Management of hyponatraemia in patients with acute cerebral insults

Initial dysnatremia and clinical outcomes in pediatric traumatic brain injury: a multicenter observational study

PURPOSE

We aimed to investigate the association between initial dysnatremia (hyponatremia and hypernatremia) and in-hospital mortality, as well as between initial dysnatremia and functional outcomes, among children with traumatic brain injury (TBI).

METHOD

We performed a multicenter observational study among 26 pediatric intensive care units from January 2014 to August 2022. We recruited children with TBI under 18 years of age who presented to participating sites within 24 h of injury. We compared demographics and clinical characteristics between children with initial hyponatremia and eu-natremia and between those with initial hypernatremia and eu-natremia. We defined poor functional outcome as a discharge Pediatric Cerebral Performance Category (PCPC) score of moderate, severe disability, coma, and death, or an increase of at least 2 categories from baseline. We performed multivariable logistic regression for mortality and poor PCPC outcome.

RESULTS

Among 648 children, 84 (13.0%) and 42 (6.5%) presented with hyponatremia and hypernatremia, respectively. We observed fewer 14-day ventilation-free days between those with initial hyponatremia [7.0 (interquartile range (IQR) = 0.0-11.0)] and initial hypernatremia [0.0 (IQR = 0.0-10.0)], compared to eu-natremia [9.0 (IQR = 4.0-12.0); p = 0.006 and p < 0.001]. We observed fewer 14-day ICU-free days between those with initial hyponatremia [3.0 (IQR = 0.0-9.0)] and initial hypernatremia [0.0 (IQR = 0.0-3.0)], compared to eu-natremia [7.0 (IQR = 0.0-11.0); p = 0.006 and p < 0.001]. After adjusting for age, severity, and sex, presenting hyponatremia was associated with in-hospital mortality [adjusted odds ratio (aOR) = 2.47, 95% confidence interval (CI) = 1.31-4.66, p = 0.005] and poor outcome (aOR = 1.67, 95% CI = 1.01-2.76, p = 0.045). After adjustment, initial hypernatremia was associated with mortality (aOR = 5.91, 95% CI = 2.85-12.25, p < 0.001) and poor outcome (aOR = 3.00, 95% CI = 1.50-5.98, p = 0.002).

CONCLUSION

Among children with TBI, presenting dysnatremia was associated with in-hospital mortality and poor functional outcome, particularly hypernatremia. Future research should investigate longitudinal sodium measurements in pediatric TBI and their association with clinical outcomes.

Glucocorticoids with or without fludrocortisone in septic shock: a narrative review from a biochemical and molecular perspective

Two randomised controlled trials have reported a reduction in mortality when adjunctive hydrocortisone is administered in combination with fludrocortisone compared with placebo in septic shock. A third trial did not support this finding when hydrocortisone administered in combination with fludrocortisone was compared with hydrocortisone alone. The underlying mechanisms for this mortality benefit remain poorly understood. We review the clinical implications and potential mechanisms derived from laboratory and clinical data underlying the beneficial role of adjunctive fludrocortisone with hydrocortisone supplementation in septic shock. Factors including distinct biological effects of glucocorticoids and mineralocorticoids, tissue-specific and mineralocorticoid receptor-independent effects of mineralocorticoids, and differences in downstream signalling pathways between mineralocorticoid and glucocorticoid binding at the mineralocorticoid receptor could contribute to this interaction. Furthermore, pharmacokinetic and pharmacodynamic disparities exist between aldosterone and its synthetic counterpart fludrocortisone, potentially influencing their effects. Pending publication of well-designed, randomised controlled trials, a molecular perspective offers valuable insights and guidance to help inform clinical strategies.

National UK guidelines for the management of paediatric craniopharyngioma

Although rare, craniopharyngiomas constitute up to 80% of tumours in the hypothalamic-pituitary region in childhood. Despite being benign, the close proximity of these tumours to the visual pathways, hypothalamus, and pituitary gland means that both treatment of the tumour and the tumour itself can cause pronounced long-term neuroendocrine morbidity against a background of high overall survival. To date, the optimal management strategy for these tumours remains undefined, with practice varying between centres. In light of these discrepancies, as part of a national endeavour to create evidence-based and consensus-based guidance for the management of rare paediatric endocrine tumours in the UK, we aimed to develop guidelines, which are presented in this Review. These guidelines were developed under the auspices of the UK Children's Cancer and Leukaemia Group and the British Society for Paediatric Endocrinology and Diabetes, with the oversight and endorsement of the Royal College of Paediatrics and Child Health using Appraisal of Guidelines for Research & Evaluation II methodology to standardise care for children and young people with craniopharyngiomas.

Suspected Cerebral Salt Wasting Syndrome with Cervical Spinal Lesion in a Domestic Shorthair Cat

A 12-year-old spayed female domestic short cat was presented with tetraplegia. The cat also showed signs of hyponatremia and dehydration, which were rapidly corrected by intravenous fluid infusion. Based on thorough physical and neurological examinations, the patient was suspected of having an intracranial disease. MRI revealed a high-signal T2 image of the bilateral parietal cerebral cortical gray matter junction, which is associated with fast electrolyte calibration, and a high-signal T2 image of the C2 spinal cord ventral area, which is associated with ischemic myelopathy. The cat reappeared three days later due to anorexia. Laboratory examinations revealed that the cat was clinically dehydrated and exhibited hyponatremia. Other causes of hyponatremia were excluded through history-taking, laboratory examination, imaging, and therapeutic response to fluid therapy, except for cerebral salt-wasting syndrome (CSWS). The cat was discharged 3 days after the start of fludrocortisone therapy with electrolytes within the normal range. Magnetic resonance imaging (MRI) was performed again 1 month after hospitalization, and the cerebral lesion disappeared, but the spinal cord lesion worsened compared to the previous image. The patient was euthanized due to the progression of the spinal lesion, with a poor prognosis and poor quality of life. This is the first case of suspected CSWS with a cervical spinal lesion in a cat.

Coexisting Cerebral Salt Wasting Syndrome and Central Diabetes Insipidus in a Patient with Posterior Cerebrovascular Infarction: A Case Report

<b><i>Background:</i></b> Disorders of sodium balance are common in critically ill neurologic patients. However, the coexisting of cerebral salt wasting syndrome (CSW) and central diabetes insipidus (CDI) in such patients is rare. Early recognition of such conditions is challenging, thus making the prognosis ominous. <b><i>Case Presentation:</i></b> A 50-year-old male patient presented with acute posterior cerebrovascular infarction complicated by several attacks of disturbed sodium homeostasis. The first attack manifested as hypernatremia (up to 161 mmol/L) and polyuria with high urine sodium (188 mmol/L) could only be explained by CSW on top of CDI. Especially the patient was not receiving any hyperosmolar or sodium-containing fluids. Serum sodium was corrected by desmopressin acetate. Later, the patient developed 2 attacks of hyponatremia (down to 119 mmol/L) diagnosed as CSW that was treated with fludrocortisone. Finally, he developed hypernatremia (up to 165 mmol/L) diagnosed as CDI and was treated with desmopressin acetate. <b><i>Conclusion:</i></b> Sodium hemostasis disorders require full consideration of serum electrolytes, intravascular volume state, and urine electrolytes in view of the clinical condition. Early diagnosis and administration of the proper treatment are the cornerstones of successful management.

Higher plasma NT-proBNP levels correlate with syndrome of inappropriate antidiuretic hormone and poor prognosis in neurological patients

Background

Hyponatremia induced by syndrome of inappropriate antidiuretic hormone secretion (SIADH) was common electrolyte disturbance encountered in critically ill neurological diseases, which has normal or increased fluid volume. Brain natriuretic peptide (BNP), which is released in equal proportion to N-terminal pro-brain natriuretic peptide (NT-proBNP), plays vital roles in regulation of volume status. The relationship between SIADH and NT-proBNP levels in neurological diseases has rarely been reported.

Methods

A retrospective cross-sectional study was conducted to analyze plasma NT-proBNP levels in 33 patients with SIADH and 23 controlled eunatremic patients with neurological diseases.

Results

Baseline NT-proBNP levels were compared between two groups [SIADH group: median 311 pg/mL, interquartile range (IQR) 110–768 pg/mL] vs. eunatremic group: median 46 pg/mL, IQR, 12–96 pg/mL) (P<0.05). Plasma NT-proBNP levels were markedly increased in hyponatremic patients who had two or more complications than those who had less complication (P<0.05). In SIADH patients, NT-proBNP levels in remission phase were lower to levels at baseline. Furthermore, no death was seen in eunatremic patients, while five SIADH patients died from complications.

Conclusions

SIADH had higher plasma NT-proBNP levels and poorer prognosis compared to eunatremic neurological patients. NT-proBNP serves as a biomarker of disease severity while not extracellular volume (ECV) status in critically ill neurological patients.

Clinical Approach to Sodium Homeostasis Disorders in Children with Pituitary-Suprasellar Tumors

Children with pituitary-suprasellar tumors are at high risk of developing sodium metabolism disorders since the tumoral mass itself or surgical and medical treatment can damage AVP release circuits. Additional risk factors are represented by the use of hypotonic fluids, the young age, total parenteral nutrition, and obstructive hydrocephalus secondary to tumor pathology. The most frequent hyponatremic disorders related to AVP in these patients are the syndrome of inappropriate ADH secretion and the cerebral/renal salt wasting syndrome, while hypernatremic conditions include central diabetes insipidus (CDI) and adipsic CDI. The main challenge in the management of these patients is to promptly distinguish the AVP release disorder at the base of the sodium imbalance and treat it correctly by avoiding rapid sodium fluctuations. These disorders can coexist or follow each other in a few hours or days; therefore, careful clinical and biochemical monitoring is necessary, especially during surgery, the use of chemotherapeutic agents, or radiotherapy. This monitoring should be performed by experienced healthcare professionals and should be multidisciplinary, including pediatric endocrinologists, neurosurgeons, and oncologists since maintaining sodium homeostasis also plays a prognostic role in terms of disease survival, therapeutic response, hospitalization rate, and mortality. In this review, we analyze the management of sodium homeostasis disorders in children with pituitary-suprasellar tumors and discuss the main challenges in the diagnosis and treatment of these conditions based on literature data and over 30 years of clinical experience at our Department of Pediatric Endocrinology.

[A case of cerebral salt wasting syndrome caused by minor head injury]

An 80-year-old woman who was hospitalized due to small subarachnoid hemorrhaging caused by a bruise in the left temporal region of the brain. Nausea/vomiting and malaise appeared after dinner on the fourth day of the illness. Head computed tomography showed that the post-traumatic status was almost normal; however, the sodium ion (Na⁺) level was 114 mEq/L, indicating severe hyponatremia. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) following a head injury was initially suspected, and water restriction and saline fluid replacement were initiated. However, the Na⁺ level did not improve, and signs of dehydration emerged. On the seventh day of the illness, drinking water restriction was discontinued, and 3% sodium chloride fluid replacement was initiated. The patient subsequently followed a favorable course, and the Na⁺ level remained normal even after fluid replacement was discontinued. It is important to differentiate between SIADH and cerebral salt wasting syndrome (CSWS), as the treatment of the two are diametrically opposite. However, distinguishing between these two diseases at an early onset can be difficult, as they have very similar laboratory findings. CSWS can occur in patients with minor head injury, as in the present case, so we should bear this disease in mind as a differential diagnosis, even when imperceptible graduations are recognized in patients.

Neurological Complications of Renal Disease

Neurological manifestations related to electrolyte disorders, drug toxicity, and uremia are common in chronic kidney disease (CKD). Seizures and coma are frequent complications of acute renal insufficiency (uremia), whereas peripheral neuropathy and encephalopathy, observed in progressive uremia, are terminal events. Failure to excrete metabolic products causes their accumulation and can lead to severe intoxication. Clinically, the signs and symptoms of uremia can vary widely, depending on the biological characteristics of the patient, the specific type of renal disease, and the time of the uremic intoxication. CKD is an increasing problem worldwide and is now being recognized as a global health burden particularly for cardiovascular and cerebrovascular ischemic events. Despite improvements in the medical management of advanced CKD, including dialysis and transplantation, patients manifest a number of symptoms that neurologists are often confronted with. Appropriate drug dosing, awareness of potential side effects of medications, prompt diagnosis, and treatment are essential in preventing neurological long-term morbidity and mortality.

[The rate of hyponatremia in neurosurgical patients (comparison between the data from the Burdenko Neurosurgical Instutite and the literature) and recommendations for the diagnosis and treatment]

Hyponatremia is a relatively frequent and serious complication in patients with various neurosurgical pathologies.

OBJECTIVE

This study is aimed at assessing the incidence of hyponatremia in neurosurgical patients depending on the pathology.

MATERIAL AND METHODS

This paper presents a retrospective analysis 39 479 cases of patients operated on at the Burdenko Neurosurgical Institute from 2008 to 2014.

RESULTS

A total of 785 hyponatremic patients with Na level lower than 130 mmol/l (2% of all operated patients) were identified. Mortality in patients with hyponatremia was 14.3%, which is tenfold higher compared to the rest of population of patients without hyponatremia who were operated on during the same period. In adults, hyponatremia most frequently occurred after resection of craniopharyngiomas (11%) and as a result of acute cerebrovascular accident (22%). In children, it occurred after resection of craniopharyngiomas (10%), astrocytomas (7%), ependymomas (24%), and germ cell tumors (10.5%).

CONCLUSION

This study, which was mainly statistical one, was not aimed at detailed investigation of hyponatremia in different groups of neurosurgical patients. We only tried to draw the attention of various experts to those categories of patients, where focused and in-depth developments are more than important. Obviously, already gained international experience should be taken into account for this

PURPOSE

Therefore, this article presents the literature data on the etiology and pathogenesis of hyponatremia. We describe the details of the various classifications of hyponatremia, its clinical symptoms, diagnosis, and treatments, primarily based on the recommendations of the last European consensus of various specialists (2014).

[Successful treatment for cryptococcal meningoencephalitis complicated by cerebral salt-wasting syndrome in a patient with chronic lymphocytic leukemia: A clinical case]

Cryptococcus neoformans is a common agent of fungal meningoencephalitis in immunocompromised patients. Cerebral salt-wasting syndrome is one of the rare causes of severe hyponatremia in patients with CNS diseases. The paper describes the first clinical case of a patient, whose onset of chronic lymphocytic leukemia was complicated by cryptococcal meningoencephalitis presenting with mental disorders and severe electrolytic imbalance. Antifungal treatment with amphotericin B and fluconazole could alleviate an infectious process and metabolic disturbances.

Management of electrolyte and fluid disorders after brain surgery for pituitary/suprasellar tumours

Disturbances in salt and water balances are relatively common in children after brain surgeries for suprasellar and pituitary tumours, presenting diagnostic and therapeutic challenges. Although hypernatraemia associated with central diabetes insipidus is commonly encountered, it is hyponatraemia (HN) that poses more of a diagnostic dilemma. The main differential diagnoses causing HN are the syndrome of inappropriate antidiuretic hormone secretion, marked by inappropriate retention of water, and cerebral salt wasting, characterized by polyuria and natriuresis. Diagnosis and management can be even more difficult when these conditions precede or coexist with each other. These diagnostic and therapeutic dilemmas are discussed in detail in this review.

Etiology of postoperative hyponatremia following pediatric intracranial tumor surgery

OBJECT Cerebral salt wasting (CSW) and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) cause postoperative hyponatremia in neurosurgery patients, can be difficult to distinguish clinically, and are associated with increased morbidity. The authors aimed to determine risk factors associated with CSW and SIADH among children undergoing surgery for intracranial tumors. METHODS This retrospective cohort study included children 0-19 years of age who underwent a first intracranial tumor surgery with postoperative hyponatremia (sodium ≤ 130 mEq/L). CSW was differentiated from SIADH by urine output and fluid balance, exclusive of other causes of hyponatremia. The CSW and SIADH groups were compared with basic bivariate analysis and recursive partitioning. RESULTS Of 39 hyponatremic patients, 17 (44%) had CSW and 10 (26%) had SIADH. Patients with CSW had significantly greater natriuresis compared with those with SIADH (median urine sodium 211 vs 28 mEq/L, p = 0.01). Age ≤ 7 years and female sex were significant risk factors for CSW (p = 0.03 and 0.04, respectively). Both patient groups had hyponatremia onset within the first postoperative week. Children with CSW had trends toward increased sodium variability and symptomatic hyponatremia compared with those with SIADH. Most received treatment, but inappropriate treatment was noted to worsen hyponatremia. CONCLUSIONS The authors found that CSW was more common following intracranial tumor surgery and was associated with younger age and female sex. Careful assessment of fluid balance and urine output can separate patients with CSW from those who have SIADH, and high urine sodium concentrations (> 100 mEq/L) support a CSW diagnosis. Patients with CSW and SIADH had similar clinical courses, but responded to different interventions, making appropriate diagnosis and treatment imperative to prevent morbidity.

Hyponatremia in children with tuberculous meningitis: A hospital-based cohort study

Background:

Hyponatremia has long been recognized as a potentially serious metabolic consequence of tuberculous meningitis (TBM) occurring in 35–65% of children with the disease. The syndrome of inappropriate antidiuretic hormone (SIADH) secretion has for long been believed to be responsible for the majority of cases of hyponatremia in TBM. Cerebral salt wasting syndrome (CSWS) is being increasingly reported as a cause of hyponatremia in some of these children.

Aim:

This study was done to determine the frequency and causes of hyponatremia in children with TBM.

Methods:

Children with newly diagnosed TBM admitted over a 2-year period (January 2009 to December 2010) were included. All patients received anti-tubercular therapy, mannitol for cerebral edema, and steroids. Patients were monitored for body weight, urine output, signs of dehydration, serum electrolytes, blood urea nitrogen, serum creatinine, and urinary sodium. Hyponatremia was diagnosed if the serum sodium was <135 mEq/L. CSWS was diagnosed if there was evidence of excessive urine output, volume depletion, and natriuresis in the presence of hyponatremia. The outcome in terms of survival or death was recorded.

Results:

Twenty-nine of 75 children (38.7%) with TBM developed hyponatremia during their hospital stay. In 19 patients, hyponatremia subsided after the discontinuation of mannitol. Ten patients with persistent hyponatremia had CSWS. There were no patients with SIADH.

Conclusions:

CSWS is an important cause of hyponatremia in children with newly diagnosed TBM. In our patients, it was more commonly seen than SIADH.

Metabolische Störungen

Im folgenden Kapitel werden die verschiedenen metabolischen Störungen betrachtet. Zunächst wird auf die allgemeinen und spezifischen neurologischen Komplikationen bei Organtransplantation eingegangen. Dann geht es um die metabolischen Enzephalopathien: Störungen der Gehirntätigkeit bei angeborenen und erworbenen Stoffwechselerkrankungen im engeren Sinn, Elektrolytstörungen, Hypovitaminosen, zerebrale Folgen einzelner Organdysfunktionen, zerebrale Hypoxien, Endotheliopathien und Mitochondropathien. Anschließend werden das Alkoholdelir und die Wernicke-Enzephalopathie erörtert. Bei zahlreichen akuten Erkrankungen von Gehirn, Rückenmark und peripherem Nervensystem treten typische Störungen vegetativer Systeme auf, deren Erkennung und Therapie insbesondere bei Intensivpatienten eine vitale Bedeutung haben kann: die autonomen Störungen. Bei der zentralen pontinen Myelinolyse kommt es zu einer akuten, vorwiegend fokal-symmetrischen Demyelinisierung im Hirnparenchym. Auch Basalganglienerkrankungen können intensivmedizinisch relevant werden. Und schließlich wird die akute Stressreaktion betrachtet, die aufgrund der vielfältigen metabolischen und endokrinen Veränderungen bei kritischen Erkrankungen entsteht. Gerade das RCVS als neuere Krankheitsentität und wichtige Differenzialdiagnose zur Vaskulitis des ZNS verdient einen eigenen Platz, in diesem Unterkapitel werden ebenfalls verwandte Syndrome wie die hypertensive Enzephalopathie und das PRES abgehandelt.

[A case of acute limbic encephalitis with cerebral salt wasting syndrome]

A 37-year-old woman presented with psychiatric symptoms. Cerebrospinal fluid analysis revealed pleocytosis and increased protein. The patient was diagnosed with limbic encephalitis on the basis of the clinical course. However, remarkable hyponatremia was noted throughout the clinical course, leading to a diagnosis of cerebral salt wasting syndrome (CSWS). The hyponatremia was alleviated by supplementation with sodium and water. The findings seen in this case indicate that differentiation between syndrome of inappropriate of antidiuretic hormone and CSWS is important in cases of hyponatremia accompanied by central nervous system disease.

Delayed postoperative hyponatremia after transsphenoidal surgery: prevalence and associated factors

Object

Transient delayed postoperative hyponatremia (DPH) after transsphenoidal surgery (TSS) is common and can have potentially devastating consequences. However, the true prevalence of transient symptomatic and asymptomatic DPH has not been studied in a large patient cohort with close and accurate follow-up.

Methods

A retrospective analysis of a single-institution prospective database was conducted; all patients undergoing TSS for lesions involving the pituitary gland were followed up in a multidisciplinary neuroendocrine clinic, and demographic, imaging, and clinical data were prospectively collected. Patients were examined preoperatively and followed up postoperatively in a standardized fashion, and their postoperative sodium levels were measured at Weeks 1 and 2 postoperatively. Levels of hyponatremia were rated as mild (serum sodium concentration 130–134 mEq/L), moderate (125–129 mEq/L), or severe (< 125 mEq/L). Routine clinical questionnaires were administered at all postoperative office visits. Postoperative hyponatremia was analyzed for correlations with demographic and clinical features and with immediate postoperative physiological characteristics.

Results

Over a 4-year interval, 373 procedures were performed in 339 patients who underwent TSS for sellar and parasellar lesions involving the pituitary gland. The mean (± SD) age of patients was 48 ± 18 years; 61.3% of the patients were female and 46.1% were obese (defined as a body mass index [BMI] ≥ 30). The overall prevalence of DPH within the first 30 days postoperatively was 15.0%; 7.2% of the patients had mild, 3.8% moderate, and 3.8% severe hyponatremia. The incidence of symptomatic hyponatremia requiring hospitalization was 6.4%. The Fisher exact test detected a statistically significant association of DPH with female sex (p = 0.027) and a low BMI (p = 0.001). Spearman rank correlation detected a statistically significant association between BMI and nadir serum sodium concentration (r = 0.158, p = 0.002) and an inverse association for age (r = −0.113, p = 0.031). Multivariate analyses revealed a positive correlation between postoperative hyponatremia and a low BMI and a trend toward association with age; there were no associations between other preoperative demographic or perioperative risk factors, including immediate postoperative alterations in serum sodium concentration. Patients were treated with standardized protocols for hyponatremia, and DPH was not associated with permanent morbidity or mortality.

Conclusions

Delayed postoperative hyponatremia was a common result of TSS; a low BMI was the only clear predictor of which patients will develop DPH. Alterations in immediate postoperative sodium levels did not predict DPH. Therefore, an appropriate index of suspicion and close postoperative monitoring of serum sodium concentration should be maintained for these patients, and an appropriate treatment should be undertaken when hyponatremia is identified.

Stress response in critical illness

Sepsis brings about neuroendocrine dysfunction in children that differs significantly from that of adults and can thus be difficult to interpret and manage. Aggressive treatment of sepsis with appropriate and judicious use of antibiotics remains a top priority. Strict glycemic control in children has been associated with significant risk of hypoglycemia, which may independently contribute to morbidity and mortality. Timely initiation of hydrocortisone in persistently hypotensive children with fluid-refractory, catecholamine-resistant shock is controversial, but its use in children with suspected or proven adrenal insufficiency is suggested. Fluid and electrolyte abnormalities must be corrected. Treatment of thyroid dysfunction has been shown to be beneficial in certain specific populations but cannot be extrapolated to all septic patients with the current available data.

Common endocrine issues in the pediatric intensive care unit

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

CSWS Versus SIADH as the Probable Causes of Hyponatremia in Children With Acute CNS Disorders

OBJECTIVE

There is a major problem about the incidence, diagnosis, and differentiation of cerebral salt wasting syndrome (CSWS) and syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in patients with acute central nervous system (CNS) disorders. According to rare reports of these cases, this study was performed in children with acute CNS disorders for diagnosis of CSWS versus SIADH.

MATERIALS & METHODS

This prospective study was done on children with acute CNS disorders. The definition of CSWS was hyponatremia (serum sodium ≤130 mEq/L), urine volume output ≥3 ml/kg/hr, urine specific gravity ≥1020 and urinary sodium concentration ≥100 mEq/L. Also, patients with hyponatremia (serum sodium ≤130 mEq/L), urine output < 3 ml/kg/hr, urine specific gravity ≥1020, and urinary sodium concentration >20 mEq/L were considered to have SIADH.

RESULTS

Out of 102 patients with acute CNS disorders, 62 (60.8%) children were male with mean age of 60.47±42.39 months. Among nine children with hyponatremia (serum sodium ≥130 mEq/L), 4 children had CSWS and 3 patients had SIADH. In 2 cases, the cause of hyponatremia was not determined. The mean day of hyponatremia after admission was 5.11±3.31 days. It was 5.25±2.75 and 5.66±7.23 days in children with CSWS and SIADH, respectively. Also, the urine sodium (mEq/L) was 190.5±73.3 and 58.7±43.8 in patients with CSWS and SIADH, respectively.

CONCLUSION

According to the results of this study, the incidence of CSWS was more than SIADH in children with acute CNS disorders. So, more attention is needed to differentiate CSWS versus SIADH in order to their different management.

Renal salt-wasting syndrome in children with intracranial disorders

Hypotonic hyponatremia, a serious and recognized complication of any intracranial disorder, results from extra-cellular fluid volume depletion, inappropriate anti-diuresis or renal salt-wasting. The putative mechanisms by which intracranial disorders might lead to renal salt-wasting are either a disrupted neural input to the kidney or the elaboration of a circulating natriuretic factor. The key to diagnosis of renal salt-wasting lies in the assessment of extra-cellular volume status: the central venous pressure is currently considered the yardstick for measuring fluid volume status in subjects with intracranial disorders and hyponatremia. Approximately 110 cases have been reported so far in subjects ≤18 years of age (male: 63%; female: 37%): intracranial surgery, meningo-encephalitis (most frequently tuberculous) or head injury were the most common underlying disorders. Volume and sodium repletion are the goals of treatment, and this can be performed using some combination of isotonic saline, hypertonic saline, and mineralocorticoids (fludrocortisone). It is worthy of a mention, however, that some authorities contend that cerebral salt wasting syndrome does not exist, since this diagnosis requires evidence of a reduced arterial blood volume, a concept but not a measurable variable.

Myelodysplastic syndrome complicated by central diabetes insipidus and cerebral salt wasting syndrome with peculiar change in magnetic resonance images

Central diabetes insipidus (CDI) could occurs in patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML), because of infiltration of leukemic cells into the neurohypophysis or some other reason and it is closely associated with abnormalities of chromosome 7. We report a case of MDS with abnormalities of chromosome 7, presenting as CDI followed by deterioration of polyuria and hyponatremia with a decreased extracellular fluid volume. Magnetic resonance imaging (MRI) revealed symmetrically enhanced lesions in the hypothalamus. Fludrocortisone treatment normalized his serum sodium level and cerebral salt wasting syndrome (CSWS) was suspected.

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.

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.

Clinical analysis of hyponatremia in acute craniocerebral injury

OBJECTIVE

To explore pathological mechanisms of central hyponatremia and its treatment.

METHODS

Synchronous assay was made for changes of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), endogenous digitalis-like substance (EDLS), antidiuretic hormone (ADH) in blood, and Na(+) concentrations in blood and urine, and plasma- and urine-osmolality in 68 patients with acute craniocerebral injury (ACI).

RESULTS

Of the 68 patients with ACI, 27 were found to have hyponatremia, and such illness was mostly concentrated on severe cases.

CONCLUSIONS

The central hyponatremia in patients with ACI may be related to the increase in the secretion of EDLS and ADH as the result of damaged functions of the hypothalamic-hypophysial system, and it seems that the decrease in blood ANP and BNP has no direct effect on Na(+) concentrations in blood. Inappropriate secretion of antidiuretic hormone syndrome and cerebral salt-wasting syndrome are the two main reasons for hyponatremia in patients with craniocerebral injury. The pathological mechanism, diagnostic standards, as well as treatment methods for the two, however, are not just the same. Intravenous injection of extrinsic thyrotropin-releasing hormone might inhibit dilutional hyponatremia arising from the increase in ADH secretion by patients with ACI.

Natriuretic Peptides, Antidiuretic Hormone and Hyponatraemia after Acute Craniocerebral Injury

We investigated the physiological mechanisms involved in central hyponatraemia in patients with acute craniocerebral injury (ACI). We measured blood concentrations of natriuretic peptides, antidiuretic hormone (ADH), and endogenous digitalis-like substance (EDLS), blood and urine sodium concentrations, and the plasma and urine osmolality in 68 patients with ACI and 24 healthy control subjects. A total of 27 ACI patients were hyponatraemic and the majority of these had grievous or severely grievous craniocerebral injuries. Blood concentrations of EDLS and ADH in hyponatraemic ACI patients were significantly higher compared with normonatraemic ACI patients and control subjects. Blood EDLS and sodium concentrations were negatively correlated with each other, whereas EDLS was positively correlated with urine sodium concentration and with urine osmotic pressure. Hyponatraemic ACI patients require different treatment based on the cause of their central hyponatraemia, so it is important to undertake a comprehensive analysis of each patient's physiological status.

[Fluid and electrolyte disorders following surgery for brain tumors]

INTRODUCTION

Fluid and electrolyte disorders such as diabetes insipidus, salt wasting syndrome (SWS) and syndrome of inappropriate antidiuretic hormone secretion (SIADH) can appear in the immediate postoperative period after surgery for brain tumors. Early diagnosis and treatment are important to prevent the potential adverse effects of these disorders on the central nervous system (CNS).

OBJECTIVES

To determine the incidence and characteristics of fluid and electrolyte disorders in the immediate postoperative period after surgery for CNS tumors in children treated in our hospital.

MATERIAL AND METHODS

We retrospectively analyzed clinical and laboratory data in all infants and children who underwent surgery for CNS tumors in our hospital from January 1998 to June 2005 and who met the laboratory criteria for diabetes insipidus, SWS or SIADH.

RESULTS

Twenty-three electrolyte disorders were identified in 149 surgical patients (an incidence of 15.4%). The median age was 5 years and 3 months (from 6 months to 17 years) and 48.7% of the patients were male. The most frequent electrolyte disturbance was diabetes insipidus (65.2% of all electrolyte disorders). On average, onset of diabetes insipidus occurred 19 hours after surgery. Treatment with desmopressin was administrated in all patients. On average, diabetes insipidus was resolved 73 hours after diagnosis, except in one patient with permanent diabetes insipidus due to a surgical lesion of the hypothalamic-pituitary axis. The second most frequent electrolyte disturbance was SWS (26.1%) with a mean time of onset of 50.4 hours after surgery. On average, SWS was resolved 57.6 hours after administration of saline solutions. Only two patients developed SIADH, which was treated with water restriction and adequate sodium supply. Both cases of SIADH resolved spontaneously in the first 36 hours after diagnosis. At discharge, none of the patients showed neurological disturbances due to an electrolytic disorder.

CONCLUSIONS

In our series, the most frequent electrolyte disorder after surgery for CNS tumors was diabetes insipidus. Early treatment with desmopressin almost always prevents hypernatremia. Unless there is a surgical lesion of the hypothalamic-pituitary axis, spontaneous resolution will take place in 3 days on average. The management of SWS and SIADH requires close monitoring of plasma sodium due to the risk of hyponatremia.

Hyponatremia in patients with traumatic brain injury: incidence, mechanism, and response to sodium supplementation or retention therapy with hydrocortisone

BACKGROUND

Hyponatremia is a frequently observed electrolyte abnormality in patients with central nervous system disease. Several mechanisms, such as SIADH, hypopituitarism, and CSWS, have been proposed with varied incidences among several studies. We attempted to clarify the incidence and mechanism of hyponatremia for each type of TBI. We also assessed the efficacy of sodium supplementation and retention therapy. For sodium retention therapy, hydrocortisone was administered, expecting its mineralocorticoid effect, when the hyponatremia was associated with excess natriuresis.

METHODS

Retrospective analysis of 298 patients with TBI between January 2003 and December 2004 was performed. The incidence, background, clinical data, and outcome were evaluated.

RESULTS

Of the 298 patients, 50 (16.8%) presented hyponatremia during the time course. Hyponatremia was associated with longer hospital stay (P < .001) and bad outcome (P = .02). Among these 50 patients, 37 recovered from the hyponatremia with simple sodium supplementation. The remaining 13 patients presented massive natriuresis and required additional sodium retention therapy. Hydrocortisone statistically reduced the amount of sodium excretion (P = .002) and returned the serum sodium level to a normal value.

CONCLUSIONS

A high rate of hyponatremia after TBI was observed. Further studies are required to establish the precise mechanism of hyponatremia after TBI. Clear definition of CSWS is required to avoid confusion of the pathophysiology that causes hyponatremia. Hydrocortisone was useful to prevent excess natriuresis.

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.

Vasopressin-receptor antagonist therapy in patients with hyponatraemia

Hyponatraemia often complicates the treatment of underlying conditions in patients who are seriously ill. Arginine vasopressin receptor antagonists block the action of arginine vasopressin and correct sodium and water imbalance in patients with euvolaemic or hypervolaemic hyponatraemia.

The effects of head trauma on hypothalamic-pituitary function in children and adolescents

PURPOSE OF REVIEW

Endocrine dysfunctions have been increasingly recognized following traumatic brain injury. Ever more numerous studies on acute head-injured adults have also raised concern about this risk in children and adolescents who have experienced head injury. The current review of the pediatric literature summarizes recent findings on acute-phase dysfunction and traumatic brain injury-associated hypopituitarism.

RECENT FINDINGS

The pathophysiologic mechanisms underlying acute-phase hyponatremic and hypernatremic disorders have been elucidated. Prospective studies on traumatic brain injury-associated hypopituitarism in pediatric patients are ongoing and preliminary data are available.

SUMMARY

Traumatic brain injury, a 'silent epidemic' that carries a considerable burden of disabilities, leads to a variety of endocrine dysfunctions in 28-69% of adult acute head-injured patients. In the acute posttraumatic phase, adrenal insufficiency and electrolyte disorders are critical conditions. Neurosurgical patients, particularly those prone to neurological damage, require prompt diagnosis. Hypopituitarism may be diagnosed months or years after a traumatic brain injury event. Since growth hormone and gonadotropin secretion are most frequently compromised, careful follow-up of growth and pubertal development is mandatory in children hospitalized for traumatic brain injury.

Diagnosis and management of cerebral salt wasting (CSW) in children: the role of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)

OBJECTIVE

The aim of this study is to report our experience with diagnosis and management of cerebral salt wasting (CSW) in children and to evaluate the role of atrial natriuretic peptide/brain natriuretic peptide (ANP/BNP) in pediatric patients.

MATERIALS AND METHODS

We present nine children suffering from prevalent cerebral disease--seven of whom underwent anesthesia and surgical procedures--with features of CSW, seen within a 22-month period. The symptoms, patient characteristics (including hormone status), monitoring, treatment protocol, and outcome are described.

RESULTS

Natriuresis (urine Na+ concentrations 131 to >250 mmol/l) and polyuria (5.5+/-1.5 ml/kg/h) with increased Na+ turnover (maximum Na+ loss: median 1.50 mmol Na+/kg/h, range 0.47 to >3.50) vanished within 2 weeks in 6/9 patients (increase in serum Na+ from 127+/-2 mmol/l to 136+/-1). K+ excretion was also high (maximum K+ loss: median 0.18 mmol K+/kg/h, range 0.09-0.53). ANP/BNP as suspected causes of salt wasting were elevated only in 1/6 and 2/7 patients, respectively. Plasma renin activities and aldosterone levels were either suppressed or in the low normal range.

CONCLUSION

Natriuresis and polyuria are the main diagnostic criteria for CSW. The fluid balance in CSW is negative, in contrast to a positive fluid balance in SIADH. The length of the disease is self-limited and generally ceases within 2 weeks, while Na+, K+, and fluid turnover should be monitored carefully. Only a minority of our children showed elevated ANP/BNP levels. A dose/effect relationship for natriuretic peptide levels and increased Na+ turnover could not be established.

Hyponatremia in neurologic patients: consequences and approaches to treatment

BACKGROUND

Hyponatremia is a common fluid-electrolyte disturbance, particularly in patients with neurologic disorders, in part because of the major role the central nervous system (CNS) plays in the regulation of sodium and water homeostasis.

REVIEW SUMMARY

The classification of hyponatremia is based on an assessment of serum sodium concentration ([Na+]), serum and urine osmolality, and body volume status. In most cases, hyponatremia is associated with hypotonicity, which causes water to move into the brain. Adaptive responses limit the impact of cerebral edema in chronic hyponatremia, but CNS symptoms and death may occur in response to rapid or large decreases in serum [Na+]. The prompt correction of serum [Na+] is mandatory in symptomatic patients, but overly rapid correction must be avoided to limit the risk of myelinolysis. In neurologic disorders, euvolemic hyponatremia (usually caused by the syndrome of inappropriate secretion of antidiuretic hormone) must be distinguished from hypovolemic states such as cerebral salt wasting because the treatment of the 2 conditions differs. Vasopressin antagonists represent a new approach to the treatment of euvolemic and hypervolemic hyponatremia secondary to arginine vasopressin dysregulation.

CONCLUSION

The optimal treatment of hyponatremia is controversial, but appropriate treatment must be determined according to the osmolality and volume status of the patient. If left untreated, serious CNS complications and adverse outcomes, including an increased risk of death, can occur.

Hypothalamo-hypophysial dysfunction after traumatic brain injury in children and adolescents: a preliminary retrospective and prospective study

With two study protocols, one retrospective and the other prospective, we evaluated hypothalamo-hypophysial dysfunction (HHD) in paediatric patients treated for traumatic brain injury (TBI) in the neurosurgical or intensive care department at our hospital. The retrospective group comprised 22 patients who had experienced TBI 0.7-7.25 years before the study. The prospective group included 30 patients assessed at TBI (T0), 26 of 30 after 6 months (T6), and 20 of 26 after 12 months (T12). Auxological and hormonal basal parameters of hypothalamo-hypophysial function were evaluated at recall in the retrospective group, and at T0, T6 and T12 in the prospective group. Basal data and standard dynamic tests in selected patients revealed one with precocious puberty, one with total anterior hypopituitarism, one with central hypogonadism, and one with growth hormone (GH) deficiency in the retrospective group; three patients with cerebral salt-wasting syndrome, one with diabetes insipidus and seven with low T3 syndrome at T0 (all transient), one with hypocorticism at T6 confirmed at T12, and one with GH deficiency at T12 in the prospective group. The results of our study show that post-TBI HHD in our paediatric cohort is not uncommon. Of the 48 patients who underwent a complete evaluation (22 retrospective study patients and 26 prospective study patients evaluated at T6) five (10.4%) developed HHD 6 months or more after TBI. HHD was newly diagnosed in one previously normal patient from the prospective group at 12 months after TBI. GH deficiency was the most frequent disorder in our paediatric cohort.

Vasopressin Antagonism

Hyponatremia is a common electrolyte disorder frequently associated with central nervous system (CNS) diseases, neurosurgical procedures, and the use of neurotropic drugs. The clinical manifestations of hyponatremia are attributable to an increase in brain water content that occurs in response to a decrease in serum osmolality. Hyponatremia triggers adaptive processes in the brain to limit this cerebral swelling, but a rapid fall in serum [Na(+)] may overwhelm this adaptive mechanism. Patients with hyponatremia for more than 48 hours are at risk for developing osmotic demyelination when overly rapid correction of hyponatremia restores serum osmolality before this adaptive process can be reversed. The infusion of hypertonic saline for the restoration of serum [Na(+)] should therefore be carefully controlled to avoid this potentially devastating complication. Other options currently available for the treatment of hyponatremia, including strict restriction of fluid intake, are limited by their inconsistent response, poor tolerability, and frequent adverse effects. Arginine vasopressin (AVP)-receptor antagonists promote aquaresis (electrolyte-sparing excretion of free water) by blocking the antidiuretic action of the hormone at the level of the collecting ducts. In clinical trials, AVP-receptor antagonists increased serum [Na] in patients with euvolemic or hypervolemic hyponatremia associated with various conditions, including syndrome of inappropriate antidiuretic hormone secretion (SIADH). Patients who have neurologic disease with SIADH-related hyponatremia may be good candidates for treatment with AVP-receptor antagonists. Careful assessment of intravascular volume status before initiation of therapy and strict monitoring of the serum [Na] during treatment are necessary to avoid complications.

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.

Central Nervous System Coccidioides immitis Infections

Coccidioidal meningitis occurs in healthy individuals and patients with AIDS or other immunosuppressive illnesses. The central nervous system infection results when Coccidioides immitis disseminates from a primary lung infection via a fungemia to reach the meninges. Cases develop primarily in individuals living in or traveling to the Lower Sonoran Life Zone of Southwest United States. Most cases begin as subacute granulomatous meningitis with occasional patients developing brain abscesses. Diagnosis may be challenging because C. immitis is isolated from cerebrospinal fluid in less than 50% of patients. However, a cerebrospinal fluid complement fixation test for IgG antibody to C. immitis has high sensitivity and specificity. Currently, optimal treatment is unclear. Standard therapy has been with life-long oral fluconazole or intrathecal amphotericin B followed by prolonged oral fluconazole. Liposomal amphotericin B given intravenously seems promising as an initial treatment as it has much higher brain penetration, less nephrotoxicity, and less severe infusion-related adverse effects than conventional amphotericin B. However, current comparative studies for efficacy of liposomal amphotericin B in coccidioidal meningitis are lacking.

Endocrine function and water metabolism in children and adolescents with surgically treated intra/parasellar tumors

Hydroelectrolytic disorders often complicate surgery of intra/parasellar tumors in children and adolescents. Eighteen patients undergoing microneurosurgical procedures for intra-supra-sellar craniopharyngioma (10 patients), hypothalamic germinomas (3 patients), hypothalamic-chiasmatic astrocytomas (3 patients), pituitary adenomas (2 patients) were studied. The hydroelectrolytic balance was assessed from 8 hours before surgery to 1 week after with a specific protocol in which water metabolism alterations were treated with standard procedure. Diabetes insipidus (DI) was observed in 10/18 patients before surgery and in 15/18 patients after surgery; during surgery it was effectively treated with synthetic desmopressin (DDAVP) and hydroelectrolytic solutions. Hyponatremia, isolated or associated (with diuresis contraction or polyuria), seen during surgery and in the following 24 hours, was treated with variation of the infusion rate. We show that close monitoring and treatment of hydroelectrolytic disorders in patients submitted to neurosurgery for intra/ parasellar tumors may significantly reduce their morbidity and mortality rate.

Hyponatremia in the neurosurgical patient: diagnosis and management

Hyponatremia is frequently encountered in patients who have undergone neurosurgery for intracranial processes. Making an accurate diagnosis between the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and cerebral salt wasting (CSW) in patients in whom hyponatremia develops is important because treatment differs greatly between the conditions. The SIADH is a volume-expanded condition, whereas CSW is a volume-contracted state that involves renal loss of sodium. Treatment for patients with SIADH is fluid restriction and treatment for patients with CSW is generally salt and water replacement. In this review, the authors discuss the differential diagnosis of hyponatremia, distinguish SIADH from CSW, and highlight the diagnosis and management of hyponatremia, which is commonly encountered in patients who have undergone neurosurgery, specifically those with traumatic brain injury, aneurysmal subarachnoid hemorrhage, recent transsphenoidal surgery for pituitary tumors, and postoperative cranial vault reconstruction for craniosynostosis.

Hyponatremia in critically ill neurological patients

BACKGROUND

Hyponatremia is the most common and important electrolyte disorder encountered in the neurologic intensive care unit (NICU). Advances in our knowledge of the pathophysiological mechanisms at play in patients with acute neurologic disease have improved our understanding of this derangement.

REVIEW SUMMARY

Evaluation of hyponatremia requires a structured approach beginning with the measurement of serum and urine osmolalities. Most cases of hyponatremia in the NICU are associated with serum hypotonicity. Iatrogenic causes, most conspicuously inadequate tonicity of intravenous fluids, should be promptly identified and removed when possible. Two main mechanisms are responsible for most non-iatrogenic cases of hyponatremia in patients with neurologic or neurosurgical disease: inappropriate secretion of antidiuretic hormone (SIADH) and cerebral salt wasting syndrome (CSW). Distinction between these two syndromes may be difficult and must be based on an accurate assessment of the patient's volume status. SIADH is associated with normal or slightly expanded volume status and should be treated with fluid restriction. Patients with CSW are hypovolemic and require adequate fluid and sodium replacement. Correction of hyponatremia should not exceed 8 to 10 mmol/L over any 24-hour period to avoid the risk of osmotic demyelination.

CONCLUSIONS

Hyponatremia may complicate the clinical course of many acute neurologic and neurosurgical disorders. It is most often iatrogenic causes, CSW, or SIADH. Physicians working with critically ill neurologic patients should be familiar with management strategies addressing these underlying pathophysiological mechanisms.

Hyponatraemia and hypovolemic shock with tuberculous meningitis

A 12-year-old boy with tuberculous meningitis and hydrocephalous, after undergoing revision of ventriculo-peritoneal shunt had persistent impairment of sensorium and episodes of hyponatremia (serum sodium 104 to 125 mmol/l), accompanied by polyuria, signs of poor peripheral, perfusion hypotension and low CVP, and high urinary sodium excretion (114-60 mmol/l). A diagnosis of cerebral salt wasting syndrome (CSWS) was made and was treated with saline replacement and fludrocortisone (10 microg/kg/day). Within next 3 days the sensorium, signs of shock, urine output and serum and urinary sodium returned to normal. The case illustrates that life-threatening hyponatremia in a child with neurological illness could be caused by CSWS, which must be differentiated from Syndrome of inappropriate antidiuretic hormone secretion (SIADH), as CSWS requires rigorous salt and volume replacement in contrast to fluid restriction in SIADH.

Hyponatremia in patients with central nervous system disease: SIADH versus CSW

The syndromes of inappropriate antidiuretic hormone secretion (SIADH) and cerebral salt wasting (CSW) are two potential causes of hyponatremia is patients with disorders of the central nervous system. Distinguishing between these two causes can be challenging because there is considerable overlap in the clinical presentation. The primary distinction lies in the assessment of the effective arterial blood volume (EABV). SIADH is a volume-expanded state because of antidiuretic hormone-mediated renal water retention. CSW is characterized by a contracted EABV resulting from renal salt wasting. Making an accurate diagnosis is important because the treatment of each condition is quite different. Vigorous salt replacement is required in patients with CSW, whereas fluid restriction is the treatment of choice in patients with SIADH. Although most physicians are familiar with SIADH, they are much less familiar with CSW. This review emphasizes the need for CSW to be included in the differential diagnosis of hyponatremia in a patient with central nervous system disease. Distinguishing between these two disorders is of crucial importance because therapy indicated for one disorder but used in the other can result in negative clinical consequences.