Nervous system disorders in dialysis patients

Hand dexterity, daily functioning and health-related quality of life in kidney transplant recipients

Impaired interplay between sensory and motor function may be an important, often overlooked cause of the decreased daily functioning and impaired health-related quality of life (HRQoL) of kidney transplant recipients (KTR). We assessed this interplay using a hand dexterity test, and investigated its potential associations with daily functioning and HRQoL among KTR enrolled at the TransplantLines Biobank and Cohort Study. A total of 309 KTR (58% male, mean age 56 ± 13 years) at median 4 [IQR: 1-11] years after transplantation were included. Impaired hand dexterity, as defined by a test performance slower than the 95th percentile of an age- and sex-specific reference population, was observed in 71 (23%) KTR. Worse hand dexterity was independently associated with worse performance on almost all measures of physical capacity, activities of daily living and societal participation. Finally, hand dexterity was independently associated with physical HRQoL (standardized beta - 0.22, 95%CI - 0.34 to - 0.09, P < 0.001). In conclusion, impaired interplay between sensory and motor function, as assessed by hand dexterity, is prevalent among KTR. In addition, poor hand dexterity was associated with impaired daily functioning and limited physical HRQoL. Impaired interplay between sensory and motor function may be therefore an important, hitherto overlooked, phenomenon in KTR.

Peripheral Neuropathy in Children With Chronic Kidney Disease: Are We Looking Enough?

Background:

Peripheral neuropathy in chronic kidney disease (CKD) is the most common neurological complication. We aimed to look at the prevalence and patterns of neuropathy in children with CKD.

Methods:

This cross-sectional study was conducted over 1 year in children with CKD, stage III and above. Nerve conduction studies (NCS) were performed as per standard protocols using surface electrodes on the muscles and by supramaximal stimulation of the corresponding nerves. Presence of electrophysiological abnormalities in the absence of clinical symptoms or signs was considered as subclinical neuropathy.

Results:

Nearly 45 children were evaluated. The majority were males (n = 39, 86.7%). The mean age was 7.9 ± 3 years (range 2–14). The mean estimated glomerular filtration rate (GFR) at enrolment was 23.3 ± 14.6 mL/min/1.73 m² (range 5–67). The majority of children were in stage III (n = 19, 42%), followed by stages V (n = 15, 33%) and IV (n = 11, 25%). There was no evidence of clinical neuropathy; 13 children (29%) showed subclinical neuropathy. All the nerves had an axonal pattern of involvement. Motor polyneuropathy was most common type of peripheral neuropathy. The commonest nerves involved were tibial and common peroneal nerves. There were no biochemical or clinical predictors of neuropathy in our cohort.

Conclusion:

The prevalence of subclinical neuropathy is high in children with CKD, stage III and above. Axonal motor polyneuropathy is the predominant pattern. Electrophysiological assessment of nerve function should be routinely done in children with advanced stages of CKD to prevent chronic complications.

Complications and safety of the transplanted organ after upper extremity surgery in patients receiving immunosuppressant therapy after solid organ transplantation

PURPOSE

The purpose of this study was to evaluate the complications and safety of transplanted organs after upper extremity surgery in patients taking immunosuppressants after solid organ transplantation (SOT).

METHODS

Seventy-two transplant recipients underwent 99 upper extremity surgeries while on immunosuppressants after SOT at our institution between January 2009 and December 2018. We retrospectively reviewed the clinical data of these patients, including their demographic information and data related to the SOT and upper extremity surgery.

RESULTS

Trigger/tendon release (n = 31, 31.3%) was the most frequently performed upper extremity surgery, followed by incision and drainage for an infection (n = 16, 16.2%). Post-operative complications occurred after ten upper extremity operative procedures (10.1%), among which uncontrolled infection after surgery for an infection (n = 4) was the most common. According to the Clavien-Dindo classification, the complications of three surgical procedures were grade I, three were grade II, and four were grade III, and all were treatable. The occurrence rate of the complications was not significantly different between emergent and elective surgery. All transplanted organ-specific indicators did not worsen significantly after emergent or elective upper extremity surgery.

CONCLUSIONS

Since the function of the transplanted organ was well-preserved after emergent or elective upper extremity surgery, common upper extremity procedures do not seem to be a worrisome practice for SOT patients. However, when treating hand and upper extremity infections in SOT patients, surgeons should explain the possible need for multiple operations  and the high complication rate.

Does aluminum exposure affect cognitive function? a comparative cross-sectional study

OBJECTIVES

This study assessed the cognitive function of aluminum-exposed participants from an alum mining zone, compared them with unexposed subjects, and aimed to elucidate the effect of aluminum exposure on cognition.

DESIGN

This was a comparative cross-sectional study. Univariate analyses were used to assess the differences between the aluminum-exposed and unexposed groups. Binary logistic regression models were applied to analyze the effect of aluminum exposure.

SETTING

The aluminum-exposed participants were included from an alum mining zone and the unexposed subjects were residents from another district without alum-mine-related factories.

PARTICIPANTS

We included 539 aluminum-exposed participants (254 men, 285 women) and 1720 unexposed participants (692 men, 1028 women).

RESULTS

The mean cognition score on Mini-Mental State Examination was 21.34 (± 6.81) for aluminum-exposed participants. The exposed group had 6.77 times (95% confidence interval, 5.09-9.00) more risk of cognitive impairment than the unexposed group, after adjusting for age, sex, and educational level. No statistically significant association was found between exposure duration and cognition.

CONCLUSIONS

This study demonstrated a significant association between aluminum exposure and lower cognitive function.

Increased cerebral blood flow is correlated with neurocognitive impairment in long-term hemodialysis patients: an arterial spin labeling MRI study

The purpose of this study was to investigate cerebral blood flow (CBF) changes in hemodialysis patients with arterial spin labeling (ASL) and to correlate these changes with clinical risk factors and neurocognitive function. Thirty-two hemodialysis patients and 35 age-, sex-, and education-matched healthy controls (HCs) were recruited in this prospective study. The Mini-Mental State Examination (MMSE) was performed to evaluate neurocognitive function. Pulsed ASL was performed to measure CBF. Two independent sample t-test was used to explore the CBF difference between the patients and HCs. Multiple stepwise regression was used to investigate the risk factors for CBF in patients. Correlation analysis was used to explore the relationship between the MMSE scores and CBF changes with and without adjusting for anemia status. Compared to HCs, the hemodialysis patients showed significantly increased CBF in some neurocognition-related cerebral regions (all P < 0.001, Bonferroni corrected). Increased CBF in the right opercular and triangular part of the inferior frontal gyrus correlated with the poorer MMSE scores (r = -0.502, P = 0.004; r = -0.423, P = 0.018, FDR corrected) and these correlations still remained after adjusting for anemia status (r = -0.516, P = 0.005; r = -0.439, P = 0.019, FDR corrected). The increased dialysis duration, and decreased hemoglobin, hematocrit, and serum phosphorus were predictive risk factors for increased CBF (P < 0.05). In conclusion, long-term hemodialysis patients had increased CBF, which correlated with neurocognitive impairment, and after adjusting for the effect of anemia, the correlation still remained.

Movement Disorders and Renal Diseases

Movement disorders often emerge from the interplay of complex pathophysiological processes involving the kidneys and the nervous system. Tremor, myoclonus, ataxia, chorea, and parkinsonism can occur in the context of renal dysfunction (azotemia and electrolyte abnormalities) or they can be part of complications of its management (dialysis and renal transplantation). On the other hand, myoglobinuria from rhabdomyolysis in status dystonicus and certain drugs used in the management of movement disorders can cause nephrotoxicity. Distinct from these well-recognized associations, it is important to appreciate that there are several inherited and acquired disorders in which movement abnormalities do not occur as a consequence of renal dysfunction or vice versa but are manifestations of common pathophysiological processes affecting the nervous system and the kidneys. These disorders are the emphasis of this review. Increasing awareness of these conditions among neurologists may help them to identify renal involvement earlier, take timely intervention by anticipating complications and focus on therapies targeting common mechanisms in addition to symptomatic management of movement disorders. Recognition of renal impairment in a patient with complex neurological presentation may narrow down the differentials and aid in reaching a definite diagnosis.

Blood lead level: an overlooked risk of carpal tunnel syndrome in hemodialysis patients

Introduction: Carpal tunnel syndrome (CTS) is a severe complication observed in long-term maintenance hemodialysis (MHD) patients. The most common cause of CTS is dialysis-related β2-microglobulin amyloidosis, which is associated with inflammation and oxidative stress in dialysis patients. Patients on MHD have higher blood lead levels (BLLs) than the general population. Lead (Pb) exposure in chronic dialysis patients has been noted to induce oxidative stress and inflammation. Therefore, lead-related inflammation and oxidative stress might contribute to CTS. Methods: The medical records of 866 MHD patients were reviewed. Two hundred and thirty-four patients with symptoms of CTS were surveyed by senior neurologists via physical examinations and nerve conduction studies. Patients in this study were stratified into groups with low-normal (<10 μg/dL), high-normal (10 to 20 μg/dL), and abnormal (>20 μg/dL) BLLs. The associations between CTS and BLLs and the clinical data were analyzed. Results: Multivariate logistic regression analyses showed that Log BLL (OR: 54.810, 95% CI: 13.622-220.54, p < .001), high-normal BLLs (OR: 4.839, 95% CI: 2.262-10.351, p < .001) with low-normal BLL as a reference, high BLLs (OR: 12.952, 95% CI: 5.391-31.119, p < .001) with low-normal BLL as a reference, and a BLL >12.3 μg/dL (OR: 6.827, 95% CI: 3.737-12.472, p < .001) were positively associated with CTS according to three different analyses. Discussion: In conclusion, blood lead levels were positively associated with CTS in patients on MHD. Dialysis patients should pay more attention to their environmental exposure to Pb. Avoidance of environmental Pb may reduce the incidence of CTS in MHD patients. Future studies will address the role of Pb in the pathophysiology of CTS in this patient population.

Is aluminum exposure a risk factor for neurological disorders?

Aluminum (Al) is widely found in the nature. Although the relation between Al and neurodegenerative diseases is still controversial, Al is related with many brain diseases including Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Al exposure occurs mainly through environment, occupational, and dietary factors for humans. Al exposure with diet can be through foods, food additives, water, and contamination of Al equipment/utensils. The aim of this review is to summarize various hypotheses, which link Al and neurodegeneration, and to determine the roles of Al exposure through different sources including diet, environment, and occupation. Future studies should be done in vulnerable subgroups of population including children, patients receiving antacid or Al-containing pharmeteucials on a daily basis, patients with reduced renal function, and patients on parenteral nutrition regimens that are likely to be affected by possible adverse health effects of Al. In addition, gender, age, and Al interactions need to be determined. One of the most important challanges in future epidemiological studies is to determine which variables should be controlled. In addition, experimental studies should be more focused and translational. In this context, exposure dose, dose-response effects, and time lapse between exposures and cognitive assessments are very important.

Advances in dialysis encephalopathy research: a review

Dialysis encephalopathy (DE) is a progressive, fatal disease with a high mortality rate. Understanding the causes of this disease and the efforts to prevent and treat it would help improve the prognosis and quality of life of affected patients. This paper reviews the etiology, clinical features, methods of examining accessory features, diagnosis, treatment, and prevention of DE. We found that DE is likely to be related to aluminum poisoning. The clinical manifestations of DE include language disorders, mental and behavioral disorders, cognitive decline, and movement disorders. Electroencephalogram (EEG) findings mainly consist of an abundance of low waves, intermittent bilateral synchronous high-amplitude spikes, and ridge waves. Assessing the clinical features and obtaining an EEG are of great value in diagnosis, and DE is treated by both reducing aluminum intake and increasing aluminum excretion. Deferoxamine (DFO) is an effective treatment for DE.

Impaired thiol-disulphide homeostasis in patients with axonal polyneuropathy

OBJECTIVE

The objective of this study is to examine thiol-disulphide homeostasis in patients with polyneuropathy dominated by diabetic or non-diabetic axonal degeneration.

MATERIALS-METHODS

Fifty-four patients diagnosed with polyneuropathy dominated by axonal damage and 41 healthy subjects were included in the study. The patients were grouped into two groups according to whether or not they had diabetes. The native thiol and total thiol concentrations were measured with the newly developed automated method.

RESULTS

While there was no significant difference between the patients with diabetic and non-diabetic polyneuropathy in terms of native thiol and total thiol levels (p > 0.05), the native thiol and total thiol levels of the groups with both diabetic polyneuropathy and non-diabetic polyneuropathy were significantly low compared to the control group (p < 0.01). The level of disulphides in the patients with diabetic polyneuropathy was significantly higher than that of the patients with non-diabetic polyneuropathy and the healthy individuals (p < 0.05). The loss in the sural nerve sensory neural action potential amplitude was positively correlated with the decrease in the levels of both native thiol and total thiol (p < 0.05).

DISCUSSION

In our study, we observed that the thiol-disulphide balance was also impaired in patients with non-diabetic polyneuropathy similar to patients with diabetic polyneuropathy, and we therefore considered that impaired the thiol-disulphide homeostasis could be the last common path in patients with polyneuropathy with axonal damage, regardless of the aetiology. Therefore, fortification of thiol deficiency with N-acetyl cysteine or alpha-lipoic acid can fix the thiol-disulphide balance and help decelerate the axonal damage.

Aluminum exposure for 60days at an equivalent human dietary level promotes peripheral dysfunction in rats

Aluminum (Al) is a neurotoxic associated with a number of chronic human diseases. We investigated the effects of Al exposure at doses similar to human dietary levels and at a high level exposure to Al on the peripheral nervous system. Wistar male rats were divided into two major groups and received orally: 1) First group - Low level - rats were subdivided and treated for 60days: a) Control - received ultrapure water; b) AlCl₃ - received Al at 8.3mg/kg body weight (bw) for 60days; and 2) Second group - High level - rats were subdivided and treated for 42days: C) Control - received ultrapure water through oral gavage; d) AlCl₃ - received Al at 100mg/kg bw for 42days. Von Frey hair test, plantar test, the presence of catalepsy and the spontaneous motor activity were investigated. Reactive oxygen species, lipid peroxidation and total antioxidant capacity, immunohistochemistry to investigate the nerve inflammation and, the specific presence of Al in the sciatic nerve fibers were investigated. Al exposure at a representative human dietary level promotes the development of mechanical allodynia, catalepsy, increased inflammation in the sciatic nerve, systemic oxidative stress and, is able to be retained in the sciatic nerve. The effects of low-dose Al were similar to those found in rats exposed to Al at a dose much higher (100mg/kg). Our findings suggest that Al may be considered toxic for the peripheral nervous system, thus inducing peripheral dysfunction.

Frequency of Polyneuropathy in Patients on Long Term Peritoneal Dialysis Treatment

INTRODUCTION

Uremic polyneuropathy is very common among patients with Chronic Kidney Disease (CKD). The patients have electrophysiologic signs of impaired nerve function, although a lower percentage of patients are symptomatic. Electrophysiological parameters are quantitative indices of Polyneuropathy (PNP) severity.

AIM

To assess the frequency of PNP in patients on long term Peritoneal Dialysis (PD) treatment.

MATERIALS AND METHODS

Twenty three PD patients were analysed, who were receiving dialysis for at least five years and the study population divided into two groups according to duration of PD treatment. Group 1 consisted of the patients who were dialysed for at least 10 years and Group 2 consisted of patients who were dialysed for five to nine years. Patients who switched from Haemodialysis (HD) to PD and patients with coexisting diseases that could lead to disturbances in nerve conduction were excluded from the study. PNP was diagnosed when slowing of Nerve Conduction Velocity (NCV) and/or lengthening of distal latencies and/or decrease in amplitude of muscle action potential were present in two or more nerves and longer F wave response was present in one or two nerves. Carpal Tunnel Syndrome (CTS) was diagnosed if slowing of NCV and/or decrease in amplitude of muscle action potential and/or lenghening of distal latency of either sensory or motor median nerve present.

RESULTS

PNP was observed in 17 of the patients {73.9%; Group 1 (n=10) and Group 2 (n=7)}. Mixed type sensory motor neuropathy was diagnosed in nine patients from Group 1 and five patients from Group 2; one patient from Group 1 had demyelinating PNP affecting motor and sensory nerves; one patient from Group 2 had axonal PNP affecting motor and sensory nerves. From Group 1, two patients had CTS related to PNP and one patient had CTS without PNP. The results of motor conductivity testing showed lower conduction velocity for left popliteal nerve in Group 1 and Group 2 patients (13.85±2.17 ms, 4.80±1.11 ms, p=0.01). In both groups, mean motor and sensory latency, amplitude and velocity of other nerves were not found to be significantly different (p>0.05).

CONCLUSION

PNP is a common complication in long term PD patients. Over five years of treatment, frequency of PNP and CTS do not increase with duration of dialysis.

Neurological Complications of Renal Disease

Neurological manifestations related to electrolyte disorders, drug toxicity, and uremia are common in chronic kidney disease (CKD). Seizures and coma are frequent complications of acute renal insufficiency (uremia), whereas peripheral neuropathy and encephalopathy, observed in progressive uremia, are terminal events. Failure to excrete metabolic products causes their accumulation and can lead to severe intoxication. Clinically, the signs and symptoms of uremia can vary widely, depending on the biological characteristics of the patient, the specific type of renal disease, and the time of the uremic intoxication. CKD is an increasing problem worldwide and is now being recognized as a global health burden particularly for cardiovascular and cerebrovascular ischemic events. Despite improvements in the medical management of advanced CKD, including dialysis and transplantation, patients manifest a number of symptoms that neurologists are often confronted with. Appropriate drug dosing, awareness of potential side effects of medications, prompt diagnosis, and treatment are essential in preventing neurological long-term morbidity and mortality.

Use of Antiepileptic Drugs in Patients with Chronic Kidney Disease and End Stage Renal Disease

Epilepsy is a disorder with an approximate worldwide prevalence of 1%. Due to complexities of metabolism, protein-binding, renal elimination, and other pharmacokinetic parameters, the dosing of antiepileptic drugs (AEDs) in patients with chronic kidney disease (CKD) or end stage renal disease (ESRD) deserves special attention. This is a review of the most commonly prescribed AEDs with special focus on their indication, pharmacokinetics, and unique considerations for use in patients with CKD and ESRD. A review of their renal toxicities is also included.