Central pontine myelinolysis induced by hypophosphatemia following Wernicke?s encephalopathy

Phosphate disorders and clinical management of hypophosphatemia and hyperphosphatemia

Serum phosphorus levels range from 2.5 and 4.5mg/dL (0.81-1.45 mmol/L) in adults, with higher levels in childhood, adolescence, and pregnancy. Intracellular phosphate is involved in intermediary metabolism and other essential cell functions, while extracellular phosphate is essential for bone matrix mineralization. Plasma phosphorus levels are maintained within a narrow range by regulation of intestinal absorption, redistribution, and renal tubular absorption of the mineral. Hypophosphatemia and hyperphosphatemia are common clinical situations, although changes are most often mild and oligosymptomatic. However, acute and severe conditions that require specific treatment may occur. In this document, members of the Mineral and Bone Metabolism Working Group of the Spanish Society of Endocrinology and Nutrition review phosphate disorders and provide algorithms for adequate clinical management of hypophosphatemia and hyperphosphatemia.

Osmotic Demyelination Syndrome in Children

Osmotic demyelination syndrome is an acute demyelination process that usually occurs several days following an osmotic stress. This syndrome is rare in adults (0.4% to 0.56%) and even more uncommon in children. We performed a review of all reported pediatric osmotic demyelination syndrome patients from 1960 to 2018. Among all 106 cases, 49 presented with isolated central pontine myelinolysis, 30 with isolated extrapontine myelinolysis, and 27 with combined central pontine myelinolysis and extrapontine myelinolysis. There was no gender preponderance, and the highest prevalence was noted between the ages one and five years. Magnetic resonance imaging remains the diagnostic modality of choice, and diffusion tensor imaging is now increasingly used for prognostication in osmotic demyelination syndrome. Sixty percent of the children had a complete neurological recovery. Current management of osmotic demyelination syndrome in children consists of supportive medical care, steroids, and intravenous immunoglobulin. Our review of the literature supports the hypothesis that steroids and immunoglobulins are potentially helpful, although additional controlled studies are needed.

[Causes, consequences and treatment of hypophosphatemia: A systematic review]

CONTEXT

Although hypophosphatemia is usually very seldom, it can reach two to 3% of hospitalized patients and until 28% of intensive care unit patients. Due to the lack of knowledge, clinical practice regarding seeking or treatment of hypophosphatemia is very heterogenous. However its clinical consequences might be heavy. A better knowledge of its causes, physiopathological effects and treatment should lead to a documented and homogenous care of these patients in clinics.

OBJECTIVE

The aim of our study was a systematic review of littérature, seeking for publications about causes, consequences and treatment of hypophosphatemia.

DOCUMENTARY SOURCES (KEYWORDS AND LANGUAGE)

A research has been conducted on the Medline database by using the following keywords "phosphorus supplementation", "hypophosphatemia" and ("physiopathology" or "complications").

RESULTS

Three mains mechanisms might be responsible for hypophosphatemia: a decrease in digestive absorption, a rise in kidney excretion and a transfer of phosphorus to the intracellular compartment. Denutrition, acid base balance troubles, parenteral nutrition or several drugs are capable of provoking or favouring hypophosphatemia. All these situations are frequently encountered in intensive care unit. Consequences of hypophosphatemia might be serious. Best studied and documented are cardiac and respiratory muscle contractility decrease, sometimes leading to acute cardiac and respiratory failure, cardiac rhythm troubles and cardiac arrest. Hypophosphatemia is frequent during sepsis. It could be responsible for leucocyte dysfunction that might favour or increase sepsis. The treatment of hypophosphatemia is usually simple through a supplementation that quickly restores a regular concentration, with few adverse effects when regularly used.

CONCLUSION

During at-risk situations, the systematic search for hypophosphatemia and its treatment may limit the occurrence of serious consequences.

Treatable Leukoencephalopathy in a Patient with Hypophosphatemia

We report the first patient with pathologically proven leukoencephalopathy associated with hypophosphatemia. A 61-year-old woman had repetitive episodes of decreased consciousness with pontine and pallidal lesions and extensive leukoencephalopathy on MRI, later found to be associated with hypophosphatemia. Although hypophosphatemia has been linked to central pontine and extrapontine myelinolysis (osmotic myelinolysis), lesions in the deep white matter have not been reported. Brain biopsy performed during the first diagnosis process revealed nonspecific demyelination with gliosis, a finding similar to that of chronic osmotic myelinolysis. After normalization of phosphate levels, her consciousness completely improved and MRI abnormalities partly resolved. We should consider that leukoencephalopathy can be associated with hypophosphatemia, which is often treatable.

Temporal evolution of the trident and piglet signs of osmotic demyelination syndrome

Central pontine myelinolysis (CPM) is a potentially-devastating complication of rapid osmolar shifts, classically attributed to overlyaggressive correction of chronic hyponatremia. Magnetic resonance imaging (MRI) allowed earlier diagnosis of CPM, but most importantly, it has revealed that the odds of good functional recovery are surprisingly high. A trident shaped pontine lesion is a typical finding in CPM (the trident sign). The "piglet sign" is a much less well-known radiologic finding in CPM. Due to the rarity of CPM, very little has been published on the evolution of these MRI findings. We present a case of CPM in an alcoholic young man, and describe the temporal evolution of both the trident and piglet signs on MRI in CPM.

A Case of Central Pontine Myelinolysis Caused by Hypophosphatemia Secondary to Refeeding Syndrome

Central pontine myelinolysis (CPM), which was originally considered to be the result of rapid correction of chronic hyponatremia, is not necessarily accompanied by hyponatremia or drastic changes in serum sodium level. Here, we report a case of an anorexic 55-year-old male with a history of pharyngo-laryngo-esophagogastrectomy, initially hospitalized with status epilepticus. Although his consciousness gradually recovered as we were controlling his convulsion, it deteriorated again with new onset of anisocoria, and magnetic resonance imaging (MRI) at this point revealed CPM. Rapid change of serum sodium or osmolarity, which is often associated with CPM, had not been apparent throughout his hospitalization. Instead, a review of the serum biochemistry test results showed that serum phosphate had drastically declined the day before the MRI first detected CPM. In this case, we suspect that hypophosphatemia induced by refeeding syndrome greatly contributed to the occurrence of CPM.

Potentially life-threatening phosphate diabetes induced by ferric carboxymaltose injection: a case report and review of the literature

We report the case of a 45-year-old female patient who developed phosphate diabetes after administration of ferric carboxymaltose. Ten days after the second dose, she complained of intense fatigue and blood analysis showed a phosphate plasma level of 0.93 mg/dL with phosphate excretion rate of 23%. She received phosphate supplementation which resulted in phosphate clearance improvement which persisted for two months. We reviewed other cases described in the literature and would draw attention to this rare but potentially life-threatening side effect.

Central pontine and extrapontine myelinolysis: a systematic review

The purpose was to perform a systematic review of studies on central pontine and extrapontine myelinolysis [forms of osmotic demyelination syndrome (ODS)] and define the spectrum of causes, risk factors, clinical and radiological presentations, and functional outcomes of this disorder. A thorough search of the literature was conducted using multiple databases (PubMed, Ovid Medline and Google) and bibliographies of key articles to identify all case series of adult patients with ODS published from 1959 to January 2013. Only series with five or more cases published in English were considered. Of the 2602 articles identified, 38 case series were included comprising a total of 541 patients who fulfilled our inclusion criteria. The most common predisposing factor was hyponatremia (78%) and the most common presentation was encephalopathy (39%). Favorable recovery occurred in 51.9% of patients and death in 24.8%. Liver transplant patients with ODS had a combined rate of death and disability of 77.4%, compared with 44.7% in those without liver transplantation (P < 0.001). ODS is found to have a good recovery in more than half of cases and its mortality has decreased with each passing decade. Favorable prognosis is possible in patients of ODS, even with severe neurological presentation. Further research is required to confirm the differences found in liver transplant recipients.

Hypophosphatemia during continuous veno-venous hemofiltration is associated with mortality in critically ill patients with acute kidney injury

Introduction

The primary aim of this study was to determine whether hypophosphatemia during continuous veno-venous hemofiltration (CVVH) is associated with the global outcome of critically ill patients with acute kidney injury (AKI).

Methods

760 patients diagnosed with AKI and had received CVVH therapy were retrospectively recruited. Death during the 28-day period and survival at 28 days after initiation of CVVH were used as endpoints. Demographic and clinical data including serum phosphorus levels were recorded along with clinical outcome. Hypophosphatemia was defined according to the colorimetric method as serum phosphorus levels < 0.81 mmol/L (2.5 mg/dL), and severe hypophosphatemia was defined as serum phosphorus levels < 0.32 mmol/L (1 mg/dL). The ratio of CVVH therapy days with hypophosphatemia over total CVVH therapy days was calculated to reflect the persistence of hypophosphatemia.

Results

The Cox proportional hazard survival model analysis indicated that the incidence of hypophosphatemia or even severe hypophosphatemia was not associated with 28-day mortality independently (p = 0.700). Further analysis with the sub-cohort of patients who had developed hypophosphatemia during the CVVH therapy period indicated that the mean ratio of CVVH therapy days with hypophosphatemia over total CVVH therapy days was 0.58, and the ratio independently associated with the global outcome. Compared with the patients with low ratio (< 0.58), those with high ratio (≥ 0.58) conferred a 1.451-fold increase in 28-day mortality rate (95% CI 1.103–1.910, p = 0.008).

Conclusions

Hypophosphatemia during CVVH associated with the global clinical outcome of critically ill patients with AKI. The ratio of CVVH therapy days with hypophosphatemia over total CVVH therapy days was independently associated with the 28-day mortality, and high ratio conferred higher mortality rate.

Osmotic demyelination syndrome associated with hypophosphataemia: 2 cases and a review of literature

AIM

Central and extrapontine myelinolysis are collectively known as osmotic demyelination syndrome. This encephalopathic illness has been well documented in the adult literature, occurring most commonly in the context of chronic alcoholism, correction of hyponatraemia and liver transplantation. Aetiology and outcome in the paediatric population are less well understood.

METHODS

Two cases of osmotic demyelination syndrome occurring in children with transient severe hypophosphataemia during the course of their illness are presented. Both had very different neurological outcomes, but the changes of central and extrapontine myelinolysis were apparent on neuroimaging. Sixty-one cases in the paediatric literature were then reviewed.

RESULTS

We summarize aetiology and outcome in paediatric cases of osmotic demyelination syndrome and postulate a role for hypophosphataemia as a contributing factor in the development of these sometimes devastating conditions.

CONCLUSION

Hypophosphataemia may contribute to the risk of developing osmotic demyelination syndrome in at-risk paediatric patients and further study of this association should be undertaken.

Wernicke's encephalopathy and central pontine myelinolysis in hyperemesis gravidarum

A pregnant woman, who had been suffering from hyperemesis gravidarum, presented with alteration of consciousness, ocular nystagmus and ataxia. Magnetic Resonance Imaging of the brain showed typical findings of Wernicke's encephalopathy and central pontine myelinolysis. The clinical features responded dramatically to thiamine supplementation.

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).

Metabolic encephalopathies

Kinnier Wilson coined the term metabolic encephalopathy to describe a clinical state of global cerebral dysfunction induced by systemic stress that can vary in clinical presentation from mild executive dysfunction to deep coma with decerebrate posturing; the causes are numerous. Some mechanisms by which cerebral dysfunction occurs in metabolic encephalopathies include focal or global cerebral edema, alterations in transmitter function, the accumulation of uncleared toxic metabolites, postcapillary venule vasogenic edema, and energy failure. This article focuses on common causes of metabolic encephalopathy, and reviews common causes, clinical presentations and, where relevant, management.

Rapid development of central pontine myelinolysis after recovery from Wernicke encephalopathy: a non-alcoholic case without hyponatremia

We describe a non-alcoholic diabetic patient with central pontine myelinolysis (CPM) and Wernicke encephalopathy (WE). A 69-year-old man developed consciousness disturbance after parenteral hyperalimentation for liver abscess and sepsis. Neurological examination revealed drowsiness and no articulation. MRI disclosed T2-hyperintense lesions in the dorsal medulla oblongata and dentate nuclei, and symmetric enhancement in the inferior colliculus. Thiamine treatment (1,000 mg/day, div) attenuated neurological deficits. Seven days later, WE-related lesions were markedly regressed and a central pontine T2-hyperintensity lesion appeared. Serum sodium levels were normal. Physicians should pay more attention to rapid development of normonatremic CPM under thiamine supplementation in non-alcoholic WE patients.

Treatment of hypophosphatemia in the intensive care unit: a review

Introduction

Currently no evidence-based guideline exists for the approach to hypophosphatemia in critically ill patients.

Methods

We performed a narrative review of the medical literature to identify the incidence, symptoms, and treatment of hypophosphatemia in critically ill patients. Specifically, we searched for answers to the questions whether correction of hypophosphatemia is associated with improved outcome, and whether a certain treatment strategy is superior.

Results

Incidence: hypophosphatemia is frequently encountered in the intensive care unit; and critically ill patients are at increased risk for developing hypophosphatemia due to the presence of multiple causal factors. Symptoms: hypophosphatemia may lead to a multitude of symptoms, including cardiac and respiratory failure. Treatment: hypophosphatemia is generally corrected when it is symptomatic or severe. However, although multiple studies confirm the efficacy and safety of intravenous phosphate administration, it remains uncertain when and how to correct hypophosphatemia. Outcome: in some studies, hypophosphatemia was associated with higher mortality; a paucity of randomized controlled evidence exists for whether correction of hypophosphatemia improves the outcome in critically ill patients.

Conclusions

Additional studies addressing the current approach to hypophosphatemia in critically ill patients are required. Studies should focus on the association between hypophosphatemia and morbidity and/or mortality, as well as the effect of correction of this electrolyte disorder.

Wernicke's encephalopathy in a patient with schizophrenia

Clinically, we most often associate Wernicke's encephalopathy (WE) with an alcohol abusing population. However, it is important to consider other causes of malnutrition and vitamin deficiency as risk factors for the development of this disorder. We present a case of a 51-year-old man with schizophrenia and malnutrition who presented with delirium, ophthalmoplegia, and seizures. He responded rapidly to the administration of IV thiamine. Because of the high rate of mortality and morbidity, WE should be high on the differential of any patient at risk for malnutrition or with ophthalmoplegia, regardless of alcohol history. This is particularly important in psychiatric patients where the syndrome may be masked and thus treatment delayed.

Central and Extrapontine Myelinolysis: Then…and Now

In this review, we emphasize neuropathologic and neurobehavioral aspects of central pontine and extrapontine myelinolysis (CPM/EPM), also known as the osmotic demyelination syndrome. The literature is reviewed from the time of the initial report in 1959 and from key developments that have occurred more recently. Particular consideration is given to pathogenic mechanisms as revealed by recent animal studies. The role of white matter pathology in neurobehavioral dysfunction is also considered. The "then" and "now" of CPM and EPM tell 2 different stories. Yet, in many respects, this expansion of information over the past nearly 50 years simply represents a continuum, as well as recognition, of the vast gaps that still persist in our understanding of this disorder.