Effect of protein supplementation on plasma sodium levels in the syndrome of inappropriate antidiuresis: a monocentric, open-label, proof-of-concept study-the TREASURE study.

IMPORTANCE: The syndrome of inappropriate antidiuresis (SIAD) can be treated with oral urea; however, compliance is impaired by its poor palatability. OBJECTIVE: To investigate whether dietary proteins could increase plasma sodium levels through urea-induced osmotic diuresis. DESIGN: An open-label, proof-of-concept trial. SETTING: University Hospital of Basel, Switzerland, between October 2021 and February 2023. PARTICIPANTS: Outpatients with chronic SIAD. INTERVENTIONS OR EXPOSURES: Ninety grams of protein daily for 7 days in the form of protein powder, followed by 30 g of oral urea daily for 7 days after a wash-out period of ≥1 week. MAIN OUTCOMES AND MEASURES: The increase in sodium levels from baseline to the end of the 7-day protein supplementation. RESULTS: Seventeen patients were included. After 7 days of 90 g daily protein supplementation (n = 17), plasma sodium levels increased from 131 (129-133) to 133 (132-137), that is, by a median of 3 mmol L-1 (0-5) (P = .01). Plasma urea levels increased by 3 mmol L-1 (1.7-4.9) (P < .01), and urine urea to creatinine ratio increased by 21.2 mmol mmol-1 (6.2-29.1) (P < .01). After 7 days of 30 g oral urea (n = 10), plasma sodium levels increased from 132 (130-133) to 134 (131-136), that is, by a median of 2 mmol L-1 (1-3) (P = .06). Plasma urea levels increased by 5.8 mmol L-1 (2.7-9.2) (P < .01), and urine urea to creatinine ratio increased by 31.0 mmol mmol-1 (18.7-45.1) (P < .01). CONCLUSIONS AND RELEVANCE: Our findings suggest that protein powder increases plasma sodium levels in patients with chronic SIAD through protein-induced ureagenesis and osmotic diuresis. The effects are comparable with oral urea.

Pearls & Oy-sters: Syndrome of Inappropriate Antidiuretic Hormone Secretion Presenting as Neuromyelitis Optica Spectrum Disorder Flare.

While it was previously believed that neuromyelitis optic spectrum disorder (NMOSD) mostly affected the optic nerves and the spinal cord, it is increasingly recognized that NMOSD can involve any area of the CNS where aquaporin-4 is highly expressed. These other areas can include the hypothalamus and the circumventricular organs that surround the third and fourth ventricles, serving as osmoregulators. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most common causes of hyponatremia and has been associated with NMOSD due to these lesions. In this report, we present a case of a patient with known NMOSD, who presented with dizziness, fatigue, and generalized weakness and whose workup revealed hyponatremia in the setting of SIADH and hypothalamic demyelinating lesions. This case illustrates an atypical presentation of NMOSD and the importance of looking for syndromes, such as SIADH. This can guide diagnostic testing, such as getting thin MRI cuts through the hypothalamus and brainstem, as well as advanced management techniques such as immunotherapy.

Intractable hyponatremia secondary to syndrome of inappropriate antidiuresis complicated with empty sella: A case report.

RATIONALE: Hyponatremia is a common electrolyte disorder in elderly critically ill patients, and it may be associated with poor outcomes, higher morbidity, and mortality. Syndrome of inappropriate antidiuresis (SIAD) is one of the main causes of hyponatremia, with an insidious onset that is highly misdiagnosed. Primary empty sella lesions are specific, mostly asymptomatic, and easily overlooked. SIAD combined with empty sella is much rarer in clinic, this article focuses on the diagnosis and management of an elderly patient with intractable hyponatremia secondary to syndrome of inappropriate antidiuresis complicated with empty sella. PATIENT CONCERNS: An 85-year-old male patient with severe pneumonia presented with progressive and intractable hyponatremia. DIAGNOSES: The patient had clinical signs of persistent hyponatremia, low plasma osmolality, elevated urinary sodium excretion, and hyponatremia that worsened with increased intravenous rehydration and was effective with appropriate fluid restriction. The diagnosis of SIAD combined with empty sella was made in combination with the findings of the pituitary and its target gland function. INTERVENTIONS: Numerous screenings were performed to clarify the cause of hyponatremia. His overall condition was poor due to recurrent episodes of hospital-acquired pneumonia. We treated with ventilation support, circulatory support, nutritional support, anti-infection, and continuous correction of electrolyte imbalance. OUTCOMES: His hyponatremia gradually improved through aggressive infection control, appropriate fluid restriction (intake controlled at 1500-2000mL/d), continuous electrolyte correction, supplementation with hypertonic salt solution, and potassium replacement therapy. LESSONS: Electrolyte disorders, especially hyponatremia, are very common in critically ill patients, but the etiology of hyponatremia is challenging to diagnose and treat, and timely attention and proper diagnosis of SIAD and individualized treatment are the significance of this article.

Initiating Continuous Renal Replacement Therapy in Patients With Transurethral Resection of Prostate Syndrome: A Case Report.

With advances and developments in hysteroscopy, cystoscopy, transurethral resection of bladder tumor, and arthroscopy, transurethral resection of prostate (TURP) syndrome has been increasingly reported. TURP syndrome is often accompanied by severe hyponatremia, fluid overload, and a plasma hypotonic state, resulting in heart failure and pulmonary and cerebral edema. Conventional treatment methods, such as intravenous infusion of hyperosmotic saline, can rapidly reverse the downward trend of serum sodium levels in efforts to prevent and treat cerebral edema. However, this may not be suitable for patients with cardiac and renal insufficiency and may induce central pontine myelinolysis due to the possibility of worsening volume load and difficulty in controlling the correction rate of serum sodium. The patient described in this report presented with severe hyponatremia (sodium<100 mmol/L) combined with intraoperative pulmonary edema; his cardiac function and oxygenation status deteriorated after an intravenous infusion of 3% hypertonic saline. He underwent continuous renal replacement therapy (CRRT) to prevent the progression of multiple-organ edema and cardiac insufficiency. CRRT has demonstrated efficacy in the treatment of chronic hyponatremia in patients with renal failure, and can slowly and continuously correct water-electrolyte imbalance, acid-base imbalance, and volume overload. TURP syndrome with severe hyponatremia and pulmonary edema was diagnosed; accordingly, the patient was treated with 3% hypertonic saline, furosemide, and CRRT, without the development of overt neurological sequelae.

Disorders of sodium balance and its clinical implications in COVID-19 patients: a multicenter retrospective study.

BACKGROUND: The worldwide spread of SARS-CoV-2 has infected millions of people leading to over 0.3 million mortalities. The disruption of sodium homeostasis, tends to be a common occurrence in patients with COVID-19. METHODS AND RESULTS: A total of 1,254 COVID-19 patients comprising 124 (9.9%) hyponatremic patients (under 135 mmol/L) and 30 (2.4%) hypernatremic patients (over 145 mmol/L) from three hospitals in Hubei, China, were enrolled in the study. The relationships between sodium balance disorders in COVID-19 patients, its clinical features, implications, and the underlying causes were presented. Hyponatremia patients were observed to be elderly, had more comorbidities, with severe pneumonic chest radiographic findings. They were also more likely to have a fever, nausea, higher leukocyte and neutrophils count, and a high sensitivity C-reactive protein (HS-CRP). Compared to normonatremia patients, renal insufficiency was common in both hyponatremia and hypernatremia patients. In addition, hyponatremia patients required extensive treatment with oxygen, antibiotics, and corticosteroids. The only significant differences between the hypernatremia and normonatremia patients were laboratory findings and clinical complications, and patients with hypernatremia were more likely to use traditional Chinese medicine for treatment compared to normonatremia patients. This study indicates that severity of the disease, the length of stay in the hospital of surviving patients, and mortality were higher among COVID-19 patients with sodium balance disorders. CONCLUSION: Sodium balance disorder, particularly hyponatremia, is a common condition among hospitalized patients with COVID-19 in Hubei, China, and it is associated with a higher risk of severe illness and increased in-hospital mortality.

Efficacy of Furosemide, Oral Sodium Chloride, and Fluid Restriction for Treatment of Syndrome of Inappropriate Antidiuresis (SIAD): An Open-label Randomized Controlled Study (The EFFUSE-FLUID Trial).

RATIONALE & OBJECTIVE: First-line therapy for syndrome of inappropriate antidiuresis (SIAD) is fluid restriction. Additional treatment for patients who do not respond to fluid restriction are water restriction with furosemide or water restriction with furosemide and salt supplementation. However, the efficacy of these treatments has never been tested in a randomized controlled study. The objective of this study was to investigate whether, combined with fluid restriction, furosemide with or without sodium chloride (NaCl) supplementation was more effective than fluid restriction alone in the treatment of hyponatremia in SIAD. STUDY DESIGN: Open-label randomized controlled study. SETTING & PARTICIPANTS: Patients with serum sodium concentrations ([Na+]) ≤ 130mmol/L due to SIAD. INTERVENTION(S): Random assignment to 1 of 3 groups: fluid restriction alone (FR), fluid restriction and furosemide (FR+FM), or fluid restriction, furosemide, and NaCl (FR+FM+NaCl). Strictness of fluid restriction (<1,000 or<500mL/d) was guided by the urine to serum electrolyte ratio. Furosemide dosage was 20 to 40mg/d. NaCl supplements were 3g/d. All treatments were continued for 28 days. OUTCOMES: The primary outcome was change in [Na+] at days 4, 7, 14, and 28 after randomization. RESULTS: 92 patients were recruited (FR, n=31; FR+FM, n=30; FR+FM+NaCl, n=31). Baseline [Na+] was 125±4mmol/L, and there were no significant differences between groups. Mean [Na+] on day 4 in all treatment groups was significantly increased from baseline by 5mmol/L (P<0.001); however, the change in [Na+] was not significantly different across groups (P=0.7). There was no significant difference in percentage of patients or time to reach [Na+] ≥ 130 or≥135mmol/L across the 3 groups. Acute kidney injury and hypokalemia (potassium≤3.0mmol/L) were more common in patients receiving furosemide. LIMITATIONS: Open-label treatment. CONCLUSIONS: In patients with SIAD, furosemide with NaCl supplement in combination with fluid restriction did not show benefits in correction of [Na+] compared with treatment with fluid restriction alone. Incidences of acute kidney injury and hypokalemia were increased in patients receiving furosemide. FUNDING: None. TRIAL REGISTRATION: Registered at the Thai Clinical Trial Registry with study number TCTR20170629004.

Hypocalcaemia and hyponatraemia masquerading the diagnosis of Gitelman syndrome.

Gitelman syndrome is the most common renal tubulopathy, recently exhibiting a dramatic rise of incidence in Asia.A 50-year-old woman presented with vomiting, fatigue and quadriparesis. Physical examination revealed a positive Trousseau sign , hypotonia and areflexia.Suspecting hypocalcaemia, she was given intravenous 10% calcium gluconate (10 mL administered slowly over 10 min) but her manifestations persisted. An exhaustive laboratory work up revealed the diagnosis of Gitelman syndrome.The peculiarity of this case however, is entailed in its coexistence with hypocalcaemia and hyponatraemia. In addition, the age of primary presentation being 50 years further culminates its atypicality.Multiple electrolyte imbalances were corrected by oral and intravenous supplementation and a high sodium-potassium diet was advocated. Administration of spironolactone imposed a pitfall in the management of our patient due to exacerbation of pre-existing hyponatraemia.On follow-up, her electrolyte profile was stable and corresponding symptoms were alleviated.

Mild water restriction with or without urea for the longterm treatment of syndrome of inappropriate antidiuretic hormone secretion (SIADH): Can urine osmolality help the choice?

BACKGROUND: Treatment options for chronic SIADH include water restriction (WR) and urea. The usefulness of urine osmolality to guide the choice of the treatment option is not clearly defined. We hypothesized that urine osmolality can indicate whether treatment with mild water restriction alone could be successful. METHODS: Retrospective Review of clinical and biochemical (blood and urine) data of patients with chronic SIADH treated for at least one year with mild WR (1.5-2l/day) either with or without urea. RESULTS: Twenty nine patients were included. Nine patients were treated by mild WR. Mean serum sodium (SNa) and mean Uosm were 129±2mEq/l and 274±78mOsm/kgH2O respectively before WR, and increased to 138.5±3mEq/l and 505±87mOsm/kgH2O (P<0.001). Eight patients were treated with mild WR and 15g urea daily, the SNa and Uosm before treatment were 127.5±3mEq/l and 340±100mOsm/kgH2O respectively and increased to 136.5±1mEq/l and 490±151mOsm/kgH2O (P<0.001). Four of the eight patients had a permanent low solute intake which contributed to hyponatremia. Twelve patients needed 30g urea daily combined with mild WR. The SNa and Uosm were respectively 126±2mEq/l and 595±176mOsm/kgH2O and increased to 136.5±2mEq/l and 698±157mOsm/kgH2O (P<0.05). Uosm increased in most of the treated patients. CONCLUSIONS: About 30% of patients could be treated by moderate WR alone. All these patients presented an initial urine osmolality lower than 400mOsm/kgH2O.

Guía de práctica clínica sobre el diagnóstico y tratamiento de la hiponatremia / Hyponatraemia diagnosis and treatment clinical practice guidelines

La hiponatremia se define como una concentración sérica de sodio <135mmol/L y es el trastorno hidroelectrolítico más frecuente en la práctica clínica. La hiponatremia puede causar un amplio espectro de síntomas clínicos, desde sutiles hasta graves o incluso mortales, y se asocia con aumento de la morbimortalidad y prolongación de la estancia hospitalaria. A pesar de ello, el manejo de los pacientes con hiponatremia sigue siendo problemático. La prevalencia de hiponatremia en enfermedades muy diferentes y su manejo por muy diversos especialistas han fomentado la existencia de protocolos de diagnóstico y tratamiento muy diversos, que varían con la especialidad y la institución. La Sociedad Europea de Medicina Intensiva (ESICM), la Sociedad Europea de Endocrinología (ESE) y la Asociación Renal Europea-Asociación Europea de Diálisis y Trasplante (ERA-EDTA), representada por la European Renal Best Practices (ERBP), han desarrollado la guía de práctica clínica sobre el enfoque diagnóstico y tratamiento de la hiponatremia como una empresa conjunta de las 3 sociedades que representan a los especialistas con un interés natural en la hiponatremia, a fin de ofrecer una visión común y holística del abordaje del problema. Además de ofrecer un enfoque riguroso en la metodología y la evaluación de la evidencia, el documento está centrado en resultados importantes para el paciente y en facilitar una herramienta útil para los médicos en la práctica clínica cotidiana. Presentamos ahora una versión abreviada de las recomendaciones y sugerencias sobre el diagnóstico y el tratamiento de la hiponatremia recogidas en la guía complete (AU)

Hyponatremia, defined as a serum sodium concentration <135mmol/l, is the most common water-electrolyte imbalance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from mild to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay. Despite this, the management of hyponatremia patients remains problematic. The prevalence of hyponatremia in a wide variety of conditions and the fact that hyponatremia is managed by clinicians with a broad variety of backgrounds have fostered diverse institution- and specialty-based approaches to diagnosis and treatment. To obtain a common and holistic view, the European Society of Intensive Care Medicine (ESICM), the European Society of Endocrinology (ESE) and the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA), represented by European Renal Best Practice (ERBP), have developed clinical practice guidelines on the diagnostic approach and treatment of hyponatremia as a joint venture of 3 societies representing specialists with a natural interest in hyponatremia. In addition to a rigorous approach to the methodology and evaluation of the evidence, the document focuses on patient-positive outcomes and on providing a useful tool for clinicians involved in everyday practice. In this article, we present an abridged version of the recommendations and suggestions for the diagnosis and treatment of hyponatremia extracted from the full guide (AU)

[Anesthetic Management of an Infant with Rapidly Developed Hyponatremia due to Bowel Perforation during Enema Reduction Using Diluted Contrast Medium].

A 7-kg 8-month-old boy was transferred to our institution after failed enema reduction of intussusception elsewhere. During the redo intervention using a 6-fold-diluted solution of Gastrografin with water as contrast medium, the bowel was perforated. Urgent surgical repair was planned and preoperative examination revealed serum sodium of 137 mEq x l(-1). On arrival in the operating room, the patient presented abdominal distension, drowsiness and tachypnea. His trachea was intubated and anesthesia was maintained with sevoflurane. Arterial blood examination immediately before the surgery (approximate by 80 minutes after the previous blood test) showed the following findings: pH 7.27, base excess -8.5 mEq x l(-1) and sodium 122 mEq x l(-1). Watery ascites estimated at 450 ml was evacuated upon a peritoneal incision. At termination of anesthesia, serum sodium recovered to 133 mEq x l(-1), resulting from replenishment of electrolytes and sodium bicarbonate administration. The patient became fully awake and his trachea was extubated in the operating room. Gastrografin has osmolarity of 1,900 mOsm x l(-1), containing sodium of 158 mEq x l(-1). Massive intraperitoneal accumulation of diluted Gastrografin is a rational explanation for the rapidly developed hyponatremia, which can lead to hyponatremic encephalopathy, especially in infants. Prompt surgical intervention is therefore essential for successful management of such cases.

[The most frequent electrolyte disorders in the emergency department : what must be done immediately?]. / Die häufigsten Elektrolytstörungen in der Notaufnahme : Was ist sofort zu tun?

Hyponatremia is the most common form of electrolyte disorder in the emergency room. The symptoms are unspecific and include nausea, dizziness and often falls. Typical symptoms of severe hypernatremia are vomiting, cerebral seizures, somnolence and even coma. The specific initial laboratory diagnostics include measurement of serum electrolytes, serum glucose, serum and urine osmolarity and sodium in urine. The main aim of the clinical examination is to estimate the volume status. If a patient has hypovolemia an infusion of isotonic sodium chloride solution (0.9 %) is the method of choice. If the patient is euvolemic the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or (neurotropic) drugs might be the cause. In these cases the primary measure is restriction of fluid intake. As a rapid correction of sodium levels can lead to pontine myelinolysis, the increase in sodium concentration must not be less than 10 mmol/l within the first 24 h and 18 mmol/l within the first 48 h. Clinical symptoms of hyperkalemia include neurological (e.g. muscle weakness, paresis, hyperreflexia, cramps and dysesthesia), gastrointestinal (e.g. nausea, vomiting and diarrhea) and cardiac symptoms (e.g. dysrhythmia and conductance disorders). Calcium injection stabilizes cardiac rhythm disorders immediately. For a rapid drop in potassium by shifting the potassium to the intracellular space, administration of glucose with insulin and high-dose inhalative administration of betamimetics can be used. Potassium elimination is achieved by infusion of isotonic sodium choride (0.9 %) with i.v. administration of furosemide, ion exchange resins and hemodialysis.

Wilderness Medical Society practice guidelines for treatment of exercise-associated hyponatremia: 2014 update.

Exercise-associated hyponatremia (EAH) is defined by a serum or plasma sodium concentration below the normal reference range of 135 mmol/L that occurs during or up to 24 hours after prolonged physical activity. It is reported to occur in individual physical activities or during organized endurance events conducted in austere environments in which medical care is limited and often not available, and patient evacuation to definitive care is often greatly delayed. Rapid recognition and appropriate treatment are essential in the severe form to ensure a positive outcome. Failure in this regard is a recognized cause of event-related fatality. In an effort to produce best practice guidelines for EAH in the austere environment, the Wilderness Medical Society convened an expert panel. The panel was charged with the development of evidence-based guidelines for management of EAH. Recommendations are made regarding the situations when sodium concentration can be assessed in the field and when these values are not known. These recommendations are graded on the basis of the quality of supporting evidence and balance between the benefits and risks/burdens for each parameter according to the methodology stipulated by the American College of Chest Physicians. This is an updated version of the original WMS Practice Guidelines for Treatment of Exercise-Associated Hyponatremia published in Wilderness & Environmental Medicine 2013;24(3):228-240.

Clinical practice guideline on diagnosis and treatment of hyponatraemia.

Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from subtle to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay in patients presenting with a range of conditions. Despite this, the management of patients remains problematic. The prevalence of hyponatraemia in widely different conditions and the fact that hyponatraemia is managed by clinicians with a broad variety of backgrounds have fostered diverse institution- and speciality-based approaches to diagnosis and treatment. To obtain a common and holistic view, the European Society of Intensive Care Medicine (ESICM), the European Society of Endocrinology (ESE) and the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA), represented by European Renal Best Practice (ERBP), have developed the Clinical Practice Guideline on the diagnostic approach and treatment of hyponatraemia as a joint venture of three societies representing specialists with a natural interest in hyponatraemia. In addition to a rigorous approach to methodology and evaluation, we were keen to ensure that the document focused on patient-important outcomes and included utility for clinicians involved in everyday practice.

Clinical practice guideline on diagnosis and treatment of hyponatraemia.

Hyponatraemia, defined as a serum sodium concentration <135 mmol/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. It can lead to a wide spectrum of clinical symptoms, from subtle to severe or even life threatening, and is associated with increased mortality, morbidity and length of hospital stay in patients presenting with a range of conditions. Despite this, the management of patients remains problematic. The prevalence of hyponatraemia in widely different conditions and the fact that hyponatraemia is managed by clinicians with a broad variety of backgrounds have fostered diverse institution- and speciality-based approaches to diagnosis and treatment. To obtain a common and holistic view, the European Society of Intensive Care Medicine (ESICM), the European Society of Endocrinology (ESE) and the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA), represented by European Renal Best Practice (ERBP), have developed the Clinical Practice Guideline on the diagnostic approach and treatment of hyponatraemia as a joint venture of three societies representing specialists with a natural interest in hyponatraemia. In addition to a rigorous approach to methodology and evaluation, we were keen to ensure that the document focused on patient-important outcomes and included utility for clinicians involved in everyday practice.

The incidence of postoperative hyponatremia and associated neurological sequelae in children with intracranial neoplasms.

OBJECT: Intracranial tumors are common pediatric neoplasms and account for substantial morbidity among children with cancer. Hyponatremia is a known complication of neurosurgical procedures and is associated with higher morbidity among neurosurgical patients. The authors aimed to estimate the incidence of hyponatremia, identify clinical characteristics associated with hyponatremia, and assess the association between hyponatremia and patient outcome among children undergoing surgery for intracranial tumors. METHODS: This is a retrospective cohort study of children ranging in age from 0 to 19 years who underwent an initial neurosurgical procedure for an intracranial tumor between January 2001 and February 2012. Hyponatremia was defined as serum sodium ≤ 130 mEq/L during admission. RESULTS: Hyponatremia during admission occurred in 39 (12%) of 319 patients and was associated with young age and obstructive hydrocephalus (relative risk [RR] 2.9 [95% CI 1.3-6.3]). Hyponatremic patients were frequently symptomatic; 21% had seizures and 41% had altered mental status. Hyponatremia was associated with complicated care including mechanical ventilation (RR 4.4 [95% CI 2.5-7.9]), physical therapy (RR 4 [95% CI 1.8-8.8]), supplemental nutrition (RR 5.7 [95% CI 3.3-9.8]), and infection (RR 5.7 [95% CI 3.3-9.5]). Hyponatremic patients had a 5-fold increased risk of moderate or severe disability on the basis of their Pediatric Cerebral Performance Category score at discharge (RR 5.3 [95% CI 2.9-9.8]). Obstructive hydrocephalus (adjusted odds ratio [aOR] 3.24 [95% CI 1.38-8.94]) and young age (aOR 0.92 [95% CI 0.85-0.99]) were independently associated with hyponatremia during admission. Hyponatremia was independently associated with moderate or worse disability by Pediatric Cerebral Performance Category score at discharge (aOR 6.2 [95% CI 3.0-13.03]). CONCLUSIONS: Hyponatremia was common, particularly among younger children and those with hydrocephalus. Hyponatremia was frequently symptomatic and was associated with more complicated hospital courses. Hyponatremia was independently associated with worse neurological outcome when adjusted for age and tumor factors. This study serves as an exploratory analysis identifying important risk factors for hyponatremia and associated sequelae. Further research into the causes of hyponatremia and the association with poor outcome is needed to determine if prevention and treatment of hyponatremia can improve outcomes in these children.

Wilderness Medical Society practice guidelines for treatment of exercise-associated hyponatremia.

Exercise-associated hyponatremia (EAH) typically occurs during or up to 24 hours after prolonged physical activity, and is defined by a serum or plasma sodium concentration below the normal reference range of 135 mEq/L. It is also reported to occur in individual physical activities or during organized endurance events conducted in austere environments in which medical care is limited or often not available, and patient evacuation to definitive care is often greatly delayed. Rapid recognition and appropriate treatment are essential in the severe form to ensure a positive outcome. Failure in this regard is a recognized cause of event-related fatality. In an effort to produce best practice guidelines for EAH in the austere environment, the Wilderness Medical Society convened an expert panel. The panel was charged with the development of evidence-based guidelines for management of EAH. Recommendations are made regarding the situations when sodium concentration can be assessed in the field and when these values are not known. These recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens for each parameter according to the methodology stipulated by the American College of Chest Physicians.

The frequency, cost, and clinical outcomes of hypernatremia in patients hospitalized to a comprehensive cancer center.

PURPOSE: To study the frequency of hypernatremia in hospitalized cancer patients and its impact on clinical outcomes and healthcare cost. METHODS: Cross-sectional analysis of data obtained from patients admitted to the University of Texas M. D. Anderson Cancer Center over a 3-month period in 2006. The clinical outcomes and hospital costs were compared among hypernatremics, eunatremics, and hyponatremics (serum sodium values include >147, 135-147, and <135 mEq/L, respectively). RESULTS: Of 3,446 patients with at least one serum sodium value, 51.4 % were eunatremic, 46.0 % hyponatremic, and 2.6 % hypernatremic with most of the hypernatremia (90 %) acquired during hospital stay. The multivariate hazard ratio (HR) for mortality in hypernatremic was 5-fold higher than eunatremic (HR for 90 days-5.09 (95 % CI, 3.32-7.81); p < 0·01) and over 2-fold higher than hyponatremic (HR for 90 days-2.79 (95 % CI, 1.91-4.11), p < 0.01). The length of hospital stay in hypernatremic was 2-fold higher than in hyponatremic and 4-fold higher than in eunatremic (e.g., 27 ± 22 days in hypernatremic vs. 6 ± 5 days in eunatremic; mean ± SD, p < 0.01). The hospital bill was higher for hypernatremic compared with the rest of the groups (46 % over eunatremic and 37 % over hyponatremic, p < 0.01 for both). CONCLUSIONS: Although hypernatremia was far less frequent than hyponatremia in the hospitalized cancer patients, most hypernatremia were acquired in the hospital and had substantially higher mortality, hospital stay, and hospital bills than eunatremic or even hyponatremic patients. Studies are warranted to determine whether avoidance of hypernatremia or its prompt and sustained correction improves clinical outcomes.

An elderly patient with chronic hyponatremia.

Hyponatremia is the most common electrolyte disorder. With the aging of the population and the greater propensity of the elderly to develop hyponatremia, this electrolyte disorder is of increasing importance to the practicing nephrologist. In this Attending Rounds, an illustrative patient with hyponatremia is presented. The reasons for the increased incidence and prevalence of hyponatremia in the elderly are discussed, with emphasis on the effects of aging on urinary dilution, the frequently multifactorial nature of hyponatremia in this population, and the absence of a definite cause for inappropriate and persistent vasopressin release in many such patients. The rationale for treating the hyponatremia, even when apparently asymptomatic, is discussed, with attention to cognitive function, gait, and bone structure disturbances that increase the risk for fractures. The various available treatment approaches, including water restriction, demeclocycline, loop diuretics with NaCl supplementation, urea, and vasopressin antagonists are summarized, with emphasis on the efficacy and limitations of each of these therapies.

TURP syndrome and severe hyponatremia under general anaesthesia.

Transurethral resection of prostate (TURP) syndrome is a complication characterised by symptoms changing from an asymptomatic hyponatremic state to convulsions, coma and death due to absorption of irrigation fluid during TURP. The syndrome appears to be related to the amount of fluid that enters the circulation via the blood vessels in the resection area. The first step in the course of action for therapy is to control bleeding and suspend the operation. In the case presented, we aimed to emphasise the importance of an early diagnosis and treatment of TURP syndrome in a patient that developed hyponatremia (90 mmol/l) while under general anaesthesia during a TURP procedure. In addition, multiple cystoscopic applications in the same session may facilitate development of the TURP syndrome.