Thiamine deficiency and unexplained encephalopathy in hemodialysis and peritoneal dialysis patients

Reframing Micronutrient Deficiencies for Modern times: A Review

Micronutrient deficiencies are often discounted in as an entity of the past when access to quality nutrition was scarce. However modern-day conditions such as hemodialysis, complex medication interactions, parenteral nutrition, gastrointestinal resections, institutional living, and substance use can place patients at risk. The metabolic demands of critical illness during prolonged hospitalization may provide added stressors. Food insecurity with reliance on inexpensive calorie-rich, nutrient poor diet may lead to deficiency without overt evidence of malnutrition. Moreover, clinical presentation may be subtle and easily attributed to other diagnoses. Increased awareness of current risk factors is essential for detection and treatment.

Consciousness disturbance in patients with chronic kidney disease: Rare but potentially treatable complication. Clinical and neuroradiological review

In patients with chronic kidney disease, particularly those in end-stage kidney failure and undergoing dialysis treatment, brain complications may arise, and their potential reversibility mainly hinges on timely diagnosis and intervention. Neurological symptoms may be non-specific ranging from slight or pronounced consciousness disturbance till coma, and imaging is the main tool to guide diagnosis and may reveal the underlying pathophysiological mechanism. Kidney impairment, causing a surge in blood pressure, increases the risk of Posterior Reversible Encephalopathy Syndrome and, leads to neurochemical alterations that result in uremic encephalopathy. In end-stage kidney failure patients, Posterior Reversible Encephalopathy Syndrome predominantly occurs in atypical locations, often involving the bilateral basal ganglia, and exhibit larger volumes compared to patients without kidney dysfunction. Uremic encephalopathy may involve the basal ganglia, white matter, and cortical or subcortical regions; in the latter case, imaging features resemble the typical location of Posterior Reversible Encephalopathy Syndrome. Dialysis Disequilibrium Syndrome, Osmotic Demyelination Syndrome, and Wernicke's encephalopathy are uncommon complications associated with dialysis. Each syndrome manifests distinct imaging patterns: Dialysis Disequilibrium Syndrome shows bilateral, patchy, diffuse white matter alterations; Osmotic Demyelination Syndrome causes central pontine and less often extrapontine lesions (involving bilateral basal ganglia, thalamus, and cerebral peduncles); Wernicke's encephalopathy determines symmetrical abnormalities in the thalamus, mammillary bodies, periaqueductal gray matter, midbrain tectal plate but the nature of brain edema associated with these complications remains controversial. Besides, in rare cases, overlapping imaging features may occur, and only the accurate patient's clinical history reconstruction along with laboratory examination results can lead to a better evaluation of MRI findings and underlying causes allowing prompt therapy.

The Approach to Altered Mental Status in the Intensive Care Unit

Altered mental status (AMS) is a syndrome posing substantial burden to patients in the intensive care unit (ICU) in both prevalence and intensity. Unfortunately, ICU patients are often diagnosed merely with syndromic labels, particularly the duo of toxic-metabolic encephalopathy (TME) and delirium. Before applying a nonspecific diagnostic label, every patient with AMS should be evaluated for specific, treatable diseases affecting the central nervous system. This review offers a structured approach to increase the probability of identifying specific causal etiologies of AMS in the critically ill. We provide tips for bedside assessment in the challenging ICU environment and review the role and yield of common neurodiagnostic procedures, including specialized bedside modalities of diagnostic utility in unstable patients. We briefly review two common etiologies of TME (uremic and septic encephalopathies), and then review a selection of high-yield toxicologic, neurologic, and infectious causes of AMS in the ICU, with an emphasis on those that require deliberate consideration as they elude routine screening. The final section lays out an approach to the various etiologies of AMS in the critically ill.

Varying association of nutrient intakes with quality of life in patients receiving different modes of dialysis

Background

Nutrients are crucial for dialysis patients, especially elderly patients. Nutrition-related complications in dialysis patients are often closely related to cardiovascular aging. However, we know little about the effect of different nutrients on the commonly used outcome predictor, health-related quality of life (HRQOL). Therefore, this study investigated the associations between different nutrients and HRQOL among dialysis patients.

Methods

A cross-sectional study was conducted on 123 dialysis adults at multiple dialysis centers. The Short Form-36 Health Survey (SF-36) assesses HRQOL. Modified quantitative subjective global assessment (MQSGA) evaluates nutritional status. A 3-day dietary record evaluated nutrient intakes.

Results

Among the 123 participants, 79 received hemodialysis (HD), and 44 were on peritoneal dialysis (PD). Patients with PD had a higher SF-36 score than HD (525 ± 136 vs. 375 ± 179, P < 0.001). A negative association between nutrition status and HRQOL was observed in HD (regression coefficient β = -17.4, P < 0.001) but not in PD (β = -12.3, P = 0.07). For HD patients, the nutrition status was negatively correlated with intakes of carbohydrates, fiber, selenium, copper, and Manganese (β = -0.02, P = 0.032; β = -0.3, P = 0.031; β = -0.1, P = 0.006; β = -2.3, P = 0.025; β = -1.3, P = 0.003, respectively). Their HRQOL was positively associated with calories, fat, niacin, and vitamin E (β = 2.19, P = 0.035; β = 2.4, P = 0.043; β = 8.5, P = 0.044; β = 6.9, P = 0.017, respectively). Conversely, for patients with PD, only vitamin B2 was found to be adversely correlated with their nutritional status (β = -5.2, P = 0.037), and increased intakes of vitamin A, vitamin C and fiber (β = 0.1, P = 0.031; β = 0.8, P = 0.028; β = 15.8, P = 0.045, respectively) were associated with a better HRQOL.

Conclusions

The nutritional intake of PD patients and HD patients affects their quality of life differently. Macronutrients significantly impact HRQOL in HD patients, while vitamins have a more substantial impact on PD patients.

Water-soluble vitamins and trace elements in children with chronic kidney disease stage 5d

Children receiving maintenance dialysis (chronic kidney disease (CKD) stage 5d) have unique risk factors for micronutrient deficiency or toxicity. Children receiving chronic dialysis often require specialized diet plans that may provide more than the recommended daily allowance (RDA) of water-soluble vitamins and micronutrients, with or without the addition of a kidney-friendly vitamin. The following is a comprehensive review of current literature on disorders of micronutrients in this population including those of water-soluble vitamins (vitamin C and vitamin B complexes) and trace elements (copper, selenium, and zinc) and has three areas of focus: (1) the risk factors and clinical presentations of disorders of micronutrients, both deficiency and toxicity, (2) the tools to evaluate micronutrient status, and (3) the central role of renal dietitians in optimizing nutritional status from a micronutrient perspective.

Hospital Outcomes in Medical Patients With Alcohol-Related and Non-Alcohol-Related Wernicke Encephalopathy

OBJECTIVE

To conduct a nationwide retrospective cohort study to assess trends and hospitalization-associated outcomes in patients with Wernicke encephalopathy.

PATIENTS AND METHODS

In this nationwide retrospective cohort study, we used in-hospital claims data of patients hospitalized with Wernicke encephalopathy in Switzerland from January 1, 2012, to December 31, 2020. We estimated incidence rates per 100,000 person-years among the overall Swiss population stratified by alcohol and non-alcohol-induced Wernicke encephalopathy. The primary outcome was all-cause in-hospital mortality. Secondary outcomes included progression to Korsakoff syndrome and 1-year hospital readmission. We estimated odds ratios (ORs) for binary outcomes.

RESULTS

It was found that 4098 of 4393 hospitalizations (93.3%) for Wernicke encephalopathy during the 8-year study were alcohol-related. Incidence rates for hospitalizations were 14-fold higher in alcohol-related compared with non-alcohol-related Wernicke encephalopathy (5.43 vs 0.39 per 100,000 person-years). The risk for in-hospital mortality was significantly lower in patients with alcohol-related vs non-alcohol-related Wernicke encephalopathy (3.2% vs 8.5%; adjusted OR, 0.38; 95% CI, 0.23 to 0.62). Patients with alcohol-related Wernicke encephalopathy had higher risk for development of Korsakoff syndrome (16.9% vs 1.7%; adjusted OR, 10.64; 95% CI, 4.37 to 25.92) and 1-year hospital readmission (31.6% vs 18.7%; adjusted OR, 1.4; 95% CI, 1.04 to 1.88).

CONCLUSION

In this Swiss nationwide cohort study, Wernicke encephalopathy was a rare but serious cause for hospitalization and mainly alcohol-related. Patients with alcohol-related Wernicke encephalopathy had lower risks of in-hospital mortality but were more likely to develop Korsakoff syndrome and be readmitted to the hospital.

Vitamin Supplement Use in Patients With CKD: Worth the Pill Burden?

All vitamins play essential roles in various aspects of body function and systems. Patients with chronic kidney disease (CKD), including those receiving dialysis, may be at increased risk of developing vitamin deficiencies due to anorexia, poor dietary intake, protein energy wasting, restricted diet, dialysis loss, or inadequate sun exposure for vitamin D. However, clinical manifestations of most vitamin deficiencies are usually subtle or undetected in this population. Testing for circulating levels is not undertaken for most vitamins except folate, B12, and 25-hydroxyvitamin D because assays may not be available or may be costly to perform and do not always correlate with body stores. The last systematic review through 2016 was performed for the Kidney Disease Outcome Quality Initiative (KDOQI) 2020 Nutrition Guideline update, so this article summarizes the more recent evidence. We review the use of vitamins supplementation in the CKD population. To date there have been no randomized trials to support the benefits of any vitamin supplementation for kidney, cardiovascular, or patient-centered outcomes. The decision to supplement water-soluble vitamins should be individualized, taking account the patient's dietary intake, nutritional status, risk of vitamins deficiency/insufficiency, CKD stage, comorbid status, and dialysis loss. Nutritional vitamin D deficiency should be corrected, but the supplementation dose and formulation need to be personalized, taking into consideration the degree of 25-hydroxyvitamin D deficiency, parathyroid hormone levels, CKD stage, and local formulation. Routine supplementation of vitamins A and E is not supported due to potential toxicity. Although more trial data are required to elucidate the roles of vitamin supplementation, all patients with CKD should undergo periodic assessment of dietary intake and aim to receive various vitamins through natural food sources and a healthy eating pattern that includes vitamin-dense foods.

Wernicke's Encephalopathy in Acute and Chronic Kidney Disease: A Systematic Review

Thiamine (vitamin B1) deficiency is relatively common in patients with kidney disease. Wernicke's encephalopathy (WE) is caused by vitamin B1 deficiency. Our aim was to systematically review the signs and symptoms of WE in patients with kidney disease. We conducted a systematic literature review on WE in kidney disease and recorded clinical and radiographic characteristics, treatment and outcome. In total 323 manuscripts were reviewed, which yielded 46 cases diagnosed with acute and chronic kidney disease and WE published in 37 reports. Prodromal characteristics of WE were loss of appetite, vomiting, weight loss, abdominal pain, and diarrhea. Parenteral thiamine 500 mg 3 times per day often led to full recovery, while Korsakoff's syndrome was found in those receiving low doses. To prevent WE in kidney failure, we suggest administering high doses of parenteral thiamine in patients with kidney disease who present with severe malnutrition and (prodromal) signs of thiamine deficiency.

Vitamin Needs and Treatment for Chronic Kidney Disease Patients

This paper summarizes the biochemistry, metabolism, and dietary needs of vitamins in patients with chronic kidney disease (CKD) and kidney transplant recipients. Evidence indicates that the dietary intake, in vivo synthesis, urinary excretion or metabolism of different vitamins may be substantially altered in kidney failure. There are discrepancies in vitamin status assessment depending on whether the assay is functional or measuring the blood vitamin level. Whether vitamin supplements should be routinely prescribed for patients with CKD is controversial. Because low dietary intake and compounds that interfere with vitamin activity are not uncommon in patients with CKD, and water-soluble vitamin supplements appear safe and not costly, the authors recommend that supplements of the water-soluble vitamins should be routinely offered to these individuals. More research is needed to assess vitamin nutrition and function and to determine the daily vitamin needs for all patients with CKD.

Does Vitamin Supplementation Play a Role in Chronic Kidney Disease?

Although the role of vitamins in the human body is proven, guidelines for patients with chronic kidney disease (CKD) remain unclear. This narrative review summarizes the findings of 98 studies of CKD and the effects of vitamin D, B, C, A, E, and K supplementation on patients on dialysis for CKD, with the aim of summarizing the existing guidelines. The findings are promising, showing the potential effectiveness of vitamin supplementation with, for example, vitamins B, D, or C. However, recommendations are still ambiguous, especially in the case of vitamins A and K, due to the potential toxicity associated with higher doses for patients. Continued research is needed to rigorously evaluate the effectiveness and carefully consider the potential risks of some vitamin supplementation for patients with CKD.

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.

Early detection of thiamine deficiency by non-thyroidal illness syndrome in a hemodialysis patient

An 88-year-old male patient on maintenance hemodialysis (HD) therapy experienced gradual losses in appetite and liveliness during the course of 1 month. Physical examinations revealed no abnormalities. However, blood testing indicated non-thyroidal illness syndrome (NTIS) typically observed in patients with severe illness, with serum levels of thyroid stimulating hormone, free triiodothyronine, and free thyroxine of 0.17 μIU/mL, < 1.0 pg/mL, and 0.23 ng/dL, respectively. Brain magnetic resonance imaging to exclude the possibility of central hypothyroidism unexpectedly displayed slight abnormalities inside of the thalami that were characteristic of Wernicke's encephalopathy. Additional examination disclosed low serum thiamine of 20 ng/mL. Thiamine injections of 100 mg at every HD treatment rapidly restored his appetite, liveliness, and NTIS findings. HD patients are at a particularly high risk of thiamine deficiency (TD) and associated severe symptoms due to losses of thiamine during HD sessions. However, its non-specific initial symptoms, including decreases in appetite and liveliness, as well as undetectability in routine blood tests complicate early detection, resulting in underdiagnosis and more severe outcomes. In the present case, TD manifested only as non-specific symptoms and was ultimately revealed by the presence of NTIS, which was resolved with thiamine supplementation. Thus, NTIS might assist in the early detection of TD as an initial sign in HD patients.

Thiamine deficiency in pregnancy and lactation: implications and present perspectives

During pregnancy, many physiologic changes occur in order to accommodate fetal growth. These changes require an increase in many of the nutritional needs to prevent long-term consequences for both mother and the offspring. One of the main vitamins that are needed throughout the pregnancy is thiamine (vitamin B1) which is a water-soluble vitamin that plays an important role in many metabolic and physiologic processes in the human body. Thiamine deficiency during pregnancy can cause can have many cardiac, neurologic, and psychological effects on the mother. It can also dispose the fetus to gastrointestinal, pulmonological, cardiac, and neurologic conditions. This paper reviews the recently published literature about thiamine and its physiologic roles, thiamine deficiency in pregnancy, its prevalence, its impact on infants and subsequent consequences in them. This review also highlights the knowledge gaps within these topics.

Brain MRI detection of early Wernicke's encephalopathy in a hemodialysis patient

A 93-year-old hemodialysis patient became hospitalized for thiamine deficiency-induced appetite loss and ultimately experienced consciousness disorder diagnosed as Wernicke's encephalopathy (WE). Since brain MRI on admission was retrospectively found to display faint WE findings, careful brain MRI assessment is recommended in hemodialysis patients with appetite loss alone.

A case of Wernicke encephalopathy arising in the early stage after the start of hemodialysis

Wernicke encephalopathy (WE) resulting from vitamin B1 (VB1) deficiency is commonly regarded as being associated with a high alcohol intake; however, recently many non-alcohol-related cases have been reported. Herein, we report a case of WE due to VB1 deficiency in the early stage after the start of hemodialysis. The patient was a 79-year-old male recommended for hemodialysis due to chronic renal failure. He was admitted to our hospital due to a hemorrhagic duodenal ulcer, but hemodialysis was started as the result of exacerbation of renal function. After the start of 3-times-weekly hemodialysis, the patient's general condition was settled and he was able to consume about half his usual dietary intake. Seventeen days after the start of hemodialysis, impaired consciousness and involuntary movements appeared, and subsequent head magnetic resonance imaging showed increased signal intensity around the cerebral aqueduct. VB1 administration based on a suspicion of WE resulted in a significant improvement in neurological symptoms and no sequelae were observed. Hemodialysis may be a risk factor for VB1 deficiency. When a dialysis patient presents with psychiatric symptoms or impaired consciousness, in particular, it is important to always keep the possibility of VB1 deficiency in mind.

Case Report: A Case of Encephalopathy Presenting the Lentiform Fork Sign on MRI in a Diabetic Dialysis Patient

Basal ganglia lesions showing an expansile high signal intensity on T2-weighted MRI are termed the lentiform fork sign. This specific finding is mainly observed in diabetic patients with uremic encephalopathy with metabolic acidosis, although there are also reports in patients with ketoacidosis, dialysis disequilibrium syndrome, intoxication, and following drug treatment (e.g., metformin). A 57-year-old Japanese man on chronic hemodialysis for 4 years because of diabetic nephropathy was admitted to our hospital for relatively rapid-onset gait disturbance, severe dysarthria, and consciousness disturbance. Brain T2-weighted MRI showed the lentiform fork sign. Hemodialysis was performed the day before admission, and laboratory tests showed mild metabolic (lactic) acidosis, but no uremia. Surprisingly, metformin, which is contraindicated for patients with end-stage kidney disease, had been prescribed for 6 months in his medication record, and his sluggish speaking and dysarthria appeared gradually after metformin treatment was started. Thus, the encephalopathy was considered to be related to metformin treatment. He received hemodialysis treatment for 6 consecutive days, and his consciousness disturbance and dysarthria improved in 1 week. At the 8-month follow-up, the size of the hyperintensity area on MRI had decreased, while the mild gait disturbance remained. Considering the rapid onset of gait and consciousness disturbance immediately before admission, diabetic uremic syndrome may also have occurred with metformin-related encephalopathy, and resulted in the lentiform fork sign, despite the patient showing no evidence of severe uremia on laboratory data.

The Changes in Antioxidant Activity of Selected Flavonoids and Caffeine Depending on the Dosage and Form of Thiamine

Phenolic compounds and thiamine may serve as therapies against oxidative stress-related neurodegenerative diseases. However, it is important to note that these components show high instability under changing conditions. The study’s aim was to determine the impact of the thiamine concentration (hydrochloride—TH and pyrophosphate—TP; in the range 0.02 to 20 mg/100 g on the indices of the chelating properties and reducing power, and free radicals scavenging indices of EGCG, EGC, ECG and caffeine added from 0.04 to 6.0 mg/100 g. Our research confirmed that higher concentrations of TH and TP can exhibit significant activity against the test antioxidant indices of all components. When above 5.0 mg/100 g of thiamine was used, the radical scavenging abilities of the compound decreased in the following order: EGCG > ECG > EGC > caffeine. The highest correlation was found for the concentration of thiamine pyrophosphate to 20.0 mg/100 g and EGCG. Knowledge of the impact of factors associated with the concentration of both EGCG, EGC, ECG or caffeine and thiamine on their activity could carry weight in regulating the quality supplemented foods, especially of nutrition support for people of all ages were oral, enteral tube feeding and parenteral nutrition).

Pediatric thiamine deficiency disorders in high-income countries between 2000 and 2020: a clinical reappraisal

Often thought to be a nutritional issue limited to low- and middle-income countries (LMICs), pediatric thiamine deficiency (PTD) is perceived as being eradicated or anecdotal in high-income countries (HICs). In HICs, classic beriberi cases in breastfed infants by thiamine-deficient mothers living in disadvantaged socioeconomic conditions are thought to be rare. This study aims to assess PTD in HICs in the 21st century. Literature searches were conducted to identify case reports of PTD observed in HICs and published between 2000 and 2020. The analyzed variables were age, country, underlying conditions, clinical manifestations of PTD, and response to thiamine supplementation. One hundred and ten articles were identified, totaling 389 PTD cases that were classified into four age groups: neonates, infants, children, and adolescents. Eleven categories of PTD-predisposing factors were identified, including genetic causes, lifestyle (diabetes, obesity, and excessive consumption of sweetened beverages), eating disorders, cancer, gastrointestinal disorders/surgeries, critical illness, and artificial nutrition. TD-associated hyperlactatemia and Wernicke encephalopathy were the most frequent clinical manifestations. The circumstances surrounding PTD in HICs differ from classic PTD observed in LMICs and this study delineates its mutiple predisposing factors. Further studies are required to estimate its magnitude. Awareness is of utmost importance in clinical practice.

Vitamin B-6-Induced Neuropathy: Exploring the Mechanisms of Pyridoxine Toxicity

Vitamin B-6 in the form of pyridoxine (PN) is commonly used by the general population. The use of PN-containing supplements has gained lots of attention over the past years as they have been related to the development of peripheral neuropathy. In light of this, the number of reported cases of adverse health effects due to the use of vitamin B-6 have increased. Despite a long history of study, the pathogenic mechanisms associated with PN toxicity remain elusive. Therefore, the present review is focused on investigating the mechanistic link between PN supplementation and sensory peripheral neuropathy. Excessive PN intake induces neuropathy through the preferential injury of sensory neurons. Recent reports on hereditary neuropathy due to pyridoxal kinase (PDXK) mutations may provide some insight into the mechanism, as genetic deficiencies in PDXK lead to the development of axonal sensory neuropathy. High circulating concentrations of PN may lead to a similar condition via the inhibition of PDXK. The mechanism behind PDXK-induced neuropathy is unknown; however, there is reason to believe that it may be related to γ-aminobutyric acid (GABA) neurotransmission. Compounds that inhibit PDXK lead to convulsions and reductions in GABA biosynthesis. The absence of central nervous system-related symptoms in PDXK deficiency could be due to differences in the regulation of PDXK, where PDXK activity is preserved in the brain but not in peripheral tissues. As PN is relatively impermeable to the blood-brain barrier, PDXK inhibition would similarly be confined to the peripheries and, as a result, GABA signaling may be perturbed within peripheral tissues, such as sensory neurons. Perturbed GABA signaling within sensory neurons may lead to excitotoxicity, neurodegeneration, and ultimately, the development of peripheral neuropathy. For several reasons, we conclude that PDXK inhibition and consequently disrupted GABA neurotransmission is the most plausible mechanism of toxicity.

Chronic and End-Stage Kidney Disease in the Neurological Intensive Care Unit

Patients with renal disease have increased rates of admission to the neurological intensive care unit related to overlapping risk factors for renal and cerebrovascular disease as well as unique risks associated with renal dysfunction alone. Management of acute neurological injury in these patients requires individualized attention to diagnostic and management factors as they relate to coagulopathy, disorders of immune function, encephalopathy and renal replacement modalities. Careful consideration of these brain-kidney interactions is necessary to optimize care for this special patient population and improve neurological and renal outcomes.

A Retrospective Case Series of Thiamine Deficiency in Non-Alcoholic Hospitalized Veterans: An Important Cause of Delirium and Falling?

Thiamine deficiency (TD) in non-alcoholic hospitalized patients causes a variety of non-specific symptoms. Studies suggest it is not rare in acutely and chronically ill individuals in high income countries and is underdiagnosed. Our aim is to demonstrate data which help define the risk factors and constellation of symptoms of TD in this population. We describe 36 cases of TD in hospitalized non-alcoholic veterans over 5 years. Clinical and laboratory data were extracted by chart review +/− 4 weeks of plasma thiamine level 7 nmol/L or less. Ninety-seven percent had two or more chronic inflammatory conditions (CICs) and 83% had one or more acute inflammatory conditions (AICs). Of possible etiologies of TD 97% had two or more of: insufficient intake, inflammatory stress, or increased losses. Seventy-five percent experienced 5% or more weight loss. Ninety-two percent had symptoms with the most common being weakness or falling (75%) followed by neuropsychiatric manifestations (72%), gastrointestinal dysfunction (53%), and ataxia (42%). We conclude that TD is underdiagnosed in this population with consequent morbidity and mortality. TD likely develops because of inflammatory stress from CIC’s compounded by AIC’s combined with decreased energy intake or increased nutrient losses.

Thiamine deficiency unrelated to alcohol consumption in high-income countries: a literature review

Thiamine deficiency has been typically associated with alcoholism or as a prevalent problem in low‐ and middle‐income countries (LMICs) whose populations rely on staple foods with a low content of thiamine. We conducted a literature review of published and unpublished data to identify relevant adult cases with confirmed thiamine deficiency of nonalcoholic cause in developed countries. We selected 17 reports with 81 adult cases of confirmed thiamine deficiency affecting adult patients with a wide range of ages and underlying conditions (e.g., cancer, gastrointestinal diseases, heart failure, and obesity). Thiamine deficiency may have been caused by disease‐related malnutrition, bariatric surgery, chronic use of diuretics, repeated vomiting, lack of thiamine in parenteral nutrition formulas, food insecurity, and reliance on monotonous or restrictive diets. Treatment with intravenous thiamine resulted in partial or complete recovery from the symptoms (cardiac, neurologic, and metabolic disorders) for most patients. The number and variety of symptomatic thiamine‐deficient adults identified in this review demonstrates that thiamine deficiency is not exclusive to LMICs and, in high‐income settings, is not exclusive to alcoholic patients. In developed countries, this serious but treatable condition can be expected in patients suffering from various medical conditions or following certain dietary patterns.

Update on Safety Profiles of Vitamins B1, B6, and B12: A Narrative Review

The neurotropic B vitamins B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) are essential for proper functioning of the nervous system. Deficiencies may induce neurological disorders like peripheral neuropathy (PN) and mainly occur in vulnerable populations (eg, elderly, diabetics, alcoholics). As epidemiologic cohort studies raised safety concerns about vitamin B6/B12 intake being potentially associated with increased risks of hip fracture (HF) and lung cancer (LC), we explored these aspects and performed comprehensive literature searches. However, we suggest not to neglect actual high-risk factors (eg, smoking in LC, higher age in HF) by focusing on individual nutrients, but to examine the complex interaction of numerous factors involved in disease development. Because it warrants continued consideration, we also provide an update on neurotoxicity associated with vitamin B6. We consider that neurological side effects due to vitamin B6 intake are rare and only occur with high daily doses and/or longer treatment duration. The benefit-risk ratio of high-dose treatment with neurotropic B vitamins in indications like PN is therefore considered advantageous, particularly if dosing recommendations are followed and serum levels monitored.

Movement Disorders in Chronic Kidney Disease - A Descriptive Review

OBJECTIVES

The objective of this study is to describe the mechanism of damage to subcortical structures in chronic kidney disease (CKD) and to describe the range of movement disorders associated with CKD.

MATERIALS AND METHODS

We have reviewed the Medline literature up to January of 2020 using key words movement disorders and chronic kidney disease. The reviewed articles were studied for mechanisms of subcortical damage in CKD as well as type of the reported movements, their frequency and updated treatment.

RESULTS

The search revealed 183 articles most of them dealing with restless legs syndrome. The damage to basal ganglia in CKD resulted from several mechanisms including accumulation of nitro tyrosine caused by reactive oxygen species and action of uremic toxins leading to endothelial damage and dysfunction of blood-brain barrier. Involuntary movements in CKD include restless legs syndrome (RLS), myoclonus, asterixis, dystonia, chorea, tremor, and Parkinsonism.

CONCLUSIONS

Chronic kidney disease can cause several abnormal involuntary movements via damaging basal ganglia and subcortical structures. The most common movement disorders in CKD are RLS, myoclonus and asterixis. Restless legs syndrome and myoclonus when severe, need and respond to treatment. Movement disorders in CKD improve with improvement of kidney function.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Case Report: A Case of Encephalopathy Presenting the Lentiform Fork Sign on MRI in a Diabetic Dialysis Patient

Basal ganglia lesions showing an expansile high signal intensity on T2-weighted MRI are termed the lentiform fork sign. This specific finding is mainly observed in diabetic patients with uremic encephalopathy with metabolic acidosis, although there are also reports in patients with ketoacidosis, dialysis disequilibrium syndrome, intoxication, and following drug treatment (e.g., metformin). A 57-year-old Japanese man on chronic hemodialysis for 4 years because of diabetic nephropathy was admitted to our hospital for relatively rapid-onset gait disturbance, severe dysarthria, and consciousness disturbance. Brain T2-weighted MRI showed the lentiform fork sign. Hemodialysis was performed the day before admission, and laboratory tests showed mild metabolic (lactic) acidosis, but no uremia. Surprisingly, metformin, which is contraindicated for patients with end-stage kidney disease, had been prescribed for 6 months in his medication record, and his sluggish speaking and dysarthria appeared gradually after metformin treatment was started. Thus, the encephalopathy was considered to be related to metformin treatment. He received hemodialysis treatment for 6 consecutive days, and his consciousness disturbance and dysarthria improved in 1 week. At the 8-month follow-up, the size of the hyperintensity area on MRI had decreased, while the mild gait disturbance remained. Considering the rapid onset of gait and consciousness disturbance immediately before admission, diabetic uremic syndrome may also have occurred with metformin-related encephalopathy, and resulted in the lentiform fork sign, despite the patient showing no evidence of severe uremia on laboratory data.

Don't seek, don't find: The diagnostic challenge of Wernicke's encephalopathy

Wernicke’s encephalopathy is caused by thiamine deficiency and has a range of presenting features, including gait disturbance, altered cognitive state, nystagmus and other eye movement disorders. In the past, Wernicke’s encephalopathy was described almost exclusively in the alcohol-dependent population. However, in current times, Wernicke’s encephalopathy is also well recognized in many other patient groups, including patients following bariatric surgery, gastrointestinal surgery, cancer and pancreatitis. Early recognition of Wernicke’s encephalopathy is vital, as prompt treatment can restore cognitive or ocular function and can prevent permanent disability. Unfortunately, Wernicke’s encephalopathy is often undiagnosed – presumably because it is relatively uncommon and has a variable clinical presentation. Clinical biochemists have a unique role in advising clinicians about potential nutritional or metabolic causes of unexplained neurological symptoms and to prompt consideration of thiamine deficiency as a potential cause in high-risk patient groups. The aim of this review is to summarize the clinical features, diagnosis and treatment of Wernicke’s encephalopathy and to highlight some non-traditional causes, such as after bariatric surgery.

Movement Disorders Due to Selective Basal Ganglia Lesions with Uremia

BACKGROUND

Basal ganglia (BG) lesions are rarely reported in patients with uremia and may manifest by movement disorders. However, their exact incidence and pathogenesis have not been extensively studied. This study aimed to determine the frequency, types, risk variables (clinical, laboratory, and imaging), and manifestations of BG lesions with uremia and patients' neurologic outcomes.

METHODS

This observational study included 70 adults (mean age: 45.87 ± 3.36 years; duration of uremia: 5.5 ± 1.5 years). They underwent extensive evaluations (clinical, laboratory, and neuroimaging) and had prospectively evaluated clinically every 3 months for 2 years. Repeated magnetic resonance imaging (MRI) brains were done to patients with movement disorders and correlated with their neurologic outcomes.

RESULTS

BG lesions were found in 15 patients (21.4%) and 6 (8.6%) had movement disorders [Parkinsonism (n = 4), choreo-dystonia (n = 1) and dystonia (n = 1)] after the onset of uremia (mean = 10 months). There were no characteristic risk variables that distinguished patients with movement disorders from those without. Five developed movement disorders prior to the period of the study and one was de novo. The majority was females and had diabetes and higher frequencies of abnormal renal dysfunction, metabolic derangements, and white matter hyperintensities in MRIs. Movement disorders persisted in all patients despite the resolution of neuroimaging in three patients.

CONCLUSIONS

There is no clear threshold for renal failure to result in movement disorders due to BG lesions. The clinical outcome is variables depending on each patient's comorbidities and complications. Persistent neuronal damage (due to uremic toxins/metabolic/nutritional and ischemic/microvascular factors) has been suggested as the cause of poor neurologic outcomes.

Characterizing the gut microbiota in patients with chronic kidney disease

Objectives: Emerging evidence suggests that gut microbiota dysbiosis plays a critical role in chronic kidney disease (CKD). However, the relationship between altered gut microbiome profiles and disease severity remains unclear. In this study, we sought to characterize the gut microbiota in CKD patients compared to healthy controls, and to explore potential relationships between gut microbiota composition and disease severity. Methods: Fecal samples were collected from 95 patients at different stages of CKD (non-dialysis patients from stage 1 to 5) and 20 healthy controls. Bacterial DNA was extracted for 16S ribosomal DNA sequencing targeting the V3-V4 region. The diversity and relative abundance of gut microbiota were analyzed as outcome indicators. Results: Differences were observed in the microbial composition and diversity of fecal samples from CKD patients and healthy controls. Specifically, disease severity was found to alter gut microbiota composition. Compared to that in healthy controls, CKD patients showed an increased abundance of Proteobacteria and decreased Synergistetes, most notably in disease stage 5. Lower levels of butyrate-producing bacteria and higher levels of potential pathogens were also detected in CKD patients. Further, Pyramidobacter and Prevotellaceae_UCG-001 were significantly decreased in the CKD1 group compared with healthy controls. Notably, nine microbial genera, including Escherichia-Shigella, Parabacteroides, Roseburia, rectale_group, Ruminococcaceae_NK4A214_group, Prevotellaceae_UCG.001, Hungatella, Intestinimonas, and Pyramidobacter, identified using a random forest model, distinguished between patients with CKD and healthy controls with high accuracy. Functional analysis also revealed that fatty acid and inositol phosphate metabolism were enriched in the CKD group, while aminoacyl-tRNA biosynthesis, oxidative phosphorylation, phenylalanine, tyrosine, and tryptophan biosynthesis, thiamine metabolism, pantothenate, and CoA biosynthesis, as well as valine, leucine, and isoleucine biosynthesis were enriched in healthy controls. Conclusion: Gut microbiota composition and function are associated with CKD severity. And, specific gut microbes are potentially helpful for CKD early diagnosis and prognosis monitoring.

Dietary Daily Sodium Intake Lower than 1500 mg Is Associated with Inadequately Low Intake of Calorie, Protein, Iron, Zinc and Vitamin B1 in Patients on Chronic Hemodialysis

Background: To measure daily sodium intake in patients on chronic hemodialysis and to compare the intake of nutrients, minerals, trace elements, and vitamins in patients who had a daily sodium intake below or above the value of 1500 mg recommended by the American Heart Association. Methods: Dietary intake was recorded for 3 days by means of 3-day diet diaries in prevalent patients on chronic hemodialysis. Each patient was instructed by a dietitian on how to fill the diary, which was subsequently signed by a next of kin. Results: We studied 127 patients. Mean sodium intake (mg) was 1295.9 ± 812.3. Eighty-seven (68.5%) patients had a daily sodium intake <1500 mg (group 1) and 40 (31.5%) ≥ 1500 mg (group 2). Correlation between daily sodium intake and daily calorie intake was significant (r = 0.474 [0.327 to 0.599]; p < 0.0001). Daily calorie intake (kcal/kg/day) was lower in group 1 (21.1 ± 6.6; p = 0.0001) than in group 2 (27.1 ± 10.4). Correlation between daily sodium intake and daily protein intake was significant (r = 0.530 [0.392 to 0.644]; p < 0.0001). The daily protein intake (grams/kg/day) was lower in group 1 (0.823 ± 0.275; p = 0.0003) than in group 2 (1.061 ± 0.419). Daily intake of magnesium, copper, iron, zinc, and selenium was significantly lower in group 1 than in group 2. Daily intake of vitamin A, B2, B3, and C did not differ significantly between group 1 and group 2. Daily intake of vitamin B1 was significantly lower in group 1 than in group 2. Significantly lower was, in group 1 than in group 2, the percentage of patients within the target value with regard to intake of calories (11.5% vs. 37.5%; p = 0.001) and proteins (9.2% vs. 27.5%; p = 0.015) as well as of iron (23% vs. 45%; p = 0.020), zinc (13.8% vs. 53.8%; p = 0.008) and vitamin B1 (8.1% vs. 50%; p < 0.001). Conclusion: A low daily intake of sodium is associated with an inadequately low intake of calorie, proteins, minerals, trace elements, and vitamin B1. Nutritional counselling aimed to reduce the intake of sodium in patients on chronic hemodialysis should not disregard an adequate intake of macro- and micronutrients, otherwise the risk of malnutrition is high.

Inflammation and Oxidative Stress in Chronic Kidney Disease-Potential Therapeutic Role of Minerals, Vitamins and Plant-Derived Metabolites

Chronic kidney disease (CKD) is a debilitating pathology with various causal factors, culminating in end stage renal disease (ESRD) requiring dialysis or kidney transplantation. The progression of CKD is closely associated with systemic inflammation and oxidative stress, which are responsible for the manifestation of numerous complications such as malnutrition, atherosclerosis, coronary artery calcification, heart failure, anemia and mineral and bone disorders, as well as enhanced cardiovascular mortality. In addition to conventional therapy with anti-inflammatory and antioxidative agents, growing evidence has indicated that certain minerals, vitamins and plant-derived metabolites exhibit beneficial effects in these disturbances. In the current work, we review the anti-inflammatory and antioxidant properties of various agents which could be of potential benefit in CKD/ESRD. However, the related studies were limited due to small sample sizes and short-term follow-up in many trials. Therefore, studies of several anti-inflammatory and antioxidant agents with long-term follow-ups are necessary.

B Vitamins in the nervous system: Current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin

Background

Neurotropic B vitamins play crucial roles as coenzymes and beyond in the nervous system. Particularly vitamin B1 (thiamine), B6 (pyridoxine), and B12 (cobalamin) contribute essentially to the maintenance of a healthy nervous system. Their importance is highlighted by many neurological diseases related to deficiencies in one or more of these vitamins, but they can improve certain neurological conditions even without a (proven) deficiency.

Aim

This review focuses on the most important biochemical mechanisms, how they are linked with neurological functions and what deficits arise from malfunctioning of these pathways.

Discussion

We discussed the main role of B Vitamins on several functions in the peripheral and central nervous system (PNS and CNS) including cellular energetic processes, antioxidative and neuroprotective effects, and both myelin and neurotransmitter synthesis. We also provide an overview of possible biochemical synergies between thiamine, pyridoxine, and cobalamin and discuss by which major roles each of them may contribute to the synergy and how these functions are inter‐related and complement each other.

Conclusion

Taking into account the current knowledge on the neurotropic vitamins B1, B6, and B12, we conclude that a biochemical synergy becomes apparent in many different pathways in the nervous system, particularly in the PNS as exemplified by their combined use in the treatment of peripheral neuropathy.

Uremic encephalopathy in patients undergoing assisted peritoneal dialysis: a case series and literature review

We sometimes hesitate to switch renal replacement therapy from peritoneal dialysis (PD) particularly in elderly patients due to their physical tolerance levels and lifestyles. Here, we describe the cases of three patients treated with PD alone despite an anuric status who subsequently developed uremic encephalopathy, which was successfully treated with hemodialysis (HD). The first patient was a 75-year-old woman who developed uremic encephalopathy with an anuric status and inadequate PD after 7 months of treatment. HD immediately improved her condition; encephalopathy did not recur with combined therapy of PD and HD. The second patient was a 69-year-old woman who developed anuria and was treated with combined therapy. Her arteriovenous fistula was obstructed; therefore, she was treated with PD alone. Total weekly Kt/V was sufficiently high at 1.95; however, she developed uremic encephalopathy the following month, which was successfully treated with HD. The third patient was an 84-year-old woman who developed anuria, but was treated with PD alone with adequate total weekly Kt/V of 2.2. PD could not be performed for 2 days because of myocardial infarction intervention; subsequently, she developed uremic encephalopathy, which was successfully treated with HD. These cases are the first of their kinds, wherein patients undergoing PD, developed uremic encephalopathy without any obvious triggers, including drugs, and illustrate the necessity of initiating combined therapy for such patients considering the risk of developing severe uremia leading to uremic encephalopathy, in spite of it being less preferable for elderly patients due to their physical conditions and lifestyles.

Cell Culture Medium Formulation and Its Implications in Cancer Metabolism

Historic cell culture media were designed to ensure continuous cancer cell proliferation in vitro. However, their composition does not recapitulate the nutritional environment of the tumor. Recent studies show that novel media formulations alleviate the nonphysiological constraints imposed by historic media, and lead to cell culture results that are more relevant to tumor metabolism.

Thiamine and Heart Failure: Challenging Cases of Modern-Day Cardiac Beriberi

Cardiac beriberi, or heart failure due to thiamine deficiency, is considered rare in the developed world. The diagnosis is often only considered in limited populations such as those with chronic alcoholism. Alternatively, the disease can be mislabeled as "alcoholic cardiomyopathy" or "nonischemic cardiomyopathy." The following 2 cases illustrate the need to expand our vigilance to other at-risk populations.

Neurologic conditions and disorders of uremic syndrome of chronic kidney disease: presentations, causes, and treatment strategies

Introduction: Uremic syndrome of chronic kidney disease (CKD) is a term used to describe clinical, metabolic, and hormonal abnormalities associated with progressive kidney failure. It is a rapidly growing public health problem worldwide. Nervous system complications occur in every patient with uremic syndrome of CKD. Areas covered: This review summarized central and peripheral nervous system complications of uremic syndrome of CKD and their pathogenic mechanisms. They include cognitive deterioration, encephalopathy, seizures, asterixis, myoclonus, restless leg syndrome, central pontine myelinolysis, stroke, extrapyramidal movement disorders, neuropathies, and myopathy. Their pathogenic mechanisms are complex and multiple. They include (1) accumulation of uremic toxins resulting in neurotoxicity, blood-brain barrier injury, neuroinflammation, oxidative stress, apoptosis, brain neurotransmitters imbalance, ischemic/microvascular changes, and brain metabolism dysfunction (e.g. dopamine deficiency), (2) metabolic derangement (as acidosis, hypocalcemia, hyperphosphatemia, hypomagnesemia, and hyperkalemia); (3) secondary hyperparathyroidism, (4) erythropoietin and iron deficiency anemia, (5) thiamin, vitamin D, and other nutritional deficiencies, (6) hyperhomocysteinemia, and (7) coagulation problems. Expert commentary: Nervous system complications of uremia contribute to the patients' morbidity and mortality. Optimizing renal replacement therapy, correction of associated metabolic and medical conditions, and improved understanding of possible pathogenic mechanisms of these complications is a major target for their prevention and treatment.

Metformin-induced encephalopathy: the role of thiamine

A case of metformin encephalopathy is presented in a patient on haemodialysis for end-stage diabetic renal failure. The patient presented with frequent falls and clinical signs of Parkinsonism, on a background of recent anorexia and significant weight loss. Magnetic resonance imaging showed bilateral, symmetrical abnormalities centred on the lentiform nuclei. Metformin was withheld and signs and symptoms quickly resolved. We hypothesise that metformin may cause thiamine deficiency in patients with end-stage renal failure resulting in a specific metabolic encephalopathy.

Vitamin and trace element deficiencies in the pediatric dialysis patient

Pediatric dialysis patients are at risk of nutritional illness secondary to deficiencies in water-soluble vitamins and trace elements. Unlike 25-OH vitamin D, most other vitamins and trace elements are not routinely monitored in the blood and, consequently, the detection of any deficiency may not occur until significant complications develop. Causes of vitamin and trace element deficiency in patients on maintenance dialysis patient are multifactorial, ranging from diminished nutritional intake to altered metabolism as well as dialysate-driven losses of water-soluble vitamins and select trace elements. In this review we summarize the nutritional sources of key water-soluble vitamins and trace elements with a focus on the biological roles and clinical manifestations of their respective deficiency to augment awareness of potential nutritional illness in pediatric patients receiving maintenance dialysis. The limited pediatric data on the topic of clearance of water-soluble vitamins and trace elements by individual dialysis modality are reviewed, including a brief discussion on clearance of water-soluble vitamins and trace elements with continuous renal replacement therapy.

Wernicke's encephalopathy after cardiac surgery

A 76-year-old woman who had been on hemodialysis for 3 years developed ischemic mitral valve insufficiency, tricuspid insufficiency, and chronic atrial fibrillation, and underwent cardiac surgery. On the 4th postoperative day, she experienced a sudden disturbance of consciousness, aphasia, and limb ataxia. Brain computed tomography and magnetic resonance imaging showed no abnormalities. Wernicke's encephalopathy was suspected and the patient was given vitamin B1, whereupon her symptoms gradually improved. On the 42nd postoperative day, she was free of neurological symptoms and discharged.

Neurological complications of renal dialysis and transplantation

Neurological complications from renal replacement therapy contribute significantly to morbidity and mortality in patients with renal failure. Such complications can affect either the central or peripheral nervous systems. Most neurological disturbances associated with the uraemic state do not respond fully to renal replacement therapy. There are also complications specifically associated with dialysis and transplantation. A multidisciplinary approach, involving both nephrologists and neurologists, is critical for the diagnosis and effective management of these disorders.

Thiamine Diphosphate Status and Dialysis-Related Losses in End-Stage Kidney Disease Patients Treated with Hemodialysis

Aim: (1) To describe the whole blood content of thiamine diphosphate (TDP), a biologically active form of vitamin B1 in end-stage kidney disease patients treated with hemodialysis (HD); (2) to establish the impact of a single HD procedure on TDP blood concentrations; and (3) to describe potential explanatory variables influencing TDP dialysis related losses, including dialysis prescription, vitamin B1 dietary intake and supplementation. Methods: Single-center, cross-sectional study in 50 clinically stable maintenance HD patients. The assessment of whole blood TDP with the High Performance Liquid Chromatography method, before and after a single, middle-week dialysis session and analysis of clinical and laboratory parameters potentially influencing TDP status Results: We report a significant difference in TDP levels before and after HD sessions - 42.5 (95% CI 38.7-46.2) μg/L and 23.6 (95% CI 18.9-28.2) μg/L, respectively (p = 0.000). The magnitude of intradialytic TDP changes is highly variable among individuals and is negatively associated only with the body weight of the patients (p < 0.013). Vitamin B1 dietary intake and supplementation do not influence whole blood TDP and dialysis-related loss of TDP. Conclusions: TDP, a bioactive compound of vitamin B1, is substantially lost during the HD procedure, and the magnitude of its loss is associated with the patient's body weight but it is not influenced by vitamin B1 dietary intake and standard supplementation dose.

Vitamins and Microelement Bioavailability in Different Stages of Chronic Kidney Disease

Chronic kidney disease (CKD) predisposes one to either deficiency or toxic excess of different micronutrients. The knowledge on micronutrients—specifically water-soluble vitamins and trace elements—in CKD is very limited. Consequently, current guidelines and recommendations are mostly based on expert opinions or poor-quality evidence. Abnormalities of micronutrient resources in CKD develop for several reasons. Dietary restrictions and anorexia lead to an insufficient micronutrient intake, while diuretics use and renal replacement therapy lead to their excessive losses. Absorption is unpredictable, and metabolism impaired. Better understanding of the micronutrient needs of CKD patients could have an impact on many complications linked to vitamin and trace element disorders, including high mortality, increased risk of atherosclerosis, inflammation, oxidative stress, anemia, polyneuropathy, encephalopathy, weakness and fragility, muscle cramps, bone disease, depression, or insomnia. Here, we summarize the up-to-date knowledge on micronutrient resources in different stages of CKD, and share our experience with the assessment of micronutrient status.

Neurological complications in chronic kidney disease

Patients with chronic kidney disease (CKD) are frequently afflicted with neurological complications. These complications can potentially affect both the central and peripheral nervous systems. Common neurological complications in CKD include stroke, cognitive dysfunction, encephalopathy, peripheral and autonomic neuropathies. These conditions have significant impact not only on patient morbidity but also on mortality risk through a variety of mechanisms. Understanding the pathophysiological mechanisms of these conditions can provide insights into effective management strategies for neurological complications. This review describes clinical management of neurological complications in CKD with reference to the contributing physiological and pathological derangements. Stroke, cognitive dysfunction and dementia share several pathological mechanisms that may contribute to vascular impairment and neurodegeneration. Cognitive dysfunction and dementia may be differentiated from encephalopathy which has similar contributing factors but presents in an acute and rapidly progressive manner and may be accompanied by tremor and asterixis. Recent evidence suggests that dietary potassium restriction may be a useful preventative measure for peripheral neuropathy. Management of painful neuropathic symptoms can be achieved by pharmacological means with careful dosing and side effect considerations for reduced renal function. Patients with autonomic neuropathy may respond to sildenafil for impotence. Neurological complications often become clinically apparent at end-stage disease, however early detection and management of these conditions in mild CKD may reduce their impact at later stages.

Association between malignancy and non-alcoholic Wernicke's encephalopathy: a case report and literature review

Background

Wernicke's encephalopathy is a serious medical condition associated with high morbidity and mortality caused by deficiency of thiamine. This disease is classically associated with alcoholism, but is underappreciated in the nonalcoholic population. There is growing acknowledgement of the development of Wernicke's encephalopathy in patients with malignancies.

Methods

We conducted a literature review in PubMed for cases of Wernicke's encephalopathy occurring in patients with malignancy. We also present the case of a 47-year-old woman with recurrent laryngeal cancer and multiple hospital admissions for malnutrition. Neurological examination was notable for pendular nystagmus, severe gait ataxia, confusion, and poor memory consolidation. MRI of the brain was significant for T2-weighted fluid-attenuated inversion recovery hyperintensities in periaqueductal regions, medial thalami, and the tectal plate, typical for Wernicke's encephalopathy. She was treated with thiamine repletion, and had marked improvement in her mental status and some improvement in her vision problems and ataxia, although some nystagmus and significant short-term memory impairment persisted.

Results

The literature review yielded dozens of case reports of Wernicke's encephalopathy in patients with malignancy, dominated by cases of patients with malignancies of the gastrointestinal system, followed by those with hematologic malignancies.

Conclusions

Malignancy is an important risk factor for the development of Wernicke's encephalopathy. This diagnosis is underappreciated and difficult for the clinician to discern from multifactorial delirium. Clinicians should be aware to treat at-risk patients with thiamine immediately, especially if multiple risk factors are present.