Central pontine myelinolysis, an update

Imaging Findings and Toxicological Mechanisms of Nervous System Injury Caused by Diquat

Diquat (DQ) is a nonselective bipyridine herbicide with a structure resembling paraquat (PQ). In recent years, the utilization of DQ as a substitute for PQ has grown, leading to an increase in DQ poisoning cases. While the toxicity mechanism of DQ remains unclear, it is primarily attributed to the intracellular generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) through the process of reduction oxidation. This results in oxidative stress, leading to a cascade of clinical symptoms. Notably, recent reports on DQ poisoning have highlighted a concerning trend: an upsurge in cases involving neurological damage caused by DQ poisoning. These patients often present with severe illness and a high mortality rate, with no effective treatment available thus far. Imaging findings from these cases have shown that neurological damage tends to concentrate on the brainstem. However, the specific mechanisms behind this poisoning remain unclear, and no specific antidote exists. This review summarizes the research progress on DQ poisoning and explores potential mechanisms. By shedding light on the nerve damage associated with DQ poisoning, we hope to raise awareness, propose new avenues for investigating the mechanisms of DQ poisoning, and lay the groundwork for the development of treatment strategies for DQ poisoning. Trial registration number: 2024PS174K.

Locked-in syndrome after central pontine myelinolysis, an outstanding outcome of two patients

OBJECTIVE

Central pontine myelinolysis (CPM) is a rare demyelinating disease that affects the pons and which can cause extreme disabilities such as locked-in syndrome (LIS) in the initial phase. The aim of the study was to describe the evolution over a 12-month period of two patients with CPM causing an initial LIS.

METHOD

We retrospectively report the unexpected clinical outcome of these two patients in relation with the anatomical damages documented by brain MRI, associated with diffusion tensor imaging and reconstruction of corticospinal tracts in tractography. The following clinical parameters systematically assessed at 3, 6, 9, and 12 months: muscle testing on 12 key muscles (Medical Research Council), prehension metrics (box and block test and purdue pegboard), and independence for acts of daily living (functional independence measure).

RESULTS

Both patients showed a progressive recovery beginning between 2 and 3 months after the onset of symptoms, leading to almost complete autonomy at 12 months (FIM > 110), with motor strength greater than 4/5 in all joint segments (MRC > 50/60). On brain MRI with tractography, CST appeared partially preserved at pons level.

INTERPRETATION

The possibility of a near-complete functional recovery at 12 months is important to consider given the ethical issues at stake and the discussions about limiting care that may take place initially. It seems to be the consequence of reversible myelin damage combined with partially preserved neurons. Development of collateral pathways or resolution of conduction block may explain this recovery. MRI comprising DTI and tractography could play a key role in the prognosis of motor recovery.

Osmotic demyelination syndrome caused by rapid correction of hyperammonemia and continuous hyperbilirubinemia: a case report and review of the literature

Osmotic demyelination syndrome (ODS) is an acute demyelinating disorder characterized by the loss of myelin in the center of the basis pons, defined as central pontine myelinolysis (CPM), and demyelination in locations outside the pons, defined as extrapontine myelinolysis (EPM). ODS including CPM and EPM is mainly caused by rapid correction of hyponatremia. However, there are several reports of ODS in medical conditions such as malnutrition; alcoholism; liver transplantation; malignancy; sepsis; and electrolyte imbalance including hypernatremia, hypokalemia, hypophosphatemia, and chronic illness. ODS caused by rapid correction of hyperammonemia or continuous hyperbilirubinemia without sodium fluctuations has rarely been reported. Because ODS may be irreversible, prevention is crucial. Herein, we report a case of ODS secondary to rapid correction of hyperammonemia and continuous hyperbilirubinemia.

Pontine lesion in hyperglycemic crises: Relevance to osmotic demyelination syndrome and posterior reversible encephalopathy syndrome

We herein describe a case of type 1 diabetes that presented with a pontine lesion during two hyperglycemic crises accompanied by marked fluctuations in serum osmotic pressure and blood pressure. Magnetic resonance imaging showed swollen pons with osmotic demyelination syndrome characteristics accompanying cytotoxic edema at the first crisis. The involvement of vasogenic edema was also assumed in the second crisis. Neurological symptoms were milder than magnetic resonance imaging findings. The patient recovered after 7 days without sequelae in both crises. Based on these findings, a pontine lesion needs to be considered in patients with poorly controlled diabetes showing rapid metabolic and blood pressure changes, as observed in hyperglycemic crises. Cytotoxic edema leading to osmotic demyelination syndrome and vasogenic edema caused by vascular endothelial cell damage might both be involved in the pathogenesis of a pontine lesion.

Neurological complications in pediatric liver transplant recipients

INTRODUCTION

There is paucity of data on neurological complications (NCs) and its predisposing factors, in pediatric liver transplant (PLT) recipients.

METHODS

Records of seventy-one children who underwent LT between October 2018 and November 2019 were reviewed. Patients were categorized into group A: with NC and group B: without NC in the post-LT period. Various risk factors contributing to NC were studied.

RESULTS

In total, 15 (21.1%) had NC (group A) and 56 (78.9%) had no NC in the post-LT period. NC included cerebrovascular accident (n = 1), seizures (n = 5; 4 generalized, 1 focal), central pontine myelolysis (CPM) (n = 1), diaphragmatic palsy (n = 2), peripheral neuropathy (n = 1), extrapyramidal movements (n = 3), and encephalopathy beyond 96 h (n = 2). The median onset of NC was at 8.5 days post-LT (1-58 days). Ten (66.7%) patients in group A had grades 2-4 hepatic encephalopathy (HE) prior to LT. Eight (14.3%) patients in group B also had pre-LT neurological issues including HE in six, epilepsy and spastic diplegia in one each. On univariate analysis, pre-existing HE, high PELD/MELD score, pre-LT ventilation, pre-LT infection, higher day 1 post-operative bilirubin (all p < .05), and higher tacrolimus were found to predict post-operative NC whereas on multivariate analysis, pre-LT HE was the only predictive factor. Median follow-up was 15.5 months. Four patients died in each group (survival log-rank p = .369). All the surviving patients in group A (n = 11) fully recovered from the NC.

CONCLUSION

Pre-transplant HE was the single most significant predisposing factor for post-LT neurological complications.

Case report: Hypoadrenocorticism crisis complicated by non-cardiogenic pulmonary edema in a dog

A 6-year-old castrated male Labradoodle was referred in uncompensated hypovolemic shock, with a 72-h history of lethargy, vomiting and diarrhea that had acutely worsened with subsequent development of profuse hemorrhagic diarrhea in the last 24 h after a visit to the groomer. In most respects this case was classic for a patient with a primary hypoadrenocortical crisis. After initial attempts to address hypovolemia and refractory hypotension, no clinical improvement was seen, and the respiratory rate had increased acutely to 80 bpm with crackles detected on thoracic auscultation and serosanguineous fluid began draining from the nose and mouth. An arterial blood gas sample while breathing room air revealed moderate hypoxemia (PaO2 59.9: RI 95–100 mmHg), an elevated alveolar-arterial (A-a) gradient at 54.7 (RI &lt; 15 mmHg) and a PaO2:FiO2 ratio of 285 mmHg. Thoracic radiographs revealed severe bilateral alveolar lung pattern largely limited to the perihilar and caudodorsal lung fields. The radiographic findings, along with signs of ongoing hypovolemia, the lack of evidence of typical long-standing acquired cardiac disease, and the rapid resolution of the pulmonary edema without the need for diuretics or long-term cardiac medications supported non-cardiogenic pulmonary edema. The proposed cause of the non-cardiogenic pulmonary edema was speculated to be neurogenically mediated. Oxygen supplementation along with mineralocorticoid and glucocorticoid replacement therapy was sufficient for the management of the non-cardiogenic pulmonary edema in this case.

Delirium Tremens and Central Pontine Myelinolysis in a Patient with Alcohol Use Disorder and Pneumonia: a Case Report and a Narrative Review

INTRODUCTION

Delirium tremens (DT) is a serious condition occurring in alcohol withdrawal syndrome. Alcohol consumption may also cause additional health problems, such as respiratory infections or neuropsychiatric conditions such as central pontine myelinolysis. In this clinical scenario, managing DT can be expected to be more compelling and complex. Alcohol decreases coughing and mucociliary clearance and disrupts the immunity of the respiratory system.

CASE

Here we report on a middle-aged man with alcohol use disorder who had developed DT due to alcohol withdrawal and comorbid pneumonia.

DISCUSSION AND CONCLUSION

In this paper, DT, the relation between respiratory infections and alcohol intake, and the correlation of alcohol consumption and central pontine myelinolysis (CPM) are discussed. Also, the literature on alcohol consumption and the additional respiratory and neurologic problems resulting from it are presented.

Diagnosis and Management of the Critically Ill Adult Patient with Hyperglycemic Hyperosmolar State

BACKGROUND

Hyperglycemic hyperosmolar state is a life-threatening complication of diabetes mellitus. Therefore, it is important for emergency physicians to be aware of this unique diagnosis and treatment considerations.

OBJECTIVE

This manuscript reviews the emergency department evaluation and management of the adult patient with hyperglycemic hyperosmolar state.

DISCUSSION

Hyperglycemic hyperosmolar state is diagnosed by an elevated glucose, elevated serum osmolality, minimal or absent ketones, and a neurologic abnormality, most commonly altered mental status. Treatment involves fluid resuscitation and correction of electrolyte abnormalities. It is important to monitor these patients closely to avoid overcorrection of osmolality, sodium, and other electrolytes. These patients are critically ill and generally require admission to an intensive care unit.

CONCLUSIONS

Hyperglycemic hyperosmolar state is associated with significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the diagnosis, management, and disposition of these patients.

[Central pontine myelinolysis during qualified alcohol withdrawal therapy. A case report]

Central pontine myelinolysis is a rare but severe disease that often occurs in alcohol-dependent and malnourished patients. One pathological mechanism is the rapid correction of chronic hyponatremia, even though the disease can occur independently of decreased serum sodium levels. Here, we present a patient suffering from malnutrition, alcohol dependency, and a severe depressive disorder, who presented himself to our clinic wishing for qualified withdrawal treatment. Because the patient reported significant weight loss and nocturnal sweating without fever, we performed different diagnostic investigations and examinations. Cranial MRI revealed the presence of a central pontine myelinolysis. In the clinical neurological examination, the patient only showed slight gait ataxia. The depressive symptoms had improved while the patient now showed problems in his short-term memory. At presentation, only slight hyponatremia was present, while no rapid correction occurred throughout treatment. The presented case reveals the importance of considering osmotic demyelination disorders as a differential diagnosis in patients suffering from neurological symptoms during alcohol withdrawal therapy. This is important independently of hyponatremia.

Follow-Up of Brain Single-Photon Emission Computed Tomography (SPECT) and Magnetic Resonance Imaging (MRI) in a Case of Seizure Caused by Osmotic Demyelination Syndrome

Patient: Male, 38-year-old

Final Diagnosis: Osmotic demyelination syndrome

Symptoms: Seizure

Medication: —

Clinical Procedure: —

Specialty: Nuclear Medicine • Radiology

The effect of white matter integrity on functional outcome in central pontine demyelination

[Purpose] Central pontine demyelination is a common osmotic demyelination syndrome. Typically, central pontine demyelination shows high signal intensity with demyelination in the mid-pons. Despite severe imaging findings, patients usually recover. This study investigated the integrity of the corticospinal tract (CST) and corticoreticular pathway (CRP) in patients at 12 months after the onset of central pontine demyelination. [Participants and Methods] This retrospective cross-sectional observational study assessed two patients with central pontine demyelination, who were ultimately able to walk without using an aid or orthosis and to use both hands but with mild residual symptoms. All participants underwent diffusion tensor imaging (DTI) at 12 months after onset. [Results] Both patients had mild ataxia at 12 months after onset. The integrity of the CST was restored in both cases, while the integrity of the CRP recovered partially. [Conclusion] The integrity of the CST and CRP at 12 months after the onset of central pontine demyelination was similar in both cases as well as the recovery status of the hand function and ambulation. These results may be useful in planning therapy for patients with central pontine demyelination.

Recent Topics on The Mechanisms of Immunosuppressive Therapy-Related Neurotoxicities

Although transplantation procedures have been developed for patients with end-stage hepatic insufficiency or other diseases, allograft rejection still threatens patient health and lifespan. Over the last few decades, the emergence of immunosuppressive agents such as calcineurin inhibitors (CNIs) and mammalian target of rapamycin (mTOR) inhibitors have strikingly increased graft survival. Unfortunately, immunosuppressive agent-related neurotoxicity commonly occurs in clinical practice, with the majority of neurotoxicity cases caused by CNIs. The possible mechanisms through which CNIs cause neurotoxicity include increasing the permeability or injury of the blood–brain barrier, alterations of mitochondrial function, and alterations in the electrophysiological state. Other immunosuppressants can also induce neuropsychiatric complications. For example, mTOR inhibitors induce seizures, mycophenolate mofetil induces depression and headaches, methotrexate affects the central nervous system, the mouse monoclonal immunoglobulin G2 antibody (used against the cluster of differentiation 3) also induces headaches, and patients using corticosteroids usually experience cognitive alteration. Therapeutic drug monitoring, individual therapy based on pharmacogenetics, and early recognition of symptoms help reduce neurotoxic events considerably. Once neurotoxicity occurs, a reduction in the drug dosage, switching to other immunosuppressants, combination therapy with drugs used to treat the neuropsychiatric manifestation, or blood purification therapy have proven to be effective against neurotoxicity. In this review, we summarize recent topics on the mechanisms of immunosuppressive drug-related neurotoxicity. In addition, information about the neuroprotective effects of several immunosuppressants is also discussed.

Neuroimaging in alcohol use disorder: From mouse to man

This article provides an overview of recent advances in understanding the effects of alcohol use disorders (AUD) on the brain from the perspective of magnetic resonance imaging (MRI) research in preclinical models and clinical studies. As a noninvasive investigational tool permitting assessment of morphological, metabolic, and hemodynamic changes over time, MRI offers insight into the dynamic course of alcoholism beginning with initial exposure through periods of binge drinking and escalation, sobriety, and relapse and has been useful in differential diagnosis of neurological diseases associated with AUD. Structural MRI has revealed acute and chronic effects of alcohol on both white and gray matter volumes. MR Spectroscopy, able to quantify brain metabolites in vivo, has shed light on biochemical alterations associated with alcoholism. Diffusion tensor imaging permits microstructural characterization of white matter fiber tracts. Functional MRI has allowed for elucidation of hemodynamic responses at rest and during task engagement. Positron emission tomography, a non-MRI imaging tool, has led to a deeper understanding of alcohol-induced receptor and neurotransmitter changes during various stages of drinking and abstinence. Together, such in vivo imaging tools have expanded our understanding of the dynamic course of alcoholism including evidence for regional specificity of the effects of AUD, hints at mechanisms underlying the shift from casual to compulsive use of alcohol, and profound recovery with sustained abstinence.

Tongue fasciculations with denervation pattern in osmotic demyelination syndrome: a case report of diagnostic dilemma

Background

The pathogenesis of osmotic demyelination syndrome is not completely understood and usually occurs with severe and prolonged hyponatremia, particularly with rapid correction. It can occur even in normonatremic patients, especially who have risk factors like alcoholism, malnutrition and liver disease. Bilateral tongue fasciculations with denervation pattern in electromyogram is a manifestation of damage to the hypoglossal nucleus or hypoglossal nerves. Tongue fasciculations were reported rarely in some cases of osmotic demyelination syndrome, but the exact mechanism is not explained.

Case presentation

A 32-year-old Sri Lankan male, with a history of daily alcohol consumption and binge drinking, presented with progressive difficulty in walking, dysphagia, dysarthria and drooling of saliva and alteration of consciousness. On examination he was akinetic and rigid resembling Parkinsonism with a positive Babinski sign. Clinical features were diagnostic of osmotic demyelination syndrome and MRI showed abnormal signal intensity within the central pons and basal ganglia. He also had tongue fasciculations. The electromyogram showed denervation pattern in the tongue with normal findings in the limbs. Medulla and bilateral hypoglossal nerves were normal in MRI.

Conclusion

We were unable to explain the exact mechanism for the denervation of the tongue, which resulted in fasciculations in this chronic alcoholic patient who developed osmotic demyelination syndrome. The hypoglossal nuclei are located in the dorsal medulla and radiologically undetected myelinolysis of the medulla is a possibility. Hypoglossal nerve damage caused by methanol or other toxic substances that can contaminate regular ethyl alcohol is another possibility, as it is known to cause neurological and radiological features similar to osmotic demyelination syndrome with long-term exposure. So these toxic substances might play a role in chronic alcoholic patients with central pontine myelinolysis.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3287-8) contains supplementary material, which is available to authorized users.

The Dilemma of Inadvertent Pontine Demyelinosis: A Review of Literature

Osmotic demyelination syndrome is classically associated with a swift adjustment of previously low serum sodium levels which lead to cellular dehydration and subsequent neurological insult. We also review the epidemiology, different postulations to explain the underlying pathophysiology, current diagnostic modalities, subsequent therapeutic interventions used to manage this phenomenon, and the resultant prognosis of this ailment.

Central Pontine Myelinolysis After Living-Donor Liver Transplant: A Report of 2 Cases

Here, we present 2 patients who developed central pontine myelinolysis after living-donor liver transplant. Both patients had abnormal sodium level before living-donor liver transplant. Patient 1 presented with severe hyponatremia on admission. After administration of 3% saline, her sodium level during the first 24 hours was kept at 100 mEq/L and then increased to 116 mEq/L during the next 24 hours. The level increased 5.8 mEq/L during the 4- to 5-hour transplant procedure. Patient 2 was admitted to the hospital with an unprovoked seizure. The serum sodium concentration was 111 mEq/L, which was treated with 3% saline infusion. Serum sodium concentration escalated to 118 mEq/L over an 8-hour period. Intraoperatively, both patients received large amounts of replacement fluids (0.9% normal saline and albumin), blood transfusion, and sodium bicarbonate during the anhepatic phase, all of which carry high sodium load. Variations in sodium levels changed rapidly in patient 1 during transplant surgery. After they underwent liver transplant, patient 1 had clear mental status and patient 2 demonstrated worsened mental status. On approximately day 14 and day 4 after liver transplant, magnetic resonance imaging showed diffuse abnormalities of the pons, resulting in diagnosis of central pontine myelinolysis. Although both patients survived, 1 remains in a vegetative state and the other continues to present with mild balance and swallowing abnormalities. To reduce the chance of inadvertent overcorrection in patients with hyponatremia, it is therefore important that sodium concentrations should be monitored frequently and fluids and electrolytes titrated carefully.

Abrus Precatorius Poisoning and Central Pontine Myelinolysis

Accidental poisoning with Abrus precatorius (AP) can rarely produce neurological complication due to its toxic principle “Abrin”. The authors report such a case in a 2-year old child, who subsequently developed central pontine myelinolysis, an association, to the best of the author’s knowledge, has never been reported in literature.

Alcohol-related diseases

Alcohol abuse and dependence are serious medical and economic problems in Western countries. Brain changes encountered in alcoholism are manifold and encompass brain atrophy, selective neuronal loss, astroglial, and microglial changes. Alcohol-related disorders are complex multifactorial disorders where the interaction of multiple genes and environment plays an important role in the pathogenesis.

Structural and microstructral imaging of the brain in alcohol use disorders

Magnetic resonance imaging (MRI), by enabling rigorous in vivo study of the longitudinal, dynamic course of alcoholism through periods of drinking, sobriety, and relapse, has enabled characterization of the effects of chronic alcoholism on the brain in the human condition. Importantly, MRI has distinguished alcohol-related brain effects that are permanent versus those that are reversible with abstinence. In support of postmortem neuropathologic studies showing degeneration of white matter, MRI has shown a specific vulnerability of brain white matter to chronic alcohol exposure by demonstrating white-matter volume deficits, yet not leaving selective gray-matter structures unscathed. Diffusion tensor imaging (DTI), by permitting microstructural characterization of white matter, has extended MRI findings in alcoholics. This review focuses on MRI and DTI findings in common concomitants of alcoholism, including Wernicke's encephalopathy, Korsakoff's syndrome, hepatic encephalopathy, central pontine myelinolysis, alcoholic cerebellar degeneration, alcoholic dementia, and Marchiafava-Bignami disease as a framework for findings in so-called "uncomplicated alcoholism," and also covers findings in abstinence and relapse.

Hypertonic salt solution for peri-operative fluid management

BACKGROUND

Fluid excess may place people undergoing surgery at risk for various complications. Hypertonic salt solution (HS) maintains intravascular volume with less intravenous fluid than isotonic salt (IS) solutions, but may increase serum sodium. This review was published in 2010 and updated in 2016.

OBJECTIVES

To determine the benefits and harms of HS versus IS solutions administered for fluid resuscitation to people undergoing surgery.

SEARCH METHODS

In this updated review we have searched the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 4, 2016); MEDLINE (January 1966 to April 2016); EMBASE (January 1980 to April 2016); LILACS (January 1982 to April 2016) and CINAHL (January 1982 to April 2016) without language restrictions. We conducted the original search on April 30th, 2007, and reran it on April 8th, 2016.

SELECTION CRITERIA

We have included randomized clinical trials (RCTs) comparing HS to IS in people undergoing surgery, irrespective of blinding, language, and publication status.

DATA COLLECTION AND ANALYSIS

Two independent review authors read studies that met our selection criteria. We collected study information and data using a data collection sheet with predefined parameters. We have assessed the impact of HS administration on mortality, organ failure, fluid balance, serum sodium, serum osmolarity, diuresis and physiologic measures of cardiovascular function. We have pooled the data using the mean difference (MD) for continuous outcomes. We evaluated heterogeneity between studies by I² percentage. We consider studies with an I² of 0% to 30% to have no or little heterogeneity, 30% to 60% as having moderate heterogeneity, and more than 60% as having high heterogeneity. In studies with low heterogeneity we have used a fixed-effect model, and a random-effects model for studies with moderate to high heterogeneity.

MAIN RESULTS

We have included 18 studies with 1087 participants of whom 545 received HS compared to 542 who received IS. All participants were over 18 years of age and all trials excluded high-risk patients (ASA IV). All trials assessed haematological parameters peri-operatively and up to three days post-operatively.There were three (< 1%) deaths reported in the IS group and four (< 1%) in the HS group, as assessed at 90 days in one study. There were no reports of serious adverse events. Most participants were in a positive fluid balance postoperatively (4.4 L IS and 2.5 L HS), with the excess significantly less in HS participants (MD -1.92 L, 95% confidence interval (CI) -2.61 to -1.22 L; P < 0.00001). IS participants received a mean volume of 2.4 L and HS participants received 1.49 L, significantly less fluid than IS-treated participants (MD -0.91 L, 95% CI -1.24 to -0.59 L; P < 0.00001). The maximum average serum sodium ranged between 138.5 and 159 in HS groups compared to between 136 and 143 meq/L in the IS groups. The maximum serum sodium was significantly higher in HS participants (MD 7.73, 95% CI 5.84 to 9.62; P < 0.00001), although the level remained within normal limits (136 to 146 meq/L).A high degree of heterogeneity appeared to be related to considerable differences in the dose of HS between studies. The quality of the evidence for the outcomes reported ranged from high to very low. The risk of bias for many of the studies could not be determined for performance and detection bias, criteria that we assess as likely to impact the study outcomes.

AUTHORS' CONCLUSIONS

HS reduces the volume of intravenous fluid required to maintain people undergoing surgery but transiently increases serum sodium. It is not known if HS affects survival and morbidity, but this should be examined in randomized controlled trials that are designed and powered to test these outcomes.

Thiazide-associated hyponatremia in the elderly: what the clinician needs to know

Thiazide-induced hyponatremia is one of the main causes of decreased sodium levels in elderly individuals. This review presents the current evidence regarding the thiazide-associated hyponatremia. Thiazide-associated hyponatremia is observed mainly in patients with certain risk factors such as those receiving large doses of thiazides, having much comorbidity, such as heart failure, liver disease or malignancy, and taking several medications, such as non-steroidal anti-inflammatory drugs, selective serotonin re-uptake inhibitors or tricyclic antidepressants. Sodium concentration should be monitored in patients with risk factors for developing thiazide-associated hyponatremia and clinicians should measure promptly serum sodium levels in patients with neurologic signs indicating reduced sodium levels. The clinical and biochemical profile of patients with thiazide-associated hyponatremia may be that of extracellular volume depletion or the syndrome of inappropriate antidiuretic hormone secretion (SIADH). The investigation of possible thiazide-associated hyponatremia includes the exclusion of other causes of decreased sodium levels and the identification of the characteristics of hyponatremia due to thiazides (extracellular volume depletion-related or SIADH-like). Treatment should be carefully monitored to avoid serious neurologic complications due to overcorrection. Clinicians should discourage prescribing thiazides in patients with a history of diuretic-associated hyponatremia and should prefer low doses of thiazides in patients with risk factors for developing thiazide-associated hyponatremia.

Hyponatremia in the intensive care unit: How to avoid a Zugzwang situation?

Hyponatremia is a common electrolyte derangement in the setting of the intensive care unit. Life-threatening neurological complications may arise not only in case of a severe (<120 mmol/L) and acute fall of plasma sodium levels, but may also stem from overly rapid correction of hyponatremia. Additionally, even mild hyponatremia carries a poor short-term and long-term prognosis across a wide range of conditions. Its multifaceted and intricate physiopathology may seem deterring at first glance, yet a careful multi-step diagnostic approach may easily unravel the underlying mechanisms and enable physicians to adopt the adequate measures at the patient’s bedside. Unless hyponatremia is associated with obvious extracellular fluid volume increase such as in heart failure or cirrhosis, hypertonic saline therapy is the cornerstone of the therapeutic of profound or severely symptomatic hyponatremia. When overcorrection of hyponatremia occurs, recent data indicate that re-lowering of plasma sodium levels through the infusion of hypotonic fluids and the cautious use of desmopressin acetate represent a reasonable strategy. New therapeutic options have recently emerged, foremost among these being vaptans, but their use in the setting of the intensive care unit remains to be clarified.

Extrapontine myelinolysis associated with pituitrin: case report and literature review

Background

Hyponatremia is the most common electrolyte abnormality encountered in hospitalized patients, resulting from a varied spectrum of conditions. Both the primary disturbance and its correction can result in life-threatening neurological consequences. Extrapontine myelinolysis is one such complication that is associated with the rapid correction of hyponatremia. Here we describe a patient who developed extrapontine myelinolysis unexpectedly after the correction of hyponatremia, which involved the drug pituitrin.

Case presentation

A 24-year-old Chinese woman was transferred to our neurology department with the symptoms of dysarthria and quadriparesis developing one day after the correction of hyponatremia (from 118 mmol/L to 140 mmol/L), which followed with a continuous intravenous drip of pituitrin used to control hemoptysis in the emergency room. During the course, she developed involuntary movement. Magnetic resonance imaging changes were consistent with extrapontine myelinolysis.

Conclusion

This present case describes the mechanism of profound hyponatremia involving pituitrin, and the subsequent development of extrapontine myelinolysis. Physicians may approach effective clinical management of patients through awareness of the adverse effect of pituitrin on serum sodium levels, and avoid rapid correction of hyponatremia in clinical practice.

Hyponatremia in patients with heart failure

The present review analyses the mechanisms relating heart failure and hyponatremia, describes the association of hyponatremia with the progress of disease and morbidity/mortality in heart failure patients and presents treatment options focusing on the role of arginine vasopressin (AVP)-receptor antagonists. Hyponatremia is the most common electrolyte disorder in the clinical setting and in hospitalized patients. Patients with hyponatremia may have neurologic symptoms since low sodium concentration produces brain edema, but the rapid correction of hyponatremia is also associated with major neurologic complications. Patients with heart failure often develop hyponatremia owing to the activation of many neurohormonal systems leading to decrease of sodium levels. A large number of clinical studies have associated hyponatremia with increased morbidity and mortality in patients hospitalized for heart failure or outpatients with chronic heart failure. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. AVP-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia. However, the effects of AVP-receptor antagonists on hard outcomes in patients with heart failure and hyponatremia have not been thoroughly examined.

Evidence of aquaporin involvement in human central pontine myelinolysis

BACKGROUND

Central pontine myelinolysis (CPM) is a demyelinating disorder of the central basis pontis that is often associated with osmotic stress. The aquaporin water channels (AQPs) have been pathogenically implicated because serum osmolarity changes redistribute water and osmolytes among various central nervous system compartments.

RESULTS

We characterized the immunoreactivity of aquaporin-1 and aquaporin-4 (AQP1 and AQP4) and associated neuropathology in microscopic transverse sections from archival autopsied pontine tissue from 6 patients with pathologically confirmed CPM. Loss of both AQP1 and AQP4 was evident within demyelinating lesions in four of the six cases, despite the presence of glial fibrillary acidic protein (GFAP)-positive astrocytes. Lesional astrocytes were small, and exhibited fewer and shorter processes than perilesional astrocytes. In two of the six cases, astrocytes within demyelinating lesions exhibited increased AQP1 and AQP4 immunoreactivities, and gemistocytes and mitotic astrocytes were numerous. Blinded review of medical records revealed that all four cases lacking lesional AQP1 and AQP4 immunoreactivities were male, whereas the two cases with enhanced lesional AQP1 and AQP4 immunoreactivities were female.

CONCLUSIONS

This report is the first to establish astrocytic AQP loss in a subset of human CPM cases and suggests AQP1 and AQP4 may be involved in the pathogenesis of CPM. Further studies are required to determine whether the loss of AQP1 and AQP4 is restricted to male CPM patients, or rather may be a feature associated with specific underlying precipitants of CPM that may be more common among men. Non-rodent experimental models are needed to better clarify the complex and dynamic mechanisms involved in the regulation of AQPs in CPM, in order to determine whether it occurs secondary to the destructive disease process, or represents a compensatory mechanism protecting the astrocyte against apoptosis.

Rapid correction rate of hyponatremia as an independent risk factor for neurological complication following liver transplantation

Hyponatremia is prevalent before liver transplantation and generally corrected immediately after transplantation. However, the clinical significance of correction rate of hyponatremia is not well investigated. The prognostic impact of pre-transplant serum sodium concentrations and post-transplant correction rate of hyponatremia were assessed. A total of 512 patients who received orthotopic liver transplants were enrolled. The correction rate of hyponatremia (delta sodium, ΔNa) was calculated based on the data collected during the first 48 hours following liver transplantation. Outcomes, including in-hospital mortality, delirium, neurological complications, acute kidney injury, and infections, were compared according to the serum sodium levels (sNa < 125, 125-135, and ≥ 135 mmol/L), and the risk factors for in-hospital mortality and neurological complications were analyzed using multivariate logistic regression methods. Patients with severe hyponatremia (sNa < 125 mmol/L) had higher rates of in-hospital mortality (9.6%, P = 0.010), delirium (54.8%, P = 0.003), neurological complications (24.7%, P = 0.003), and acute kidney injury (57.5%, P = 0.005). In multivariate analysis, serum sodium levels (OR = 0.975, P = 0.402) and delta sodium (OR = 1.097, P = 0.066) were not independent risk factors for in-hospital mortality. However, delta sodium (OR = 1.093, P = 0.003) and fast correction rate of hyponatremia (ΔNa ≥ 12 mmol/L/24h, OR = 3.397, P = 0.023) were significantly associated with post-transplant neurological complications. Pre-transplantation hyponatremia was not independently associated with clinical outcomes. However, rapid correction of hyponatremia is an independent risk factor for the development of post-transplant neurological complications.

Movement disorders and the osmotic demyelination syndrome

With the advent of MRI, osmotic demyelination syndromes (ODS) are increasingly recognised to affect varied sites in the brain in addition to the classical central pontine lesion. Striatal involvement is seen in a large proportion of cases and results in a wide variety of movement disorders. Movement disorders and cognitive problems resulting from ODS affecting the basal ganglia may occur early in the course of the illness, or may present as delayed manifestations after the patient survives the acute phase. Such delayed symptoms may evolve over time, and may even progress despite treatment. Improved survival of patients in the last few decades due to better intensive care has led to an increase in the incidence of such delayed manifestations of ODS. While the outcome of ODS is not as dismal as hitherto believed - with the acute akinetic-rigid syndrome associated with striatal myelinolysis often responding to dopaminergic therapy - the delayed symptoms often prove refractory to medical therapy. This article presents a review of the epidemiology, pathophysiology, clinical features, imaging, and therapy of movement disorders associated with involvement of the basal ganglia in ODS. A comprehensive review of 54 previously published cases of movement disorders due to ODS, and a video recording depicting the spectrum of delayed movement disorders seen after recovery from ODS are also presented.

Posterior reversible encephalopathy syndrome after bevacizumab therapy in a normotensive patient

Posterior reversible encephalopathy syndrome (PRES) is a neurological disorder characterised by distinct radiological features. Common precipitants of this disorder include acute medical illness, hypertensive crisis, eclampsia, immunosuppressive therapy and chemotherapy. We present the case of a patient with advanced ovarian carcinoma who developed PRES shortly after receiving bevacizumab (Avastin), an inhibitor of vascular endothelial growth factor. The patient's medical history and clinical presentation both suggest bevacizumab as the precipitator for PRES. This agent has been often overlooked as a possible cause of this rare neurological syndrome.

Common endocrine issues in the pediatric intensive care unit

Thyroid hormone is central to normal development and metabolism. Abnormalities in thyroid function in North America often arise from autoimmune diseases, but they rarely present as critical illness. Severe deficiency or excess of thyroid hormone both represent life-threatening disease, which must be treated expeditiously and thoroughly. Such deficiencies must be considered, because presentation may be nonspecific.

Spectrum of brain abnormalities detected on whole body F-18 FDG PET/CT in patients undergoing evaluation for non-CNS malignancies

We present the pattern of metabolic brain abnormalities detected in patients undergoing whole body (WB) F-18 flurodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) examination for non-central nervous system (CNS) malignancies. Knowledge of the PET/CT appearance of various intracranial metabolic abnormalities enables correct interpretation of PET scans in oncological patients where differentiation of metastasis from benign intracranial pathologies is important and improves specificity of the PET study. A complete clinical history and correlation with CT and MRI greatly helps in arriving at a correct imaging diagnosis.

Central and extrapontine myelinolysis affecting the brain and spinal cord. An unusual presentation of pancreatic encephalopathy

Pancreatic encephalopathy refers to a gamut of neuropsychiatric symptoms complicating acute pancreatitis. Osmotic myelinolysis is a known complication of pancreatic encephalopathy. We evaluated a 58-year-old woman with pancreatic encephalopathy associated to pontine and extrapontine myelinolysis involving the brain and spinal cord. To our knowledge, this is the first clinic pathological case report of pancreatic encephalopathy involving the spinal cord.

Central pontine and extrapontine myelinolysis in children: a review of 76 patients

This study aimed to identify the causes and contributing factors, neurologic presentation, and outcomes of central pontine and extrapontine myelinolysis and to examine any trends in the presentation and course of these disorders over the past 50 years. Seventy-six pediatric cases were identified in the literature. Age, sex, decade of diagnosis, neurologic presentation, outcome, and attributed causes were extracted. The results showed that the diagnosis, course, and outcomes of central pontine and extrapontine myelinolysis clearly have changed over the past few decades. Early cases generally were diagnosed at autopsy as opposed to computed tomography or magnetic resonance imaging more recently. Ninety-four percent of cases prior to 1990 and only 7% of cases from 1990 onward resulted in patient mortality. The decade in which the case was reported was the strongest predictor of outcome (P < .001), followed by sodium dysregulation (P = .045) and dehydration (P = .07).

Forensic aspects of water intoxication: four case reports and review of relevant literature

Water intoxication (WI) is a rare condition that originates from over-consumption of water, with a potentially fatal outcome. Increased water intake (polydipsia) is followed by urination of high amount of diluted urine (polyuria) which are the main initial symptoms of WI. We present four case reports of WI. Two of them are unusual pediatric clinical cases using medical documentation and police case files, one of which is related to child abuse, and the other to a psychiatric disorder. The other two cases are fatal adult cases submitted to autopsy from a psychiatric hospital. Also, we present a diagnostic algorithm for polydipsia and polyuria before death. WI is usually seen in patients with psychiatric disorders, victims of child abuse or torture, drug abusers or it can be iatrogenically induced.

Hyponatremia: mechanisms and newer treatments

OBJECTIVE

To review the neural and renal mechanisms of osmotic homeostasis, provide a rationale for the sensitivity of the central nervous system to hyponatremia, and outline modern approaches to therapy of acute and chronic hyponatremia.

METHODS

Review of relevant literature with focus on physiologic mechanisms.

RESULTS

With careful monitoring, acute hyponatremia can be managed, while minimizing risks both of continued hyponatremia and the osmotic demyelination that can occur with overly rapid correction of severe hyponatremia. Chronic hyponatremia due to disorders of volume regulation (congestive heart failure or cirrhosis) or to syndrome of inappropriate antidiuretic hormone release can be managed effectively with vasopressin V2 receptor antagonists, but there is no evidence that controlling the hyponatremia enhances survival associated with the underlying diseases.

CONCLUSIONS

Therapy in the acute setting balances the risk of the osmotic disturbance with the risk of overly rapid correction. The V2 receptor antagonist tolvaptan has enhanced our ability to improve chronic hyponatremia in conditions such as congestive heart failure, cirrhosis, and syndrome of inappropriate antidiuretic hormone hypersecretion.

Neuroimaging findings in alcohol-related encephalopathies

OBJECTIVE

Our aim was to review the emergent neuroimaging findings of alcohol-related CNS nontraumatic disorders. Alcohol (ethanol) promotes inflammatory processes, increases DNA damage, and creates oxidative stress. In addition, the accompanying thiamine deficiency may lead to Wernicke encephalopathy. Associated changes in serum osmolarity may lead to acute demyelination.

CONCLUSION

Alcohol-related encephalopathies can be life-threatening conditions but can be prevented or treated, if recognized.

Primary bilateral pontine demyelination in a cat with similarity to central pontine myelinolysis

An adult cat was presented with the history of 3 months' weight loss and more recent loss of balance and ataxia. An abdominal mass was palpable; results of neurologic examination suggested a brainstem disorder. The owners elected euthanasia. Postmortem findings included suppurative jejunal lymphadenitis and bilateral demyelination in the ventral pons with sparing of axons and neuronal soma. The location and character of the lesion mimicked those of human central pontine myelinolysis, an iatrogenic condition that may follow rapid correction of hyponatremia or develop spontaneously in patients with malnutrition or energy deprivation. In this cat, the poor nutritional state may have contributed to the development of this novel pontine lesion.

Hypertonic saline for peri-operative fluid management

BACKGROUND

Fluid excess may place patients undergoing surgery at risk for various complications. Hypertonic saline (HS) maintains intravascular volume with less intravenous fluid than isotonic salt (IS) solutions, but may increase serum sodium.

OBJECTIVES

To determine the benefits and harms of HS versus IS solutions administered to patients undergoing surgery.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library) Issue 1, 2009; MEDLINE (1966 to 2009); EMBASE (1980 to 2009); LILACS (to August 2009) and CINAHL (1982 to 2009) without language restrictions.

SELECTION CRITERIA

We included randomized clinical trials where HS was compared to IS in patients undergoing surgery, irrespective of blinding, language, and publication status.

DATA COLLECTION AND ANALYSIS

We assessed the impact of HS administration on mortality, organ failure, fluid balance, serum sodium, serum osmolarity, diuresis and physiologic measures of cardiovascular function. We pooled data using odds ratio or mean difference (MD) for binary and continuous outcomes, respectively, using random-effects models.

MAIN RESULTS

We included 15 studies with 614 participants. One death in each group and no other serious adverse events were reported. While all patients were in a positive fluid balance postoperatively, the excess was significantly less in HS patients (standardized mean difference (SMD) -1.43L, 95% confidence interval (CI) 0.8 to 2.1 L less; P < 0.00001). Patients treated with HS received significantly less fluid than IS-treated patients (MD -2.4L 95% (CI) 1.5 to 3.2 L less; P < 0.00001) without differences in diuresis between the groups. Maximum intraoperative cardiac index was significantly increased with HS (SMD 0.6 L/min/M2 higher, 95% CI 0.1 to 1.0, P = 0.02) but Intraoperative pulmonary artery wedge pressure remained unchanged. While the maximum serum sodium and the serum sodium at the end of the study were significantly higher in HS patients, the level remained within normal limits (136 to 146 meq/L).

AUTHORS' CONCLUSIONS

HS reduces the volume of intravenous fluid required to maintain patients undergoing surgery but transiently increases serum sodium. It is not known if HS effects patient survival and morbidity but it should be tested in randomized clinical trials that are designed and powered to test these outcomes.