Hyponatremia in acute brain disease: the cerebral salt wasting syndrome

The association between serum sodium level and tuberculous meningitis compared with viral and bacterial meningitis

We evaluated the association between hyponatremia and tuberculous meningitis (TBM) with the aim of providing additional information for differential diagnosis from other types of infectious meningitis, especially viral meningitis (VM). Cross-sectional and longitudinal data involving 5026 participants older than 18 years were analyzed in the total population and a propensity-matched population. The initial and lowest sodium levels and longitudinal changes in TBM, bacterial meningitis (BM), and VM patients were compared. Participants in the TBM group were enrolled when they were diagnosed as possible, probable, or definite TBM according to the Marais' criteria. The initial serum sodium level was significantly lower in TBM patients than in BM and VM patients (136.9 ± 5.9 vs. 138.3 ± 4.7 mmol/L, p < 0.001 for TBM vs. BM, and 139.0 ± 3.1, p < 0.001 for TBM vs. VM), and it decreased significantly more steeply to lower levels in both the TBM and BM patients compared with VM patients. The lowest serum sodium level was in the order of TBM < BM < VM patients, and the change was statistically significant in all subgroups (131.8 ± 6.4, 133.1 ± 5.1, 137.4 ± 3.7, respectively, p < 0.001). Participants with lower serum sodium level were more likely to have a diagnosis of TBM rather than VM, and this association was more pronounced for the lowest sodium level than the initial sodium level [OR 4.6 (95% CI 2.4-8.8, p < 0.001)]. These findings indicate that baseline and longitudinal evaluation of serum sodium level can provide information for differential diagnosis of TBM from BM or VM.

Prognostic Significance of Hyponatremia in Acute Stroke: A Systematic Review and Meta-Analysis

<b><i>Objective:</i></b> Hyponatremia is a common electrolyte disorder in patients with stroke, which leads to various fatal complications. We performed a systematic review and meta-analysis to investigate the outcomes of acute stroke patients with hyponatremia. <b><i>Methods:</i></b> We searched MEDLINE, EMBASE, and the Cochrane Library databases for relevant literature in English published up to March 2020. Two review authors independently screened and selected the studies by assessing the eligibility and validity based on the inclusion criteria. Mortality at 90 days was set as the primary end point, and in-hospital mortality and length of hospital stay were set as the secondary end points. We conducted the data synthesis and analyzed the outcomes by calculating the odds ratio (OR) and mean difference. <b><i>Results:</i></b> Of 835 studies, 15 studies met the inclusion criteria (<i>n</i> = 10,745). The prevalence rate of stroke patients with hyponatremia was 7.0–59.2%. They had significantly higher 90-day mortality (OR, 1.73; 95% confidence interval (CI), 1.24–2.42) and longer length of hospital stay (mean difference, 10.68 days; 95% CI, 7.14–14.22) than patients without hyponatremia. Patients with hyponatremia had a higher tendency of in-hospital mortality than those without hyponatremia (OR, 1.61; 95% CI, 0.97–2.69). <b><i>Conclusions:</i></b> The development of hyponatremia in the clinical course of stroke is associated with higher short-term mortality and a longer hospital stay. Although the causal relationship is unclear, hyponatremia could be a significant predictor of poor outcomes after stroke.

Inappropriate Antidiuretic Hormone Secretion and Cerebral Salt-Wasting Syndromes in Neurological Patients

The differential diagnosis of syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral salt-wasting syndrome (CSWS) in patients with neurological disorders has been a perplexing clinical controversy. The purpose of this review is to summarize the characteristics and risk factors of patients with different types of neurological disorders complicated by hyponatremia (HN) and review various methods to distinguish SIADH from CSWS. Common neurological disorders with high rates of HN include subarachnoid hemorrhage (SAH), traumatic brain injuries, stroke, cerebral tumors, central nervous system (CNS) infections, and Guillain-Barré syndrome (GBS), which have their own characteristics. Extracellular volume (ECV) status of patients is a key point to differentiate SIADH and CSWS, and a comprehensive assessment of relevant ECV indicators may be useful in differentiating these two syndromes. Besides, instead of monitoring the urinary sodium excretion, more attention should be paid to the total mass balance, including Na⁺, K⁺, Cl^-, and extracellular fluid. Furthermore, the dynamic detection of fractional excretions (FE) of urate before and after correction of HN and a short-term infusion of isotonic saline solution may be useful in identifying the etiology of HN. As for brain natriuretic peptide (BNP) or N-terminal prohormone of BNP (NT-proBNP), more prospective studies and strong evidence are needed to determine whether there is a pertinent and clear difference between SIADH and CSWS.

Effects of oxytocin administration on the hydromineral balance of median eminence-lesioned rats

In the clinical setting, acute injuries in hypothalamic mediobasal regions, along with polydipsia and polyuria, have been observed in patients with cerebral salt wasting (CSW). CSW is also characterised by hypovolaemia and hyponatraemia as a result of an early increase in natriuretic peptide activity. Salt and additional amounts of fluid are the main treatment for this disorder. Similarly, experimental lesions to these brain regions, which include the median eminence (ME), produce a well-documented neurological model of polydipsia and polyuria in rats, which is preceded by an early sodium excretion of unknown cause. In the present study, oxytocin (OT) was used to increase the renal sodium loss and prolong the hydroelectrolyte abnormalities of ME-lesioned animals during the first few hours post-surgery. The objective was to determine whether OT-treated ME-lesioned animals increase their sodium appetite and water intake to restore the volume and composition of extracellular body fluid. Electrolytic lesion of the ME increased water intake, urinary volume and sodium excretion of food-deprived rats and also decreased urine osmolality and estimated plasma sodium concentration. OT administration at 8 hours post-surgery reduced water intake, urine output and plasma sodium concentration and also increased urine osmolality and urine sodium excretion between 8 and 24 hours post-lesion. From 24 to 30 hours, more water and hypertonic NaCl was consumed by OT-treated ME-lesioned rats than by physiological saline-treated-ME-lesioned animals. Food availability from 30 to 48 hours reduced the intake of hypertonic saline solution by ME/OT animals, which increased their water and food intake during this period. OT administration therefore appears to enhance the natriuretic effect of ME lesion, producing hydroelectrolyte changes that reduce the water intake of food-deprived animals. Conversely, the presence of hypertonic NaCl increases the fluid intake of these animals, possibly as a result of the plasma sodium depletion and hypovolaemic states previously generated. Finally, the subsequent increase in food intake by ME/OT animals reduces their need for hypertonic NaCl but not water, possibly in response to osmotic thirst. These results are discussed in relation to a possible transient activation of the ME with the consequent secretion of natriuretic peptides stored in terminal swellings, which would be augmented by OT administration. Electrolytic lesion of the ME may therefore represent a useful neurobiological model of CSW.

Hyponatremia After Spontaneous Aneurysmal Subarachnoid Hemorrhage-A Prospective Observational Study

OBJECTIVE

Hyponatremia has been frequently observed after aneurysmal subarachnoid hemorrhage (SAH), and some data have suggested a correlation with symptomatic cerebral vasospasm and poor outcomes. The present prospective study investigated sodium and water disturbances after aneurysmal SAH with regard to symptomatic vasospasm and patient outcomes.

METHODS

Data from all patients with aneurysmal SAH treated in our department during a 2-year period were collected. Daily natriuresis, sodium levels, water balance, and serum and urine osmolality were measured at 4 different points: day 1 of admission or bleeding, day 3, day 7, and day 14-21 or discharge. The clinical parameters (i.e., Hunt and Hess grade, aneurysm location and treatment, onset of vasospasm) were reviewed. The patients' outcome was assessed using the Glasgow outcome score and modified Rankin scale.

RESULTS

A total of 101 patients (70 women; median age, 52 years) were enrolled in the present study. Of these 101 patients, 59.4% had a good grade SAH (Hunt and Hess grade 1-3). The most common aneurysm location was the anterior communicating artery (37%). The results from an electrolyte analysis were available for ≤91 patients at days 1 and 78 at discharge. In 33 patients (32.7%), hyponatremia had been diagnosed at any time point. Hyponatremia was most frequently observed at day 1 and later at days 7-10. A location in the anterior communicating artery resulted in hyponatremia more frequently only at day 1 (P = 0.007). The main causes of hyponatremia were cerebral salt-wasting syndrome (early onset) and syndrome of inappropriate antidiuretic hormone secretion (early and late onset).

CONCLUSION

Distinguishing early- and late-onset hyponatremia is of major relevance, because different therapeutic approaches are required. Only hyponatremia at discharge resulted in less favorable outcomes.

Hyponatremia in Neurosurgical Patients: Syndrome of Inappropriate Antidiuretic Hormone or Cerebral Salt Wasting Syndrome?

Nutritional Support Consultant features issues pertinent to the clinical aspects of pharmacy nutrition support practice. The column is edited by Dr. Roland Dickerson, Associate Professor of Pharmacy, University of Tennessee Health Sciences Center, Memphis, TN.

Electrolyte Disturbances in Critically Ill Cancer Patients: An Endocrine Perspective

Electrolyte disturbances are frequently encountered in critically ill oncology patients. Hyponatremia and hypernatremia as well as hypocalcemia and hypercalcemia are among the most commonly encountered electrolyte abnormalities. In the intensive care unit, management of critical electrolyte disturbances is focused on initial evaluation and immediate treatment plan to prevent severe complications. A PubMed search was performed to identify best available evidence for evaluation and management of dysnatremias, hypocalcemia, and hypercalcemia. Current literature was reviewed regarding the management of electrolyte disturbances. The role of new therapeutic options, for example, vaptans for hyponatremia, teriparatide for hypocalcemia, and denosumab for hypercalcemia, is discussed. Early diagnosis and appropriate management are expected to reduce adverse outcomes.

Cerebral salt wasting following traumatic brain injury

Summary

Hyponatraemia is the most commonly encountered electrolyte disturbance in neurological high dependency and intensive care units. Cerebral salt wasting (CSW) is the most elusive and challenging of the causes of hyponatraemia, and it is vital to distinguish it from the more familiar syndrome of inappropriate antidiuretic hormone (SIADH). Managing CSW requires correction of the intravascular volume depletion and hyponatraemia, as well as mitigation of on-going substantial sodium losses. Herein we describe a challenging case of CSW requiring large doses of hypertonic saline and the subsequent substantial benefit with the addition of fludrocortisone.

Learning points:

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.

Complications in Aneurysmal Subarachnoid Hemorrhage Patients With and Without Subdural Electrode Strip for Electrocorticography

PURPOSE

Patients with aneurysmal subarachnoid hemorrhage (aSAH) frequently develop secondary noninfectious and infectious complications with an important impact on clinical course and outcome. In this study, we report on the rate of typical extracranial and intracranial complications in 30 prospectively enrolled patients with severe aSAH who received a linear subdural recording strip for continuous electrocorticography to detect ictal epileptiform events and spreading depolarizations.

METHODS

The group was compared with 30 retrospectively included patients with aSAH who had not received a subdural recording strip, but were treated during the same period. The control group was matched according to an aSAH grading system, sex, and establishment of external ventricular drainage, but could not be matched according to aneurysm treatment and focal brain lesions such as initial intracerebral hemorrhages.

RESULTS

No evidence was found that procedures of the electrocorticography study led to clinically relevant complications. In particular, the subdural strip did not lead to local damage of brain tissue or any increased rate of meningitis/ventriculitis. The median score on the modified Rankin Scale on day 15 was the same in both groups. Minor differences between both groups are explained by the limitations in the study design.

CONCLUSIONS

Our study suggests that neuromonitoring with a subdural recording strip for up to 15 days can be safely performed in patients with aSAH.

A study of hyponatremia in tuberculous meningitis

SETTING

In view of paucity of studies on predictors of hyponatremia in tuberculous meningitis (TBM) and its influence on outcome, this study was undertaken.

OBJECTIVE

To study the frequency, predictors and prognosis of hyponatremia in TBM.

DESIGN

In this prospective hospital based study, 76 patients with TBM (definite 18 and probable 58) were enrolled. The severity of meningitis was graded as I-III and hyponatremia as severe (<120mEq/L), moderate (120-129mEq/L) or mild (130-134mEq/L). Hospital death was noted and functional outcome was assessed by modified Rankin Scale (mRS) on discharge.

RESULTS

34 (44.7%) TBM patients had hyponatremia (mild 3, moderate 23 and severe 8). Hyponatremia was due to cerebral salt wasting in 17, syndrome of inappropriate secretion of antidiuretic hormone in 3 and miscellaneous causes in 14 patients. Hyponatremia was related to GCS score and basal exudates. Outcome of TBM was related to duration of hospitalization, GCS score, focal deficit, mechanical ventilation, severity of TBM, age and comorbidities. Cerebral salt wasting was related to severity of TBM.

CONCLUSION

Hyponatremia occurred in 44.7% of TBM patients. Cerebral salt wasting was the commonest cause of hyponatremia and was related to the severity of TBM.

Polyuria in relation to dysnatraemias in neurocritical care

INTRODUCTION

Polyuria has the potential to cause severe water and sodium imbalance. We studied the epidemiology of polyuria in association with dysnatraemias and whether polyuria is an independent risk factor for higher mortality and poorer outcome in neurocritical care.

METHODS

We performed an analysis of a 3-year prospective database containing 902 neurocritical care patients. Polyuria was defined as diuresis above 4000 ml/day, hyponatraemia as a serum sodium (SeNa) < 135 mmol/l and hypernatraemia as SeNa > 150 mmol/l.

RESULTS

We identified polyuria in 236 (26.2%) patients (639 days). Polyuric patients stayed in the neurointensive care unit (NICU) longer than those without polyuria (mean: 10.7 vs. 3.5 days, p < 0.001). These patients also had more frequent cerebral complications (p < 0.001) and a poorer outcome upon discharge from the NICU (p = 0.032). NICU mortality had borderline significance in relation to whether the patients were polyuric (p = 0.055). There were only 49 (20.8%) patients with dysnatraemia who were shown to have a significantly higher NICU mortality (p = 0.006). There were no differences in frequency between hyponatraemic and hypernatraemic polyuric patients (p = 0.127). Polyuric patients with hypernatraemia suffered poorer outcomes (p = 0.009) and higher NICU mortality (p < 0.001), but they had a lower Glasgow Coma Scale or GCS recorded at the onset of polyuria (p < 0.001). Cerebral salt wasting (CSW) was thought to be the cause of polyuria in 7 (3.0%) patients and central diabetes insipidus (CDI) in another 5 (2.1%) patients. Univariate models showed polyuria to be a risk factor for poor outcome (odds ratio [OR] = 1.39, p = 0.032) and had a borderline significance for mortality during their NICU stay (OR = 1.83, p = 0.055). These factors did not appear as significant following multivariate logistic regression analysis.

CONCLUSION

Polyuria often occurred in neurocritical care patients, but was not usually associated with sodium imbalance, CSW or CDI. We did not find that polyuria was a significant predictor of increased mortality or poorer outcome in NICU patients.

The relevance of hyponatraemia to perioperative care of surgical patients

BACKGROUND

Hyponatraemia is the most common electrolyte disturbance in hospitalized patients. There is an increasing awareness of the impact of hyponatraemia on the perioperative management of surgical patients.

METHODS

We performed a literature review. We have included relevant data from different surgical disciplines for analysis. In this review we discuss the differential diagnosis of hyponatraemia, and explain the specific relevance of hyponatraemia to pre-, peri- and post-operative care.

RESULTS

Hyponatraemia is common during the preoperative period and is associated with an increase in subsequent peri-operative complications, such as wound infection, pneumonia, higher mortality rate and higher direct and indirect costs. Furthermore, data shows poorer surgical outcomes when plasma sodium concentration drops. Careful preoperative evaluation of the hyponatraemic patient enables assessment of surgical risk and individualization of the management of hyponatraemia.

CONCLUSIONS

We outline a practical guide to the assessment of the cause of hyponatraemia, which dictates the correct management of hyponatraemia and the correct selection of perioperative fluids. Finally, for the therapeutic role of the new vasopressin antagonist drugs in the treatment of surgical hyponatraemia is discussed in two illustrative surgical clinical cases.

Impact of perioperative hyponatremia in children: A narrative review

For more than 50 years, hypotonic fluids (crystalloids) have been the standard for maintenance fluid used in children. In the last decade, several studies have evaluated the risk of hyponatremia associated with the use of hypotonic vs isotonic fluids, which has lead to an intense debate. Children undergoing surgery have several stimuli for release of antidiuretic hormone, which controls renal water handling, including pain, nausea, vomiting, narcotic use and blood loss. The body’s primary defense against the development of hyponatremia is the ability of the kidneys to excrete free water and dilute urine. Increased levels of antidiuretic hormone can result in hyponatremia, defined as a plasma sodium level < 136 mmol/L, which causes cells to draw in excess water and swell. This manifests as central nervous system symptoms such as lethargy, irritability and seizures. The risk for symptomatic hyponatremia is higher in children than in adults. It represents an emergency condition, and early diagnosis, prompt treatment and close monitoring are essential to reduce morbidity and mortality. The widespread use of hypotonic fluids in children undergoing surgery is a matter of concern and more focus on this topic is urgently needed. In this paper, we review the literature and describe the impact of perioperative hyponatremia in children.

Prevalence of hyponatremia in intensive care unit patients with brain injury in kashan shahid-beheshti hospital in 2012

Background

Hyponatremia is a common disorder in patients with brain injury. It can result in acute and chronic complications providing this electrolytic disorder is not diagnosed and treated in due time.

Objectives

The aim of this study was to evaluate the prevalence of hyponatremia in 95 brain injury patients hospitalized in the intensive care unit (ICU) in Kashan Shahid-Veheshti hospital.

Patients and Methods

This trans-sectional study was conducted on brain injury patients (brain traumas, brain hemorrhage, meningitis and brain tumors) during their six-month stay in the ICU in Kashan Shahid-Beheshti hospital. Data were analyzed after excluding cases of pseudohyponatremia.

Results

Ninety-five patients with brain injury (69.5% male and 30.5% female ( had a mean age of 42.85 ± 22.59 years, while the hyponatremic patients had a mean age of 48.37 ± 24.03 years. Prevalence and occurrence of hyponatremia were 31.6% and 9.29 ± 6.8 days, respectively. This study revealed no meaningful differences between age, sex, underlying disease and the prevalence of hyponatremia.

Conclusions

Our study showed an elevated frequency of hyponatremia in patients with brain injuries in ICU which demands the effective approaches for an accurate and timely diagnosis of this electrolyte disorder.

Cerebral salt wasting treated with fludrocortisone in a 17-year-old boy

Cerebral salt wasting is characterized by inappropriate natriuresis and volume contraction with associated cerebral pathology. It is distinct from the syndrome of inappropriate antidiuretic hormone secretion, which is characterized by inappropriate retention of free water. We report a patient with a porencephalic cyst who developed cerebral salt wasting. His initial treatment was supplementation of water and salt, which did not improve natriuresis or volume contraction. Fludrocortisone administration effectively managed the cerebral salt wasting.

Sodium Disturbances Commonly Encountered in the Neurologic Intensive Care Unit

Disorders of sodium and water balance are common in patients with central nervous system (CNS) disease. These disorders frequently complicate the treatment course by precipitating or worsening neurological symptoms. These patients are not only at risk for symptoms secondary to dysnatremia but also at risk from the consequences of treatment. If not treated properly, this electrolyte disturbance can vastly increase morbidity and can even lead to death. Appropriate diagnosis and intervention requires an understanding of the physiologic and pathophysiologic mechanisms involved in sodium and water homeostasis.

Hyponatremia and brain injury: absence of alterations of serum brain natriuretic peptide and vasopressin

OBJECTIVE

To study any possible relation between hyponatremia following brain injury and the presence of cerebral salt-wasting syndrome (CSWS) or the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), and if vasopressin, brain natriuretic peptide (BNP) and aldosterone have a role in its mechanism.

METHOD

Patients with brain injury admitted to the intensive care unit were included and had their BNP, aldosterone and vasopressin levels dosed on day 7.

RESULTS

Twenty six adult patients were included in the study. Nine (34.6%) had hyponatremia and presented with a negative water balance and higher values of urinary sodium, serum potassium and diuresis than patients with normonatremia. The serum levels of BNP, aldosterone, and vasopressin were normal and no relation was observed between plasma sodium and BNP, aldosterone or vasopressin.

CONCLUSION

The most likely cause of hyponatremia was CSWS and there was no correlation between BNP, aldosterone and vasopressin with serum sodium level.

Hyponatremia in neurosurgical patients: clinical guidelines development

OBJECTIVE

Neurosurgical patients have a high risk of hyponatremia and associated complications. We critically evaluated the existing literature to identify the determinants for the development of hyponatremia and which management strategies provided the best outcomes.

METHODS

A multidisciplinary panel in the areas of neurosurgery, nephrology, critical care medicine, endocrinology, pharmacy, and nursing summarized and classified hyponatremia literature scientific studies published in English from 1950 through 2008. The panel's recommendations were used to create an evaluation and treatment protocol for hyponatremia in neurosurgical patients at the University of Florida.

RESULTS

Hyponatremia should be further investigated and treated when the serum sodium level is less than 131 mmol/L (class II). Evaluation of hyponatremia should include a combination of physical examination findings, basic laboratory studies, and invasive monitoring when available (class III). Obtaining levels of hormones such as antidiuretic hormone and natriuretic peptides is not supported by the literature (class III). Treatment of hyponatremia should be based on severity of symptoms (class III). The serum sodium level should not be corrected by more than 10 mmol/L/d (class III). Cerebral salt wasting should be treated with replacement of serum sodium and intravenous fluids (class III). Fludrocortisone may be considered in the treatment of hyponatremia in subarachnoid hemorrhage patients at risk of vasospasm (class I). Hydrocortisone may be used to prevent natriuresis in subarachnoid hemorrhage patients (class I). Hyponatremia in subarachnoid hemorrhage patients at risk of vasospasm should not be treated with fluid restriction (class II). Syndrome of inappropriate antidiuretic hormone may be treated with urea, diuretics, lithium, demeclocycline, and/or fluid restriction (class III).

CONCLUSION

The summarized literature on the evaluation and treatment of hyponatremia was used to develop practice management recommendations for hyponatremia in the neurosurgical population. However, the practice management recommendations relied heavily on expert opinion because of a paucity of class I evidence literature on hyponatremia.

Nephrogenic syndrome of inappropriate antidiuresis: a novel cause of euvolemic hypotonic hyponatremia in newborns. Diagnosis and practical management

Hyponatremia, defined by a serum sodium concentration of less than 135 mmmol/l, is a complex clinical occurrence frequently manifested in newborns admitted to the neonatal intensive care unit. The pathogenetic mechanisms and clinical timing underlying the onset of hyponatremia have not been well established in the newborn. Aim of this review is to present a practical approach and management of hypotonic hyponatremia in newborns, with particular emphasis on nephrogenic syndrome of inappropriate antidiuresis, recently described by us for the first time in the literature in a newborn.

Cervicothoracolumbar spinal epidural abscess and cerebral salt wasting

BACKGROUND CONTEXT

Spinal epidural abscess (SEA) is a rare infectious disease. However, if left unrecognized and untreated, the clinical outcome of SEA can be devastating.

PURPOSE

To report a rare clinical presentation of a cervicothoracolumbar SEA with cerebral salt wasting (CSW).

STUDY DESIGN

Case report.

METHODS

Clinical history, physical and laboratory findings, and magnetic resonance imaging studies of a patient with cervicothoracolumbar SEA and CSW.

RESULTS

We report the case of a 15-year-old boy with cervicothoracolumbar SEA complicated with CSW and treated with conservative methods.

CONCLUSIONS

In conclusion, CSW can be seen at the follow-up period of the SEA and the clinicians must be aware of this entity.

Combined central diabetes insipidus and cerebral salt wasting syndrome in children

Central diabetes insipidus, a common consequence of acute central nervous system injury, causes hypernatremia; cerebral salt wasting syndrome can cause hyponatremia. The two conditions occurring simultaneous are rarely described in pediatric patients. Pediatric cases of combined diabetes insipidus and cerebral salt wasting after acute central nervous system injury between January 2000 and December 2007 were retrospectively reviewed, and clinical characteristics were systemically assessed. Sixteen patients, aged 3 months to 18 years, met study criteria: 11 girls and 5 boys. The most common etiologies were severe central nervous system infection (n = 7, 44%) and hypoxic-ischemic event (n = 4, 25%). In 15 patients, diabetes insipidus was diagnosed during the first 3 days after acute central nervous system injury. Onset of cerebral salt wasting syndrome occurred 2-8 days after the onset of diabetes insipidus. In terms of outcome, 13 patients died (81%) and 3 survived under vegetative status (19%). Central diabetes insipidus and cerebral salt wasting syndrome may occur after acute central nervous system injury. A combination of both may impede accurate diagnosis. Proper differential diagnoses are critical, because the treatment strategy for each entity is different.

Cerebral salt wasting syndrome: review

Hyponatremia is the most frequent electrolyte disorder in critically neurological patients. Cerebral salt wasting syndrome (CSW) is defined as a renal loss of sodium during intracranial disease leading to hyponatremia and a decrease in extracellular fluid volume. The pathogenesis of this disorder is still not completely understood. Sympathetic responses as well as some natriuretic factors play a role in this syndrome. Distinction between SIADH and CSW might be difficult. The essential point is the volemic state. It is necessary to rule out other intermediate causes. Treatment requires volume replacement and maintenance of a positive salt balance. Mineral corticoids may be useful in complicated cases.

Disorders of water and salt metabolism associated with pituitary disease

Disorders of water and sodium homeostasis are very common problems encountered in clinical medicine. Disorders of water metabolism are divided into hyperosmolar and hypoosmolar states, with hyperosmolar disorders characterized by a deficit of body water in relation to body solute and hypoosmolar disorders characterized by an excess of body water in relation to total body solute. This article briefly reviews the physiology of hyperosmolar and hypoosmolar syndromes, then focuses on a discussion of the pathophysiology, evaluation, and treatment of specific pre- and postoperative disorders of water metabolism in patients with pituitary lesions.

Tumor-related hyponatremia

Hyponatremia is an important and common electrolyte disorder in tumor patients and one that has been reported in association with a number of different primary diagnoses. The correct diagnosis of the pathophysiological basis for each patient is important because it significantly alters the treatment approach. In this article, we review the epidemiology and presentation of patients with hyponatremia, the pathophysiologic groups for the disorder with respect to sodium and water balance and the diagnostic measures for determining the correct pathophysiologic groups. We then present the various treatment options based on the pathophysiologic groups including a mathematical approach to the use of hypertonic saline in management. In cancer patients, hyponatremia is a serious comorbidity that requires particular attention as its treatment varies by pathophysiologic groups, and its consequences can have a deleterious effect on the patient's health.

Hyponatremia in neurological patients: cerebral salt wasting versus inappropriate antidiuretic hormone secretion

OBJECTIVE

To assess whether hyponatremia in acute neurological patients is associated with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or with the cerebral salt-wasting syndrome (CSWS).

DESIGN

Clinical, controlled, prospective study.

SETTING

Department of intensive care of a tertiary care academic hospital.

PATIENTS

Forty acute neurological patients with hyponatremia suggesting SIADH or CSWS (20) or with normonatremia (20).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Measurement of clinical and biological variables. Measurement of blood, plasma, and red blood cell volumes to discriminate SIADH and CSWS. Renal, adrenal and thyroid functions were normal in all patients. Average blood, plasma, and red blood cell volumes were 54, 37 and 17ml/kg in control patients and 54, 37 and 18ml/kg in hyponatremic patients, respectively.

CONCLUSIONS

The adequate blood volumes in hyponatremic patients confirm the diagnosis of SIADH and do not support the concept of CSWS.

Mineralocorticoid deficiency in post-operative cerebral salt wasting

Acute hyponatremia, following neurosurgery, results from inappropriate antidiuretic hormone secretion (SIADH) or cerebral salt wasting (CSW). CSW is due to abnormally high atrial or brain natriuretic peptides (ANP, BNP), which block all stimulators of zona glomerulosa steroidogenesis, resulting in mineralocorticoid deficiency. A 3 year-old girl presented CSW at day 4, after resection of craniopharyngioma and hypophysectomy. Hyponatremia, hyperkalemia and high natriuresis occurred on day 8, with low renin and aldosterone and elevated BNP 120.3 ng/ml (undetectable before surgery). Fludrocortisone 100 microg/day controlled natriuresis and restored electrolytes within 24 hours. A 5 year-old boy presented CSW at day 6 after partial resection of optic glioma. Fludocortisone 100 microg/day restored electrolytes within 8 hours. ANP was elevated, 60.6 ng/l, aldosterone and renin were low. Fludrocortisone supplementation should be considered in CSW, as excessive natriuresis is controlled, and electrolytes are easily restored, avoiding life-threatening complications of this complex disorder.

Plasma arginine vasopressin and atrial natriuretic peptide concentration in patients with hyponatremia at diagnosis and following treatment

BACKGROUND

Much evidence for arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) in the pathogenesis of hyponatremia in humans is based on single measurements. To study the roles of AVP and ANP in the pathogenesis and recovery of hyponatremia, sequential measurements of ANP and AVP were taken during treatment in a group of hyponatremic patients with different etiologies.

METHODS

Consecutive adult patients with hyponatremia (serum Na <130 mmol/l) and healthy controls were studied. Volume status was determined by clinical and laboratory criteria. Plasma AVP and ANP, fractional sodium excretion, and urine osmolality were determined daily until serum Na was above 135 mmol/l or for at most 7 days.

RESULTS

A total of 16 controls and 40 hyponatremic patients (12 normovolemic, 9 hypervolemic, and 19 hypovolemic) were studied. Patients' plasma AVP on the first day [1.0 (0.3-2.3) ng/l] and on the last day [1.1 (0.3-2.5) ng/l] of the study did not differ from that of controls [0.7 (0.5-1.0) ng/l]. Serum sodium concentration increased significantly in patients between the first and the last day. Patients had significantly lower ANP concentrations, both on the first day [25 (15-46) ng/l] and on the last day [29 (17-46) ng/l], than controls [41 (28-51) ng/l]. Plasma AVP was elevated relative to serum osmolality on the first day and to a lesser extent on the last day of the study.

CONCLUSIONS

AVP is inappropriately high in a majority of hyponatremic patients. Plasma AVP and ANP concentrations do not change during treatment in hyponatremic patients despite a significant increase in serum osmolality. A low ANP concentration in clinically normovolemic and hypovolemic patients indicates volume depletion, which may lead to baroreceptor-stimulated AVP secretion.

Diabetes insipidus

Water balance is precisely regulated by vasopressin, thirst and the kidneys; plasma osmolality is maintained within a narrow range, despite large variations in normal water intake and loss. Disruption of these finely balanced mechanisms is common, however, and can be precipitated by various disease states. Diabetes insipidus is a disease process with several underlying pathogenic mechanisms--all ultimately resulting in excretion of large volumes of dilute urine. This review will discuss the pathophysiology, diagnosis and treatment of diabetes insipidus, with emphasis on disorders of osmoregulation following neurosurgery of the pituitary and hypothalamus.

Vasopressin antagonists: role in the management of hyponatremia

Hyponatremia is a common electrolyte disorder associated with potentially serious or life-threatening consequences. Serum osmolality and sodium concentration [Na+] are regulated by thirst, the hormone arginine vasopressin (AVP), and renal water and sodium handling. Hyponatremia is frequently caused by dysregulation of AVP, which accompanies disorders of water retention, such as congestive heart failure (CHF) and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Clinical trials with AVP receptor antagonists have confirmed the important role of AVP in the pathophysiology of hyponatremia and suggest these agents are efficacious in treating hyponatremia associated with SIADH, cirrhosis, and CHF. Acting directly at AVP receptors in the renal tubules, these agents promote aquaresis - the electrolyte-sparing excretion of free water - in patients with hyponatremia. In clinical trials, AVP receptor antagonists have been shown to increase the serum [Na+] and urine output while decreasing urine osmolality.

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Traitement des tuberculoses cérébro-méningées

INTRODUCTION

Tuberculous meningitis and brain tuberculomas are currently rare in the western world but remain serious. Improved outcome requires early recognition and treatment of these conditions.

STATE OF ART

Treatment is usually begun before diagnostic confirmation. Therapeutic principles are now better defined thanks to recent recommendations and studies. Antituberculous therapy begins with two months of a combination of four drugs: isoniazid, rifampicin, ethambutol and pyrazinamid. Then follows a longer phase of bitherapy with isoniazid and rifampicin, lasting at least four months but usually extended to seven or ten months as a precaution. Patients at risk of toxic neuropathy should receive pyridoxine supplementation. Corticosteroids must be systematically added during the first eight weeks of treatment, beginning with high dose before progressive tapering. Hyponatremia is common, often induced by emesis and cerebral salt wasting syndrome. Therefore saline supply rather than water restriction is required. Non-obstructive hydrocephaly can usually be managed with diuretic therapy including acetazolamid, sometimes complemented by serial lumbar punctures. Neurosurgical interventions are rarely needed. Monitoring of treatment tolerance and efficacy is mainly clinical. Central nervous system imaging and cerebro-spinal fluid analysis are only required to explain clinical deterioration.

CONCLUSION

With adequate and prompt anti-tuberculous, anti-inflammatory and supportive treatment, the prognosis of central nervous system tuberculosis can be greatly improved.

Recurrent hyponatremia after intrathecal methotrexate not related to antidiuretic hormone: is a natriuretic peptide activated?

We report the development of recurrent hyponatremia after intrathecal methotrexate that was not associated with elevated levels of antidiuretic hormone. We speculate that a central nervous system natriuretic peptide may be involved in the pathogenesis of the naturesis following intrathecal methotrexate.

Disturbances of sodium in critically ill adult neurologic patients: a clinical review

Disorders of sodium and water balance are common in critically ill adult neurologic patients. Normal aspects of sodium and water regulation are reviewed. The etiology of possible causes of sodium disturbance is discussed in both the general inpatient and the neurologic populations. Areas of importance are highlighted with regard to the differential diagnosis of sodium disturbance in neurologic patients, and management strategies are discussed. Specific discussions of the etiology, diagnosis, and management of cerebral salt wasting syndrome, the syndrome of inappropriate antidiuretic hormone secretion, and central diabetes insipidus are presented, as well as the problems of overtreatment. The importance of diagnosis at an early stage of these diseases is stressed, with a recommendation for conservative management of milder cases.

The incidence and pathophysiology of hyponatraemia after subarachnoid haemorrhage

BACKGROUND

Hyponatraemia is common following subarachnoid haemorrhage (SAH) but the pathogenesis is unclear. Objective To establish the incidence, pathophysiology and consequences of hyponatraemia following SAH.

METHODS

A retrospective case-note analysis of all patients with SAH admitted to Beaumont Hospital between January 2002 and September 2003. Three hundred and sixteen cases of SAH were substantiated by computed tomography (CT) scan and angiogram findings. Hyponatraemia was defined as plasma sodium < 135 mmol/l.

RESULTS

One hundred and seventy-nine patients (56.6%) developed hyponatraemia and 62 (19.6%) developed significant hyponatraemia (plasma sodium < 130 mmol/l). The incidence of severe hyponatraemia following hypophysectomy was lower in the period of analysis (5/81, 6.2%, P < 0.01). Hyponatraemia was more common in patients with identified aneurysms (anterior circulation 102/168, 60.7%, posterior circulation 56/95, 60.8%) than in those with no radiological aneurysm (21/54, 38.8%, P < 0.001). Hyponatraemia was more common after aneurysmal clipping (68/103, 66%) or coiling (82/132, 62%) than after conservative treatment (29/81, 36%, P < 0.001). The aetiology of significant hyponatraemia was the syndrome of inappropriate antidiuretic hormone secretion (SIADH) 39/62 (69.2%), cerebral salt-wasting syndrome (CSWS) 4/62 (6.5%), hypovolaemic hyponatraemia 13/62 (21%), hypervolaemic hyponatraemia 3/62 (4.8%) and mixed CSW/SIADH 3/62 (4.8%). Hyponatraemia was associated with longer hospital stay (24.0 +/- 2.6 vs. 11.8 +/- 0.8 days, P < 0.001) but did not affect mortality (P = 0.07). Hyponatraemia developed more than 7 days following SAH in 21.4% and more then 7 days following intervention in 31.8%.

CONCLUSIONS

Hyponatraemia is common following SAH and is associated with longer hospital stay. Clipping and coiling of aneurysms are associated with higher rates of hyponatraemia. SIADH is the commonest cause of hyponatraemia after SAH. Delayed hyponatraemia is common, and has implications for early discharge strategies.

Cerebral salt wasting syndrome after calvarial remodeling in craniosynostosis

Hyponatremia and increased urine output after calvarial remodeling have been noted in pediatric patients with craniosynostosis. If not treated properly, patients develop hypoosmotic conditions that can lead to cerebral edema, increased intracranial pressure, and collapsed circulation. Postoperative hyponatremia after central nervous system surgery is considered as the syndrome of inappropriate antidiuretic hormone (SIADH) secretion. Recently, however, cerebral salt wasting syndrome (CSWS) instead of SIADH has been reported frequently. CSWS is associated with a decreased serum sodium level, increased urinary sodium level, increased urine output, decreased ECF volume, increased atrial natriuretic peptide (ANP) level, and increased brain natriuretic peptide (BNP) level. We experienced nine patients with craniosynostosis who underwent calvarial remodeling. By postoperative day 1, the ANP and BNP levels increased by 3-6 folds compared with the preoperative levels. They returned to the normal levels by postoperative day 5. The ADH level was within the normal range even after operation. The urinary sodium level increased in all patients by postoperative day 1 and 3. But the serum sodium level, and serum and urine osmolarity were normal due to appropriate replacement of sodium and fluid. After calvarial remodeling, the potential development of CSWS should be considered and distinguished from SIADH. The patients with CSWS require normal saline resuscitation and should prophylactically receive normal saline.

Cerebral salt wasting syndrome in patients with aneurysmal subarachnoid hemorrhage

OBJECTIVE

Hydroelectrolytic disturbances are part of the complications of subarachnoid hemorrhage. Cerebral salt wasting syndrome (CSWS) must be considered when hyponatremia is associated with a decrease in circulating volume. We performed this study to determine the clinical characteristics and management paradigm of patients with serum sodium concentration abnormalities and aneurysmatic subarachnoid hemorrhage.

METHODS

We analyzed retrospectively clinical and laboratory data from eight patients with subarachnoid hemorrhage due to rupture of an intracranial saccular aneurysm and cerebral salt wasting syndrome. Their course, as well as their clinical findings and treatment, are described.

RESULTS

In eight patients, hyponatremia that lasted for more than 24 hours was detected (serum sodium under 135 mEq/l). The sodium disturbance occurred between day 3 and day 10 in all cases, in six of them in day 7 or day 8. The specific treatment for CSWS was to increase volume delivery according to the characteristics of the patient. Except for one case, none of the remaining patients required more than 72 hours of treatment to correct hyponatremia. No treatment-related complications were found

CONCLUSION

Cerebral salt wasting syndrome, occurring in some patients with subarachnoid hemorrhage, is more commonly related to certain specific anatomic locations of the ruptured aneurysm, responds to sodium replacement therapy and fluids and can be diagnosed and treated based on the clinical, hydroelectrolytic and hemodynamic course of the patient. Further studies are needed to define the underlying mechanism of this condition.

Management of severe malaria: interventions and controversies

This article emphasizes that for many controversial reasons, severe malaria in travelers differs from that seen in endemic areas. There is no controversy, however, that malaria in individuals living in endemic areas should retain research priority. Some of the questions raised might never be amenable to randomized controlled trials, either because of ethical or logistical restraints. A possibly indulgent wish list of outcome (mortality) studies using currently known treatment modalities, however, includes the loading dose of quinine, vigorous fluid replacement, ET, the artemisinins, mannitol, and N-acetylcysteine in the treatment of severe malaria. There may clearly be many more. The treatment of severe malaria remains a challenge to those with an interest in managing life-threatening disease with complex and fascinating pathophysiology. As challenging as the studies listed previously may seem, however, priority must inevitably be given to research on how one can prevent and treat mild disease in the first place.

Cerebral salt wasting in subarachnoid hemorrhage rats: model, mechanism, and tool

Cerebral salt wasting (CSW) frequently occurs concomitantly with aneurysmal subarachnoid hemorrhage (SAH). CSW induces excessive natriuresis and osmotic diuresis, and reduces total blood volume. As a result, the risk of symptomatic cerebral vasospasm may be elevated. Therefore, it is important to determine the mechanism of CSW. The purpose of this study was to evaluate whether the rat SAH model exhibits CSW and to investigate the relationship between CSW and natriuretic peptides. A SAH model was produced in 24 rats by perforating a cerebral artery with a nylon thread up through the common carotid artery. To evaluate CSW, urine was cumulatively collected from SAH onset to 12 hours and sodium (Na) excretion was analyzed. Body weight and hematocrit were analyzed before and after SAH onset. Concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in plasma were also analyzed. Urine volume and total Na excretion of SAH rats were significantly higher than those of sham rats (p<0.05). Body weight of SAH rats significantly decreased and hematocrit significantly increased (p < 0.05). ANP concentration was significantly decreased in SAH rats (p<0.05). However, BNP concentrations did not change. This study demonstrated for the first time that a rat SAH model exhibited CSW. It was suggested that the cause of CSW was neither ANP nor BNP. In addition, this rat SAH model will be useful for study of CSW after SAH.

Two cases of cerebral salt wasting syndrome developing after cranial vault remodeling in craniosynostosis children

Hyponatremia has been recognized as an important postoperative metabolic complication after central nervous system (CNS) operations in children. If not appropriately treated, the postoperative hyponatremia can cause several types of CNS and circulatory disorders such as cerebral edema, increased intracranial pressure. The postoperative hyponatremia after CNS surgery has been considered as one of the underlying causes of the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). In some cases, however, the cerebral salt wasting (CSW) syndrome has been detected. CSW syndrome is far less well-known than SIADH and also different from SIADH in diagnosis and treatment. It causes an increase in urine output and urine sodium after a trauma of CNS and dehydration symptoms. The appropriate treatment of CSW syndrome is opposite the usual treatment of hyponatremia caused by SIADH. The latter is treated with fluid restriction because of the increased level of free water and its dilutional effect causing hyponatremia, whereas the former is treated with fluid and sodium resuscitation because of the unusual loss of high urinary sodium. Early diagnosis and treatment of CSW syndrome after CNS surgery are, therefore, essential. We made a diagnosis of CSW syndrome in two craniosynostosis children manifesting postoperative hyponatremia and supplied them an appropriate amount of water and sodium via intravenous route. The hyponatremia or natricuresis of the children improved and neurologic and circulatory sequelae could be prevented.