Nerve cross-sectional area in advanced uremic neuropathy: A nerve ultrasound pilot study

BACKGROUND AND PURPOSE

Uremic neuropathy (UN) is a disabling neuropathy in end-stage kidney disease (ESKD) affecting the majority of patients receiving long-term hemodialysis (HD). One previous nerve ultrasound study reported an increased cross-sectional area (CSA) of the median nerve in moderate UN, while another study found enlarged sural nerves in small-fiber polyneuropathy associated with ESKD. The present cohort study aims to analyze bilateral CSA of multiple nerves in UN.

METHODS

Ten nondiabetic ESKD patients with UN on HD for at least 2 years and 10 healthy age-matched controls underwent bilateral ultrasound examinations with CSA measurements in 13 arm and leg nerve sites. Nerve conduction studies (NCS) and the total neuropathy score (TNS) were recorded. Pearson's coefficient and the Mann-Whitney U-test were used to analyze correlations and compare groups.

RESULTS

ESKD patients presented advanced neuropathic symptoms (mean TNS 15.9). NCS showed significantly reduced motor and sensory amplitudes in the UN group compared to the control group, and a slightly reduced nerve CSA was observed in 5 of 13 nerve sites (p < .05); the other nerve sites were not enlarged. Sural nerve CSA (p < .05) and sensory amplitude (p < .01) were negatively correlated with the TNS.

CONCLUSIONS

Nerve enlargement was not observed in the present study in advanced UN. A reduced nerve CSA observed in the sural nerve suggests an axonal loss associated with long-term HD in ESKD. During clinical workup of an acute disease of the peripheral nervous system in ESKD patients, nerve enlargement might be attributable to other causes than chronic UN.

Accelerated neuropathy among chronic kidney disease patients undergoing hemodialysis: Analysis of an institutional cluster

BACKGROUND

Accelerated neuropathy is a rare syndrome of rapidly worsening peripheral neuropathy, typically described in end-stage kidney disease (ESKD) patients undergoing dialysis. In our center, we encountered a surge in the occurrence of accelerated neuropathy among ESKD patients undergoing hemodialysis, which prompted systematic research.

METHODS

In this case-control study, we present the clinical features, electrophysiologic findings, and outcome of a series of patients who developed accelerated neuropathy after commencing hemodialysis for ESKD. Those who initiated hemodialysis and did not develop accelerated neuropathy were included as controls. We used logistic regression to identify predictors of accelerated neuropathy.

RESULTS

Among 436 ESKD patients who initiated hemodialysis over 4 years, 17 were diagnosed with accelerated neuropathy. The median-time (interquartile range) from hemodialysis initiation to presentation with accelerated neuropathy was 3 weeks (2-6). It typically presented as acute onset of unsteadiness of gait necessitating assistance for ambulation. Electrophysiology revealed length-dependent symmetric sensorimotor axonal neuropathy. Diabetes mellitus (odds ratio [OR] 4.1, 95% CI 1.2-13.9, p = 0.02), pre-existing peripheral neuropathy (OR 9.25, 95% CI 2.79-30.6, p < 0.001), and serum alkaline phosphatase (OR 1.2 for every 10 U increase, 95% CI 1.00-1.52, p = 0.04) significantly predicted accelerated neuropathy. With continued dialysis and supportive care, neurologic status improved, total-neuropathy score (summary score of peripheral nerve dysfunction incorporating clinical and electrophysiological parameters) declined from 26.5 to 18.4 (p < 0.001) and most regained unassisted ambulation.

CONCLUSION

This study presents the largest series of patients with accelerated neuropathy and has identified predictors. However, in view of the unusually high incidence of accelerated neuropathy we speculate that other unidentified factor(s) could be underlying its pathogenesis.

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.

Peripheral nerve morphology and intraneural blood flow in chronic kidney disease with and without diabetes

Introduction/Aims

Sonographic alterations of peripheral nerves in pre‐dialytic kidney disease are yet to be determined. We aimed to assess peripheral nerve cross‐sectional area (CSA) and intraneural blood flow in patients with pre‐dialytic chronic kidney disease (CKD) and diabetic kidney disease (DKD).

Methods

Subjects with CKD (n = 20) or DKD (n = 20) underwent ultrasound to assess CSA of the median and tibial nerves as well as intraneural blood flow of the median nerve. Blood flow was quantified using maximum perfusion intensity. Neuropathy was assessed using the Total Neuropathy Score. A 6‐m timed walk test was also performed. Healthy controls (n = 28) were recruited for comparison.

Results

The DKD group had more severe neuropathy (p = .024), larger tibial nerve CSA (p = .002) and greater median nerve blood flow than the CKD group (p = .023). Blood flow correlated with serum potassium in disease groups (r = 0.652, p = .022). Disease groups had larger tibial nerve CSA than controls (p < .05). No blood flow was detected in controls. Tibial nerve enlargement was associated with slower maximal walking speeds in disease groups (r = −0.389, p = .021).

Discussion

Subjects with DKD demonstrated enlarged tibial nerve CSA and increased median nerve blood flow compared to those with CKD. Elevations in serum potassium were associated with increased blood flow. Sonographic alterations were detectable in pre‐dialytic kidney disease compared to controls, highlighting the utility of ultrasound in the assessment of nerve pathology in these patient groups.

Effect of Hemodiafiltration on the Progression of Neuropathy with Kidney Failure: A Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Neuropathy is a common complication of kidney disease that lacks proven disease-modifying treatments. Hemodiafiltration improves clearance of uremic toxins and is associated with better nerve function than hemodialysis. We aimed to determine whether hemodiafiltration reduces the progression of neuropathy in people receiving hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Filtration in the Neuropathy of End-Stage Kidney Disease Symptom Evolution (FINESSE) study was an open-label, blinded end point assessment, controlled trial that randomized maintenance hemodialysis recipients to hemodiafiltration or high-flux hemodialysis for 48 months or until death or cessation of dialysis at four study centers. The primary outcome was the mean change in the yearly modified total neuropathy score from baseline, with time points weighted equally.

RESULTS

A total of 124 participants were randomized and followed for a mean of 41 months. At baseline, neuropathy was present in 91 (73%) participants (modified total neuropathy score greater than or equal to two), and 38 (31%) had moderate to severe neuropathy (modified total neuropathy score 9-28). Convection volume in the hemodiafiltration arm was a median of 24.7 (interquartile range, 22.4-26.5) L. The mean modified total neuropathy score (SEM) worsened by 1.7 (0.4)/28 and 1.2 (0.4)/28 in the hemodiafiltration and hemodialysis groups, respectively, with a mean difference of 0.5 (95% confidence interval, -0.7 to 1.7; P=0.37). There was no difference in survival (hazard ratio, 1.24; 95% confidence interval, 0.61 to 2.51; log rank P=0.55) or any of the prespecified adverse events. There was no difference between groups in the number of participants who suffered an adverse event adjusted by follow-up time (relative risk, 1.05; 95% confidence interval, 0.83 to 1.32; P=0.68).

CONCLUSIONS

Neuropathy is still a common complication of kidney disease without disease-altering therapy. Hemodiafiltration did not affect neuropathy progression compared with hemodialysis.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Filtration in the Neuropathy of End-Stage Kidney Disease Symptom Evolution (FINESSE), ACTRN12609000615280.

The Role of Protein Adduction in Toxic Neuropathies of Exogenous and Endogenous Origin

The peripheral (axonal) neuropathy associated with repeated exposure to aliphatic and aromatic solvents that form protein-reactive γ-diketones shares some clinical and neuropathological features with certain metabolic neuropathies, including type-II diabetic neuropathy and uremic neuropathy, and with the largely sub-clinical nerve damage associated with old age. These conditions may be linked by metabolites that adduct and cross-link neuroproteins required for the maintenance of axonal transport and nerve fiber integrity in the peripheral and central nervous system.

Neurophysiological and Neuroradiological Changes in Children With Chronic Kidney Disease

Background: Patients with chronic kidney disease (CKD) on maintenance hemodialysis frequently present with neurological complications. These complications include peripheral neuropathy, encephalopathy, and stroke. Objectives: To detect the prevalence of neurological manifestations and complications in children with CKD through neurophysiological and neuro-radiological findings. Methods: The study included 50 patients with CKD admitted to a pediatric nephrology unit. Their history and complete physical and neurological examination findings had been recorded. All patients underwent nerve conduction, electromyography, electroencephalography, and magnetic resonance imaging of the brain. Results: Fifty children of both sexes (23 males and 27 females) with a mean age of (12.08 ± 3.46 year) were studied. Eleven (22%) patients with CKD developed polyneuropathy, mostly of an axonal polyneuropathy pattern, while 39 (78%) of them showed normal electrophysiological studies. No myopathy was detected. Abnormal electroencephalography findings were detected in 18% of patients, mostly generalized and focal (temporal, occipital, and frontal) epileptogenic activity. Abnormal MRI brain findings were detected in 16% of patients, mostly of encephalomalacia. Conclusion: Uremic neuropathy was highly prevalent in children with CKD on maintenance hemodialysis. They developed polyneuropathy, mostly of an axonal polyneuropathy pattern. EEG is a useful method for early recognition of subclinical uremic encephalopathy and/or epileptogenic activity. Early demonstration and management of uremic neurological conditions may decrease the physical disability of CKD patients.

Identifying Common Genetic Risk Factors of Diabetic Neuropathies

Type 2 diabetes mellitus (T2DM) is a global public health problem of epidemic proportions, with 60-70% of affected individuals suffering from associated neurovascular complications that act on multiple organ systems. The most common and clinically significant neuropathies of T2DM include uremic neuropathy, peripheral neuropathy, and cardiac autonomic neuropathy. These conditions seriously impact an individual's quality of life and significantly increase the risk of morbidity and mortality. Although advances in gene sequencing technologies have identified several genetic variants that may regulate the development and progression of T2DM, little is known about whether or not the variants are involved in disease progression and how these genetic variants are associated with diabetic neuropathy specifically. Significant missing heritability data and complex disease etiologies remain to be explained. This article is the first to provide a review of the genetic risk variants implicated in the diabetic neuropathies and to highlight potential commonalities. We thereby aim to contribute to the creation of a genetic-metabolic model that will help to elucidate the cause of diabetic neuropathies, evaluate a patient's risk profile, and ultimately facilitate preventative and targeted treatment for the individual.

Uremic neuropathy

Polyneuropathy is a common complication of end-stage renal failure especially when treatment with periodic hemodialysis is started too late. Large myelinated fibers bear the brunt of the many biological changes associated with renal failure. Nerve conduction slowing is common in this setting. Compression of the median nerve in the carpal tunnel commonly occurs in these patients, as a result of amyloid deposits at this site. End-stage renal failure in diabetic patients is often associated with severe distal motor and sensory deficits. Improved quality of periodic hemodialysis and renal transplantation have dramatically reduced the prevalence and severity of peripheral neuropathy in these patients.