Establishment of a single-center-based early prognostic scoring system for Guillain-Barré syndrome.

BACKGROUND: Previous studies have developed clinical prognostic models for Guillain-Barré syndrome including EGOS and mEGOS, they have good reliability and accuracy, but individual entries are poor. This study aims to establish a scoring system to predict the early prognosis, in order to provide additional treatment for patients with poor prognosis and shorten the length of hospital stay. METHODS: We retrospectively analyzed risk factors affecting the short-term prognosis of Guillain-Barré syndrome, and developed a scoring system for early determination of disease prognosis. Sixty two patients were divided into two groups based on the Hughes GBS disability score at discharge. Groups were compared for differences in gender, age at onset, antecedent infection, cranial nerve involvement, pulmonary infection, mechanical ventilation support, hyponatremia, hypoproteinemia, impaired fasting glucose, and peripheral blood neutrophil-to-lymphocyte ratio. Statistically significant factors were included in a multivariate logistic regression analysis, and a scoring system to predict the short-term prognosis was established based on the regression coefficients. The receiver operating characteristic curve of this scoring system was plotted, and the area under the ROC curve was calculated to assess the accuracy of the prediction model. RESULTS: Univariate analysis revealed that age at onset, antecedent infection, pneumonia, mechanical ventilation support, hypoalbuminemia, hyponatremia, impaired fasting glucose, and elevated peripheral blood neutrophil-to-lymphocyte ratio were risk factors for poor short-term prognosis. The above factors were included in the multivariate logistic regression analysis, and pneumonia, hypoalbuminemia, and hyponatremia could be used as independent predictors. The receiver operating characteristic curve was plotted with a calculated area under the ROC curve of 82.2% (95% CI 0.775-0.950, P < 0.0001). The best cut-off value for the model score was 2, with a sensitivity of 0.9091, a specificity of 0.7255, and a Youden index of 0.6346. CONCLUSION: Pneumonia, hyponatremia, and hypoalbuminemia were independent risk factors for poorer short-term prognosis in patients with Guillain-Barré syndrome. The short-term prognosis scoring system of Guillain-Barré syndrome we constructed using these variables had some predictive value, and the short-term prognosis with quantitative scores of 2 or more was worse.

Hyperfibrinogenemia and hyponatremia as predictors of perforated appendicitis in children: A retrospective cohort study.

PURPOSE: The aim of this study was to investigate the predictive value of hyperfibrinogenemia and hyponatremia for perforated appendicitis in children. METHODS: A retrospective review of 521 pediatric patients (≤ 15 years) with acute appendicitis confirmed by histopathology from January 2017 to December 2020 was performed. Patients were divided in two groups, those with non-perforated (n = 379; 73%) and perforated appendicitis (n = 142; 27%). The serum values of sodium and fibrinogen were taken before surgery. We performed the receiver operating characteristic analysis for the two biochemical markers. The sensitivity, specificity, positive and negative predictive values for perforated appendicitis in the presence of hyponatremia and hyperfibrinogenemia were calculated. RESULTS: Hyperfibrinogenemia (≥ 4.0 g/L) was found in 58.45% of perforated appendicitis and 104 of 142 (73.34%) children with perforated appendicitis had hyponatremia (≤ 135 mmol/L). The perforated appendicitis group had a higher mean fibrinogen concentration (P = 0.001). There was a statistically significant difference in mean serum sodium levels between the perforated appendicitis and non-perforated appendicitis groups (P = 0.016). Receiver operating characteristic curve analysis for fibrinogen, sodium and combination of the both markers shown the combination had the largest area under the curve in identifying children with perforated acute appendicitis (0.858) (95% CI, 0.82-0.90) compared with fibrinogen (0.815) (95% CI, 0.77-0.86) and sodium 0.818 (95% CI, 0.78-0.86) alone. Furthermore, the combination of both markers had the best positive and negative predictive value for appendix perforation compared to fibrinogen and sodium. CONCLUSION: Hyponatremia and/or hyperfibrinogenemia are excellent markers for predicting perforated appendicitis in children. We propose that plasma sodium and/or fibrinogen concentrations be utilized as a supplementary to guide individual treatment decisions in children with appendicitis, such as surgery timing and nonoperative management options.

Profound hyponatremia and dehydration: A case of cisplatin induced renal salt wasting syndrome.

Cisplatin is a well-known chemotherapeutic agent that can be associated with hyponatremia. It is known to be associated with a multitude of renal disorders including acute kidney injury with reduced glomerular filtration, Fanconi syndrome, and renal tubular acidosis, nephrogenic diabetes insipidus and renal salt wasting syndrome. We report a case of an elderly male presenting with significant recurrent hyponatremia, and prerenal azotemia. With recent exposure to cisplatin along with significant hypovolemia and urinary loss of sodium, he was diagnosed to have cisplatin induced renal salt wasting syndrome.

The differential risk of severe hyponatraemia based on the use patterns of hyponatraemia-inducing medications in older adults.

BACKGROUND: the identification and minimization of hyponatraemia-inducing medication (HIM) usage is among the effective strategies for preventing hyponatraemia. However, the differential risk of severe hyponatraemia is unknown. OBJECTIVE: to evaluate the differential risk of severe hyponatraemia associated with newly started and concurrently used HIMs in older people. DESIGN AND SETTING: a case-control study using national claims databases. METHODS: we identified patients aged >65 years with severe hyponatraemia as those hospitalised with a primary diagnosis of hyponatraemia or who had received tolvaptan or 3% NaCl. A 1:20 matched control with the same visit date was constructed. Multivariable logistic regression was performed to assess the association of newly started or concurrently used HIMs comprising 11 medication/classes with severe hyponatraemia after covariate adjustment. RESULTS: among 47,766,420 older patients, we identified 9,218 with severe hyponatraemia. After adjusting for covariates, all HIM classes were found to be significantly associated with severe hyponatraemia. Compared with persistently used HIMs, newly started HIMs increased the likelihood of severe hyponatraemia for eight classes of HIMs, with the highest increase being observed for desmopressin (adjusted odds ratio: 3.82, 95% confidence interval: 3.01-4.85). Concurrent use increased the risk of severe hyponatraemia compared to that with individually administered HIMs: thiazide-desmopressin (4.86, 3.90-6.07), medications causing the syndrome of inappropriate anti-diuretic hormone secretion (SIADH)-desmopressin (2.65, 2.25-3.11), medications causing SIADH-thiazides (1.87, 1.75-1.98) and combination among medications causing SIADH (1.36, 1.28-1.45). CONCLUSIONS: in older adults, newly started and concurrently used HIMs increased the risk of severe hyponatraemia compared with persistently and singly used HIMs.

Presentation of severe brucellosis in 5-year-old boy - challenges and results.

Brucellosis is highly contagious zoonotic bacterial disease caused by gram-negative genus. It has a wide spectrum of clinical manifestations and due to variety and nonspecificity of clinical signs the diagnostics can be very complicated. We present a clinical case of severe chronic brucellosis in a 5-years old boy with long-term course of disease and multiorgan involvement. A different complication of brucellosis including severe syndrome of inappropriate ADH secretion (SIADH) are discussed. Despite severe course of disease patient achieved significant clinical improvement due to multidisciplinary approach and optimal etiotropic and pathogenetic treatment.

Tolvaptan resistance is related with a short-term poor prognosis in patients with lung cancer and syndrome of inappropriate anti-diuresis.

Purpose: Tolvaptan (TVP), a vasopressin receptor antagonist, represents a therapeutic option in the syndrome of inappropriate anti-diuresis (SIAD). The aim of this study was to evaluate the effect of TVP to treat and solve hyponatremia in oncologic patients. Methods: 15 oncologic patients who developed SIAD have been enrolled. Patients receiving TVP belonged to group A, whereas group B was characterized by hyponatremic patients treated with hypertonic saline solutions and fluid restriction. Results: In group A, the correction of serum sodium was achieved after 3.7±2.8 days. In group B, the target levels were obtained more slowly, after 5.2±3.1 days (p: 0.01) than in group A. The hospital stay and incidence of re-hospitalization were higher in group B than in group A. In this latter, 37% of patients had hyponatremic relapses, notwithstanding the progressive increase of doses from 7.5 to 60 mg per day of TVP, revealing a complete lack of response to TVP. In these patients, a growth of tumor mass or new metastatic lesions has been revealed. Conclusion: TVP improved hyponatremia more efficiently and stably than hypertonic solutions and fluid restrictions. Positive consequences have been obtained about the rate of chemotherapeutical cycles concluded, hospital stay, rate of relapse of hyponatremia, and re-hospitalization. Our study also suggested potential prognostic information that could be deduced from TVP patients, in whom sudden and progressive hyponatremia occurred, despite TVP dosage increase. A re-staging of these patients to rule out tumor mass growth or new metastatic lesions is suggested.

Hyponatremia Demystified: Integrating Physiology to Shape Clinical Practice.

Hyponatremia is one of the most common problems encountered in clinical practice and one of the least-understood because accurate diagnosis and management require some familiarity with water homeostasis physiology, making the topic seemingly complex. The prevalence of hyponatremia depends on the nature of the population studied and the criteria used to define it. Hyponatremia is associated with poor outcomes including increased mortality and morbidity. The pathogenesis of hypotonic hyponatremia involves the accumulation of electrolyte-free water caused by either increased intake and/or decrease in kidney excretion. Plasma osmolality, urine osmolality, and urine sodium can help to differentiate among the different etiologies. Brain adaptation to plasma hypotonicity consisting of solute extrusion to mitigate further water influx into brain cells best explains the clinical manifestations of hyponatremia. Acute hyponatremia has an onset within 48 hours, commonly resulting in severe symptoms, while chronic hyponatremia develops over 48 hours and usually is pauci-symptomatic. However, the latter increases the risk of osmotic demyelination syndrome if hyponatremia is corrected rapidly; therefore, extreme caution must be exercised when correcting plasma sodium. Management strategies depend on the presence of symptoms and the cause of hyponatremia and are discussed in this review.

Age-Associated Abnormalities of Water Homeostasis.

Deficits in renal function, thirst, and responses to osmotic and volume stimulation have been repeatedly demonstrated in older populations. The lessons learned over the past six decades serve to emphasize the fragile nature of water balance characteristic of aging. Older individuals are at increased risk for disturbances of water homeostasis due to both intrinsic disease and iatrogenic causes. These disturbances have real-life clinical implications in terms of neurocognitive effects, falls, hospital readmission and need for long-term care, incidence of bone fracture, osteoporosis, and mortality.

The Nephrology Nurse Practitioner's Diagnostic Guide to Hyponatremia.

Hyponatremia affects patients in various settings. Nurse practitioners often face challenges in the evaluation and treatment of hyponatremia, due to the existence in the literature of different clinical guidelines and various schematic models. This article describes a systematic approach to diagnosing hyponatremia.

Hyponatraemia caused by transient syndrome of inappropriate antidiuresis to urinary retention.

Hyponatraemia is frequently seen in the emergency department, possibly caused by the syndrome of inappropriate antidiuresis (SIAD). We report three cases in which we believe urinary retention with bladder distention caused hyponatraemia. Laboratory findings fulfilled the criteria for SIAD, for which no cause was found. Possibly pain or sympathetic nerve system activation leads to SIAD. Brisk diuresis occurred after placement of an indwelling urinary catheter with overly correction of sodium for which treatment was necessary. Clinicians should be aware that placement of an indwelling urinary catheter may prompt brisk water diuresis and a tendency to overcorrection.

Pantoprazole associated dyspepsia hypocalcemia and hyponatremia: A disproportionality analysis in FDA adverse event reporting system (FAERS) database.

BACKGROUND AND STUDY AIM: The study was designed to detect novel Adverse Events (AEs) of pantoprazole by disproportionality analysis in the FDA (Food and Drug Administration) database of Adverse Event Reporting System (FAERS) using Data Mining Algorithms (DMAs). Pantoprazole, the most commonly over-utilized Over The Counter (OTC) medication, was selected to assess any short-term or long-term AEs. The study aimed to analyze the novel adverse events of pantoprazole using the FAERS database. MATERIALS AND METHODS: A retrospective case/non-case disproportionality analysis was performed in the FAERS database. This study was based on AEs reported to FAERS from 2006Q1-2021Q3. Openvigil 2.1 was used for data extraction. Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), and Information Component (IC) were applied to measure the disproportionality in reporting. A value of ROR-1.96SE > 1, PRR ≥ 2, and IC-2SD > 0 were considered as the threshold for a positive signal. RESULTS: A total of 1050 reports of dyspepsia, 7248 reports of hypocalcemia and 995 reports of hyponatremia were identified. A potential positive signal for dyspepsia (ROR-1.96SE = 2.231, PRR = 2.359, IC-2SD = 1.13), hypocalcemia (4.961, 5.45, 2.23) and hyponatremia (3.948, 4.179, 1.92) were identified for pantoprazole. CONCLUSION: Data mining in the FAERS database produced three potential signals associated with pantoprazole. As a result, further clinical surveillance is needed to quantify and validate potential hazards associated with pantoprazole-related adverse events.

Community-based serum chloride abnormalities predict mortality risk.

INTRODUCTION: This population-based study aimed to investigate the prognostic value of ambulatory serum chloride abnormalities, often ignored by physicians. METHODS: The study population included all non-hospitalized adult patients, insured by "Clalit" Health Services in Israel's southern district, who underwent at least 3 serum chloride tests in community-based clinics during 2005-2016. For each patient, each period with low (≤97 mmol/l), high (≥107 mmol/l) or normal chloride levels were recorded. A Cox proportional hazards model was used to estimate the mortality risk of hypochloremia and hyperchloremia periods. RESULTS: 664,253 serum chloride tests from 105,655 subjects were analyzed. During a median follow up of 10.8 years, 11,694 patients died. Hypochloremia (≤ 97 mmol/l) was independently associated with elevated all-cause mortality risk after adjusting for age, co-morbidities, hyponatremia and eGFR (HR 2.41, 95%CI 2.16-2.69, p<0.001). Crude hyperchloremia (≥107 mmol/L) was not associated with all-cause mortality (HR 1.03, 95%CI 0.98-1.09 p = 0.231); as opposed to hyperchloremia ≥108 mmol/l (HR 1.14, 95%CI 1.06-1.21 p<0.001). Secondary analysis revealed a dose-dependent elevated mortality risk for chloride levels of 105 mmol/l and below, well within the "normal" range. CONCLUSION: In the outpatient setting, hypochloremia is independently associated with an increased mortality risk. This risk is dose-dependent where the lower the chloride level, the higher is the risk.

Progression of chronic kidney disease among black patients attending a tertiary hospital in Johannesburg, South Africa.

BACKGROUND: Chronic kidney disease (CKD) is a major public health issue worldwide and is an important contributor to the overall non-communicable disease burden. Chronic kidney disease is usually asymptomatic, and insidiously and silently progresses to advanced stages in resource limited settings. METHODOLOGY: A prospective longitudinal study was carried out on black patients with CKD attending the kidney outpatient clinic at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) in South Africa, between September 2019 to March 2022. Demographic and clinical data were extracted from the ongoing continuous clinic records, as well as measurements of vital signs and interviews at baseline and at follow up. Patients provided urine and blood samples for laboratory investigations as standard of care at study entry (0) and at 24 months, and were followed up prospectively for two (2) years. Data were descriptively and inferentially entered into REDcap and analysed using STATA version 17, and multivariable logistic regression analysis was used to identify predictors of CKD progression. RESULTS: A total of 312 patients were enrolled into the study, 297 (95.2%) patients completed the study, 10 (3.2%) patients were lost to follow and 5 (1.6%) patients died during the study period. The prevalence of CKD progression was 49.5%, while that of CKD remission was 33% and CKD regression was 17.5%. For patients with CKD progression the median age at baseline was 58 (46-67) years, the median eGFR was 37 (32-51) mL/min/1.73 m2, median urine protein creatinine ratio (uPCR) was 0.038 (0.016-0.82) g/mmol and the median haemoglobin (Hb) was 13.1 (11.7-14.4) g/dl; 95.2% had hypertension, 40.1% patients had diabetes mellitus and 39.5% had both hypertension and diabetes mellitus. Almost half (48.3%) of patients with CKD progression had severely increased proteinuria and 45.6% had anaemia. Variables associated with higher odds for CKD progression after multivariable logistic regression analysis were severely increased proteinuria (OR 32.3, 95% CI 2.8-368.6, P = 0.005), moderately increased proteinuria (OR 23.3, 95% CI 2.6-230.1, P = 0.007), hypocalcaemia (OR 3.8, 95% CI 1.0-14.8, P = 0.047), hyponatraemia (OR 4.5, 95% CI 0.8-23.6, P = 0.042), anaemia (OR 2.1, 95% CI 1.0-4.3, P = 0.048), diabetes mellitus (OR 1.8, 95% CI 0.9-3.6, P = 0.047), elevated HbA1c (OR 1.8, 95% CI 1.2-2.8, P = 0.007) and current smoking (OR 2.8, 95% CI 0.9-8.6, P = 0.049). CONCLUSION: Our study identified a higher prevalence of CKD progression in a prospective longitudinal study of black patients with CKD compared with literature reports. CKD Progression was associated with proteinuria, diabetes mellitus, elevated HbA1c, anaemia, hypocalcaemia, hyponatraemia and current smoking in a cohort of black patients with CKD who had controlled hypertension and diabetes mellitus at baseline.

The combined impact of hyponatremia and hematocrit on the risk for 90-day readmission and death in patients with heart failure: dilutional hyponatremia versus depletional hyponatremia.

BACKGROUND: Hyponatremia is common in hospitalized patients with heart failure (HF) and predicts a poor prognosis after discharge. In general, hyponatremia can be divided into two types: dilutional or depletional. OBJECTIVE: Assess the impact of hyponatremia type on short-term outcomes. DESIGN: Retrospective cohort SETTINGS: Single center in China PATIENTS AND METHODS: We sorted patients by hyponatremia into two types: dilutional hyponatremia (DiH, with hematocrit <35%) and depletional hyponatremia (DeH, with hematocrit ≥35%). The Kaplan-Meier method and Cox regression analysis were used to identify the impact of hyponatremia types on the risk for 90-day readmission and death. MAIN OUTCOME MEASURES: 90-day readmission and death combined. SAMPLE SIZE: 1770 patients. RESULTS: Hyponatremia was present in 324/1770 patients with 182 cases classified as DiH versus 142 as DeH. Kaplan-Meier analyses showed a higher incidence of poor short-term outcomes in hyponatremia compared with normonatremia (log-rank P<.001), and the risk was higher in DiH than DeH although the difference was not statistically significant (log-rank P=.656). Multivariate Cox regression analyses showed that only DiH was independently associated with short-term outcomes (HR=1.34, 95%CI: 1.02-1.77, P=.038), but not DeH (HR=1.32, 95%CI: 0.97-1.80, P=.081). Analysis of the secondary endpoints showed that DiH increased the risk of readmission but not death (HR=1.36, P=.035 for readmission; HR=1.13, P=.831 for all-cause death). CONCLUSIONS: Low hematocrit, rather than high hematocrit, with hyponatremia was associated with a risk of 90-day readmission in patients with HF. LIMITATIONS: Single center, nonrandomized. CONFLICT OF INTEREST: None.

Risk factors for hyponatremia in acute exacerbation chronic obstructive pulmonary disease (AECOPD): a multicenter cross-sectional study.

BACKGROUND: Hyponatremia is an independent predictor of poor prognosis, including increased mortality and readmission, in COPD patients. Identifying modifiable etiologies of hyponatremia may help reduce adverse events in patients with AECOPD. Therefore, the aim of this study was to explore the risk factors and underlying etiologies of hyponatremia in AECOPD patients. METHODS: A total of 586 AECOPD patients were enrolled in this multicenter cross-sectional study. Finally, 323 had normonatremia, and 90 had hyponatremia. Demographics, underlying diseases, comorbidities, symptoms, and laboratory data were collected. The least absolute shrinkage and selection operator (LASSO) regression was used to select potential risk factors, which were substituted into binary logistic regression to identify independent risk factors. Nomogram was built to visualize and validate binary logistics regression model. RESULTS: Nine potential hyponatremia-associated variables were selected by LASSO regression. Subsequently, a binary logistic regression model identified that smoking status, rate of community-acquired pneumonia (CAP), anion gap (AG), erythrocyte sedimentation rate (ESR), and serum magnesium (Mg2+) were independent variables of hyponatremia in AECOPD patients. The AUC of ROC curve of nomogram was 0.756. The DCA curve revealed that the nomogram could yielded more clinical benefits if the threshold was between 10% and 52%. CONCLUSIONS: Collectively, our results showed that smoking status, CAP, AG, ESR, and serum Mg2+ were independently associated with hyponatremia in AECOPD patients. Then, these findings indicate that pneumonia, metabolic acidosis, and hypomagnesemia were the underlying etiologies of hyponatremia in AECOPD patients. However, their internal connections need further exploration.

Predictive correction of serum sodium concentration with formulas derived from the Edelman equation in patients with severe hyponatremia.

Severe hyponatremia can cause life-threatening cerebral edema. Treatment comprises rapid elevation of serum sodium concentration; however, overcorrection can result in osmotic demyelination. This study investigated potential factors, including predictive correction based on the Edelman equation, associated with appropriate correction in 221 patients with a serum sodium concentration ≤ 120 mEq/L who were admitted to a hospital in Nagoya, Japan. Appropriate correction was defined as an elevation in serum sodium concentration in the range of 4-10 mEq/L in the first 24 h and within 18 mEq/L in the first 48 h after the start of the correction. Appropriate corrections were made in 132 (59.7%) of the 221 patients. Multivariate analysis revealed that predictive correction with an infusate and fluid loss formula derived from the Edelman equation was associated with appropriate correction of serum sodium concentration (adjusted odds ratio, 7.84; 95% confidence interval, 2.97-20.64). Relative without its use, the predictive equation results in a lower proportion of undercorrection (14.3% vs. 48.0%, respectively) and overcorrection (1.0% vs. 12.2%, respectively). These results suggest that predictive correction of serum sodium concentrations using the formula derived from the Edelman equation can play an essential role in the appropriate management of patients with severe hyponatremia.

Akutt binyrebarksvikt hos et barn.

BACKGROUND: Primary adrenal insufficiency is relatively common in children, but primary presentation with acute shock/adrenal crisis is rare. Congenital adrenal hyperplasia (CAH) is the most common cause in children and is part of the newborn diagnostic screening programme in Norway. CASE PRESENTATION: We admitted a schoolgirl with a history of nausea and morning sickness for the previous three weeks. Shortly after admission she was somnolent, tachycardic (148 beats per minute) and pale. After initial administration of a 500 ml bolus of Ringers acetate she was transmitted to the ICU. She responded poorly on IV fluids and epinephrine alone. Arterial blood gas test showed metabolic acidosis with hyponatraemia 122 mmol/L, hyperkalaemia 5,6 mmol/L and hypoglycaemia 2,2 mmol/L, and adrenal insufficiency was suspected. She responded well to treatment with hydrocortisone and was transferred to a university hospital for further examination and diagnosis. INTERPRETATION: Acute adrenal crisis is a rare primary presentation of adrenal insufficiency, especially in the paediatric population. It is an important differential diagnosis of shock and has high morbidity and mortality.

Intractable hyponatremia complicated by a reset osmostat: a case report.

BACKGROUND: Hyponatremia associated with a low serum osmolality is a common and confounding electrolyte disorder. Correcting hyponatremia is also complicated, especially in the setting of chronic hyponatremia. Here, we provide a rational approach to accurately detecting and safely treating acute on chronic euvolemic hyponatremia in the setting of acute polydipsia with a chronic reset osmostat. CASE PRESENTATION: A 71-year-old hispanic gentleman with chronic hyponatremia presented with hiccups, polydipsia, and a serum sodium concentration of 120 mEq/L associated with diffuse weakness, inattentiveness, and suicidal ideation. Symptomatic euvolemic hyponatremia warranted hypertonic saline treatment in the acute phase and water restriction in the chronic phase. Both interventions resulted in improvement in symptoms and/or the serum sodium concentration, but to a serum sodium level that persistently remained below the normal range. Remarkably, the urine osmolality appropriately fell when the serum sodium concentration fell below 126 mEq/L. Also remarkable was the appropriate increase in urine osmolality when the serum sodium concentration exceeded 126 mEq/L. The preservation of both concentration and dilution, albeit at a lower-than-normal serum osmolality, shows that the osmostat regulating antidiuretic hormone release had been "reset." Both physiologic and pharmacologic resetting of the osmostat are discussed. CONCLUSIONS: Preservation of urinary concentrating and diluting ability at a lower-than-normal serum sodium concentration, especially in the setting of chronic hyponatremia, is diagnostic of a reset osmostat. The presence of a reset osmostat often confounds the treatment of concomitant acute hyponatremia. Early recognition of a reset osmostat avoids the need to normalize serum sodium concentration, expedites hospital discharge, and limits potential harm from overcorrecting acute hyponatremia.