSPERO registration number: CRD42014014547. We included research published in English, Spanish and Portuguese, from 2000 to present, describing experience of illness and healthcare of people with CKD and caregivers. Searches were conducted in MEDLINE, Embase, CINAHL Plus, PsycINFO, Scopus, Scientific Electronic Library Online and Red de Revistas Científicas de América Latina y el Caribe, España y Portugal. Content was analysed with theoretical framework using middle-range theories.

RESULTS

Searches resulted in 260 studies from 30 countries (5115 patients and 1071 carers). Socioeconomic status was central to the experience of CKD, especially in its advanced stages when renal replacement treatment is necessary. Unfunded healthcare was fragmented and of indeterminate duration, with patients often depending on emergency care. Treatment could lead to unemployment, and in turn, to uninsurance or underinsurance. Patients feared catastrophic events because of diminished financial capacity and made strenuous efforts to prevent them. Transportation to and from haemodialysis centre, with variable availability and cost, was a common problem, aggravated for patients in non-urban areas, or with young children, and low resources. Additional work for those uninsured or underinsured included fund-raising. Transplanted patients needed to manage finances and responsibilities in an uncertain context. Information on the disease, treatment options and immunosuppressants side effects was a widespread problem.

CONCLUSIONS

Being a person with end-stage kidney disease always implied high burden, time-consuming, invasive and exhausting tasks, impacting on all aspects of patients' and caregivers' lives. Further research on BoT could inform healthcare professionals and policy makers about factors that shape patients' trajectories and contribute towards a better illness experience for those living with CKD.

PROSPERO REGISTRATION NUMBER

CRD42014014547.

The Impact of Uremic Toxins on Cerebrovascular and Cognitive Disorders

Individuals at all stages of chronic kidney disease (CKD) have a higher risk of developing cognitive disorders and dementia. Stroke is also highly prevalent in this population and is associated with a higher risk of neurological deterioration, in-hospital mortality, and poor functional outcomes. Evidence from in vitro studies and in vivo animal experiments suggests that accumulation of uremic toxins may contribute to the pathogenesis of stroke and amplify vascular damage, leading to cognitive disorders and dementia. This review summarizes current evidence on the mechanisms by which uremic toxins may favour the occurrence of cerebrovascular diseases and neurological complications in CKD.

Uremic Solute-Aryl Hydrocarbon Receptor-Tissue Factor Axis Associates with Thrombosis after Vascular Injury in Humans

Individuals with CKD are particularly predisposed to thrombosis after vascular injury. Using mouse models, we recently described indoxyl sulfate, a tryptophan metabolite retained in CKD and an activator of tissue factor (TF) through aryl hydrocarbon receptor (AHR) signaling, as an inducer of thrombosis across the CKD spectrum. However, the translation of findings from animal models to humans is often challenging. Here, we investigated the uremic solute-AHR-TF thrombosis axis in two human cohorts, using a targeted metabolomics approach to probe a set of tryptophan products and high-throughput assays to measure AHR and TF activity. Analysis of baseline serum samples was performed from 473 participants with advanced CKD from the Dialysis Access Consortium Clopidogrel Prevention of Early AV Fistula Thrombosis trial. Participants with subsequent arteriovenous thrombosis had significantly higher levels of indoxyl sulfate and kynurenine, another uremic solute, and greater activity of AHR and TF, than those without thrombosis. Pattern recognition analysis using the components of the thrombosis axis facilitated clustering of the thrombotic and nonthrombotic groups. We further validated these findings using 377 baseline samples from participants in the Thrombolysis in Myocardial Infarction II trial, many of whom had CKD stage 2-3. Mechanistic probing revealed that kynurenine enhances thrombosis after vascular injury in an animal model and regulates thrombosis in an AHR-dependent manner. This human validation of the solute-AHR-TF axis supports further studies probing its utility in risk stratification of patients with CKD and exploring its role in other diseases with heightened risk of thrombosis.