Dialysis disequilibrium syndrome: a narrative review

The Impact of Potassium Dynamics on Cardiomyocyte Beating in Hemodialysis Treatment

Background: Observational studies of intermittent hemodialysis therapy have reported that the excess decrease in K+ concentration in plasma (KP) during treatment is associated with the destabilization of cardiac function. Elucidating the mechanism by which the decrease in KP impairs myocardial excitation is indispensable for a deeper understanding of prescription design. Methods: In this study, by using an electrophysiological mathematical model, we investigated the relationship between KP dynamics and cardiomyocyte excitability for the first time. Results: The excess decrease in KP during treatment destabilized cardiomyocyte excitability through the following events: (1) a decrease in KP led to the prolongation of the depolarization phase of ventricular cells due to the reduced potassium efflux rate of the Kr channel, temporarily enhancing contraction force; (2) an excess decrease in KP activated the transport of K+ and Na+ through the funny channel in sinoatrial nodal cells, disrupting automaticity; (3) the excess decrease in KP also resulted in a significant decrease in the resting membrane potential of ventricular cells, causing contractile dysfunction. Avoiding an excess decrease in KP during treatment contributed to the maintenance of cardiomyocyte excitability. Conclusions: The results of these mathematical analyses showed that it is necessary to implement personal prescription or optimal control of K+ concentration in dialysis fluid based on predialysis KP from the perspective of regulatory science in dialysis treatment.

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.

A Rare Case of Postoperative Encephalopathy in Twin

The clinical picture of encephalopathy invites a broad differential with multiple etiologies. It is with judicious history, hospital course, lab testing, and imaging that the ultimate cause is identified. We present a unique case of identical twins who share a similar clinical presentation of postoperative encephalopathy. The striking similarities in both twins suggest a genetic component requiring further research to identify patients who are genetically predisposed.

A Case of Drug-Resistant Myoclonus Improved by Only Slight Adjustment to the Hemodialysis Setting

Myoclonus, a rare complication in patients with end-stage renal disease, is typically ameliorated through hemodialysis. The present case concerns an 84-year-old male with chronic renal failure undergoing hemodialysis, presenting involuntary movements in his limbs, which gradually worsened from the initiation of hemodialysis without constant elevation of serum blood urea nitrogen and electrolytes levels. Surface electromyography revealed characteristic findings consistent with myoclonus. He was diagnosed with subcortical-nonsegmental myoclonus related to hemodialysis, and the myoclonus was significantly alleviated after slightly increasing the post-dialysis target weight even though drug treatment was ineffective. This case suggests that drug-resistant myoclonus in patients with renal failure may be improved by adjusting hemodialysis settings, even in cases of atypical dialysis disequilibrium syndrome.

Narrative review of migraine management in patients with renal or hepatic disease

OBJECTIVES/BACKGROUND

Treatment of migraine in the setting of either renal or hepatic disease can be daunting for clinicians. Not only does the method of metabolism have to be considered, but also the method of elimination/excretion of the parent drug and any active or toxic metabolites. Furthermore, it is difficult to think about liver or kidney disease in isolation, as liver disease can sometimes contribute to impaired renal function and renal disease can sometimes impair hepatic metabolism, through the cytochrome P450 system.

METHODS

A detailed search for terms related to liver disease, renal disease, and migraine management was performed in PubMed, Ovid Medline, Embase, and the Cochrane Library.For each medication, product labels were retrieved and reviewed using the US FDA website, with additional review of IBM Micromedex, LiverTox, and the Renal Drug Handbook.

RESULTS

This manuscript provides an overview of migraine drug metabolism and how it can be affected by liver and renal impairment. It reviews the standard terminology recommended by the US Food and Drug Administration for the different stages of hepatic and renal failure. The available evidence regarding the use of abortive and preventative medicines in the setting of organ failure is discussed in detail, including more recent therapies such as lasmiditan, gepants, and calcitonin gene-related peptide antibodies.

CONCLUSIONS

For acute therapy, the use of NSAIDS should be limited, as these carry risk for both severe hepatic and renal disease. Triptans can be selectively used, often with dose guideline adjustments. Ubrogepant may be used in severe hepatic disease with dose adjustment and lasmiditan can be used in end stage renal disease. Though non-medicine strategies may be the most reasonable initial approach, many preventative medications can be used in the setting of hepatic and renal disease, often with dose adjustment. This review provides tables of guidelines, including reduced dosing recommendations, for the use of abortive and preventative migraine medications in hepatic and renal failure.

Dialysis Disequilibrium: Is Acidosis More Important than Urea?

Dialysis disequilibrium syndrome is a severe complication associated with dialysis treatment. Manifestations may range from mild such as headache to severe such as seizures and coma. Risk factors for development include initial dialysis treatment, uraemia, metabolic acidosis, and extremes of age. We report a case of dialysis disequilibrium in a patient with a failing kidney transplant secondary to the recurrence of IgA nephropathy. Disturbance in cognition and neurologic functioning occurred six hours after the completion of initiation of intermittent haemodialysis. During two sessions of intermittent haemodialysis of 3 and 4 hours, urea was reduced by 21.9 and 17.2 mmol/L and measured serum osmolality was reduced by 25 and 14 mOsm/kg, respectively. Subsequent admission to the intensive care unit and initiation of continuous renal replacement therapy for 48 hours resulted in complete resolution of symptoms. In this case report, we discuss atypical clinical and radiologic features of dialysis disequilibrium occurring with modest reductions in urea and serum osmolality.

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.

Neuroimaging Considerations in Patients with Chronic Kidney Disease

Chronic Kidney Disease is a common medical condition that frequently overlaps with neurologic disease. Neuroimaging can be a useful tool to aid in the diagnoses of neurologic illness, including those that result from renal impairment. Some neuroimaging studies also have the potential to lead to adverse effects on the kidneys necessitating a thoughtful approach to selection of imaging modalities. In particular, multimodal imaging is becoming increasingly common in patients presenting with symptoms of acute stroke, a population that may be at higher risk for renal complications. This article will summarize the neuroimaging manifestations of conditions with shared renal and neurologic involvement and highlight considerations regarding the use of contrast media, nephrogenic systemic fibrosis, and metformin-associated lactic acidosis.

Half the V by 120: A practical approach to the prevention of the dialysis disequilibrium syndrome

The dialysis disequilibrium syndrome (DDS) results from osmotic shifts between the blood and the brain compartments. Patients at risk for DDS include those with very elevated blood urea nitrogen, concomitant hypernatremia, metabolic acidosis, and low total body water volumes. By understanding the underlying pathophysiology and applying urea kinetic modeling, it is possible to avoid the occurrence of this disorder. A urea reduction ratio (URR) of no more than 40%-45% over 2 h is recommended for the initial hemodialysis treatment. The relationship between the URR and Kt/V is useful when trying to model the dialysis treatment to a specific URR target. A simplified relationship between Kt/V and URR is provided by the equation: Kt/V = -ln (1 - URR). A URR of 40% is roughly equivalent to a Kt/V of 0.5. The required dialyzer urea clearance to achieve this goal URR in a 120-min treatment can simply be calculated by dividing half the patient's volume of distribution of urea by 120. The blood flow rate and dialyzer mass transfer coefficient (K₀ A) required to achieve this clearance can then be plotted on a nomogram. Other methods to reduce the risk of DDS are reviewed, including the use of continuous renal replacement therapy.

Dialysis Disequilibrium Syndrome in a Patient With Acute Kidney Injury on Chronic Kidney Disease

Dialysis disequilibrium syndrome (DDS) is a neurological complication that has been known to occur after hemodialysis (HD). In recent years, the prevalence of DDS has been low as the symptoms are widely recognized; hence, preventive therapies, such as the slow and gentle procedure for HD, are often administered before starting dialysis. However, once DDS occurs, it may cause seizures, coma, and even death in severe cases. Since there has been no established treatment, recognizing risk factors and preventing the syndrome is important.

A 76-year-old man was admitted to our hospital due to exacerbation of chronic heart failure. He also had a history of chronic kidney disease and had consulted with his home doctor about the preparation for HD a month before admission. After treatment with diuretics, the symptoms ameliorated, but he experienced presyncope and malaise. Laboratory tests revealed acute anemia and a decrease in renal function. Upper gastrointestinal endoscopy revealed active bleeding from a gastric ulcer, which was successfully stopped. However, his consciousness deteriorated because of uremia; hence, HD was initiated. We used a cellulose triacetate membrane with a surface area of 1.3 m² and maintained a dialysate flow rate of 500 ml/min with a blood flow rate of 120 ml/min. Four hours after starting HD, he suddenly developed generalized tonic convulsions. The dialysis was immediately stopped, and the patient was transferred to an intensive care unit. A computed tomography scan of the head showed mild edematous change of the brain, and laboratory tests also revealed a rapid decrease of urea nitrogen. We rationalized that he might have developed DDS. After injection of levetiracetam for the treatment of seizures, we initiated continuous hemodiafiltration as renal replacement therapy. Fortunately, his consciousness gradually improved, and he was completely alert on day 18 after admission.

With reference to our current report, DDS can occur even following acute kidney injury, as the progression rate of the injury and accumulation of blood urea may not correlate with the risk of the syndrome.

EEG spectral changes induced by hemodialysis

OBJECTIVE

To investigate the EEG spectral changes induced during hemodialysis in patients with chronic kidney disease (CKD), and to identify the risk factors associated with changes in the Central Nervous System (CNS) during hemodialysis. Paradoxical neurological deterioration at the end of hemodialysis sessions, known as dialysis disequilibrium syndrome (DDS) has been described, but previous studies on EEG spectral changes during hemodialysis were controversial.

METHODS

We performed quantitative EEG spectral analysis in 56 consecutive patients who underwent hemodialysis. We compared EEG at the start and at the end of the hemodialysis, and we correlated the spectral changes with the biochemical and clinical characteristics of the patients, using multivariate analysis.

RESULTS

At the end of hemodialysis sessions, we found a significant increase in total EEG power, relative power in delta frequency band and the ratio of delta-theta/alpha-beta power. EEG spectral changes were associated with younger age, recent start of hemodialysis therapy, level of uremia and lower level of glycaemia.

CONCLUSIONS

Quantitative EEG spectral analysis showed that hemodialysis induced slowing of the EEG background activity. These changes were associated with risk factors of DDS.

SIGNIFICANCE

EEG spectral changes are potential biomarkers for monitoring CNS function during hemodialysis.

Brain Herniation and Intracranial Hypertension

This article introduces the basic concepts of intracranial physiology and pressure dynamics. It also includes discussion of signs and symptoms and examination and radiographic findings of patients with acute cerebral herniation as a result of increased as well as decreased intracranial pressure. Current best practices regarding medical and surgical treatments and approaches to management of intracranial hypertension as well as future directions are reviewed. Lastly, there is discussion of some of the implications of critical medical illness (sepsis, liver failure, and renal failure) and treatments thereof on causation or worsening of cerebral edema, intracranial hypertension, and cerebral herniation.

A case report with a literature review: cerebral meningioma diagnosed by convulsion and consciousness disorder on initiating hemodialysis

Background

Neurological symptoms sometimes occur in hemodialysis patients, with causes including cerebral infarction, cerebral hemorrhaging, meningitis, and encephalitis. Dialysis disequilibrium syndrome (DDS) is widely known as a complication of hemodialysis and is typically encountered in severe uremic patients newly started on hemodialysis. The pathogenesis of DDS is thought to be brain edema that manifests as neurological symptoms, including headache, nausea, confusion, seizures, and coma. However, the relationship between brain tumors and neurological manifestations during hemodialysis is poorly understood.

Case presentation

The patient was a 55-year-old man with severe renal dysfunction and uremia symptoms. Blood chemistry showed severe azotemia and acidosis. The patient was placed on short-duration hemodialysis (2 h) with a relatively small surface area, low blood flow (100 mL/min), and intradialytic glycerol infusion to prevent DDS. However, after his first hemodialysis treatment, he complained of disturbed consciousness. We diagnosed his neurological condition as DDS and observed the progress carefully. The next morning, his symptoms had completely resolved, so the patient was started on his second hemodialysis session with the same conditions. However, 2 h after starting the second hemodialysis session, he suffered convulsions accompanied by impaired consciousness. Brain computed tomography (CT) revealed a convexity meningioma and cerebral edema with a midline shift. Before starting the hemodialysis, he had shown no history of seizures, morning headache, or other neurological symptoms. In this case, meningioma was diagnosed based on an increase in the intracranial pressure which occurred after the initiation of hemodialysis.

Conclusion

We report this suggestive case to prompt physicians to consider the potential effect of hemodialysis introduction on the brain pressure.

Neurophysiological and Neuroradiological Changes in Children With Chronic Kidney Disease

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

Electrophysiological insights into the relationship between calcium dynamics and cardiomyocyte beating function in chronic hemodialysis treatment

For patients in which the Ca²⁺ concentration of dialysis fluid is lower than that in plasma, chronic hemodialysis treatment often leads to cardiac beating dysfunction. By applying these conditions to an electrophysiological mathematical model, we evaluated the impact of body fluid Ca²⁺ dynamics during treatment on cardiomyocyte beating and, moreover, explored measures that may prevent cardiomyocyte beating dysfunction. First, Ca²⁺ concentrations in both plasma and interstitial fluid were decreased with treatment time, which induced both a slight decline in beating rhythm on a sinoatrial nodal cell and a wane in contraction force on a ventricular cell. These simulated results were in agreement with clinical observations. Next, a relationship between the intracellular Ca²⁺ concentration and ion current dynamics of ion transporters were examined to elucidate the mechanism underlying cardiomyocyte beating dysfunction. The inward current of the Na/Ca exchanger (NCX) increased with a decrease in Ca²⁺ concentration in interstitial fluid and induced a reduction in intracellular Ca²⁺ concentration during treatment. Furthermore, the decline in intracellular Ca²⁺ concentration reduced the contraction force. These findings implied that ion transport through the NCX is a dominant factor that induces cardiomyocyte beating dysfunction during hemodialysis. Finally, the replenishment of Ca²⁺ or application of an NCX inhibitor during treatment suppressed the decrease in intracellular Ca²⁺ concentration and contributed to the stabilization of cardiomyocyte beating function. In summary, the clinical implementation of hepatically cleared NCX inhibitor may be a suitable approach to improving the quality of life for patients on chronic hemodialysis.

Dialysis Disequilibrium Syndrome and Cerebellar Herniation with Successful Reversal Using Mannitol

Dialysis disequilibrium syndrome (DDS) is a morbid but rare complication of dialysis. Feared sequalae of this diagnosis are brain herniation and death. This report presents a patient who was diagnosed with DDS with subsequent tonsillar herniation shown on imaging with complete resolution of clinical signs and symptoms, as well as imaging findings of herniation after prompt initiation of intravenous mannitol. This is the first known case of reversal and survival of DDS-induced tonsillar herniation using mannitol.

A vanishing complication of haemodialysis: Dialysis disequilibrium syndrome

Dialysis disequilibrium syndrome (DDS) is a rare syndrome characterised by neurological symptoms related to cerebral oedema. New patients who are started on haemodialysis are at the greatest risk for developing dialysis disequilibrium syndrome. Classical DDS develops during or immediately after haemodialysis. It is a generally self-limiting condition and settles with supportive management. Our case report describes DDS in a patient on chronic haemodialysis. She developed a tonic-clonic seizure shortly after completing 4 h of haemodialysis. This occurred in the context of having missed one session of dialysis, but with no new changes made to her usual dialysis regime. She was managed supportively in the intensive care unit and made a full recovery.

Real-time Noninvasive Monitoring of Intracranial Fluid Shifts During Dialysis Using Volumetric Integral Phase-Shift Spectroscopy (VIPS): A Proof-of-Concept Study

BACKGROUND

Cerebral edema, which is associated with increased intracranial fluid, is often a complication of many acute neurological conditions. There is currently no accepted method for real-time monitoring of intracranial fluid volume at the bedside. We evaluated a novel noninvasive technique called "Volumetric Integral Phase-shift Spectroscopy (VIPS)" for detecting intracranial fluid shifts during hemodialysis.

METHODS

Subjects receiving scheduled hemodialysis for end-stage renal disease and without a history of major neurological conditions were enrolled. VIPS monitoring was performed during hemodialysis. Serum osmolarity, electrolytes, and cognitive function with mini-mental state examination (MMSE) were assessed.

RESULTS

Twenty-one monitoring sessions from 14 subjects (4 women), mean group age 50 (SD 12.6), were analyzed. The serum osmolarity decreased by a mean of 6.4 mOsm/L (SD 6.6) from pre- to post-dialysis and correlated with an increase in the VIPS edema index (E-Dex) of 9.7% (SD 12.9) (Pearson's correlation r = 0.46, p = 0.037). Of the individual determinants of serum osmolarity, changes in serum sodium level correlated best with the VIPS edema index (Pearson's correlation, r = 0.46, p = 0.034). MMSE scores did not change from pre- to post-dialysis.

CONCLUSIONS

We detected an increase in the VIPS edema index during hemodialysis that correlated with decreased serum osmolarity, mainly reflected by changes in serum sodium suggesting shifts in intracranial fluids.

Dialysis disequilibrium syndrome revisited: Feeling "Disequilibrated" due to inner ear dyshomeostasis?

Dizziness is one of the most common hemodialysis-associated symptoms, and has been thought to be caused by cerebral edema or intravascular hypovolemia. However, the possibility of a peripheral vestibular disturbance due to hemodialysis has not been addressed as a cause of hemodialysis-associated dizziness. In the present study, we propose a new hypothesis accounting for hemodialysis-associated dizziness, i.e., the decrease in serum osmolality due to rapid removal of urea during dialysis causes inner ear fluid dyshomeostasis, leading to density difference between perilymph and endolymph.

Tolvaptan Efficiently Reduces Intracellular Fluid: Working Toward a Potential Treatment Option for Cellular Edema

Objective Tolvaptan is a class of diuretics that reduce body water through aquaresis. One of the most prominent characteristics of these agents is that worsening of the renal function is less likely to occur. We investigated the underlying mechanism concerning the change in the intracellular fluid (ICF) when the body fluid is reduced. Methods In this retrospective observational study, five overhydrated chronic kidney disease (CKD) patients with edema or pleural effusion treated with tolvaptan were assessed by the bioelectrical impedance method twice: once before and once after tolvaptan therapy. The changes in the ICF rate were compared with those in 11 hemodialysis patients undergoing body fluid reduction by hemodialysis. Results Removal of the body fluid either by tolvaptan or by hemodialysis increased the post/pre-ratio of ICW/total body water (TBW). Tolvaptan reduced the ICF more efficiently than hemodialysis. Conclusion Tolvaptan treatment lessens body fluid by the efficient reduction of the ICF.

Atypical Causes of Urinary Tract Obstruction

Acute kidney injury due to urinary tract obstruction invariably suggests lower urinary tract obstruction or bilateral ureteric obstruction since obstruction of a single kidney while the contralateral kidney is normal and not obstructed would not cause a perceptible rise in creatinine. Assuming a total body volume of 42 L, 70 kg male that generates approximately 1400 mg of creatinine daily (20 mg/kg/day) who has complete urinary tract obstruction would experience a 3.33 mg/dL per day increase in serum creatinine. Thus, for an individual who had prior normal renal function and who presents with a creatinine of 30 mg/dL, one could surmise that the obstructive pathology had lasted at least 10 days. However, the rise in serum creatinine is a poor marker of renal injury and subsequent prognosis. Urinary tract obstruction leading to AKI can be due to a variety of causes, and its management is tailored to the underlying etiology. This case series describes the varied clinical course of four patients at our center who experienced AKI from atypical causes of obstructive uropathy. Current and future diagnostic modalities and caveats in the treatment of this disease entity are also discussed.

Headache in pediatric and adolescent patients with chronic kidney disease, with and without hemodialysis: A comparative cohort study

Background Several studies have reported dialysis-related headache in adults. We investigated headache and its characteristics in pediatric and adolescent patients with chronic kidney disease and patients treated with dialysis, and compared characteristics of patients with and without headache in the entire cohort and separately among dialysis and among chronic kidney disease patients. Methods Patients and their parents who attended a nephrology clinic and hemodialysis unit were interviewed regarding the existence of headache and its characteristics. We reviewed hospital files for medical history, blood test results, and pharmacologic treatment. Headache was defined according to International Headache Society criteria. Results The cohort comprised 60 patients: 39 with chronic kidney disease without hemodialysis and 21 treated with hemodialysis; 39 were males, mean age 11.9 ± 5.3 years. Twenty-six (43.3%) reported experiencing headaches. The hemodialysis group had a higher rate of headache than the chronic kidney disease patients, at 76.2% vs. 25.5%, p < 0.001. In the hemodialysis group, 15 out of 16 reported dialysis-related headache; 14 (87.5%) of these had migraine characteristics. For the entire cohort, headache was associated with hemodialysis, chronic kidney disease grade, lower glomerular filtration rate anemia and a higher parathyroid hormone level. In logistic regression analysis, glomerular filtration rate was significantly associated with headache, odds ratio 2.74 (95% CI 1.56-4.82, p < 0.001). Conclusions A high rate of headache, mostly migraine type, was reported by hemodialysis patients. Hemodialysis, anemia, higher parathyroid hormone levels, phosphate, and lower glomerular filtration rate are strongly associated with headache among chronic kidney disease pediatric and adolescent patients.

Asymptomatic Brain Edema after Hemodialysis Initiation in a Patient with Severe Uremia

A 66-year-old man with severe renal insufficiency presented with mild confusion associated with uremia. Cranial magnetic resonance imaging (MRI) showed no remarkable changes. The patient was placed on short-duration hemodialysis (2 hours) with smaller surface area and low blood flow (100 mL/min) to avoid dialysis disequilibrium syndrome (DDS). His consciousness gradually improved and he did not develop apparent DDS symptoms. However, T2-weighted FLAIR MRI showed increased signal intensities bilaterally in the cortical and subcortical areas of the occipital lobe on day 15. In other words, cranial MRI showed cerebral edema, indicating asymptomatic DDS. On day 29, cranial MRI showed a return to findings on admission. In this case, because the patient did not have apparent DDS symptoms despite MRI changes, we diagnosed asymptomatic cerebral edema. The patient was discharged on regular intermittent HD without any neurological deficits. No further neurological disturbances were noted during 1-year follow-up. MRI findings in ESKD patients without DDS symptoms help to clarify the diagnosis of cerebral edema. In this case, the patient did not have apparent DDS symptoms and was therefore diagnosed with asymptomatic cerebral edema.

Dialysis disequilibrium leading to posterior reversible encephalopathy syndrome in chronic renal failure

Dialysis disequilibrium syndrome is a neurological adverse effect of acute hemodialysis in advanced uremic patients. Dialysis disequilibrium has a wide spectrum of clinical manifestations starting from subtle uneasiness, confusion, to florid and complex life threatening neurological deficit. In this case study, we present a patient who developed sudden cortical blindness following hemodialysis due to posterior reversible encephalopathy, which is a rare presentation of dialysis disequilibrium syndrome.

Increased Intracranial Pressure during Hemodialysis in a Patient with Anoxic Brain Injury

Dialysis disequilibrium syndrome (DDS) is a serious neurological complication of hemodialysis, and patients with acute brain injury are at increased risk. We report a case of DDS leading to intracranial hypertension in a patient with anoxic brain injury and discuss the subsequent dialysis strategy. A 13-year-old girl was admitted after prolonged resuscitation from cardiac arrest. Computed tomography (CT) revealed an inferior vena cava aneurysm and multiple pulmonary emboli as the likely cause. An intracranial pressure (ICP) monitor was inserted, and, on day 3, continuous renal replacement therapy (CRRT) was initiated due to acute kidney injury, during which the patient developed severe intracranial hypertension. CT of the brain showed diffuse cerebral edema. CRRT was discontinued, sedation was increased, and hypertonic saline was administered, upon which ICP normalized. Due to persistent hyperkalemia and overhydration, ultrafiltration and intermittent hemodialysis were performed separately on day 4 with a small dialyzer, low blood and dialysate flow, and high dialysate sodium content. During subsequent treatments, isolated ultrafiltration was well tolerated, whereas hemodialysis was associated with increased ICP necessitating frequent pauses or early cessation of dialysis. In patients at risk of DDS, hemodialysis should be performed with utmost care and continuous monitoring of ICP should be considered.

Diagnosis, Treatment, and Prevention of Hemodialysis Emergencies

Given the high comorbidity in patients on hemodialysis and the complexity of the dialysis treatment, it is remarkable how rarely a life-threatening complication occurs during dialysis. The low rate of dialysis emergencies can be attributed to numerous safety features in modern dialysis machines; meticulous treatment and testing of the dialysate solution to prevent exposure to trace elements, toxins, and pathogens; adherence to detailed treatment protocols; and extensive training of dialysis staff to handle medical emergencies. Most hemodialysis emergencies can be attributed to human error. A smaller number are due to rare idiosyncratic reactions. In this review, we highlight major emergencies that may occur during hemodialysis treatments, describe their pathogenesis, offer measures to minimize them, and provide specific interventions to prevent catastrophic consequences on the rare occasions when such emergencies arise. These emergencies include dialysis disequilibrium syndrome, venous air embolism, hemolysis, venous needle dislodgement, vascular access hemorrhage, major allergic reactions to the dialyzer or treatment medications, and disruption or contamination of the dialysis water system. Finally, we describe root cause analysis after a dialysis emergency has occurred to prevent a future recurrence.

Neurologic Complications in the Intensive Care Unit

Complications involving the central and peripheral nervous system are frequently encountered in critically ill patients. All components of the neuraxis can be involved including the brain, spinal cord, peripheral nerves, neuromuscular junction, and muscles. Neurologic complications adversely impact outcome and length of stay. These complications can be related to underlying critical illness, pre-existing comorbid conditions, and commonly used and life-saving procedures and medications. Familiarity with the myriad neurologic complications that occur in the intensive care unit can facilitate their timely recognition and treatment. Additionally, awareness of treatment-related neurologic complications may inform decision-making, mitigate risk, and improve outcomes.

Dialysis Headache: A Narrative Review

BACKGROUND

Patients with chronic kidney disease who need dialysis often have poor quality of life. Dialysis headache is a frequent complication of hemodialysis and is often a challenge for nephrologists, neurologists, and headache specialists.

METHOD

This was a narrative review.

RESULTS

The prevalence of dialysis headache varies between 27% and 73%. Among the characteristics of this headache are the pulsatile pattern, frontal location, moderate to severe intensity, and onset a few hours after the beginning of dialysis. The headache may be accompanied by nausea and vomiting. The physiopathology of hemodialysis headache is still not completely understood. Some factors that seem to be associated with it are variations in urea, sodium, magnesium, blood pressure, and weight levels. The hematoencephalic barrier has an important role. Variations in electrolyte and urea levels occur in the systemic circulation during hemodialysis, but the cerebral concentrations of these substances are stable over the first few hours of the procedure. The flow of free water through the hematoencephalic barrier may lead to cerebral edema. Other potential pathophysiological factors include nitric oxide, calcitonin gene-related peptide, and substance P. There are recommendations for maintenance of volume and control over electrolytes and blood pressure and avoidance of caffeine for prevention of hemodialysis headache. However, there are no controlled studies of prophylactic or abortive hemodialysis headache treatment.

CONCLUSION

Despite its prevalence, hemodialysis headache has been poorly studied, thus making it difficult to understand the pathophysiological mechanisms involved in its genesis. Current clinical management practices are therefore necessarily empiric with minimal to no evidence base.

Cerebral Edema in a Child after Preemptive Kidney Transplantation

Dialysis disequilibrium syndrome (DDS) is characterized by acute neurological manifestations in patients undergoing first dialysis treatment. The mechanisms for the development of DDS include the reverse urea effect, transient intracranial acidosis, and idiogenic osmoles which can increase intracellular osmolality and promote water movement into the brain. We present a case of a 4-year-old child with chronic kidney disease who underwent a preemptive living unrelated donor kidney transplant. He had a 24 mEq/L drop in his sodium concentration, 92% reduction in blood urea nitrogen (BUN) concentration, and a 67 mOsm/kg drop in serum osmolality within 18 hours after transplant, with concurrent development of symptomatic and radiologic cerebral edema, similar to that described in DDS. Mental status rapidly returned to baseline after administration of 3% hypertonic saline. This case highlights the risk of cerebral edema in patients who have a high pretransplant BUN. It emphasizes the need for close monitoring of vital signs, mental status, and electrolytes in children undergoing renal transplant. Hypertonic solutions can be used to prevent or manage cerebral edema in these patients when serum osmolality decreases rapidly. Pretransplant dialysis is another consideration to proactively reduce serum hyperosmolality.

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.

Disequilibrium syndrome and prevention in nonhemodialysis patients

Disequilibrium syndrome (DS) is a central nervous system disorder described in hemodialysis (HD) patients. The authors present 4 cases of elevated blood urea nitrogen (BUN); the first patient passed away from suspected DS, whereas the other 3 patients were identified as having a high risk of developing DS on the basis of their BUN. The authors tried to lower their BUN slowly and prevent rapid correction by different methods. This is the first study in which DS has been studied in patients who are not on HD, and methods are described to identify and prevent DS in such patients. They also review the existing literature on the pathogenesis of DS and highlight the importance of recognizing this syndrome in non-HD patients, while suggesting some innovative ways to prevent it.

Outcomes of Hemodialysis in Children: A 35-Year Experience at Severance Hospital

PURPOSE

The aim of this study was to analyze the results of children treated with hemodialysis (HD) at Severance Hospital over 35 years in terms of incidence, etiologies, characteristics, complications, and clinical outcomes.

MATERIALS AND METHODS

We analyzed 46 children admitted to Severance Hospital who had undergone HD between January 1979 and December 2013.

RESULTS

The main etiologies of the 23 end-stage renal disease (ESRD) patients who had received HD were chronic glomerulonephritis (7 patients, 30.4%) and congenital anomalies of the kidney and urinary tract (7 patients, 30.4%), whereas the etiology of the 23 acute kidney injury (AKI) patients was hemolytic uremic syndrome (6 patients, 26.1%). Compared with ESRD patients, hemocatheter placement in the femoral vein was preferred over the subclavian or internal jugular vein in the AKI patients (p=0.012). The most common complication was catheter related complication (10 patients, 21.7%). The site of hemocatheter insertion was not related to the frequency of oozing. Placing the hemocatheter in the femoral vein resulted in significantly more events of catheter obstruction than insertion in the internal jugular vein or the subclavian vein (p=0.001). Disequilibrium syndrome occurred more frequently in older patients (p=0.004), as well as patients with a greater body weight (p=0.008) and a higher systolic and diastolic blood pressure before HD (systolic: p=0.021; diastolic: p=0.040).

CONCLUSION

Based on the 35 years of experience in our center, HD can be sufficiently and safely carried out even in children without significant complications.

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.

Development of dialysis disequilibrium-like clinical signs during postobstructive management of feline urethral obstruction

OBJECTIVE

To describe the clinical features, treatment, and outcome of a cat with acute neurologic signs subsequent to relief of urethral obstruction and rapid resolution of severe azotemia, suggesting a process similar to dialysis disequilibrium syndrome.

CASE SUMMARY

A male castrated domestic short-hair cat was presented for weakness and dull mentation. Initial physical examination was consistent with urethral obstruction and laboratory data demonstrated severe azotemia, hyperkalemia, and acidemia. Interventions for hyperkalemia and urethral catheterization were performed without complication. The patient demonstrated a marked postobstructive diuresis and 7 hours after presentation suffered a grand mal seizure and was neurologically inappropriate. These changes corresponded with marked decreases in blood urea nitrogen (from 89.25 mmol/L to 19.99 mmol/L [250 mg/dL to 56 mg/dL]) and calculated serum osmolality (429 mOsm/kg to 359 mOsm/kg) from initial presentation without other apparent cause for seizure activity. The patient was treated with hypertonic saline (bolus and continuous infusion) for presumed osmotic injury (dialysis disequilibrium-like clinical signs) along with other supportive care. All neurologic signs resolved within 48 hours, the urinary catheter was removed, and the patient was discharged after 24 hours of observation of spontaneous urination.

NEW OR UNIQUE INFORMATION PROVIDED

Dialysis disequilibrium syndrome has been documented in small animals, but similar signs have not been reported as a sequelae of treatment of feline urethral obstruction. Urethral obstruction is a common emergency and practitioners should be aware of this potential complication as a cause of delayed neurologic recovery or seizures in the postobstructive period.

Cerebro-renal interactions: impact of uremic toxins on cognitive function

Cognitive impairment (CI) associated with chronic kidney disease (CKD) has received attention as an important problem in recent years. Causes of CI with CKD are multifactorial, and include cerebrovascular disease, renal anemia, secondary hyperparathyroidism, dialysis disequilibrium, and uremic toxins (UTs). Among these causes, little is known about the role of UTs. We therefore selected 21 uremic compounds, and summarized reports of cerebro-renal interactions associated with UTs. Among the compounds, uric acid, indoxyl sulfate, p-cresyl sulfate, interleukin 1-β, interleukin 6, TNF-α, and PTH were most likely to affect the cerebro-renal interaction dysfunction; however, sufficient data have not been obtained for other UTs. Notably, most of the data were not obtained under uremic conditions; therefore, the impact and mechanism of each UT on cognition and central nervous system in uremic state remains unknown. At present, impacts and mechanisms of UT effects on cognition are poorly understood. Clarifying the mechanisms and establishing novel therapeutic strategies for cerebro-renal interaction dysfunction is expected to be subject of future research.

Diabetes mellitus suppresses hemodialysis-induced increases in tear fluid secretion

Background

Hemodialysis is essential for the survival of patients suffering from chronic renal failure. However, in diabetics the incidence of dry eye disease is higher than in non-diabetic individuals. Accordingly, we evaluated if this difference is attributable to different effects of hemodialysis on basal tear fluid secretion.

Methods

A modified Schirmer´s eye test determined if hemodialysis improved basal tear secretion rates in 36 diabetic and non-diabetic patients undergoing hemodialysis.

Results

Basal tear secretion was invariant in diabetic patients whereas in non-diabetic individuals this process increased.

Conclusion

In non-diabetic patients, autonomic neuropathy appears to be less severe and somewhat reversible since only in these individuals hemodialysis improved basal tear fluid secretion. This difference may be a factor contributing to the lower incidence of dry eye disease in non-diabetic patients.

Dialysis dose and intradialytic hypotension: results from the HEMO study

BACKGROUND

Intradialytic hypotension (IDH) is common and is associated with increased morbidity and mortality in chronic hemodialysis patients. A higher dialysis 'dose' may generate transient intradialytic osmotic gradients, predisposing to intracellular fluid shifts and resulting in hypotension.

STUDY DESIGN

We performed a post hoc analysis of the HEMO study, a multicenter trial that randomized chronic hemodialysis patients to high versus standard Kt/V and higher versus lower membrane flux. In order to achieve dose targets, per protocol, adjustments were made in membrane efficiency, blood flow or dialysate flow before changing session length. Detailed hemodynamic and urea kinetic modeling data were abstracted from 1,825 individuals. The primary outcome was the occurrence of hypotensive events necessitating clinical intervention (saline infusion, lowering of ultrafiltration rate or reduced blood flow).

RESULTS

Intradialytic hypotensive events occurred more frequently in the higher-Kt/V group (18.3 vs. 16.8%; p < 0.001). Participants randomized to higher-target Kt/V had a greater adjusted risk of IDH than those randomized to standard Kt/V [odds ratio (OR) 1.12; 95% confidence interval (CI) 1.01-1.25]. Higher vs. lower dialyzer mass transfer-area coefficient for urea and rate of urea removal were associated with greater adjusted odds of IDH (OR 1.15; 95% CI 1.04-1.27 and OR 1.05; 95% CI 1.04-1.06 per mg/dl/h, respectively).

CONCLUSIONS

Higher dialysis dose, at relatively constrained treatment times, may associate with an increased risk of IDH. These findings support the possibility that rapidity of intradialytic reductions in plasma osmolality may play an important role in mediating hemodynamic instability during dialysis.