Vitamin B6 supplementation can improve peripheral polyneuropathy in patients with chronic renal failure on high-flux haemodialysis and human recombinant erythropoietin

Interventions for preventing haemodialysis dysequilibrium syndrome

BACKGROUND

Dialysis dysequilibrium syndrome (DDS) refers to neurological symptoms usually seen during or after new initiation or following reinitiation of haemodialysis (HD) after missing multiple sessions. DDS is associated with death and morbidity. We studied interventions aimed at preventing DDS.

OBJECTIVES

To evaluate the benefits and harms of different types of interventions for preventing DDS.

SEARCH METHODS

We contacted the information specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 8 May 2024 using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared any intervention against standard care, including individuals initiated on HD, regardless of age.

DATA COLLECTION AND ANALYSIS

Two authors independently determined study eligibility, assessed quality and extracted data. Data were collected on methods, interventions, participants, and outcomes (DDS incidence, severe DDS, death, adverse events). Risk ratios (RR) and confidence intervals (CI) were calculated. Study quality was assessed using the Cochrane Risk of Bias 2 (ROB2) tool. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included two RCTs, enrolling 32 adult participants. Interventions included were slow dialysis, sodium modelling, standard sodium dialysate, and high sodium dialysate. The risk of bias was of some concern to high risk of bias in both studies. Slow dialysis compared to sodium modelling (1 study, 15 participants) may result in little to no difference in DDS, severe DDS, and death (low certainty evidence) and has uncertain effects on adverse events (RR 1.33, 95% CI 0.15 to 11.64; very low certainty evidence). Standard sodium dialysate compared to high sodium dialysate (1 study, 17 participants) has uncertain effects on the incidence of DDS (RR 0.07, 95% CI 0.00 to 1.12), severe DDS (RR 0.47, 95% CI 0.02 to 10.32), and adverse events (RR 0.29, 95% CI 0.08 to 1.02) (very low certainty evidence).

AUTHORS' CONCLUSIONS

In HD patients, sodium modelling, compared to slow dialysis, may result in little to no difference in DDS and death (low certainty evidence) and has uncertain effects on adverse events (very low certainty evidence). The evidence is very uncertain for the effect of high-sodium dialysate and standard sodium dialysate on DDS, death and adverse events (very low certainty evidence).

The Role of Vitamin B6 in Peripheral Neuropathy: A Systematic Review

INTRODUCTION

Vitamin B6 is a water-soluble vitamin that is naturally present in many foods and is accessible in many dietary supplements. The three natural forms are pyridoxine, pyridoxal, and pyridoxamine. Both vitamin B6 deficiency and high B6 intake have been described as risk factors for developing peripheral neuropathy (PN). The aim of this systematic review is to characterize and comprehensively describe B6-related PN.

METHOD

A systematic, computer-based search was conducted using the PubMed database. Twenty articles were included in this review.

RESULTS

Higher vitamin B6 levels, which usually occur following the taking of nutritional supplements, may lead to the development of a predominantly, if not exclusively, sensory neuropathy of the axonal type. After pyridoxine discontinuation, such patients subjectively report improved symptoms. However, although low vitamin B6 levels can be seen in patients suffering from peripheral neuropathy of various etiologies, there is no firm evidence that low B6 levels have a direct causal relationship with PN. Many studies suggest subjective improvement of neuropathy symptoms in patients suffering from PN of various etiologies after receiving B6 supplementation; however, no data about B6 administration as a monotherapy exist, only as part of a combination treatment, usually with other vitamins. Therefore, the potential therapeutic role of B6 cannot be confirmed to date. Supplementation with vitamin B6, even as part of a nutritional multivitamin supplement, has not been proven harmful at permitted daily doses in patients who already suffer from PN.

CONCLUSION

Current scientific evidence supports a neurotoxic role of B6 at high levels. Although some studies suggest that low B6 is also a potential risk factor, further studies in this area are needed.

Extracorporeal treatment for ethylene glycol poisoning: systematic review and recommendations from the EXTRIP workgroup

Ethylene glycol (EG) is metabolized into glycolate and oxalate and may cause metabolic acidemia, neurotoxicity, acute kidney injury (AKI), and death. Historically, treatment of EG toxicity included supportive care, correction of acid-base disturbances and antidotes (ethanol or fomepizole), and extracorporeal treatments (ECTRs), such as hemodialysis. With the wider availability of fomepizole, the indications for ECTRs in EG poisoning are debated. We conducted systematic reviews of the literature following published EXTRIP methods to determine the utility of ECTRs in the management of EG toxicity. The quality of the evidence and the strength of recommendations, either strong ("we recommend") or weak/conditional ("we suggest"), were graded according to the GRADE approach. A total of 226 articles met inclusion criteria. EG was assessed as dialyzable by intermittent hemodialysis (level of evidence = B) as was glycolate (Level of evidence = C). Clinical data were available for analysis on 446 patients, in whom overall mortality was 18.7%. In the subgroup of patients with a glycolate concentration ≤ 12 mmol/L (or anion gap ≤ 28 mmol/L), mortality was 3.6%; in this subgroup, outcomes in patients receiving ECTR were not better than in those who did not receive ECTR. The EXTRIP workgroup made the following recommendations for the use of ECTR in addition to supportive care over supportive care alone in the management of EG poisoning (very low quality of evidence for all recommendations): i) Suggest ECTR if fomepizole is used and EG concentration > 50 mmol/L OR osmol gap > 50; or ii) Recommend ECTR if ethanol is used and EG concentration > 50 mmol/L OR osmol gap > 50; or iii) Recommend ECTR if glycolate concentration is > 12 mmol/L or anion gap > 27 mmol/L; or iv) Suggest ECTR if glycolate concentration 8-12 mmol/L or anion gap 23-27 mmol/L; or v) Recommend ECTR if there are severe clinical features (coma, seizures, or AKI). In most settings, the workgroup recommends using intermittent hemodialysis over other ECTRs. If intermittent hemodialysis is not available, CKRT is recommended over other types of ECTR. Cessation of ECTR is recommended once the anion gap is < 18 mmol/L or suggested if EG concentration is < 4 mmol/L. The dosage of antidotes (fomepizole or ethanol) needs to be adjusted during ECTR.

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.

Nutritional neuropathies

Neuropathies associated with nutritional deficiencies are routinely encountered by the practicing neurologist. Although these neuropathies assume different patterns, most are length-dependent, sensory axonopathies. Cobalamin deficiency neuropathy is the exception, often presenting with a non-length-dependent sensory neuropathy. Patients with cobalamin and copper deficiency neuropathy characteristically have concomitant myelopathy, whereas vitamin E deficiency is uniquely associated with a spinocerebellar syndrome. In contrast to those nutrients for which deficiencies produce neuropathies, pyridoxine toxicity results in a non-length-dependent sensory neuronopathy. Deficiencies occur in the context of malnutrition, malabsorption, increased nutrient loss (such as with dialysis), autoimmune conditions such as pernicious anemia, and with certain drugs that inhibit nutrient absorption. When promptly identified, therapeutic nutrient supplementation may result in stabilization or improvement of these neuropathies.

Interventions for chronic kidney disease-associated restless legs syndrome

BACKGROUND

Restless legs syndrome (RLS) is defined as the spontaneous movement of the limbs (mainly legs) associated with unpleasant, sometimes painful sensation which is relieved by moving the affected limb. Prevalence of RLS among people on dialysis has been estimated between 6.6% and 80%. RLS symptoms contribute to impaired quality of life and people with RLS are shown to have increased cardiovascular morbidity and mortality.Various pharmacological and non-pharmacological interventions have been used to treat primary RLS. However, the evidence for use of these interventions in people with chronic kidney disease (CKD) is not well established. The agents used in the treatment of primary RLS may be limited by the side effects in people with CKD due to increased comorbidity and altered drug pharmacokinetics.

OBJECTIVES

The aim of this review was to critically look at the benefits, efficacy and safety of various treatment options used in the treatment of RLS in people with CKD and those undergoing renal replacement therapy (RRT). We aimed to define different group characteristics based on CKD stage to assess the applicability of a particular intervention to an individual patient.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 12 January 2016 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCT) and quasi-RCTs that assessed the efficacy of an intervention for RLS in adults with CKD were eligible for inclusion. Studies investigating idiopathic RLS or RLS secondary to other causes were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for eligibility and conducted risk of bias evaluation. Results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

We included nine studies enrolling 220 dialysis participants. Seven studies were deemed to have moderate to high risk of bias. All studies were small in size and had a short follow-up period (two to six months). Studies evaluated the effects of six different interventions against placebo or standard treatment. The interventions studied included aerobic resistance exercise, gabapentin, ropinirole, levodopa, iron dextran, and vitamins C and E (individually and in combination).Aerobic resistance exercise showed a significant reduction in severity of RLS compared to no exercise (2 studies, 48 participants: MD -7.56, 95% CI -14.20 to -0.93; I2 = 65%), and when compared to exercise with no resistance (1 study, 24 participants: MD -11.10, 95% CI -17.11 to -5.09), however there was no significant reduction when compared to ropinirole (1 study, 22 participants): MD -0.55, 95% CI -6.41 to 5.31). There were no significant differences between aerobic resistance exercise and either no exercise or ropinirole in the physical or mental component summary scores (using the SF-36 form). Improvement in sleep quality varied. There was no significant difference in subjective sleep quality between exercise and no exercise; however one study reported a significant improvement with ropinirole compared to resistance exercise (MD 3.71, 95% CI 0.89 to 6.53). Using the Epworth Sleepiness Scale there were no significant differences between resistance exercise and no exercise, ropinirole, or exercise with no resistance. Two studies reported there were no adverse events and one study did not mention if there were any adverse events. In one study, one patient in each group dropped out but the reason for dropout was not reported. Two studies reported no adverse events and one study did not report adverse events.Gabapentin was associated with reduced RLS severity when compared to placebo or levodopa, and there was a significant improvement in sleep quality, latency and disturbance reported in one study when compared to levodopa. Three patients dropped out due to lethargy (2 patients), and drowsiness, syncope and fatigue (1 patient).Because of a short duration of action, rebound and augmentation were noted with levodopa treatment even though it conferred some benefit in reducing the symptoms of RLS. Reported adverse events were severe vomiting, agitation after caffeine intake, headaches, dry mouth, and gastrointestinal symptoms.One study (25 participants) reported iron dextran reduced the severity of RLS at weeks one and two, but not at week four. Vitamins C, E and C plus E (1 study, 60 participants) helped the symptoms of RLS with minimal side effects (nausea and dyspepsia) but more evidence is needed before any conclusions can be drawn.

AUTHORS' CONCLUSIONS

Given the small size of the studies and short follow-up, it can only be concluded that pharmacological interventions and intra-dialytic exercise programs have uncertain effects on RLS in haemodialysis patients. There have been no studies performed in non-dialysis CKD, peritoneal dialysis patients, or kidney transplant recipients. Further studies are warranted before any conclusions can be drawn. Aerobic resistance exercise and ropinirole may be suitable interventions for further evaluation.

Vitamin B and its derivatives for diabetic kidney disease

BACKGROUND

Diabetes is a leading cause of end-stage kidney disease (ESKD) mainly due to development and progression of diabetic kidney disease (DKD). In absence of definitive treatments of DKD, small studies showed that vitamin B may help in delaying progression of DKD by inhibiting vascular inflammation and endothelial cell damage. Hence, it could be beneficial as a treatment option for DKD.

OBJECTIVES

To assess the benefits and harms of vitamin B and its derivatives in patients with DKD.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 29 October 2012 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials comparing vitamin B or its derivatives, or both with placebo, no treatment or active treatment in patients with DKD. We excluded studies comparing vitamin B or its derivatives, or both among patients with pre-existing ESKD.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility, risk of bias and extracted data. Results were reported as risk ratio (RR) or risk differences (RD) with 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) with 95% CI for continuous outcomes. Statistical analyses were performed using the random-effects model.

MAIN RESULTS

Nine studies compared 1354 participants randomised to either vitamin B or its derivatives with placebo or active control were identified. A total of 1102 participants were randomised to single vitamin B derivatives, placebo or active control in eight studies, and 252 participants randomised to multiple vitamin B derivatives or placebo. Monotherapy included different dose of pyridoxamine (four studies), benfotiamine (1), folic acid (1), thiamine (1), and vitamin B12 (1) while combination therapy included folic acid, vitamin B6, and vitamin B12 in one study. Treatment duration ranged from two to 36 months. Selection bias was unclear in three studies and low in the remaining six studies. Two studies reported blinding of patient, caregiver and observer and were at low risk of performance and detection bias, two studies were at high risk bias, and five studies were unclear. Attrition bias was high in one study, unclear in one study and low in seven studies. Reporting bias was high in one study, unclear in one study, and low in the remaining seven studies. Four studies funded by pharmaceutical companies were judged to be at high risk bias, three were at low risk of bias, and two were unclear.Only a single study reported a reduction in albuminuria with thiamine compared to placebo, while second study reported reduction in glomerular filtration rate (GFR) following use of combination therapy. No significant difference in the risk of all-cause mortality with pyridoxamine or combination therapy was reported. None of the vitamin B derivatives used either alone or in combination improved kidney function: increased in creatinine clearance, improved the GFR; neither were effective in controlling blood pressure significantly compared to placebo or active control. One study reported a significant median reduction in urinary albumin excretion with thiamine treatment compared to placebo. No significant difference was found between vitamin B combination therapy and control group for serious adverse events, or one or more adverse event per patient. Vitamin B therapy was reported to well-tolerated with mild side effects in studies with treatment duration of more than six months. Studies of less than six months duration did not explicitly report adverse events; they reported that the drugs were well-tolerated without any serious drug related adverse events. None of the included studies reported cardiovascular death, progression from macroalbuminuria to ESKD, progression from microalbuminuria to macroalbuminuria, regression from microalbuminuria to normoalbuminuria, doubling of SCr, and quality of life. We were not able to perform subgroup or sensitivity analyses or assess publication bias due to insufficient data.

AUTHORS' CONCLUSIONS

There is an absence of evidence to recommend the use of vitamin B therapy alone or combination for delaying progression of DKD. Thiamine was found to be beneficial for reduction in albuminuria in a single study; however, there was lack of any improvement in kidney function or blood pressure following the use of vitamin B preparations used alone or in combination. These findings require further confirmation given the limitations of the small number and poor quality of the available studies.

Water-soluble vitamins in people with low glomerular filtration rate or on dialysis: a review

People with low glomerular filtration rate and people on dialysis are spontaneously at risk for vitamin deficiency because of the potential for problems with decreased appetite and decreased sense of smell and taste, leading to decreased intake, and because decreased energy or decreased cognitive ability results in difficulties in shopping and cooking. Imposed dietary restrictions because of their renal dysfunction and because of comorbidities such as hypertension and diabetes exacerbate this problem. Finally, particularly for water-soluble vitamins, loss may occur into the dialysate. We did not identify any randomized trials of administering daily doses close to the recommended daily allowances of these vitamins. In people who are eating at all, deficiencies of B5 and B7 seem unlikely. It is unclear whether supplements of B2 and B3 are necessary. Because of dialyzability and documented evidence of insufficiency in dialysis patients, B1 supplementation is likely to be helpful. B6, B9, and B12 are implicated in the hyperhomocysteinemia observed in patients on dialysis. These vitamins have been studied in combinations, in high doses, with the hope of reducing cardiovascular outcomes. No reductions in patient-important outcomes were seen in adequately powered randomized trials. Because of their involvement in the homocysteine pathway, however, supplementation with lower doses, close to the recommended daily allowances, may be helpful. Vitamin C deficiency is common in patients on dialysis who are not taking supplements: low-dose supplements are warranted. Vitamins for dialysis patients contain most or all of the B vitamins and low-dose vitamin C. We are not aware of any medical reasons to choose one over another.

Neurologic manifestations of acute and chronic renal disease

Acute and chronic renal disease is prevalent in hospitalized and ambulatory patient populations. Most patients with acute or chronic renal disease exhibit some degree of neurologic dysfunction affecting the CNS, peripheral nervous system, or both. Neurologic manifestations may be a direct consequence of the uremic state or a consequence of renal replacement therapy. Early recognition of common central and peripheral nervous system dysfunction as it relates to renal disease may provide opportunities for therapeutic intervention and improved outcomes. This review will summarize the most frequently encountered manifestations of acute and chronic renal disease, organized with respect to their occurrence as a direct consequence of advanced renal dysfunction or renal replacement therapy.

Effect of diclofenac with B vitamins on the treatment of acute pain originated by lower-limb fracture and surgery

The aim of this study was to compare the efficacy of diclofenac, for the treatment of acute pain originated by lower-limb fracture and surgery, with that of diclofenac plus B vitamins. This was a single-center, prospective, randomized, and double-blinded clinical trial. Patients with lower-limb closed fractures rated their pain on a 10 cm visual analog scale (VAS). Patients were then randomized to receive diclofenac or diclofenac plus B vitamins (thiamine, pyridoxine, and cyanocobalamin) intramuscularly twice daily. Patient evaluations of pain intensity were recorded throughout two periods: twenty-four hours presurgery and twenty-four hours postsurgical. One hundred twenty-two patients completed the study. The subjects' assessments of limb pain on the VAS showed a significant reduction from baseline values regardless of the treatment group. Diclofenac plus B vitamins combination was more effective to reduce the pain than diclofenac alone. The results showed that the addition of B vitamins to diclofenac increased its analgesic effect. The novelty of this paper consists in that diclofenac and diclofenac plus B vitamins were useful for treatment of acute pain originated by lower-limb fracture and surgery.

Neurologic presentations of nutritional deficiencies

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of appropriate nutrients. The first section of this review discusses neurologic manifestations related to deficiency of key nutrients such as vitamin B(12), folate, copper, vitamin E, thiamine, and others. The second section addresses neurologic complications related to bariatric surgery. The third sections includes neurologic presentations caused by nutrient deficiencies in the setting of alcoholism. The concluding section addresses neurologic deficiency diseases that have a geographic predilection.

Neurological complications of chronic kidney disease

Chronic kidney disease (CKD) is a critical and rapidly growing global health problem. Neurological complications occur in almost all patients with severe CKD, potentially affecting all levels of the nervous system, from the CNS through to the PNS. Cognitive impairment, manifesting typically as a vascular dementia, develops in a considerable proportion of patients on dialysis, and improves with renal transplantation. Patients on dialysis are generally weaker, less active and have reduced exercise capacity compared with healthy individuals. Peripheral neuropathy manifests in almost all such patients, leading to weakness and disability. Better dialysis strategies and dietary modification could improve outcomes of transplantation if implemented before surgery. For patients with autonomic neuropathy, specific treatments, including sildenafil for impotence and midodrine for intradialytic hypotension, are effective and well tolerated. Exercise training programs and carnitine supplementation might be beneficial for neuromuscular complications, and restless legs syndrome in CKD responds to dopaminergic agonists and levodopa treatment. The present Review dissects the pathophysiology of neurological complications related to CKD and highlights the spectrum of therapies currently available.

Neuromuscular disease in the dialysis patient: an update for the nephrologist

Neuromuscular disease is an extremely common complication of end-stage kidney disease (ESKD), manifesting in almost all dialysis patients, and leading to weakness, reduced exercise capacity, and disability. Recent studies have suggested that hyperkalemia may underlie the development of neuropathy. As such, maintenance of serum K(+) within normal limits between periods of dialysis in ESKD patients manifesting early neuropathic symptoms may reduce neuropathy development and progression. For patients with more severe neuropathic syndromes, increased dialysis frequency or a switch to high-flux dialysis may prevent further deterioration, while ultimately, renal transplantation is required to improve and restore nerve function. Exercise training programs are beneficial for ESKD patients with muscle weakness due to neuropathy or myopathy, and are capable of improving exercise tolerance and quality of life. Specific treatments have recently been evaluated for symptoms of autonomic neuropathy, including sildenafil for impotence and midodrine for intra-dialytic hypotension, and have been shown to be effective and well tolerated. Other important management strategies for neuropathy include attention to foot care to prevent callus and ulceration, vitamin supplementation, and erythropoietin. Treatment with membrane-stabilizing agents, such as amitryptiline and gabapentin, are highly effective in patients with painful neuropathy.

Vitamin B for treating peripheral neuropathy

BACKGROUND

Vitamin B is frequently used for treating peripheral neuropathy but its efficacy is not clear.

OBJECTIVES

The objective of this review was to assess the effects of vitamin B for treating generalised peripheral neuropathy.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Register (searched August 2005), MEDLINE (January 1966 to September 2005), EMBASE (January 1980 to September 2005), Philippine databases (searched September 2005) and reference lists of articles. We also contacted manufacturers and researchers in the field.

SELECTION CRITERIA

Randomised and quasi-randomised trials where vitamin B was compared with placebo or another treatment in generalised peripheral neuropathy.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

Thirteen studies involving 741 participants with alcoholic or diabetic neuropathy were included. In the comparison of vitamin B with placebo, two small trials showed no significant short-term benefit in pain intensity while one of the trials showed a small significant benefit in vibration detection from oral benfotiamine, a derivative of thiamine. In the larger of two trials comparing different doses of vitamin B complex, there was some evidence that higher doses resulted in a significant short-term reduction in pain and improvement in paraesthesiae, in a composite outcome combining pain, temperature and vibration, and in a composite outcome combining pain, numbness and paraesthesiae. There was some evidence that vitamin B is less efficacious than alpha-lipoic acid, cilostazol or cytidine triphosphate in the short-term improvement of clinical and nerve conduction study outcomes but the trials were small. There were few minor adverse effects reported.

AUTHORS' CONCLUSIONS

There are only limited data in randomised trials testing the efficacy of vitamin B for treating peripheral neuropathy and the evidence is insufficient to determine whether vitamin B is beneficial or harmful. One small trial in alcoholic peripheral neuropathy reported slightly greater improvement in vibration perception threshold with oral benfotiamine for eight weeks than placebo. In another small study, a higher dose of oral vitamin B complex for four weeks was more efficacious than a lower dose in reducing symptoms and signs. Vitamin B administered by various routes for two to eight weeks was less efficacious than alpha-lipoic acid, cilostazol or cytidine triphosphate in short-term improvement of clinical and nerve conduction study outcomes. Vitamin B is generally well-tolerated.

Nutritional neuropathies

Optimal functioning of the central and peripheral nervous system is dependent on appropriate nutrients. Neurologic consequences of nutritional deficiencies are not restricted to underdeveloped countries. Multiple nutritional deficiencies can coexist. Obesity is of particular concern in the developed world. The rising rate of bariatric surgery are accompanied by neurologic complications related to nutrient deficiencies. Prognosis depends on prompt recognition and institution of appropriate therapy. This review discusses peripheral nervous system manifestations related to the deficiency of key nutrients, neurologic complications associated with bariatric surgery, and conditions that have a geographic significance associated with bariatric surgery and certain conditions that have a geographic predilection.

Use of alternative medicine by patients with stage 5 chronic kidney disease

The use of complementary and alternative medicine (CAM) in the United States is growing at a remarkable speed. Herbal products and dietary supplements are CAM therapies that have grown faster than any other CAM treatments. Little information is available about herbs and dietary supplement use in the stage 5 chronic kidney disease population. These products contain a myriad of pharmacologically active compounds that, when used by people with kidney disease, may be hazardous. Members of the renal dietitian listserv were queried about herbs and dietary supplements reportedly used by dialysis patients. Up-to-date information on the use, safety, efficacy, adverse effects, and recommended dosages in the nondialysis population are presented for 24 products. In the dialysis population, Noni juice should be avoided because of its high potassium content. In addition, bulk-forming laxatives such as flaxseed should be used with caution because of the need for increased fluid intake. Dialysis practitioners should include specific questions about herbs and dietary supplement use in medical and nutrition histories, and they should increase their knowledge about these products to advise patients appropriately. A list of reliable sources of information for the health care provider on herbs and dietary supplements is also presented.

Neurological complications in renal failure: a review

Neurological complications whether due to the uremic state or its treatment, contribute largely to the morbidity and mortality in patients with renal failure. Despite continuous therapeutic advances, many neurological complications of uremia, like uremic encephalopathy, atherosclerosis, neuropathy and myopathy fail to fully respond to dialysis. Moreover, dialytic therapy or kidney transplantation may even induce neurological complications. Dialysis can directly or indirectly be associated with dialysis dementia, dysequilibrium syndrome, aggravation of atherosclerosis, cerebrovascular accidents due to ultrafiltration-related arterial hypotension, hypertensive encephalopathy, Wernicke's encephalopathy, hemorrhagic stroke, subdural hematoma, osmotic myelinolysis, opportunistic infections, intracranial hypertension and mononeuropathy. Renal transplantation itself can give rise to acute femoral neuropathy, rejection encephalopathy and neuropathy in graft versus host disease. The use of immunosuppressive drugs after renal transplantation can cause encephalopathy, movement disorders, opportunistic infections, neoplasms, myopathy and progression of atherosclerosis. We address the clinical, pathophysiological and therapeutical aspects of both central and peripheral nervous system complications in uremia.

Effect of vitamin B6 on oxygen radicals, mitochondrial membrane potential, and lipid peroxidation in H2O2-treated U937 monocytes

Vitamin B6 (Vit.B6) supplementation has been shown to be beneficial in reducing diabetic complications, cognitive aging, and in the prevention of coronary heart disease. It was hypothesized that Vit.B6 compounds may function as antioxidants and thus offer protection against oxidative stress under various pathophysiological and or experimental conditions. To test this hypothesis, U937 monocytes were cultured with pyridoxine (P), pyridoxal phosphate (PP) and pyridoxamine (PM) and H2O2, either alone or together for 2 h. Oxidative stress was determined by measuring superoxide radical production, lipid peroxidation, and mitochondrial transmembrane potential. Results demonstrate that Vit.B6 compounds can prevent the oxygen radical generation and lipid peroxidation caused by hydrogen peroxide in U937 monocytes, and that some of the protective effect of Vit.B6 may occur via modification of mitochondrial function.