Osmotic demyelination syndrome with a dysequilibrium syndrome: reversible MRI findings

Prevention of dialysis disequilibrium syndrome in children with advanced uremia with a structured hemodialysis protocol: A quality improvement initiative study

BACKGROUND

Dialysis disequilibrium syndrome (DDS) is a rare but significant concern in adult and pediatric patients undergoing dialysis initiation with advanced uremia or if done after an interval. It is imperative to gain insights into the epidemiological patterns, pathophysiological mechanisms, and preventive strategies aimed at averting the onset of this ailment.

DESIGN

Prospective observational quality improvement initiative cohort study.

SETTING AND PARTICIPANTS

A prospective single-center study involving 50 pediatric patients under 18 years recently diagnosed with chronic kidney disease stage V with blood urea ≥200 mg/dL, admitted to our tertiary care center for dialysis initiation from January 2017 to October 2023.

QUALITY IMPROVEMENT PLAN

A standardized protocol was developed and followed for hemodialysis in pediatric patients with advanced uremia. This protocol included measures such as lower urea reduction ratios (targeted at 20%-30%) with shorter dialysis sessions and linear dialysate sodium profiling. Prophylactic administration of mannitol and 25% dextrose was also done to prevent the incidence of dialysis disequilibrium syndrome.

MEASURES

Incidence of dialysis disequilibrium syndrome and severe dialysis disequilibrium syndrome, mortality, urea reduction ratios (URRs), neurological outcome at discharge, and development of complications such as infection and hypotension. Long-term outcomes were assessed at the 1-year follow-up including adherence to dialysis, renal transplantation, death, and loss to follow-up.

RESULTS

The median serum creatinine and urea levels at presentation were 7.93 and 224 mg/dL, respectively. A total of 20% of patients had neurological symptoms attributable to advanced uremia at the time of presentation. The incidence of dialysis disequilibrium syndrome was 4% (n = 2) with severe dialysis disequilibrium syndrome only 2% (n = 1). Overall mortality was 8% (n = 4) but none of the deaths were attributed to dialysis disequilibrium syndrome. The mean urea reduction ratios for the first, second, and third dialysis sessions were 23.45%, 34.56%, and 33.50%, respectively. The patients with dialysis disequilibrium syndrome were discharged with normal neurological status. Long-term outcomes showed 88% adherence to dialysis and 38% renal transplantation.

LIMITATIONS

This study is characterized by a single-center design, nonrandomized approach, and limited sample size.

CONCLUSIONS

Our structured protocol served as a framework for standardizing procedures contributing to low incidence rates of dialysis disequilibrium syndrome.

Dialysis disequilibrium syndrome (DDS) in pediatric patients on dialysis: systematic review and clinical practice recommendations

BACKGROUND AND OBJECTIVES

Dialysis disequilibrium syndrome (DDS) is a rare neurological complication, most commonly affecting patients undergoing new initiation of hemodialysis (HD), but can also be seen in patients receiving chronic dialysis who miss regular treatments, patients having acute kidney injury (AKI), and in those treated with continuous kidney replacement therapy (CKRT) or peritoneal dialysis (PD). Although the pathogenesis is not well understood, DDS is likely a result of multiple physiological abnormalities. In this systematic review, we provide a synopsis of the data available on DDS that allow for a clear picture of its pathogenesis, preventive measures, and focus on effective management strategies.

METHODS

We conducted a literature search on PubMed/Medline and Embase from January 1960 to January 2021. Studies were included if the patient developed DDS irrespective of age and gender. A summary table was used to summarize the data from individual studies and included study type, population group, age group, sample size, patient characteristics, blood and dialysate flow rate, and overall outcome. A descriptive analysis calculating the frequency of population size, symptoms, and various treatments was performed using R software version 3.1.0.

RESULTS

A total of 49 studies (321 samples) were identified and analyzed. Out of the included 49 studies, a total of 48 studies reported the presence of DSS among patients (1 study reported based on number of dialysis and therefore was not considered for analysis). Among these 48 studies, 74.3% (226/304) patients were reported to have DSS. The most common symptoms were nausea (25.2%), headache (24.8%), vomiting (23.9%), muscle cramps (18.1%), affected level of consciousness (8.8%), confusion (4.4%), and seizure (4.9%) among the 226 DDS patients. Furthermore, 12 studies decided to switch from HD to alternative dialysis modalities including continuous venovenous hemofiltration/hemodiafiltration (CVVH/CVVHDF) or PD which reported no DDS symptoms.

CONCLUSION

Early recognition and timely prevention are crucial for DDS patients. We have provided comprehensive clinical practice points for pediatric, adolescent, and young adult populations. However, it is essential to recognize that DDS was reported more frequently in the early dialysis era, as there was a lack of advanced dialysis technology and limited resources.

Long-term hemodialysis may affect enlarged perivascular spaces in maintenance hemodialysis patients: evidence from a pilot MRI study

BACKGROUND

Hemodialysis (HD) causes various nervous system abnormalities. Alterations in white matter (WM) microstructure after long-term HD have been reported in a few previous studies; however, no studies have been performed to investigate enlarged perivascular spaces (PVS) in WM regions. We measured cerebral blood flow (CBF) and white matter volume (WMV) in HD patients to assess enlarged PVS severity in the WM across the whole brain and suggest possible explanations for this.

METHODS

Fifty-one HD patients and 51 age-, sex-, and education-matched healthy controls (HCs) were recruited. The number of enlarged PVS in the centrum semiovale (CS), cerebral watershed (CW), and basal ganglia (BG) regions were assessed by T2-weighted MRI. CBF was estimated by arterial spin labeling (ASL), which is a non-invasive perfusion imaging technique. WMV was assessed by the computational anatomy toolbox (CAT12), which is a statistical analysis package. Differences in descriptive variables (two-tailed t-tests, χ² tests, Mann-Whitney U tests, and Friedman M tests), an intra-class correlation between radiologists, the relationship between enlarged PVS number and HD duration, normalized CBF and WMV (multiple regression), and group differences in CBF and WMV {voxel-wise t-tests with age and sex as covariates [cluster size >50 voxels, false discovery rate (FDR) corrected, P<0.05]} were assessed.

RESULTS

HD patients displayed a more significant number of CS-PVS and CW-PVS in WM regions compared with the HCs, but there was no significant difference in the number of BG-PVS. The number of CS-PVS and CW-PVS were positively associated with HD duration. The number of CW-PVS was positively associated with CBF changes and WMV alteration in HD patients. Meanwhile, significant differences in the blood pressure (BP) readings pre-HD, intra-HD, and post-HD were observed in HD patients. Compared with the HCs, the HD patients showed higher CBF in the CS, CW, and BG regions (P<0.05). Hence, decreased WMV in the CS, CW, and BG regions were shown in the HD patients compared with the HCs (P<0.05).

CONCLUSIONS

Enlarged CS-PVS and CW-PVS on MRI might be a feature of long-term HD patients. Enlarged CW-PVS number is associated with higher CBF in the CW region and lower WMV in the CW region in HD patients.

A preliminary report of longitudinal white matter alterations in patients with end-stage renal disease: A three-year diffusion tensor imaging study

PURPOSE

End-stage renal disease (ESRD) patients exhibit silent white-matter alterations after long-term hemodialysis, which may be due to ESRD itself or the hemodialysis. The purpose of this study was to investigate the longitudinal white-matter alterations in the ESRD patients under 3-year long-term hemodialysis using voxel-wise analysis of diffusion tensor imaging (DTI).

MATERIALS AND METHODS

15 ESRD patients and 15 age-matched healthy controls participated in this study. Due to the development of abnormal brain lesions in some cases, 13 ESRD patients and 13 age-matched healthy controls were enrolled and underwent cognitive function assessment and DTI acquisition at two-time points separated by 3 years. Voxel-based analysis was performed to globally detect white-matter alterations between the two groups as well as between the two scans within the two groups.

RESULTS

In the ESRD patients, diffusivity indices were significantly increased and the fractional anisotropy was significantly decreased in both scans, as compared with healthy controls. Longitudinal comparisons showed significant white-matter alterations in healthy controls in three years, but little or no significant alterations were noted in the ESRD patients after additional 3-year hemodialysis.

CONCLUSION

Poorer white matter integrity and cognitive function are noted in ESRD patients and the toxic effect of ESRD may be the major factor of white matter alterations.

Evaluation of MRI-detected White Matter Changes in Relation to Hemodialysis Duration and Renal Transplantation

Compared to the normal population, renal transplant recipients and end-stage renal disease (ESRD) patients on hemodialysis have a higher incidence of white matter changes (WMC) on brain magnetic resonance imaging (MRI). The lesions appear as focal or patchy areas in the periventricular white matter. Both these patient groups are known to be affected by accelerated atherosclerosis, which produces small-vessel disease. This may lead to thromboembolic complications that cause these white matter lesions. This study retrospectively assessed the frequency of MRI-detected WMC in ESRD patients on hemodialysis and kidney recipients, and correlated the rates with hemodialysis duration and post-transplantation interval. Focal and patchy type lesions were distinguished, and the frequencies of these were studied. Also, in the respective groups, comparisons were made among patients with different hemodialysis durations and post-transplantation intervals. The results showed that specifically focal lesions increase in parallel with hemodialysis duration, but there was no statistical relationship between WMC and post-transplantation interval.

Diffuse Leukoencephalopathy Associated with Dialysis Disequilibrium Syndrome

A 52-year-old woman, previously treated for gastric cancer, began hemodialysis (HD) to treat the onset of severe acidemia. After her initial HD sessions, she suffered from a prolonged coma for approximately ten days. Magnetic resonance imaging revealed diffuse leukoencephalopathy, with increased apparent diffusion coefficient. Magnetic resonance spectroscopy showed a reduction of the N-acetylaspartate/creatine ratio. Her neuroimaging findings gradually resolved. Her transient cerebral white matter lesions were thought to be interstitial edema derived from dialysis disequilibrium syndrome (DDS), which might have been amplified by subclinical brain injury due to past chemotherapy. Her history of cancer chemotherapy may be a risk factor for an exacerbation of DDS.

The choice of dialysate sodium is influenced by hemodialysis frequency and duration: what should it be and for what modality?

Cardiovascular disease is the leading cause of mortality in hemodialysis patients. A chronic state of volume and pressure overload contributes, and central to this is the net sodium balance over the course of a hemodialysis. Of recent interest is the contribution of the dialysate sodium concentration (Dial-Na+) to clinical outcomes. Abundant evidence confirms that in thrice-weekly conventional hemodialysis, higher Dial-Na+ associates with increased intradialytic weight gain, blood pressure, and cardiovascular morbidity and mortality. On the other hand, low Dial-Na+ associates with intradialytic hypotension in the same patient population. However, the effect of Dial-Na+ in short hours daily hemodialysis (SHD; often referred to as "quotidian" dialysis), or nocturnal dialysis (FHND) is less well studied. Increased frequency and duration of exposure to a diffusive sodium gradient modulate the way in which DPNa+ alters interdialytic weight gain, predialysis blood pressure, and intradialytic change in blood pressure. Furthermore, increased dialysis frequency appears to decrease the predialysis plasma sodium setpoint (SP), which is considered stable in conventional thrice-weekly patients. This review discusses criteria to determine optimal Dial-Na+ in conventional, SHD and FHND patients, and identifies areas for future research.

Widespread white matter alterations in patients with end-stage renal disease: a voxelwise diffusion tensor imaging study

BACKGROUND AND PURPOSE

ESRD results in excessive accumulation of urea and toxic metabolites. Hemodialysis is usually performed to maintain health in patients with ESRD; however, it may cause silent white matter alterations in the earlier stages. Hence, this study aimed to perform voxelwise diffusion tensor analysis for global detection of subtle white matter alterations in patients with ESRD.

MATERIALS AND METHODS

Twenty-eight patients with ESRD and 25 age-matched control subjects were enrolled in this study. Each subject underwent CASI assessment and DTI. After spatial normalization of DTI images, voxelwise statistical analyses were performed to compare DTI parameters between the 2 groups.

RESULTS

In patients with ESRD, AD, RD, and MD values were significantly increased, whereas the FA value was significantly decreased, mostly in the corpus callosum, bilateral sagittal stratum, and pons. Multiple regression analysis further revealed that both RD and MD were positively correlated with the duration of hemodialysis in the pons; however, no significant correlation was observed with FA. Negative correlations of RD and MD and a positive correlation of FA with the CASI score were observed in the corona radiata.

CONCLUSIONS

We concluded that voxelwise DTI analysis is helpful in the detection of white matter alterations caused by hemodialysis.

Patterns in early diffusion-weighted MRI in children with haemolytic uraemic syndrome and CNS involvement

OBJECTIVES

Diffusion-weighted imaging (DWI) in children with diarrhoea associated haemolytic uraemic syndrome (D+HUS) and cerebral involvement was evaluated retrospectively.

METHODS

DWI within 24 h of onset of neurological symptoms. The apparent diffusion coefficient (ADC) was measured in grey/white matter and correlated with clinical and laboratory findings.

RESULTS

DWI was abnormal in all. Abnormal ADC was detected in the supratentorial white matter (6/12) and cortex (1/12), the basal ganglia (5/12), the thalami (4/12), and the cerebellum (1/12). ADC was reduced in 5/12, increased in 4/12, and both in 3/12. Mean serum sodium was lower in patients with DWI abnormalities affecting the white matter (6/12), than in those with basal ganglia/thalamic involvement (6/12). Neurological outcome was normal in 4/11 and abnormal in 7/11, and 1 patient died, outcome did not correlate to either localisation or type of DWI abnormality.

CONCLUSIONS

In D+HUS with neurological symptoms, early DWI may reveal abnormal ADC not only in the basal ganglia/thalami, but also in the white matter/cortex. Besides thrombotic microangiopathy, toxic effects of shiga toxin, azotaemia and hyponatraemia / hypoosmolality may be involved in cerebral involvement in children with D+HUS. Findings on early MRI seem not to predict clinical course or outcome.

KEY POINTS

• DWI MR imaging may detect early CNS involvement in haemolytic uraemic syndrome • Different pathogenetical mechanisms may contribute to the CNS disease in HUS • Early MRI findings do not seem to allow prediction of clinical outcome.

Leukoencephalopathy Associated with Dialysis Disequilibrium Syndrome

Dialysis disequilibrium syndrome (DDS) is usually seen in severely uremic patients who are dialyzed aggressively. DDS mostly appeared within 24 hours after hemodialysis (HD) and may last for a few hours. This diagnosis is made by the exclusion of other causes including metabolic and intracranial events and has been recognized for more than 40 years. Few reports described the cerebral radiographic features associated with DDS. We present an 83-year-old uremic patient experiencing DDS at initial HD. DDS-related cerebral radiographic manifestations reported in the literature are reviewed, along with a discussion of the role of neuroimaging in the diagnosis of DDS.

Dialysis disequilibrium syndrome: a narrative review

Dialysis Disequilibrium Syndrome (DDS) is characterized by neurological symptoms caused by rapid removal of urea during hemodialysis. It develops primarily from an osmotic gradient that develops between the brain and the plasma as a result of rapid hemodialysis. This results in brain edema that manifests as neurological symptoms such as headache, nausea, vomiting, muscle cramps, tremors, disturbed consciousness, and convulsions. In severe cases, patients can die from advanced cerebral edema. Recent advancements in cell biology implicate the role of urea disequilibrium (with a smaller contribution from organic osmolytes) as the pathophysiological mechanism responsible for this syndrome. In this review, we discuss the pathogenesis, clinical features and prevention of DDS.

Central pontine lesions observed with MRI in four diabetic patients

We report four diabetic patients with a central pontine lesion on magnetic resonance imaging (MRI). All patients also had hypertension, diabetic neuropathy and nephropathy, and three had chronic hepatitis C. Their neurological symptoms were disproportionately mild compared with the MRI features, which were of high intensity on T2-weighted images, but were less prominent on T1- and diffusion-weighted images. A subclinical pontine lesion was found in two patients who had undergone MRI previously. We consider that diabetes mellitus is an important factor for developing a pontine lesion with or without symptoms, probably in association with hepato-renal problems and hypertension.

Cerebellar peduncular myelinolysis in a patient receiving hemodialysis

Here, we report the observation of extrapontine lesions, in addition to the pontine lesions previously documented in a diagnosed case of hemodialysis-associated osmotic demyelination syndrome due to end-stage renal disease. The patient exhibited lesions on bilateral middle cerebellar peduncles, and had been receiving regular hemodialysis as treatment for end-stage renal disease. He presented with progressive gait disturbance and postural instability. Accompanying symptoms included peduncular hallucinations and mild cognitive dysfunction. Brain MRI revealed high signal intensity in the area of bilateral cerebellar peduncles on the diffusion and T2-weighted images, with a decreased signal intensity noted on the ADC map. The ataxic form of osmotic myelinolysis syndrome is quite rare. The involvement of the cerebellar peduncles in extrapontine myelinolysis in a patient with end stage renal disease has not, to our knowledge, been previously reported. Here, we describe the MRI findings and clinical features associated with this unique case, and include a review of the relevant literature.

Evaluation of neurologic complications by brain MRI in kidney and liver transplant recipients

The aim of this study was to retrospectively analyze brain magnetic resonance imaging (MRI) findings in patients who developed neurologic complications after liver and kidney transplantation. The results in 216 organ transplant recipients, who had brain MRI were evaluated retrospectively. We performed 187 brain MRI on kidney recipients and 29 liver recipients. Neuroradiologic findings were classified in three groups: group 1 findings were related to transplantation; group 2 findings, to chronic parenchymal disease; and group 3 to neither transplantation nor chronic parenchymal disease. In group 1, six patients (20.6%) after liver and three (1.6%) after kidney transplantation had posterior reversible encephalopathy syndrome; two patients (1.1%) after renal and one (3.4%) after liver transplantation had tuberculosis granulomas; one patient (0.5%) after renal transplantation had osmotic demyelination syndrome; one patient (0.5%) had a Nocardia abcess and one (0.5%) focal cerebritis after renal transplantation. Among group 2, 38 patients (20.3%) had brain atrophy; 37 (20%), white matter changes; 3 (1.6%), sinus thrombosis; 8 (4.3%), lacunar infarct; 1 (0.5%), had renal osteodystrophy in the cranial bones; and 4 (2.2%), had intracranial hemorrhage secondary to end-stage renal disease. Brain atrophy in nine patients (31%), hyperintensity in the globus pallidus on T1-weighted MR images owing to manganese deposits in nine patients (31%), hyperintensity in basal ganglia on T2-weighted MR images owing to copper depositions in one patient (3.4%) were seen secondary to chronic liver disease. In group 3, three patients (1.6%) had intracranial lipomas; one (0.5%), mesial temporal sclerosis; and one (0.5%), an anterior cerebral artery aneurysm in renal transplant patients. Periventricular and subcortical white matter hyperintensities were observed on T2-weighted MR images in six liver transplant patients (20.7%). Neurologic complications after organ transplantation may be secondary to transplantation itself, to chronic parenchymal disease, or to neither transplantation nor chronic parenchymal disease.

Osmotic Demyelination Syndrome in End-Stage Renal Disease After Recent Hemodialysis:MRI of the Brain

OBJECTIVE

Osmotic demyelination syndrome has been reported in patients with end-stage renal disease, but the specific MRI findings in this patient group have not been documented in detail. Our aims were to present the brain MRI findings during an episode after hemodialysis and at follow-up, and to identify possible factors that may contribute to lesion development.

MATERIALS AND METHODS

Seventeen patients with osmotic demyelination syndrome who had undergone hemodialysis at least once and had brain MRI examinations were retrospectively reviewed. Neurologic and MRI examinations were performed during a clinical episode. Serum levels of sodium, creatinine, blood urea nitrogen, and glucose were assessed, and serum osmolality and the ratio of blood urea nitrogen to creatinine (BUN:Cr) were calculated. Follow-up MRI was performed in nine cases. Laboratory and imaging findings were evaluated.

RESULTS

An altered level of consciousness and convulsions were the most common neurologic symptoms. The pons was involved in 11 patients (65%) and extrapontine sites in 12 (71%). Four patients had dysequilibrium syndrome. Follow-up MRI showed complete resolution in six patients and lesion reduction in three within a short time. The most common biochemical changes at the time of MRI were hyponatremia and low BUN:Cr in the blood. Only one patient showed rapid correction of hyponatremia and a rapid change in osmolality during the acute stage.

CONCLUSION

In patients who develop osmotic demyelination syndrome after hemodialysis, the lesions may involve the pons or the pons and extrapontine sites. Most lesions that were followed up resolved rapidly and almost completely, favoring transient edema rather than demyelination. Blood chemistries suggested underlying changes in osmolality, particularly as a result of urea shift from the extracellular fluid.

Central pontine and extrapontine myelinolysis owing to disequilibrium syndrome

Neurologic disorders can be seen in patients with end-stage renal failure owing to complications of hemodialysis or peritoneal dialysis. The disequilibrium syndrome can be seen, usually soon after or toward the end of dialysis. We report a patient with central pontine and extrapontine myelinolysis owing to disequilibrium syndrome. The patient had depressed consciousness, agitation, tremor, stupor and hyperactive deep tendon reflexes toward the end of the second peritoneal dialysis. A brain computed tomographic (CT) scan showed hypodense lesions in pontine and extrapontine locations without radiocontrast medium enhancement After 2 days, the patient had only minimal memory deficits. A control brain CT scan 1 week later showed a decrease of the lesions in central pontine and extrapontine locations. Central pontine and extrapontine myelinolysis should be suspected and investigated in the acute neurologic disorders of dialysis patients.