Identifying Risk Factors for Central Pontine and Extrapontine Myelinolysis After Liver Transplantation: A Case–Control Study

Bridging the critically ill patient with acute to chronic liver failure to liver transplantation

Liver transplantation (LT) has emerged as an effective therapy for severe forms of acute-on-chronic liver failure (ACLF), an entity characterized by the development of multiorgan failure and high short-term mortality. The aim of critical care management of ACLF patients is to rapidly treat precipitating events and aggressively support failing organs to ensure that patients may successfully undergo LT or, less frequently, recover. Malnutrition and sarcopenia are frequently present, adversely impacting the prognosis of these patients. Management of critical care patients with ACLF is complex and requires the participation of different specialties. Once the patient is stabilized, a rapid evaluation for salvage LT should be performed because the time window for LT is often narrow. The development of sepsis and prolonged organ support may preclude LT or diminish its chances of success. The current review describes strategies to bridge severe ACLF patients to LT, highlights the minimal evaluation required for listing and the currently suggested contraindications to proceed with LT, and addresses different aspects of management during the perioperative and early posttransplant period.

Thalamic Neuron Resilience during Osmotic Demyelination Syndrome (ODS) Is Revealed by Primary Cilium Outgrowth and ADP-ribosylation factor-like protein 13B Labeling in Axon Initial Segment

A murine osmotic demyelinating syndrome (ODS) model was developed through chronic hyponatremia, induced by desmopressin subcutaneous implants, followed by precipitous sodium restoration. The thalamic ventral posterolateral (VPL) and ventral posteromedial (VPM) relay nuclei were the most demyelinated regions where neuroglial damage could be evidenced without immune response. This report showed that following chronic hyponatremia, 12 h and 48 h time lapses after rebalancing osmolarity, amid the ODS-degraded outskirts, some resilient neuronal cell bodies built up primary cilium and axon hillock regions that extended into axon initial segments (AIS) where ADP-ribosylation factor-like protein 13B (ARL13B)-immunolabeled rod-like shape content was revealed. These AIS-labeled shaft lengths appeared proportional with the distance of neuronal cell bodies away from the ODS damaged epicenter and time lapses after correction of hyponatremia. Fine structure examination verified these neuron abundant transcriptions and translation regions marked by the ARL13B labeling associated with cell neurotubules and their complex cytoskeletal macromolecular architecture. This necessitated energetic transport to organize and restore those AIS away from the damaged ODS core demyelinated zone in the murine model. These labeled structures could substantiate how thalamic neuron resilience occurred as possible steps of a healing course out of ODS.

Evidence-based hyponatremia management in liver disease

Hyponatremia is primarily a water balance disorder associated with high morbidity and mortality. The pathophysiological mechanisms behind hyponatremia are multifactorial, and diagnosing and treating this disorder remains challenging. In this review, the classification, pathogenesis, and step-by-step management approaches for hyponatremia in patients with liver disease are described based on recent evidence. We summarize the five sequential steps of the traditional diagnostic approach: 1) confirm true hypotonic hyponatremia, 2) assess the severity of hyponatremia symptoms, 3) measure urine osmolality, 4) classify hyponatremia based on the urine sodium concentration and extracellular fluid status, and 5) rule out any coexisting endocrine disorder and renal failure. Distinct treatment strategies for hyponatremia in liver disease should be applied according to the symptoms, duration, and etiology of disease. Symptomatic hyponatremia requires immediate correction with 3% saline. Asymptomatic chronic hyponatremia in liver disease is prevalent and treatment plans should be individualized based on diagnosis. Treatment options for correcting hyponatremia in advanced liver disease may include water restriction; hypokalemia correction; and administration of vasopressin antagonists, albumin, and 3% saline. Safety concerns for patients with liver disease include a higher risk of osmotic demyelination syndrome.

Intraoperative Renal Replacement Therapy in Orthotopic Liver Transplantation

Acute kidney injury in patients admitted to the hospital for liver transplantation is common, with up to 80% of pretransplant patients having some form of acute kidney injury. Many of these patients start on dialysis prior to their transplant and have it continued intraoperatively during their surgery. This review discusses the limited existing literature and expert opinion around the indications and outcomes around intraoperative dialysis (intraoperative renal replacement therapy) during liver transplantation. More specifically, we discuss which patients may benefit from intraoperative renal replacement therapy and the impact of hyponatremia and hyperammonemia on the dialysis prescription. Additionally, we discuss the complex interplay between anesthesia and intraoperative renal replacement therapy and how the need for clearance and ultrafiltration changes throughout the different phases of the transplant (preanhepatic, anhepatic, and postanhepatic). Lastly, this review will cover the limited data around patient outcomes following intraoperative renal replacement therapy during liver transplantation as well as the best evidence for when to stop dialysis.

2021 Clinical Update in Liver Transplantation

In 2021, the United States performed 9,236 liver transplantations, an increase of 3.7% from 2020. As the specialty of transplant anesthesiologist continues to grow, so does the body of evidence-based research to improve patient care. New technology in organ preservation offers the possibility of preserving marginal organs for transplant or improving the graft for transplantation. The sequalae of end-stage liver disease have wide-ranging consequences that affect neurologic outcomes of patients both during and after transplantation that anesthesiologists should monitor. Obesity presents several challenges for anesthesiologists. As an increasing number of patients with nonalcoholic steatohepatitis are listed for transplant, managing their multiple comorbidities can be challenging. Finally, the rebalanced hemostasis of end-stage liver disease can cause both bleeding and thrombus. Often, bleeding risks predominate as a concern, but anesthesiologists should be aware of risks of intracardiac thrombus and review therapeutic options for prevention and treatment.

Hyponatremia in Cirrhosis

Hyponatremia is the most common electrolyte disorder encountered in clinical practice, and it is a common complication of cirrhosis reflecting an increase in nonosmotic secretion of arginine vasopressin as a result of of the circulatory dysfunction that is characteristic of advanced liver disease. Hyponatremia in cirrhosis has been associated with poor clinical outcomes including increased risk of morbidity and mortality, poor quality of life, and heightened health care utilization. Despite this, the treatment of hyponatremia in cirrhosis remains challenging as conventional therapies such as fluid restriction are frequently ineffective. In this review, we discuss the epidemiology, clinical outcomes, pathogenesis, etiology, evaluation, and management of hyponatremia in cirrhosis.

Hyponatremia and Liver Transplantation: A Narrative Review

Hyponatremia is a common electrolyte disorder in patients with end-stage liver disease (ESLD) and is associated with increased mortality on the liver transplantation (LT) waiting list. The impact of hyponatremia on outcomes after LT is unclear. Ninety-day and one-year mortality may be increased, but the data are conflicting. Hyponatremic patients have an increased rate of complications and longer hospital stays after transplant. Although rare, osmotic demyelination syndrome (ODS) is a feared complication after LT in the hyponatremic patient. The condition may occur when the serum sodium (sNa) concentration increases excessively during or after LT. This increase in sNa concentration correlates with the degree of preoperative hyponatremia, the amount of intraoperative blood loss, and the volume of intravenous fluid administration. The risk of developing ODS after LT can be mitigated by avoiding large perioperative increases in sNa concentration . This can be achieved through measures such as carefully increasing the sNa pretransplant, and by limiting the intravenous intra- and postoperative amounts of sodium infused. SNa concentrations should be monitored regularly throughout the entire perioperative period.

Cerebral Diseases in Liver Transplant Recipients: Systematic Review of Clinical Evidence

This systematic review presents clinical evidence on early and long-term cerebral diseases in liver transplant recipients. The literature search led to the retrieval of 12 relevant studies. Early postoperative cerebral complications include intracranial hemorrhage associated with a coexisting coagulopathy, perioperative hypertension, and higher MELD scores and is more frequent in critically ill recipients; central pontine and extrapontine myelinolysis are associated with notable perioperative changes in the plasma Na+ concentration and massive transfusion. Long-term follow-up cerebral complications include focal brain lesions, cerebrovascular diseases, and posterior reversible encephalopathy; there is no proven relationship between the toxicity immunosuppressive drugs and cerebral complications. This SR confirms a very low incidence of opportunistic cerebral infections.

Occurrence of osmotic demyelination syndrome in diabetes mellitus: A case report and literature review of various etiologies for osmotic demyelination syndrome

Osmotic demyelination syndrome is a rare condition reported mainly in the case of rapid correction of hyponatremia, but it can occur even in the case of complicated diabetes mellitus either during rapid correction of hyperglycemia or anytime during the complicated diabetes mellitus. We report a case of complicated diabetes mellitus developing osmotic demyelination syndrome. The patient had presented with altered sensorium and seizure, which was initially diagnosed as hyperglycemia, but during his treatment, the magnetic resonance imaging of brain revealed central pontine myelinolysis. Our search on the causes of osmotic demyelination syndrome other than rapid correction of hyponatremia has revealed several other causes like autoimmune liver disease, Sjogren’s syndrome and non-Hodgkin’s lymphoma in addition to diabetes mellitus.

The Changing Face of Osmotic Demyelination Syndrome: A Retrospective, Observational Cohort Study

Objective

To describe the long-term outcomes of osmotic demyelination syndrome (ODS) in an updated cohort.

Methods

We performed a retrospective medical records review of cases of ODS at the Massachusetts General and Brigham and Women's Hospitals using International Classification of Diseases-9th edition codes and a text-based search for central pontine myelinolysis, extrapontine myelinolysis, and osmotic demyelination syndrome (1999-2018). Cases were individually selected based on patients having neuroimaging and symptoms consistent with ODS and no other potentially explanatory etiology. Modified Rankin scale (mRS) scores were extracted at prehospitalization, hospital discharge, 6 months post discharge, and the most recently available clinical visit.

Results

We identified 45 cases of ODS (mean age 48.4 years, range 0.07-75 years; 58% female patients). Common comorbidities included liver disease (27%, n = 12), alcoholism (44%, n = 20), and kidney failure (20%, n = 9). Twenty-nine percent of patients had a rapid correction of hyponatremia. Twenty-nine percent had other electrolyte abnormalities. Only 59% (24/41) of patients with complete electrolyte data had abnormalities that could explain their ODS. At the 6-month follow-up, 16% of the patients were dead and 60% of patients had minimal-to-no disability (mRS 0-2).

Conclusions

ODS has a diverse range of clinical presentations. Not all patients have electrolyte abnormalities. The prognosis is generally favorable, although 1 in 6 patients had died at 6 months, likely because of underlying disease states.

Central Pontine Myelinosis and Osmotic Demyelination Syndrome

BACKGROUND

Osmotic demyelination syndrome (ODS), which embraces central pontine myelinolysis (CPM) and extrapontine myelinosis (EPM), is often underdiagnosed in clinical practice, but can be fatal. In this article, we review the etiology, patho- physiology, clinical features, diagnosis, treatment, and prognosis of ODS.

METHODS

Pertinent publications from the years 1959 to 2018 were retrieved by a selective search in PubMed.

RESULTS

The most common cause of ODS is hyponatremia; particular groups of patients, e.g., liver transplant recipients, are also at risk of developing ODS. The pathophysiology of ODS consists of cerebral apoptosis and loss of myelin due to osmotic stress. Accordingly, brain areas that are rich in oligodendrocytes and myelin tend to be the most frequently affected. Patients with ODS often have a biphasic course, the first phase reflecting the underlying predisposing illness and the second phase reflecting ODS itself, with pontine dysfunction, impaired vigilance, and movement disorders, among other neurological abnormalities. The diagnostic modality of choice is magnetic resonance imaging (MRI) of the brain, which can also be used to detect oligosymptomatic ODS. The current mainstay of management is prevention; treatment strategies for manifest ODS are still experimental. The prognosis has improved as a result of MRI-based diagnosis, but ODS can still be fatal (33% to 55% of patients either die or remain permanently dependent on nursing care).

CONCLUSION

ODS is a secondary neurological illness resulting from a foregoing primary disease. Though rare overall, it occurs with greater frequency in certain groups of patients. Clinicians of all specialties should therefore be familiar with the risk constellations, clinical presentation, and prevention of ODS. The treatment of ODS is still experimental at present, as no evidence-based treatment is yet available.

2019 Clinical Update in Liver Transplantation

Liver transplantation continues be the standard for treatment of end-stage liver disease, and even with recent advances in organ preservation, the anesthetic management continues to require understanding of multiple organ systems beyond the liver. Multiple factors contribute to hemodynamic changes after reperfusion of the liver graft that anesthesiologists should be aware of before unclamping. Concomitant renal dysfunction in end-stage liver disease is not uncommon, and preparation for continuous renal replacement therapy may need to be considered in certain cases. Cardiac evaluation of liver transplantation patients with an emphasis on arrhythmias, including atrial fibrillation, can help prevent both intraoperative and postoperative complications detrimental to the patient and graft. Finally, combined liver and thoracic organ transplantations may be indicated for certain disease processes that affect multiple organs. These cases require an understanding of the surgical technique and acknowledgment that some goals of the procedures may be in direct opposition to each other.

Neurologic Considerations and Complications Related to Liver Transplantation

Neurologic complications of surgery can be devastating. The authors review neurologic considerations and complications associated with liver transplantation and discuss strategies to prevent, identify, and treat such adverse outcomes in the perioperative period.

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.

Prevention of the Osmotic Demyelination Syndrome After Liver Transplantation: A Multidisciplinary Perspective

The osmotic demyelination syndrome (ODS) is a serious neurologic condition that occurs in the setting of rapid correction of hyponatremia. It presents with protean manifestations, from encephalopathy to the "locked-in" syndrome. ODS can complicate liver transplantation (LT), and its incidence may increase with the inclusion of serum sodium as a factor in the Mayo End-Stage Liver Disease score. A comprehensive understanding of risk factors for the development of ODS in the setting of LT, along with recommendations to mitigate the risk of ODS, are necessary. The literature to date on ODS in the setting of LT was reviewed. Major risk factors for the development of ODS include severe pretransplant hyponatremia (serum sodium [SNa] < 125 mEq/L), the magnitude of change in SNa pre- versus posttransplant, higher positive intraoperative fluid balance, and the presence of postoperative hemorrhagic complications. Strategies to reduce the risk of ODS include correcting hyponatremia pretransplant via fluid restriction and/or ensuring an appropriate rate of increase from the preoperative SNa via close attention to fluid and electrolyte management both during and after surgery. Multidisciplinary management involving transplant hepatology, nephrology, neurology, surgery, and anesthesiology/critical care is key to performing LT safely in patients with hyponatremia.

Anesthesia for Intestinal Transplantation

The diagnosis of irreversible intestinal failure confers significant morbidity, mortality, and decreased quality of life. Patients with irreversible intestinal failure may be treated with intestinal transplantation. Intestinal transplantation may include intestine only, liver-intestine, or other visceral elements. Intestinal transplantation candidates present with systemic manifestations of intestinal failure requiring multidisciplinary evaluation at an intestinal transplantation center. Central access may be difficult in intestinal transplantation candidates. Intestinal transplantation is a complex operation with potential for hemodynamic and metabolic instability. Patient and graft survival are improving, but graft failure remains the most common postoperative complication.

Electrolyte and Acid-Base Disturbances in End-Stage Liver Disease: A Physiopathological Approach

Electrolyte and acid-base disturbances are frequent in patients with end-stage liver disease; the underlying physiopathological mechanisms are often complex and represent a diagnostic and therapeutic challenge to the physician. Usually, these disorders do not develop in compensated cirrhotic patients, but with the onset of the classic complications of cirrhosis such as ascites, renal failure, spontaneous bacterial peritonitis and variceal bleeding, multiple electrolyte, and acid-base disturbances emerge. Hyponatremia parallels ascites formation and is a well-known trigger of hepatic encephalopathy; its management in this particular population poses a risky challenge due to the high susceptibility of cirrhotic patients to osmotic demyelination. Hypokalemia is common in the setting of cirrhosis: multiple potassium wasting mechanisms both inherent to the disease and resulting from its management make these patients particularly susceptible to potassium depletion even in the setting of normokalemia. Acid-base disturbances range from classical respiratory alkalosis to high anion gap metabolic acidosis, almost comprising the full acid-base spectrum. Because most electrolyte and acid-base disturbances are managed in terms of their underlying trigger factors, a systematic physiopathological approach to their diagnosis and treatment is required.

Prognosis of neurologic complications in critical illness

Neurologic complications of critical illness require extensive clinical and neurophysiologic evaluation to establish a reliable prognosis. Many sequelae of intensive care unit (ICU) treatment, such as delirium and ICU-acquired weakness, although highly associated with adverse outcomes, are less suitable for prognostication, but should rather prompt clinicians to seek previously unnoticed persisting underlying illnesses. Prognostication can be confounded by drug administration particularly because its clearance is abnormal in critical illness. Some neurological complications are severe, and can last for months or years after discharge from ICU. The most important ethical aspects regarding neurologic complications in critically ill patients are prevention, recognition, and identification, and prevention of self-fulfilling prophecies. This chapter summarizes the tool of prognostication of major neurological complications of critical illness.

Analyzing the efficacy of frequent sodium checks during hypertonic saline infusion after elective brain tumor surgery

OBJECTIVE

To assess the utility of frequent sodium checks (every 6h) in patients receiving hypertonic saline (HS) after elective brain tumor surgeries.

PATIENTS AND METHODS

A single-institution retrospective review of patients having undergone elective craniotomies for brain tumors and treated with postoperative continuous intravenous infusions of 3% HS was performed. Changes in serum sodium values were analyzed at different time points. The rates of <12.5, 25, and 50cc/h infusions were also examined. Healthcare cost analysis was performed by extrapolating our cohort to the total number of craniotomies performed in the United States.

RESULTS

No significant differences among sodium values checked between 0 to 4, 4-6, 6-8, 8-10, and >10h were observed (P=.64). In addition, no differences in serum sodium values among the rates of <12.5, 25, and 50cc/h were found (P=.30). No patients developed symptoms of acute hypernatremia.

CONCLUSIONS

Serum sodium values did not significantly change more than 10h after infusion of HS. Further studies are needed to determine the optimal frequency of routine sodium checks to increase the quality of care and decrease healthcare costs.

Influence of preoperative sodium concentration on outcome of patients with hepatitis B virus cirrhosis after liver transplantation

OBJECTIVES

Whether preoperative serum sodium concentration could influence post-transplant patients' prognosis remains controversial. The aim of this study was to evaluate the influence of patients' pretransplant sodium concentration on the prognosis after liver transplantation in a cohort of patients with hepatitis B virus-related cirrhosis.

PATIENTS AND METHODS

Data derived from the Chinese Liver Transplantation Registry system from 1 January 2000 to 31 December 2011 were extracted. The serum sodium concentrations and model for end-stage liver disease scores were recorded at listing before liver transplantation, and the relationship between the above parameters and patients' outcome was analyzed.

RESULTS

A total of 2733 patients were included in this study. Compared with patients in the normal group (serum sodium between 135 and 150 mmol/l), patients in the severe hyponatremia group (<125 mmol/l) (P=0.022) and hypernatremia group (>150 mmol/l) (P=0.008) had a poorer prognosis. No significant differences were found among the moderate hyponatremia group (125-130 mmol/l) (P=0.113) and the mild hyponatremia group (130-135 mmol/l) (P=0.461). The 5-year cumulative survivals for the hyponatremia (≤135 mmol/l), normal (135-150 mmol/l), and hypernatremia (≥150 mmol/l) pretransplant group are 79.52, 82.23, and 69.30%, respectively.

CONCLUSION

Our analysis showed that for patients with hepatitis B virus-related cirrhosis in mainland China, patients with abnormal serum sodium concentrations have poorer prognosis; both preoperative hyponatremia and hypernatremia were identified as negative risk factors for patients' outcome.

Short-Term, Low-Dose Use of Tolvaptan as a Bridge Therapy to Expedite Liver Transplant for Severe Hyponatremic, Cirrhotic Patients With High Model for End-Stage Liver Disease Scores

For patients on liver transplant waiting lists, hyponatremia is associated with increased mortality before transplant and complications during the early posttransplant period. Conventional therapies, such as fluid restriction or hypertonic saline infusion, are of limited value. We describe 2 patients with high Model for End-Stage Liver Disease scores (> 30) who were referred to our unit for expedited liver transplant. While on waiting lists, these patients developed severe hyponatremia (< 125 mEq/L) that was refractory to conventional therapies. Low-dose, short-term tolvaptan therapy (15 mg/d for 5 d) was then administered, as a bridge therapy to transplant, resulting in prompt restoration of serum sodium levels without any major clinical event. One patient died a few days later as no suitable grafts were available. The other received a liver transplant, and the outcome was uneventful. In conclusion, our report demonstrates that a short-term, low-dose tolvaptan-based strategy promptly resolves hyponatremia in patients who are on expedited waiting lists for liver transplant, allowing surgery with improved sodium levels and possibly limiting peritransplant complications.

Correction of hyper- and hyponatraemia during continuous renal replacement therapy

BACKGROUND

Severe hyper- and hyponatraemia is associated with significant risks, yet its correction can also have serious consequences when implemented too fast or inadequately. The safe correction of serum sodium levels is particularly challenging when renal replacement therapy (RRT) is required.

METHODS

Using 2 case scenarios, we aim to illustrate a simple method of correcting hyper- and hyponatraemia safely by step-wise manipulation of the dialysate/replacement fluid.

RESULTS

During continuous RRT, hypernatraemia can be corrected effectively and safely by adding small pre-calculated amounts of 30% NaCl to the dialysate/replacement fluid bags aiming for a [Na(+)] in the fluid that allows safe equilibration and correction of the serum [Na(+)]. To correct hyponatraemia safely, pre-calculated amounts of sterile water can be added in a step-wise manner to achieve a fluid [Na(+)] that equals the desired target serum [Na(+)].

CONCLUSION

During continuous RRT, the step-wise adjustment of [Na(+)] of dialysate/replacement fluids offers a safe and reliable method to correct sodium disorders.

Central nervous system syndromes in solid organ transplant recipients

Solid organ transplant recipients have a high incidence of central nervous system (CNS) complications, including both focal and diffuse neurologic deficits. In the immunocompromised host, the initial clinical evaluation must focus on both life-threatening CNS infections and vascular or anatomic lesions. The clinical signs and symptoms of CNS processes are modified by the immunosuppression required to prevent graft rejection. In this population, these etiologies often coexist with drug toxicities and metabolic abnormalities that complicate the development of a specific approach to clinical management. This review assesses the multiple risk factors for CNS processes in solid organ transplant recipients and establishes a timeline to assist in the evaluation and management of these complex patients.