High Incidence Of Hyponatremia Research Articles

The efficacy and safety of isotonic and hypotonic fluids in intravenous maintenance fluid therapy in term newborns: national multicenter observational "neofluid" study.

The objective of this study was to evaluate the efficacy and safety of isotonic and hypotonic intravenous fluids in maintenance fluid therapy for term infants. This was a multi-centre, prospective, observational study conducted in 21 participating centres from December 30, 2020, to June 30, 2023. The study included term newborns requiring parenteral fluid therapy for maintenance (NCT04781361). The fluid treatment was divided into two groups based on the concentration of sodium in the parenteral fluid, designated as hypotonic (NaCl <130 mmol/L) and isotonic (NaCl = 130-154 mmol/L). The primary outcomes were the change in mean plasma sodium (pNa) levels per hour (∆pNa mmol/L/h), the incidence of hyponatremia (pNa <135 mmol/L) and hypernatremia (pNa >145 mmol/L), and the occurrence of clinically significant changes in sodium levels (∆pNa >0.5 mmol/L/h). A total of 420 patients from 21 centers were included. The ∆pNa was negative in the hypotonic fluid group and positive in the isotonic fluid group, with a significant difference between the groups [respectively -0.07 ± 0.03 (95% CI: -0.13 to -0.02); 0.04 ± 0.03 (95%CI: -0.02 to 0.09), p = 0.04]. There was no difference between the groups in terms of the development of hypernatremia or a clinically meaningful pNa increase. The hypotonic fluid group had a higher incidence of hyponatremia and a clinically meaningful sodium decrease compared to the isotonic fluid group [7.9% vs. 1.2% (OR:6.5, p:0.03)] and [12.2% vs.4.2% (OR:2.9, p = 0.03)]. Contrary to current understanding, this large-scale study is the first to demonstrate that the use of hypotonic fluids in maintenance fluid therapy for newborns poses a risk of hyponatremia development, whereas isotonic fluid therapy appears safe.

Frequency of Hyponatremia &amp; Hypokalemia in Children under 5 Years with Acute Diarrhoea

Background: Acute diarrhea poses a significant health threat to children globally, often leading to severe morbidity and mortality, particularly in developing countries. Electrolyte imbalances, including hyponatremia and hypokalemia, are common complications associated with acute diarrhea, further exacerbating the risk of adverse outcomes. Objective: This study aimed to evaluate the frequency of sodium and potassium abnormalities, specifically hyponatremia and hypokalemia, in children presenting with acute diarrhea. Methodology: A prospective cohort study was conducted at the Pediatric department of a tertiary hospital from July 2022 to June 2023. A total of 130 pediatric patients aged up to 5 years, presenting with acute diarrhea, were included in the study. Clinical examinations were conducted, and demographic data, including age, gender, residence, and socioeconomic status, were recorded. Serum sodium and potassium levels were determined from venous blood samples, and hyponatremia and hypokalemia were defined as sodium levels &lt;130 mmol/l and potassium levels &lt;3.5 mmol/l, respectively. Statistical analysis was performed using SPSS 24.0. Results: The mean age of the patients was 2.38 years, with a disease duration of 3.54 days. Male patients accounted for 60% of the cohort, and urban residency was predominant (55%). Clinical symptoms included loose motion (100%), abdominal pain (70%), fever (35%), vomiting (31%), and lethargy (27%). Hyponatremia was observed in 30% of patients, while hypokalemia was present in 40% of cases. Conclusion: Sodium and potassium imbalances are prevalent among children with acute diarrhea, highlighting the need for vigilant monitoring and appropriate management strategies to prevent adverse outcomes. The high incidence of hyponatremia and hypokalemia underscores the importance of early recognition and intervention in pediatric patients presenting with acute diarrhea.

The diagnosis and management of dehydration in children with wasting or nutritional edema: A systematic review.

Dehydration is a major cause of death among children with wasting and diarrhea. We reviewed the evidence for the identification and management of dehydration among these children. Two systematic reviews were conducted to assess 1) the diagnostic performance of clinical signs or algorithms intended to measure dehydration, and 2) the efficacy and safety of low-osmolarity ORS versus ReSoMal on mortality, treatment failure, time to full rehydration, and electrolyte disturbances (management review). We searched PubMed/Medline, Embase, and Global Index Medicus for studies enrolling children 0-60 months old with wasting and diarrhea. The diagnostic review included four studies. Two studies found the Integrated Management of Childhood Illness (IMCI) and the Dehydration: Assessing Kids Accurately (DHAKA) algorithms had similar diagnostic performance, but both algorithms had high false positive rates for moderate (41% and 35%, respectively) and severe (76% and 82%, respectively) dehydration. One further IMCI algorithm study found a 23% false positive rate for moderate dehydration. The management review included six trials. One trial directly compared low osmolarity ORS to ReSoMal and found no difference in treatment failure rates, although ReSoMal had a shorter duration of treatment (16.1 vs. 19.6 hours, p = 0.036) and a higher incidence of hyponatremia. Both fluids failed to correct a substantial number of hypokalemia cases across studies. In conclusion, the IMCI dehydration assessment has comparable performance to other algorithms among wasted children. Low osmolarity ORS may be an alternative to ReSoMal for children with severe wasting, but might require additional potassium to combat hypokalemia.

Hyponatremia in Melioidosis: Analysis of 10-year Data from a Hospital-Based Registry.

Introduction:Hyponatremia is a frequent finding in hospitalized patients and is associated with poor clinical outcomes. While hyponatremia is known to commonly occur in certain infections, its association with melioidosis has not been studied previously. We studied incidence and impact of hyponatremia on clinical outcomes in melioidosis.Methods:This was a retrospective analysis of a single-center hospital registry of culture-positive patients with melioidosis hospitalized during a 10-year period (January 01, 2010, through January 31, 2021). Hyponatremia was defined as serum sodium of <135 mmol/L, and severe hyponatremia as serum sodium <120 mmol/L. The association of hyponatremia with in-hospital mortality, need for intensive care unit (ICU) stay and mechanical ventilation was studied.Results:Of 201 patients with melioidosis, 169 (84.1%) had hyponatremia, with severe hyponatremia in 35 (17.4%) patients. Older age (adjusted odds ratios [OR] 1.03, 95% confidence intervals [CI]: 1.00–1.06; P = 0.049) and acute kidney injury (AKI) (adjusted OR 3.30, 95% CI: 1.19-9.19; P = 0.02) were independently associated with hyponatremia. Twenty-two patients had been evaluated for cause of hyponatremia and of these, 11 (50%) had syndrome of inappropriate antidiuresis. Severe hyponatremia was associated with in-hospital mortality (adjusted OR 3.75, 95% CI: 1.37–10.27; P = 0.01), need for ICU stay (adjusted OR 7.04, 95% CI: 2.88–17.19; P < 0.001) and mechanical ventilation (adjusted OR 3.99, 95% CI: 1.54–10.32; P = 0.004).Conclusion:Hyponatremia occurs in 84.1% of hospitalized patients with melioidosis. Older age and AKI are associated with a higher incidence of hyponatremia. The presence of severe hyponatremia is an independent predictor of in-hospital mortality, need for mechanical ventilation and ICU stay.

High Incidence of Hyponatremia in Patients Operated for Nonsellar/Suprasellar Supratentorial Tumors—A Prospective Observational Study

Abstract Background The incidence of hyponatremia is high in supratentorial tumors. However, most studies of supratentorial tumors have included patients with sellar/suprasellar tumors. It is common knowledge that sellar tumors have higher incidence and severity of hyponatremia. Incidence of hyponatremia is not known if we exclude sellar/suprasellar tumors. Therefore, this study was designed to evaluate the incidence of hyponatremia in supratentorial tumors after excluding sellar/suprasellar tumors. Methods After institutional ethics committee approval and written informed consent, adult patients with supratentorial tumors (nonsellar/suprasellar) were recruited, and data were collected prospectively. In all patients, serum electrolytes were measured every 2 to 3 days. Hyponatremia was defined as serum sodium of &lt;135 mEq/L. All the patients were followed up till death or discharge from the hospital. Results A total of 61 patients’ data were analyzed. There were 31 male and 30 female patients with an average age of 44 years. There were 23 meningiomas, 36 gliomas, and 2 other tumors. Forty patients (66%) developed hyponatremia during hospital stay. There were 29 mild cases (serum sodium 131–134 mEq/L), 7 were moderate (serum sodium 126–130 mEq/L), and 4 were severe (serum sodium &lt;126 mEq/L). Three hyponatremic meningioma patients died, of which two had mild hyponatremia and one had severe hyponatremia. Duration of hospital stay was longer in hyponatremic patients. Conclusion The incidence of hyponatremia is high in supratentorial tumor patients after excluding sellar/suprasellar lesions. In the majority of patients, the disturbance is mild. Hyponatremic patients has a longer hospital stay and higher mortality.

Improving Isotonic Maintenance Intravenous Fluid Use in the Emergency Department.

Maintenance intravenous fluids (IVFs) are commonly used in the hospital setting. Hypotonic IVFs are commonly used in pediatrics despite concerns about high incidence of hyponatremia. We aimed to increase isotonic maintenance IVF use in children admitted from the emergency department (ED) from a baseline of 20% in 2018 to >80% by December 2019. We included patients aged 28 days to 18 years receiving maintenance IVFs (rate >10 mL/hour) at the time of admission. Patients with active chronic medical problems were excluded. Interventions included institutional discussions on isotonic IVF based on literature review, education on isotonic IVF use per the American Academy of Pediatrics guideline (isotonic IVF use with appropriate potassium chloride and dextrose), electronic medical record changes to encourage isotonic IVF use, and group practice review with individual physician audit and feedback. Balancing measures were the frequency of serum electrolyte checks within 24 hours of ED admission and occurrence of hypernatremia. Data were analyzed by using statistical process control charts. Isotonic maintenance IVF use improved, with special cause observed twice; the 80% goal was met and sustained. No difference was noted in serum electrolyte checks within 24 hours of admission (P > .05). There was no increase in occurrence of hypernatremia among patients who received isotonic IVF compared with those who received hypotonic IVF (P > .05). The application of improvement methods resulted in improved isotonic IVF use in ED patients admitted to the inpatient setting. Institutional readiness for change at the time of the American Academy of Pediatrics guideline release and hardwiring of preferred fluids via electronic medical record changes were critical to success.

Hyponatremia: Is it related to the seasons?

BackgroundHyponatremia is a common electrolyte disorder in inpatients related to morbidity and mortality. In this study, we aimed to examine whether there is a relationship between the incidence of hyponatremia and the seasons among the patients hospitalized in our nephrology department.MethodsThe inpatients in our Nephrology Department between 2012 and 2015 were retrospectively analyzed. The patients with serum sodium levels below 135 mmol/L were included in the study. Hyponatremia incidence was calculated as the proportion of inpatients with low sodium levels in a season to the total number of inpatients in the same season.ResultsOut of 1950 inpatients in four years, 509 were found to have hyponatremia (26.1%). The mean serum sodium level of the patients was 129.7±4.7 mmol/L. Hyponatremia incidences in autumn, winter, spring, and summer were found to be 28.7%, 15.4%, 20.4%, and 36.6%, respectively. Upon comparing the incidence of hyponatremia in patients hospitalized in winter and summer seasons, there was a significantly higher incidence of hyponatremia in summer (p<0.001). We found a positive correlation between hyponatremia incidence and temperature (r=0.867, p=0.001). However, there was a negative correlation between hyponatremia incidence and relative humidity (r=-0.735, p=0.001).ConclusionsThe highest hyponatremia incidence was observed in summer in a four-year period. Loss of sodium by perspiration, along with increased temperature and/or excessive hypotonic fluid intake, might contribute to the development of hyponatremia.

Clinical characteristics of hospitalized patients with 2019 novel coronavirus disease indicate potential proximal tubular dysfunction.

Clinical characteristics of hospitalized patients with 2019 novel coronavirus disease indicate potential proximal tubular dysfunction.

Managing hyponatremia.

Despite the high incidence of hyponatremia, the correct approach to management, particularly in patients with severe hyponatremia (serum sodium of 120 mEq/L or less), is controversial. This article reviews two major consensus guidelines and recent studies that can help clinicians make evidence-based treatment decisions and reduce patient risk for iatrogenic osmotic demyelination from overly aggressive treatment.

Clinical Practice Guideline: Maintenance Intravenous Fluids in Children.

Maintenance intravenous fluids (IVFs) are used to provide critical supportive care for children who are acutely ill. IVFs are required if sufficient fluids cannot be provided by using enteral administration for reasons such as gastrointestinal illness, respiratory compromise, neurologic impairment, a perioperative state, or being moribund from an acute or chronic illness. Despite the common use of maintenance IVFs, there is high variability in fluid prescribing practices and a lack of guidelines for fluid composition administration and electrolyte monitoring. The administration of hypotonic IVFs has been the standard in pediatrics. Concerns have been raised that this approach results in a high incidence of hyponatremia and that isotonic IVFs could prevent the development of hyponatremia. Our goal in this guideline is to provide an evidence-based approach for choosing the tonicity of maintenance IVFs in most patients from 28 days to 18 years of age who require maintenance IVFs. This guideline applies to children in surgical (postoperative) and medical acute-care settings, including critical care and the general inpatient ward. Patients with neurosurgical disorders, congenital or acquired cardiac disease, hepatic disease, cancer, renal dysfunction, diabetes insipidus, voluminous watery diarrhea, or severe burns; neonates who are younger than 28 days old or in the NICU; and adolescents older than 18 years old are excluded. We specifically address the tonicity of maintenance IVFs in children.The Key Action Statement of the subcommittee is as follows:1A: The American Academy of Pediatrics recommends that patients 28 days to 18 years of age requiring maintenance IVFs should receive isotonic solutions with appropriate potassium chloride and dextrose because they significantly decrease the risk of developing hyponatremia (evidence quality: A; recommendation strength: strong).

Desmopressin administration and rebleeding in subarachnoid hemorrhage: analysis of an observational prospective database.

Rebleeding remains a frequent and catastrophic event leading to poor outcome after subarachnoid hemorrhage (SAH). Reduced platelet function after the initial bleed is associated with higher risk of early rebleeding. Desmopressin (DDAVP) is a well-known hemostatic agent, and recent guidelines already suggest its use in individuals exposed to antiplatelet drugs. The authors hypothesized that DDAVP administration in patients with SAH at admission would be associated with lower risks of rebleeding. The authors performed an observational cohort study of patients enrolled in the Columbia University SAH Outcome Project between August 1996 and July 2015. The authors compared the rate of rebleeding between patients who were and those who were not treated with DDAVP. After adjustment for known predictors, logistic regression was used to measure the association between treatment with DDAVP and risks of rebleeding. Among 1639 patients with SAH, 12% were treated with DDAVP. The main indication for treatment was suspected exposure to an antiplatelet agent. The overall incidence of rebleeding was 9% (1% among patients treated with DDAVP compared with 8% among those not treated). After adjustment for antiplatelet use and known predictors, treatment with DDAVP was associated with a 45% reduction in the risks of rebleeding (adjusted OR 0.55, 95% CI 0.27-0.97). DDAVP was associated with a higher incidence of hyponatremia but not with thrombotic events or delayed cerebral ischemia. Treatment with DDAVP was associated with a lower risk of rebleeding among patients with SAH. These findings support further study of DDAVP as first-line therapy for medical hemostasis in patients with SAH.

High incidence of hyponatremia in trained rowers during a four-week training camp

High incidence of hyponatremia in trained rowers during a four-week training camp

The effect of the implementation of therapeutic hypothermia on fluid balance and incidence of hyponatremia in neonates with moderate or severe hypoxic-ischaemic encephalopathy

To investigate the effect of the therapeutic hypothermia (TH), used in infants with moderate or severe hypoxic-ischaemic encephalopathy (HIE), on fluid balance and incidence of hyponatremia. Retrospective cohort study of moderate and severe HIE infants before (pre) and after (post) TH implementation. Daily fluid and electrolytes intake/output were collected from the medical records of each patient from day 1 to day 4 of life. Hyponatremia was defined as sodium <130mEq/L. A total of 67 infants were studied: pre-TH=29 and post-TH=38. Infants in the post-TH group had greater weight gain [140g (62, 227) vs. 10g (-100, 105) p<0.001] and lower serum sodium (130.9±4.5mmol/L vs. 133.4±5.7, p=0.008). The incidence of hyponatremia increased from 48 to 76% (p=0.02). In our centre, the implementation of TH was followed by an increased fluid retention and higher incidence of hyponatremia. Centres adopting TH should have clear guidelines for fluid and electrolyte management.

Ecstacy-associated hyponatremia: why are women at risk?

Hyponatremia, serum sodium <135 mEq/L, is the most common electrolyte abnormality affecting ∼30% of hospitalized patients [1]. An infrequent yet serious complication of hyponatremia is hyponatremic encephalopathy. Hyponatremia can result in an influx of water to the intracellular space. This results in cellular swelling that can lead to cerebral edema and encephalopathy. Patients at highest risk of developing hyponatremic encephalopathy in the hospital setting are postoperative patients and patients with SIADH receiving hypotonic fluids [2]. Hyponatremic encephalopathy in the outpatient setting is usually seen as a complication due to medications such as thiazide diuretics or SSRIs, or can result from exerciseassociated hyponatremia or psychogenic polydypsia [3]. A significant risk factor for developing hyponatremic encephalopathy is female gender, with the majority of cases of death or permanent neurological injury from hyponatremic encephalopathy reported in females [4]. An increasingly common cause of hyponatremic encephalopathy in the outpatient setting is use of the recreational drug ecstasy (3,4-methylenedioxymethamphetamine [MDMA]) [5]. In this issue of NDT, van Dijken et al. [6] report on the high incidence of hyponatremia in females using ecstasy. Ecstasy is an illegal synthetic amphetamine that was initially developed as an appetite suppressant but never used for this purpose. It first emerged as a recreational drug in the 1980s popular with young adults at night club parties referred to as ‘rave parties’ [7]. A rave is typically a commercially arranged elaborate all-night dance party that combines electronic music played by disc jockeys with a laser light show. Rave parties are extremely popular in North America and Europe, with thousands of people in attendance at rave events. An annual New Year’s Eve rave party in Los Angeles is reported to have almost 50 000 attendants [8]. Ecstasy is frequently taken on such occasions for its mood-enhancement properties. Users experience feelings such as euphoria, increased empathy and sociability, happiness and a sense of well-being, and increased energy [9]. Ecstasy exerts its effect by the release of neuroactive compounds in the central nervous system, including serotonin, dopamine and norepinephrine [10]. With the rise in popularity of ecstasy, medical complications began to be reported including hyponatremia, non-traumatic rhabdomyolysis, seizures, acute kidney injury, hyperthermia, cardiac tachyarrhythmia and sudden death, to name a few [5, 11, 12]. Ecstasy is believed to be the third most commonly used illicit drug, following marijuana and amphetamines, and ahead of cocaine, with an estimated consumption of over 28 million tablets yearly [7]. Emergency medical services are frequently on site at large, commercially organized rave parties [8]. One of the most serious medical complications associated with ecstasy use is hyponatremic encephalopathy [11]. There are over 25 reports of ecstasy-associated hyponatremic encephalopathy in the literature, and over half of them are fatalities. Almost all cases are reported in young females between the ages of 15 and 30 with a serum sodium of ≤130 following the ingestion of just one dose of ecstasy [5]. Symptoms typically develop within 2–12 h of ecstasy ingestion. Presenting symptoms are headache, nausea and vomiting followed by altered mental status, coma, seizure, cardio respiratory arrest, brainstem herniation and death [5]. A common yet frequently unrecognized presenting feature in these patients is neurogenic pulmonary edema, also referred to as Ayus–Arieff syndrome (Figure 1). This complication was first reported in females with post-operative and exercise-associated hyponatremia [11, 13, 14]. This is a particularly dangerous complication as hypoxia impairs brain IN F O C U S

Isotonic versus hypotonic fluid supplementation in term neonates with severe hyperbilirubinemia – a double‐blind, randomized, controlled trial

To compare the incidence of hyponatremia in full-term neonates with severe hyperbilirubinemia, receiving intravenous fluid supplementation with 0.2% saline in 5% dextrose versus 0.9% saline in 5% dextrose, to prevent blood exchange transfusion (BET). In this double-blind, randomized, controlled trial, full-term newborns (≥37 weeks), appropriate for gestational age, with severe non-haemolytic hyperbilirubinemia (serum bilirubin ≥ 20 mg/dL) were enrolled. Eligible neonates were randomized to receive either 0.2% saline in 5% dextrose (hypotonic fluid group) or 0.9% saline in 5% dextrose (isotonic fluid group) over 8 hrs, in addition to phototherapy. The primary outcome was proportion of neonates developing hyponatremia (serum Na < 135 mmol/L) after 8 h. Forty-two neonates were analysed in each group. Proportion of neonates developing hyponatremia after 8 h was higher in hypotonic fluid group as compared to isotonic fluid group (48.8% vs. 10.5%, p < 0.001). However, a larger proportion in isotonic fluid group developed hypernatremia (39.5% vs. 12.2%, p < 0.001). The rate of BET was similar in both groups. In full-term neonates with severe hyperbilirubinemia, administration of hypotonic fluid to prevent BET was associated with a higher incidence of hyponatremia while isotonic fluid was associated with an increased incidence of hypernatremia.

Improving intravenous fluid therapy in children with gastroenteritis

Gastroenteritis is one of the most common medical conditions seen by pediatricians. The standard approach to intravenous fluid therapy for these children has been to administer a 0.9% sodium chloride (NaCl) bolus followed by a hypotonic solution ranging from 0.2-0.45% NaCl to replace the remaining deficit plus maintenance. We have questioned the safety of this approach as there have been reports of death or permanent neurologic impairment from hyponatremic encephalopathy. Hanna and Saberi (Pediatr Nephrol. doi: 10.1007/s00467-009-1428-y ) found the incidence of hospital-acquired hyponatremia (sodium < 135 mEq/L) to be 18.5% for patients presenting with isonatremic dehydration from gastroenteritis. This confirms that the current approach of using hypotonic fluids results in a high incidence of hyponatremia. Hypotonic fluids are not appropriate for rehydration in patients with gastroenteritis as it is a state of arginine vasopressin (AVP) excess due to both hemodynamic stimuli from volume depletion and non-hemodynamic stimuli such as nausea and vomiting. Free water will be retained until the volume deficit is corrected and the hemodynamic stimulus for AVP production abates. A safer and more effective approach is the administration of 0.9% NaCl in a continuous infusion following bolus therapy. 0.9% NaCl not only serves as prophylaxis against hyponatremia, but it is superior to hypotonic fluids as an extracellular volume expander and corrects the volume deficit more rapidly.

Improved Care and Growth Outcomes by Using Hybrid Humidified Incubators in Very Preterm Infants

To identify changes in temperature, fluid and electrolyte management, growth, and short-term outcome in extremely low birth weight (ELBW) infants nursed in humidified hybrid incubators (HI group) compared with a cohort of patients cared for in nonhumidified conventional incubators (CI group). Body temperature (BT), fluid and electrolyte balance, and growth velocity (GV) were collected retrospectively on 182 ELBW infants. The CI group included ELBW infants cared for with radiant warmers followed by an incubator without humidity. The HI group included ELBW infants cared for in the radiant warmer mode in a Giraffe OmniBed, followed by the incubator mode using high humidity. The CI group included more multiple births (50.6%) than the HI group (35.8%; P < .05), but there was no difference in demographic characteristics. BT was similar during the first week. The HI group had less fluid intake, urine output, and insensible water loss, less maximum weight loss, and a lower incidence of hypernatremia during the first week than did the CI group (P < .05). The HI group also had a lower frequency of electrolyte sampling and packed red cell transfusion (P < .05), a higher incidence of hyponatremia on postnatal day 1 than the CI group (P < .05), and a higher GV than the CI group (15.2 +/- 5.0 vs 13.5 +/- 4.8 g/kg per day), especially among those with a birth weight of <or=749 g (P < .01). There was no difference in sepsis, necrotizing enterocolitis, intraventricular hemorrhage, and all bronchopulmonary dysplasia (BPD), but there was a decreased incidence of severe BPD (5.1% [HI] vs 16.4% [CI]; P < .05) and duration of assisted ventilation in the HI group compared with the CI group (15.5 +/- 2.1 vs 19.6 +/- 2.4 days, respectively; P = .068). Use of a humidified hybrid incubator improved care for ELBW infants by making it possible to decrease fluid intake, improve electrolyte balance, and enhance GV without a disturbance of BT compared with conventional care. By adjusting fluid intake when using these devices, benefits may be enhanced and the risk of BPD and severe BPD may be reduced.

A review on hyponatremia associated with SSRIs, reboxetine and venlafaxine

Hyponatremia, defined as serum sodium below 135 mmol/l, is a potentially life-threatening condition and was shown to be more frequent in elderly and psychiatric patients. In the last years numerous case reports on SSRI- and venlafaxine-induced hyponatremia were published indicating a higher incidence than previously thought. Only few studies have been performed and the incidence reported varies widely from 4.6/1000 people to 25%. It is still unclear if any single SSRI shows a higher incidence of hyponatremia than the others. Some data suggest that venlafaxine may have a stronger association to hyponatremia than SSRIs. Risk factors include age, female sex, low body mass index, severe physical illness, history of former hyponatremia and co-medications known to induce hyponatremia, especially thiazide diuretics. Symptoms of hyponatremia are usually neuropsychiatric (e.g. restlessness, lethargy, cognitive impairment), and any worsening in psychiatric symptoms in patients with a corresponding risk-profile receiving SSRIs or venlafaxine should give cause to check serum electrolytes. Usually SSRI-induced hyponatremia occurs within approximately 30 days and is reported to improve after withdrawal of the drug. Further controlled studies to confirm the true incidence of hyponatremia due to SSRI or venlafaxine and to define predictors more precisely are needed.

High incidence of hyponatremia in patients with ruptured anterior communicating artery aneurysms

We studied the incidence and timing of hyponatremia (Na < 135 mEq l~1) after subarachnoid hemorrhage (SAH) with special reference to ruptured anterior communicating artery (A-com) aneurysms. Hunt and Kosnik (HK) grading, symptomatic vasospasm in A-com aneurysm, and hydrocephalus were analyzed for connections to hyponatremia in 55 patients with ruptured A-com aneurysms, 65 with ruptured internal cerebral artery (ICA) aneurysms, and 49 with ruptured middle cerebral artery (MCA) aneurysms. Hyponatremia occurred in 28 (51%) of 55 patients with A-com aneurysms and in nine (18%) of 49 patients with MCA aneurysms. Severe hyponatremia (Na < 130 mEq-1) occurred in 16 patients (29%) in the A-com group, four patients (6%) in the ICA group, and three patients (6%) in the MCA group. The A-com aneurysm group had a significantly higher incidence of mild hyponatremia (p < 0.01) and severe hyponatremia (p< 0.001) than other groups. Among A-com cases, hyponatremia occurred significantly more often in HK grade III and IV cases (p < 0.05), in cases with vasospasm (p < 0.001), and in cases with hydrocephalus (p < 0.01). Respective days of onset for symptomatic vasospasm and for hyponatremia were day 7.6 ±4.4 and day 10.6± 5.8 following SAH, representing a 3-day delay for hyponatremia (p<0.05). In most patients hyponatremia resolved within 28 days following SAH. Hyponatremia occurred more often with A-com aneurysms, possibly because of vasospasm around the A-com or hydrocephalus causing hypothalamic dysfunction. Since hypervolemic therapy can cause hyponatremia, particularly careful observation is required during such therapy in patients with A-com aneurysm. [Neurol Res 2000; 22: 151-155

Late hyponatremia in very low birthweight infants. (less than 1.3 kilograms).

Late hyponatremia (plasma Na+ less than 130 mEq/liter) occurred frequently (on 54 of 159 occasions) in 46 very low virthweight (VLBW) infants (less than 1.3 kg at birth) between 2 and 6 weeks of age while receiving a sodium intake of less than or equal to 2 mEg/kg/24 hr. To elucidate possible pathogenetic mechanisms five groups of such infants were studied while receiving a commercially available formula reconstituted to give two different volumes and two different Na+ concentrations. Sodium intake in the nonsupplemented (NS) infants (n = 23) was less than 2 mEq/kg/24 hr. Supplemented (S) infants (n = 16) received approximately 3 mEq Na+/kg/24 hr. A further group of seven infants given a high volume (200 ml/kg/24 hr), high caloric (100 cal/dl) formula and Na+ supplementation (to 3 mEq/kg/24 hr) was also included. Infants were studied from age 14 days until they weighed 1.80 +/- 0.05 kg at a mean age of 47 days. At the time of start of the study, 6 of 20 NS and 6 of 19 S infants were hyponatremic. After supplementation only two episodes of hyponatremia occurred in S infants, both during the first study week, whereas the high incidence of hyponatremia in NS infants period. During baseline urine collections all infants excreted between 80 and 100 ml/kg/24 hr urine, but those receiving 150 ml/kg/24 hr formula decreased their urinary output rapidly to 50 ml/kg/24 hr, whereas infants receiving high volume feeds (200 ml/kg/24 hr) did not decrease their urinary output until the third balance at an average age of 45 days. All infants excreted between 1.0 and 1.2 mEq/kg/24 hr of sodium in their urine during the initial collection. Nonsupplemented infants reduced their urinary Na+ excretion more rapidly than supplemented babies (NS: from 1.03 to 0.55 mEq/kg/24 hr, first vs second balance; S: from 1.00 to 0.80 mEq/kg/24 hr, first vs third balance). Mean potassium excretion remained unchanged in NS and S infants during the study period and was not affected by the volume or caloric content of the formula. Extracellular volume (ECV) and total body water (TBW) were measure serially, and there were no differences between S and NS infants in the distribution of body water. The percentage of TBW and ECV decreased in all groups with increasing postnatal age.