Hyponatraemia and the inappropriate ADH syndrome in pneumonia

Fluid and electrolyte pathophysiology in common febrile illness in children and the implications for clinical management

Achieving fluid homeostasis and the management of fluid and electrolyte complications are constants in the treatment of seriously ill children worldwide. Consensus on the most appropriate fluid strategy for unwell children has been difficult to achieve and has evolved over the last two decades, most notably in high-income countries where adverse events relating to poor fluid management were identified more readily, and official robust inquiries were possible. However, this has not been the situation in many low-income settings where fluids that are prohibited from use in high-income countries may be all that are available, local guidelines and processes to recognise adverse events are not developed, and there has been limited training on safe fluid management for front-line healthcare workers. This narrative review outlines the fluid and electrolyte pathophysiology of common febrile illnesses in children, describes the evolution of this field and concludes with implications and principles of a fluid management strategy for seriously ill children. This review was prepared as a physiological background paper to support evidence presented to the WHO Guideline Development Group for Fluid Guidelines in Children, Geneva, March 2024.

Dyselectrolytemia in Children With Severe Pneumonia: A Prospective Study

Background Pneumonia is a condition characterized by inflammation of the lung parenchyma. It is one of the leading causes of mortality in children below five years of age. While predominantly prevalent in developing countries, it is also associated with significant healthcare-associated costs in developed countries. Among the many risk factors for childhood pneumonia, incomplete immunization, nonexclusive breastfeeding for less than six months, delayed weaning, poor household air quality, malnutrition, and low birth weight are the most commonly found. Electrolyte disturbances, also known as dyselectrolytemia, have been associated with a broad spectrum of acute infections, including pneumonia, particularly hyponatremia. It occurs in the majority of community-acquired pneumonia. Hyper- and hypokalemia are less frequently occurring electrolyte disturbances. Electrolyte disturbances are due to impairment of the intrarenal mechanism of urine dilution due to extracellular fluid volume depletion and inappropriate secretion of antidiuretic hormone. The central nervous system is imminently affected by acute hyponatremia. This condition frequently culminates in cerebral edema, a result of the rapid fluid shift, and causes sudden fatality. Aim of the study This study aims to study dyselectrolytemia in children with severe pneumonia. Objectives The study objectives are to assess dyselectrolytemia in children with severe pneumonia and to correlate dyselectrolytemia with morbidity and hospital stay. Methodology  This prospective study was conducted on 80 children in the age group of two months up to five years who visited our tertiary care center and had severe pneumonia. We evaluated the extent of dyselectrolytemia in our study population by analyzing the frequency correlation of different kinds of electrolyte imbalances. We also analyzed the correlation between morbidity and hospital stay. Results Out of 80 children in this study with severe pneumonia, 47 (59%) had electrolyte imbalance. Among the patients with electrolyte imbalance, 31 (39%) patients had hyponatremia followed by hypokalemia in 12 (15%) patients, hypernatremia in 3 (4%) patients, and hyperkalemia in 1 (1%) patient. Among the 17 (21%) children with pneumonia requiring ICU admission, 16 (94%) had dyselectrolytemia and 4 (24%) experienced fatal outcomes. Conclusions The majority of the children who were admitted to the ICU had severe pneumonia along with electrolyte imbalance. This necessitates the monitoring of the electrolyte and nutritional status of the patients with pneumonia. Providing proper nutrition advice for children with pneumonia may reduce morbidity and mortality. Early detection and treatment of electrolyte imbalances in pneumonia cases can decrease prolonged hospital stays, ICU admissions, and the need for mechanical ventilation, ultimately contributing to a reduction in morbidity and mortality.

The prevalence and outcomes of hyponatremia in children with COVID-19 and multisystem inflammatory syndrome in children (MIS-C)

Introduction

To assess the prevalence of hyponatremia among pediatric patients with coronavirus disease 2019 (COVID-19) and Multisystem Inflammatory Syndrome in Children (MIS-C) and determine if pediatric hyponatremia was associated with an increased length of stay, higher rates of mechanical ventilation, and/or elevated inflammatory markers on admission as compared to eunatremic patients.

Methods

Electronic health records were retrospectively analyzed for 168 children less than 18 years old with COVID-19 or MIS-C who were admitted to pediatric units within the Northwell Health system. The primary exposure was hyponatremic status (serum sodium <135 mEq/L) and the primary outcomes were length of stay, mechanical ventilation usage and increased inflammatory markers.

Results

Of the 168 children in the study cohort, 95 (56%) were admitted for COVID-19 and 73 (43.5%) for MIS-C. Overall, 60 (35.7%) patients presented with hyponatremia on admission. Patients with hyponatremia had higher rates of intensive care unit admission when compared to eunatremic patients (32/60 [53.3%] vs. 39/108 [36.1%], p = 0.030). In regression models, hyponatremia was not significantly associated with increased length of stay or mechanical ventilation rates. After adjustment for relevant confounders, hyponatremia remained associated with an increased square root CRP (β = 1.79: 95% CI: 0.22-3.36) and lower albumin levels (β = -0.22: 95% CI: -0.42--0.01).

Conclusion

Hyponatremia is common in pediatric COVID-19 and MIS-C. Hyponatremia was associated with a lower albumin and higher square root CRP levels. This may suggest an association of inflammation with lower serum sodium levels.

Incidence and Risk Factors for Hyponatremia in Hospitalized Children with Lower Respiratory Tract Infections

Lower respiratory tract infection (LRTI) is an important cause of hospitalization in pediatric population. Hyponatremia is frequently present in children hospitalized with pneumonia and bronchiolitis and is associated with poorer outcomes. We conducted a study to identify the risk factors for hyponatremia in hospitalized children with LRTI and to evaluate the relationship between serum sodium levels and severity of respiratory distress. A total of 147 patients between 2 months and 12 years of age, admitted with the diagnosis of LRTI at the Mahatma Gandhi Mission Hospital and Medical College, a tertiary hospital in Navi Mumbai, Maharashtra, India, between December 2017 and November 2019, were studied prospectively. Patients with any other comorbidities were excluded. The severity of respiratory distress at presentation was graded using the Clinical Respiratory score (CRS). Serum electrolytes were sent within 1 hour of hospital admission. Median age of enrolled patients was 14 months. Overall, 23 (16%) children had mild respiratory distress, 97 (66%) had moderate respiratory distress, and 26 (18%) had severe distress. The incidence of hyponatremia in children admitted with LRTI was 66% and majority of them (70%) had mild hyponatremia. The incidence, as well as severity of hyponatremia differed significantly with etiology (p < 0.05). An inverse correlation was found between serum sodium levels and CRS at presentation (r = − 0.26, p = 0.001). In multivariate analyses, parenchymal disease was an independent risk factor for development of hyponatremia (adjusted odds ratio [aOR] = 5.64 (2.52–12.59), p < 0.001). Incidence and severity of hyponatremia in children with LRTI increased with severity of respiratory distress and presence of parenchymal disease.

Kidney Transplant Recipient with Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) secondary to COVID-19 pneumonia: A Case Report

Background

Currently, COVID-19 is becoming one of the most common causes of viral pneumonia worldwide. In the medical literature, very few case reports describe the association between COVID-19 and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) in kidney transplant patients.

Methods

A 74-year-old immunocompromised man post–kidney transplant presented with nonspecific symptoms consisting of fatigue, malaise, and anorexia. He was also found to have hyponatremia in the context of pulmonary insults. SIADH in the setting of COVID-19 pneumonia was diagnosed after exclusion of other causes of hyponatremia. He was treated for COVID-19 pneumonia with antiviral therapy, secondary bacterial infection prophylaxis, dexamethasone and ventilatory support in addition to modification of antirejection medications.

Results

The patient has improved and his serum sodium normalized with management of primary insult.

Conclusions. SIADH should be suspected in transplant patients with COVID-19 pneumonia once they develops hyponatremia. The decision of intravenous fluid administration should be taken carefully in these settings.

Acute and Chronic Hyponatremia

Hyponatremia is the most common electrolyte disorder in clinical practice. Catastrophic complications can occur from severe acute hyponatremia and from inappropriate management of acute and chronic hyponatremia. It is essential to define the hypotonic state associated with hyponatremia in order to plan therapy. Understanding cerebral defense mechanisms to hyponatremia are key factors to its manifestations and classification and subsequently to its management. Hypotonic hyponatremia is differentiated on the basis of urine osmolality, urine electrolytes and volume status and its treatment is decided based on chronicity and the presence or absence of central nervous (CNS) symptoms. Proper knowledge of sodium and water homeostasis is essential in individualizing therapeutic plans and avoid iatrogenic complications while managing this disorder.

Clinical characteristics of influenza with or without Streptococcus pneumoniae co-infection in children

BACKGROUND/PURPOSE

Influenza is frequently complicated with bacterial co-infection. This study aimed to disclose the significance of Streptococcus pneumoniae co-infection in children with influenza.

METHODS

We retrospectively reviewed medical records of pediatric patients hospitalized for influenza with or without pneumococcal co-infection at the National Taiwan University Hospital from 2007 to 2019. Clinical characteristics and outcomes were compared between patients with and without S. pneumoniae co-infection.

RESULTS

There were 558 children hospitalized for influenza: 494 had influenza alone whereas 64 had S. pneumoniae co-infection. Patients with S. pneumoniae co-infection had older ages, lower SpO₂, higher C-Reactive Protein (CRP), lower serum sodium, lower platelet counts, more chest radiograph findings of patch and consolidation on admission, longer hospitalization, more intensive care, longer intensive care unit (ICU) stay, more mechanical ventilation, more inotropes/vasopressors use, more surgical interventions including video-assisted thoracoscopic surgery (VATS) and extracorporeal membrane oxygenation (ECMO), and higher case-fatality rate.

CONCLUSION

Compared to influenza alone, patients with S. pneumoniae co-infection had more morbidities and mortalities. Pneumococcal co-infection is considered when influenza patients have lower SpO₂, lower platelet counts, higher CRP, lower serum sodium, and more radiographic patches and consolidations on admission.

Prevalence and fluid management of dehydration in children without diarrhoea admitted to Kenyan hospitals: a multisite observational study

OBJECTIVES

To examine the prevalence of dehydration without diarrhoea among admitted children aged 1-59 months and to describe fluid management practices in such cases.

DESIGN

A multisite observational study that used routine in-patient data collected prospectively between October 2013 and December 2018.

SETTINGS

Study conducted in 13 county referral hospitals in Kenya.

PARTICIPANTS

Children aged 1-59 months with admission or discharge diagnosis of dehydration but had no diarrhoea as a symptom or diagnosis. Children aged <28 days and those with severe acute malnutrition were excluded.

RESULTS

The prevalence of dehydration in children without diarrhoea was 3.0% (2019/68 204) and comprised 15.9% (2019/12 702) of all dehydration cases. Only 55.8% (1127/2019) of affected children received either oral or intravenous fluid therapy. Where fluid treatment was given, the volumes, type of fluid, duration of fluid therapy and route of administration were similar to those used in the treatment of dehydration secondary to diarrhoea. Pneumonia (1021/2019, 50.6%) and malaria (715/2019, 35.4%) were the two most common comorbid diagnoses. Overall case fatality in the study population was 12.9% (260/2019).

CONCLUSION

Sixteen per cent of children hospitalised with dehydration do not have diarrhoea but other common illnesses. Two-fifths do not receive fluid therapy; a regimen similar to that used in diarrhoeal cases is used in cases where fluid is administered. Efforts to promote compliance with guidance in routine clinical settings should recognise special circumstances where guidelines do not apply, and further studies on appropriate management for dehydration in the absence of diarrhoea are required.

Hydroelectrolytic Disorder in COVID-19 patients: Evidence Supporting the Involvement of Subfornical Organ and Paraventricular Nucleus of the Hypothalamus

Multiple neurological problems have been reported in coronavirus disease-2019 (COVID-19) patients because severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) likely spreads to the central nervous system (CNS) via olfactory nerves or through the subarachnoid space along olfactory nerves into the brain's cerebrospinal fluid and then into the brain's interstitial space. We hypothesize that SARS-CoV-2 enters the subfornical organ (SFO) through the above routes and the circulating blood since circumventricular organs (CVOs) such as the SFO lack the blood-brain barrier, and infection of the SFO causes dysfunction of the hypothalamic paraventricular nucleus (PVN) and supraoptic nucleus (SON), leading to hydroelectrolytic disorder. SARS-CoV-2 can readily enter SFO-PVN-SON neurons because these neurons express angiotensin-converting enzyme-2 receptors and proteolytic viral activators, which likely leads to neurodegeneration or neuroinflammation in these regions. Considering the pivotal role of SFO-PVN-SON circuitry in modulating hydroelectrolyte balance, SARS-CoV-2 infection in these regions could disrupt the neuroendocrine control of hydromineral homeostasis. This review proposes mechanisms by which SARS-CoV-2 infection of the SFO-PVN-SON pathway leads to hydroelectrolytic disorder in COVID-19 patients.

Activation of Vasopressin System During COVID-19 is Associated With Adverse Clinical Outcomes: An Observational Study

Background

Activation of the vasopressin system plays a key role for the maintenance of osmotic, cardiovascular, and stress hormone homeostasis during disease. We investigated levels of copeptin, the C-terminal segment of the vasopressin prohormone, that mirrors the production rate of vasopressin in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods

We measured levels of copeptin on admission and after days 3/4, 5/6, and 7/8 in 74 consecutive hospitalized adult COVID-19 patients and compared its prognostic accuracy to that of patients with community-acquired pneumonia (n = 876) and acute or chronic bronchitis (n = 371) from a previous study by means of logistic regression analysis. The primary endpoint was all-cause 30-day mortality.

Results

Median admission copeptin levels in COVID-19 patients were almost 4-fold higher in nonsurvivors compared with survivors (49.4 pmol/L [iterquartile range (IQR) 24.9–68.9 pmol/L] vs 13.5 pmol/L [IQR 7.0–26.7 pmol/L]), resulting in an age- and gender-adjusted odds ratio of 7.0 (95% confidence interval [CI] 1.2–40.3), p < 0.03 for mortality. Higher copeptin levels in nonsurvivors persisted during the short-term follow-up. Compared with the control group patients with acute/chronic bronchitis and pneumonia, COVID-19 patients did not have higher admission copeptin levels.

Conclusions

A pronounced activation of the vasopressin system in COVID-19 patients is associated with an adverse clinical course in COVID-19 patients. This finding, however, is not unique to COVID-19 but similar to other types of respiratory infections.

Prevalence and Impact of Hyponatremia in Patients With Coronavirus Disease 2019 in New York City

OBJECTIVES

Hyponatremia occurs in up to 30% of patients with pneumonia and is associated with increased morbidity and mortality. The prevalence of hyponatremia associated with coronavirus disease 2019 and the impact on outcome is unknown. We aimed to identify the prevalence, predictors, and impact on outcome of mild, moderate, and severe admission hyponatremia compared with normonatremia among coronavirus disease 2019 patients.

DESIGN

Retrospective, multicenter, observational cohort study.

SETTING

Four New York City hospitals that are part of the same health network.

PATIENTS

Hospitalized, laboratory-confirmed adult coronavirus disease 2019 patients admitted between March 1, 2020, and May 13, 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Hyponatremia was categorized as mild (sodium: 130-134 mmol/L), moderate (sodium: 121-129 mmol/L), or severe (sodium: ≤ 120 mmol/L) versus normonatremia (135-145 mmol/L). The primary outcome was the association of increasing severity of hyponatremia and in-hospital mortality assessed using multivariable logistic regression analysis. Secondary outcomes included encephalopathy, acute renal failure, mechanical ventilation, and discharge home compared across sodium levels using Kruskal-Wallis and chi-square tests. In exploratory analysis, the association of sodium levels and interleukin-6 levels (which has been linked to nonosmotic release of vasopressin) was assessed. Among 4,645 patient encounters, hyponatremia (sodium < 135 mmol/L) occurred in 1,373 (30%) and 374 of 1,373 (27%) required invasive mechanical ventilation. Mild, moderate, and severe hyponatremia occurred in 1,032 (22%), 305 (7%), and 36 (1%) patients, respectively. Each level of worsening hyponatremia conferred 43% increased odds of in-hospital death after adjusting for age, gender, race, body mass index, past medical history, admission laboratory abnormalities, admission Sequential Organ Failure Assessment score, renal failure, encephalopathy, and mechanical ventilation (adjusted odds ratio, 1.43; 95% CI, 1.08-1.88; p = 0.012). Increasing severity of hyponatremia was associated with encephalopathy, mechanical ventilation, and decreased probability of discharge home (all p < 0.001). Higher interleukin-6 levels correlated with lower sodium levels (p = 0.017).

CONCLUSIONS

Hyponatremia occurred in nearly a third of coronavirus disease 2019 patients, was an independent predictor of in-hospital mortality, and was associated with increased risk of encephalopathy and mechanical ventilation.

COVID-19 presented with syndrome of inappropriate ADH secretion(SIADH): A case report from Bangladesh

Backgound

Novel corona virus(SARS-CoV-2) which emerged from Wuhan, China, has spread to whole worlds very rapidly causing enormous health effect and death. Current publications worldwide showed that COVID-19 is a disease involving multiple system of the body with many unusual presentations. So physicians face the challenges to manage it in the hospital.

Case report

The syndrome of inappropriate secretion of anti diuretic hormone (SIADH) is one of the most common causes of hyponatremia accounts for approximately one-third of all cases. In the diagnosis of SIADH it is important to ascertain the euvolemic state of extra cellular fluid volume, both clinically and laboratory measurement. Several infections associated with SIADH have been reported. Howover, Coronavirus disease 2019(COVID-19) associated with SIADH were only few cases reported. We are presenting a case of 70 year old female admitted with unconsciousness later diagnosed as severe hyponatremia along with COVID-19 complicated with severe pneumonia.

Prognostic Value of Hyponatremia During Acute Painful Episodes in Sickle Cell Disease

BACKGROUND

Low plasma sodium concentration has been recognized as a prognostic factor in several disorders but never evaluated in sickle cell disease. The present study evaluates its value at admission to predict a complication in adult patients with sickle cell disease hospitalized for an initially uncomplicated acute painful episode.

METHODS

The primary outcome of this retrospective study, performed between 2010 and 2015 in a French referral center for sickle cell disease, was a composite criterion including acute chest syndrome, intensive care unit transfer, red blood cell transfusion or inpatient death. Analyses were adjusted for age, sex, hemoglobin genotype and concentration, lactate dehydrogenase (LDH) concentration, and white blood cell count.

RESULTS

We included 1218 stays (406 patients). No inpatient death occurred during the study period. Hyponatremia (plasma sodium ≤135 mmol/L) at admission in the center was associated with the primary outcome (adjusted odds ratio [OR] 1.95, 95% confidence interval [CI] 1.3-2.91, P = 0.001), with acute chest syndrome (OR 1.95 [95% CI 1.2-3.17, P = 0.008]), and red blood cell transfusion (OR 2.71 [95% CI 1.58-4.65, P <0.001]) but not significantly with intensive care unit transfer (OR 1.83 [95% CI 0.94-3.79, P = 0.074]). Adjusted mean length of stay was longer by 1.1 days (95% CI 0.5-1.6, P <0.001) in patients with hyponatremia at admission.

CONCLUSIONS

Hyponatremia at admission in the medical department for an acute painful episode is a strong and independent prognostic factor of unfavorable outcome and, notably, acute chest syndrome. It could help targeting patients who may benefit from closer monitoring.

COVID-19 presenting with diarrhoea and hyponatraemia

COVID-19 is a viral disease with a high infectivity rate. The full spectrum of the disease is not yet understood. This understanding may help in limiting potential exposure. We present a young man with diarrhoea, abdominal pain and hyponatraemia who turned out to be positive for COVID-19.

Acute symptomatic hyponatremia in setting of SIADH as an isolated presentation of COVID-19

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is one of the most common causes of hyponatremia in hospitalized patients. Wide spectrum of etiologies associated with hyponatremia pose significant challenges in detecting and treating this disorder. Several infectious causes of SIADH have been reported; however, hyponatremia associated with SIADH and Coronavirus disease 2019 (COVID-19) was only recently mentioned in a few case reports. We discuss a unique presentation of COVID-19, in which the patient presented with acute severe symptomatic hyponatremia thought to be the initial and isolated presentation of SARS-CoV-2 infection.

Hyponatraemia in patients with community-acquired pneumonia; prevalence and aetiology, and natural history of SIAD

OBJECTIVE

Hyponatraemia is common in community-acquired pneumonia (CAP) and is associated with increased mortality. The mechanism of hyponatraemia in CAP is not completely understood and treatment is therefore ill-defined. We aimed to define the causation of hyponatraemia in CAP.

DESIGN

Prospective, single-centre, observational study of all patients with CAP and hyponatraemia (≤ 130 mmol/L) during a 9-month period.

PATIENTS

The prevalence of each subtype of hyponatraemia, and the associated mortality, was determined in 143 admissions with CAP (Study 1). A sub-cohort of patients with SIAD (n = 10) was prospectively followed, to document the natural history of SIAD associated with CAP (Study 2).

MEASUREMENTS

In Study 2, blood and urine were collected on day 1, 3, 5 and 7 following admission for measurement of plasma vasopressin, sodium, osmolality and urine osmolality.

RESULTS

In study 1, 143/1723(8.3%) of CAP patients had hyponatraemia (≤130 mmol/L). About 66 had SIAD (46%), 60(42%) had hypovolaemic hyponatraemia (HON), 13(9%) had hypervolaemic hyponatraemia (HEN) and 4(3%) patients had hyponatraemia due to glucocorticoid hormone deficiency. Mortality was higher in the HEN than in the HON, SIAD or normonatraemic groups (P < 0.01). In Study 2, plasma sodium concentration normalized in 8/10 (80%) by day 7. Two patients with persistent hyponatraemia were discovered to have underlying bronchiectasis.

CONCLUSIONS

Hyponatraemia in CAP is most commonly secondary to SIAD or hypovolaemia. HEN is less common, but has worse prognosis. Prospective observation demonstrates that in SIAD, plasma AVP and sodium concentrations normalize with antimicrobials; failure of reversal of suggests underlying lung disease, such as bronchiectasis.

Syndrome of Inappropriate Antidiuresis

The syndrome of inappropriate antidiuresis (SIAD) is a common cause of hyponatremia in hospitalized children. SIAD refers to euvolemic hyponatremia due to nonphysiologic stimuli for arginine vasopressin production in the absence of renal or endocrine dysfunction. SIAD can be broadly classified as a result of tumors, pulmonary or central nervous system disorders, medications, or other causes such as infection, inflammation, and the postoperative state. The presence of hypouricemia with an elevated fractional excretion of urate can aid in the diagnosis. Treatment options include fluid restriction, intravenous saline solutions, oral sodium supplements, loop diuretics, oral urea, and vasopressin receptor antagonists (vaptans).

Hyponatremia in children with respiratory infections: a cross-sectional analysis of a cohort of 3938 patients

Hyponatremia can be a life-threatening illness among hospitalized children. The aims of this study were to evaluate the incidence and risk factors of hyponatremia in 3938 children who were admitted to the Cheil General Hospital and Women’s Health Care Center with respiratory infections. Clinical data were collected, and multiplex RT-PCR analyses were done for various microorganisms. Hyponatremia was observed in 531 (13.5%) patients. The incidence of hyponatremia differed according to the respiratory tract infection (P < 0.0001) and microorganism (P = 0.001). In children with hyponatremia, the age at admission was significantly older (P < 0.0001), male gender was more frequent (P = 0.019), CRP was higher (P < 0.0001), and coinfection with multiple organisms was more common (P = 0.001) than in children without hyponatremia. In multivariate analyses, an older age at admission (P = 0.006), male gender (P = 0.004), and increased CRP (P < 0.0001) were independent risk factors. Sodium levels correlated negatively with WBC (P = 0.037), CRP (P < 0.0001), and number of hospital days (P = 0.020). The AUC values of age (0.586, P < 0.0001), CRP (0.599, P < 0.0001), and blood urea nitrogen (0.559, P < 0.0001) were all significant predictors of hyponatremia. This study is the first to show that the incidence of hyponatremia differs according to infecting microorganism and radiological findings.

Mechanism of Hyponatremia in Community-Acquired Pneumonia: Does B-type Natriuretic Peptide Play a Causative Role?

OBJECTIVE

Hyponatremia is a well-known sequela of community-acquired pneumonia (CAP). B-type natriuretic peptide (BNP) has a natriuretic effect and was found to be elevated in patients with CAP. We investigated whether BNP has a role in the pathophysiology of hyponatremia in pediatric CAP.

METHODS

Serum and urine electrolytes and osmolality, as well as NT-pro-BNP (N-BNP), were obtained in 49 hospitalized pediatric patients with CAP (29 with hyponatremia, 20 with normal sodium levels.

RESULTS

Urine sodium levels were lower in the hyponatremic group compared with the normonatremic group (24.3 meq/L vs 66.7 meq/L, P = 0.006). No difference in N-BNP levels was found between groups (median, 103.8 vs 100.1; P = 0.06; interquartile range, 63.7-263.3 pg/mL vs 47.4-146.4 pg/mL). N-BNP was not associated with serum or urinary sodium levels.

CONCLUSIONS

These results indicate that BNP is unlikely to play a causative role in the mechanism of hyponatremia in CAP.

The Economic Burden of Hyponatremia: Systematic Review and Meta-Analysis

BACKGROUND

Hyponatremia is the most common electrolyte abnormality observed in clinical practice. Several studies have demonstrated that hyponatremia is associated with an increased length of hospital stay and of hospital resource utilization. To clarify the impact of hyponatremia on the length of hospitalization and costs, we performed a meta-analysis based on published studies that compared hospital length of stay and cost between patients with and without hyponatremia.

METHODS

An extensive Medline, Embase, and Cochrane search was performed to retrieve all studies published up to April 1, 2015 using the following words: "hyponatremia" or "hyponatraemia" AND "hospitalization" or "hospitalisation." A meta-analysis was performed including all studies comparing duration of hospitalization and hospital readmission rate in subjects with and without hyponatremia.

RESULTS

Of 444 retrieved articles, 46 studies satisfied the inclusion criteria, encompassing a total of 3,940,042 patients; among these, 757,763 (19.2%) were hyponatremic. Across all studies, hyponatremia was associated with a significantly longer duration of hospitalization (3.30 [2.90-3.71; 95% CIs] mean days; P < .000). Similar results were obtained when patients with associated morbidities were analyzed separately. Furthermore, hyponatremic patients had a higher risk of readmission after the first hospitalization (odds ratio 1.32 [1.18-1.48; 95% CIs]; P < .000). A meta-regression analysis showed that the hyponatremia-related length of hospital stay was higher in males (Slope = 0.09 [0.05-0.12; 95% CIs]; P = .000 and Intercept = -1.36 [-3.03-0.32; 95% CIs]; P = .11) and in elderly patients (Slope = 0.002 [0.001-0.003; 95% CIs]; P < .000 and Intercept = 0.89 [0.83-0.97; 95% CIs]; P < .001). A negative association between serum [Na(+)] cutoff and duration of hospitalization was detected. No association between duration of hospitalization, serum [Na(+)], and associated morbidities was observed. Finally, when only US studies (n = 8) were considered, hyponatremia was associated with up to around $3000 higher hospital costs/patient when compared with the cost of normonatremic subjects.

CONCLUSIONS

This meta-analysis confirms that hyponatremia is associated with a prolonged hospital length of stay and higher risk of readmission. These observations suggest that hyponatremia may represent one important determinant of the hospitalization costs.

Intravenous maintenance fluid therapy in children

Intravenous fluids are frequently used in paediatrics but have been associated with significant adverse outcomes. Understanding the composition of fluid prescribed and administering an appropriate rate is essential for safe fluid administration, along with regular monitoring. Recent evidence has shown that using an isotonic fluid with a sodium concentration similar to plasma can decrease the risk of hyponatraemia without an increase in adverse effects. This should lead to a change in guidelines: isotonic fluid should now be used as the primary maintenance intravenous fluid given to the majority of children.

140 mmol/L of sodium versus 77 mmol/L of sodium in maintenance intravenous fluid therapy for children in hospital (PIMS): a randomised controlled double-blind trial

BACKGROUND

Use of hypotonic intravenous fluid to maintain hydration in children in hospital has been associated with hyponatraemia, leading to neurological morbidity and mortality. We aimed to assess whether use of fluid solutions with a higher sodium concentration reduced the risk of hyponatraemia compared with use of hypotonic solutions.

METHODS

We did a randomised controlled double-blind trial of children admitted to The Royal Children's Hospital (Melbourne, VIC, Australia) who needed intravenous maintenance hydration for 6 h or longer. With an online randomisation system that used unequal block sizes, we randomly assigned patients (1:1) to receive either isotonic intravenous fluid containing 140 mmol/L of sodium (Na140) or hypotonic fluid containing 77 mmol/L of sodium (Na77) for 72 h or until their intravenous fluid rate decreased to lower than 50% of the standard maintenance rate. We stratified assignment by baseline sodium concentrations. Study investigators, treating clinicians, nurses, and patients were masked to treatment assignment. The primary outcome was occurrence of hyponatraemia (serum sodium concentration <135 mmol/L with a decrease of at least 3 mmol/L from baseline) during the treatment period, analysed by intention to treat. The trial was registered with the Australian New Zealand Clinical Trials Registry, number ACTRN1260900924257.

FINDINGS

Between Feb 2, 2010, and Jan 29, 2013, we randomly assigned 690 patients. Of these patients, primary outcome data were available for 319 who received Na140 and 322 who received Na77. Fewer patients given Na140 than those given Na77 developed hyponatraemia (12 patients [4%] vs 35 [11%]; odds ratio [OR] 0·31, 95% CI 0·16-0·61; p=0·001). No clinically apparent cerebral oedema occurred in either group. Eight patients in the Na140 group (two potentially related to intravenous fluid) and four in the Na77 group (none related to intravenous fluid) developed serious adverse events during the treatment period. One patient in the Na140 had seizures during the treatment period compared with seven who received Na77.

INTERPRETATION

Use of isotonic intravenous fluid with a sodium concentration of 140 mmol/L had a lower risk of hyponatraemia without an increase in adverse effects than did fluid containing 77 mmol/L of sodium. An isotonic fluid should be used as intravenous fluid for maintenance hydration in children.

FUNDING

National Health and Medical Research Council, Murdoch Childrens Research Institute, The Royal Children's Hospital, and the Australian and New Zealand College of Anaesthetists.

The Golden Hours in Paediatric Septic Shock—Current Updates and Recommendations

Introduction: Paediatric sepsis is a global health problem. It is the leading cause of mortality in infants and children worldwide. Appropriate and timely initial management in the first hours, often termed as the “golden hours”, has great impact on survival. The aim of this paper is to summarise the current literature and updates on the initial management of paediatric sepsis. Materials and Methods: A comprehensive literature search was performed via PubMed using the search terms: ‘sepsis’, ‘septic shock’, ‘paediatric’ and ‘early goal-directed therapy’. Original and review articles were identified and selected based on relevance to this review. Results: Early recognition, prompt fluid resuscitation and timely administration of antibiotics remain key in the resuscitation of the septic child. Use of steroids and tight glycaemic control in this setting remain controversial. Conclusion: The use of early goal-directed therapy has had significant impact on patient outcomes and protocolised resuscitation of children in septic shock is recommended. Key words: Child, Early goal-directed therapy, Emergency, Sepsis

Impact of hyponatremia and the syndrome of inappropriate antidiuresis on mortality in elderly patients with aspiration pneumonia

BACKGROUND

Hyponatremia is associated with pneumonia, and aspiration pneumonia is common in the elderly, however, there has been no study of hyponatremia in this population.

OBJECTIVE

To determine the impact of hyponatremia on mortality in elderly patients with aspiration pneumonia, while focusing on the comparison between those with and without the syndrome of inappropriate antidiuresis (SIAD).

DESIGN

Retrospective review of existing database and medical records.

SETTING

A community teaching hospital in Japan.

PATIENTS

Two hundred and twenty-one elderly patients hospitalized with aspiration pneumonia.

MEASUREMENTS

Multivariate logistical regression models were used to compare 30-day and in-hospital mortality, in patients with hyponatremia of various severities and etiologies, with that in patients with normal serum sodium concentrations.

RESULTS

Sixty-five (29%) of 221 patients had hyponatremia. Of these 62 (95%) had hypotonic hyponatremia, which were further assessed as having hypovolemic (39 [63%]), hypervolemic (3 [5%]), and euvolemic (20 [32%]) hyponatremia. Of the 20 euvolemic patients, 14 (70%) had SIAD. Both moderate and severe hypotonic hyponatremia were significantly associated with increased in-hospital mortality (odds ratio [OR] 6.05, 95% confidence interval [CI] 1.46-25.0, and OR 5.65, 95% CI 1.14-28.1, respectively). Hyponatremia due to SIAD was significantly associated with both increased 30-day mortality (OR 7.40, 95% CI 1.73-31.7) and increased in-hospital mortality (OR 22.3, 95% CI 4.26-117). In contrast, hypovolemic hyponatremia was not significantly associated with increased mortality.

CONCLUSIONS

Hyponatremia due to SIAD was strongly associated with increased mortality in elderly patients with aspiration pneumonia, whereas hypovolemic hyponatremia was not associated with increased mortality.

Intravenous fluid management for the acutely ill child

PURPOSE OF REVIEW

To review the principles of prescribing intravenous fluids (IVFs) to the acutely ill child and of adjusting sodium composition and fluid rate to prevent disorders in serum sodium or volume status from occurring.

RECENT FINDINGS

Recent data have revealed that the historic approach of administering hypotonic IVFs results in a high incidence of hospital-acquired hyponatremia in children. The majority of hospitalized children requiring IVFs are at risk for developing hyponatremia from numerous stimuli for arginine vasopressin (AVP) production, such as volume depletion, pain, stress, nausea, vomiting, respiratory or central nervous system (CNS) disorders, or the postoperative state. Multiple recent prospective studies in over 600 children have demonstrated that hypotonic fluids cause acute hyponatremia, whereas 0.9% sodium chloride (NaCl) effectively prevents it. 0.9% NaCl is the most appropriate IVF for the majority of hospitalized children. Fluid and sodium restriction will be needed for children with edematous or oliguric states and hypotonic fluids needed for children with urinary or extra-renal free water losses or hypernatremia.

SUMMARY

Hypotonic fluids should not be administered routinely in children due to the risk of hospital-acquired hyponatremia. 0.9% NaCl is the preferred IVF for the vast majority of hospitalized children.

Advising patients to increase fluid intake for treating acute respiratory infections

BACKGROUND

Acute respiratory infection is a common reason for people to present for medical care. Advice to increase fluid intake is a frequent treatment recommendation. Attributed benefits of fluids include replacing increased insensible fluid losses, correcting dehydration from reduced intake and reducing the viscosity of mucus. However, there are theoretical reasons for increased fluid intake to cause harm. Anti-diuretic hormone secretion is increased in lower respiratory tract infections of various aetiologies. This systematic examination of the evidence sought to determine the benefit versus harm from increasing fluid intake.

OBJECTIVES

To answer the following questions.1. Does recommending increased fluid intake as a treatment for acute respiratory infections improve duration and severity of symptoms? 2. Are there adverse effects from recommending increased fluids in people with acute respiratory infections? 3. Are any benefits or harms related to site of infection (upper or lower respiratory tract) or a different severity of illness?

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, issue 4), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to November Week 3, 2010), EMBASE (1974 to December 2010), Current Contents (2000 to December 2010) and CINAHL (1982 to December 2010). We searched reference lists of articles identified and contacted experts in the relevant disciplines.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that examined the effect of increasing fluid intake in people with acute respiratory infections.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the identified studies to determine eligibility for inclusion.

MAIN RESULTS

No RCTs assessing the effect of increasing fluid intake in acute respiratory infections were found.

AUTHORS' CONCLUSIONS

There is currently no evidence from RCTs for or against the recommendation to increase fluids in acute respiratory infections. The implications for fluid management of acute respiratory infections in the outpatient or primary care setting have not been studied in any RCTs to date. Some non-experimental (observational) studies report that increasing fluid intake in acute respiratory infections of the lower respiratory tract may cause harm. RCTs need to be done to determine the true effect of this very common medical advice.

Hyponatraemia in cases of children with pneumonia

INTRODUCTION

Hyponatraemia is the most common electrolyte imbalance seen in clinical practice, and a common laboratory finding in children with community-acquired pneumonia (CAP). This study aimed to identify the incidence of hyponatraemia in cases of CAP, to find predictive tools in order to classify the severity and outcome of CAP and to explore possible differences of clinical importance between the two sexes.

MATERIAL AND METHODS

The medical files of 54 children (66.4% males), 4.67 ±2.88 years old, were retro-prospectively reviewed.

RESULTS

35/54 (64.8%) children with pneumonia had normal values of sodium at admission, 18/54 (33.3%) had mild hyponatraemia and 1 child (1.9%) moderate hyponatraemia. Increased heart rhythm and tachypnoea at admission were correlated with lower values of sodium (z= -2.664, p = 0.007 and z = -1.705, p = 0.089 respectively). No differences were found between the two sexes concerning the characteristics of pneumonia or the range of sodium in serum at admission. A correlation was found between sodium admission values and: a) C-reactive protein (p = 0.000), and b) leukocyte count (p = 0.006). Sedimentation rate (p = 0.021) was also considered as a possible risk factor affecting the value of sodium at admission to hospital. Finally, a negative association was also observed between the degree of hyponatraemia and the duration of hospitalization (z = -3.398, p = 0.001).

CONCLUSIONS

Although studies in larger population groups are needed, in our study increased heart rhythm, tachypnoea, leucocyte count, C-reactive protein, and also erythrocyte sedimentation rate could be considered as possible risk factors influencing the degree of hyponatraemia, and thus the outcome of hospitalized children with CAP.

Pneumonia and other respiratory infections

Pneumonia is a leading killer of children in developing countries and results in significant morbidity worldwide. This article reviews the management of pneumonia and its complications from the perspective of both developed and resource-poor settings. In addition, evidence-based management of other respiratory infections, including tuberculosis, is discussed. Finally, the management of common complications of pneumonia is reviewed.

Hyponatremia in pediatric community-acquired pneumonia

Studies focusing on serum sodium disorders in children with community-acquired-pneumonia (CAP) are nearly entirely lacking, though clinical experience suggests that at least hyponatremia (HN) might be rather common. We evaluated the incidence of hypo- and hypernatremia, in relation to other clinical, laboratory and etiological findings, in pediatric CAP. Serum sodium concentration was measured in 108 ambulatory and hospitalized children with radiologically confirmed CAP of variable severity. The etiology of CAP was revealed by serology in 97 patients. HN (serum sodium < 135 mmol/l) was present in 49 (45.4%) children, and it was mild (> 130 mmol/l) in 92% of the cases. On admission, hyponatremic patients had higher body temperature (38.96 degrees C vs 38.45 degrees C, P = 0.008), white blood cell count (21,074/microl vs 16,592/microl, P = 0.008), neutrophil percentage (78.93% vs 69.33%, P = 0.0001), serum C-reactive protein (168.27 mg/l vs 104.75 mg/l, P = 0.014), and serum procalcitonin (22.35 ng/ml vs 6.87 ng/ml, P = 0.0001), and lower calculated osmolality (263.39 mosmol/l vs 272.84 mosmol/l, P = 0.0001) than normonatremic ones. No association was found with plasma glucose, type of radiological consolidation or etiology of CAP. HN is common but usually mild in children with CAP. HN seems to be associated with the severity of CAP, assessed by fever, need of hospitalization and serum non-specific inflammatory markers.

[Etiology, diagnostics and therapy of hyponatremias]

Etiopathogenesis, diagnostics and therapy of hyponatremias are summarized for clinicians. Hyponatremia is the most common electrolyte abnormality. Mild to moderate hyponatremia and severe hyponatremia are found in 15-30% and 1-4% of hospitalized patients, respectively. Pathophysiologically, hyponatremias are classified into two groups: hyponatremia due to non-osmotic hypersecretion of vasopressin (hypovolemic, hypervolemic, euvolemic) and hyponatremia of non-hypervasopressinemic origin (pseudohyponatremia, water intoxication, cerebral salt wasting syndrome). Patients with mild hyponatremia are almost always asymptomatic. Severe hyponatremia is usually associated with central nervous system symptoms and can be life-threatening. Diagnostic evaluation of patients with hyponatremia is directed toward identifying the extracellular fluid volume status, the neurological symptoms and signs, the severity and duration of hyponatremia, the rate at which hyponatremia developed. The first step to determine the probable cause of hyponatremia is the differentiation of the hypervasopressinemic and non-hypervasopressinemic hyponatremias with measurement of plasma osmolality, glucose, lipids and proteins. For further differential diagnosis of hyponatremia, the determination of urine osmolality, the clinical assessment of extracellular fluid volume status and the measurement of urine sodium concentration provide important information. The most important representative of euvolemic hyponatremias is SIADH. The diagnosis of SIADH is based on the exclusion of other hyponatremic conditions; low plasma osmolality (<275 mosmol/kg) and inappropriate urine concentration (urine osmolality >100 mosmol/kg) are of pathognomic value. Acute (<48 hrs) severe hyponatremia (<120 mmol/l) necessitates emergency care with rapid restoration of normal osmotic milieu (1 mmol/l/hr increase rate of serum sodium). Patients with chronic symptomatic hyponatremia have a high risk of osmotic demyelination syndrome in brain if rapid correction of the plasma sodium occurs (maximal rate of correction of serum sodium should be 0.5 mmol/l/hr or less). The conventional treatments for chronic asymptomatic hyponatremia (except hypovolemic patients) include water restriction and/or the use of demeclocycline or lithium or furosemide and salt supplementation. Vasopressin receptor antagonists have opened a new forthcoming therapeutic era. V2 receptor antagonists, such as lixivaptan, tolvaptan, satavaptan and the V2+V1A receptor antagonist conivaptan promote the electrolyte-sparing excretion of free water and lead to increased serum sodium.

Hyponatremic seizure associated with acute respiratory infection

A 66-year-old woman was admitted to our hospital because of vomiting and appetite loss. For the 2 days prior to admission, she had a cold, which had developed into acute viral bronchitis on admission. Because laboratory data on admission showed hyponatremia, intravenous infusion of Ringer's lactate solution was started. However, generalized seizures appeared, and she developed a coma on the day of admission. Her plasma antidiuretic hormone (ADH) level was high in the context of a low serum osmolality on the second hospital day. The infusion rate was increased, and the patient's consciousness level returned to normal. However, her normalized serum Na level declined again as she drank much water to reduce throat discomfort. As the throat discomfort caused by the throat inflammation improved with azulene gargling, her water intake was reduced, and the serum Na concentration returned to normal. Thus, polydipsia caused by a throat inflammation partially contributed to hyponatremia in this patient. We note that increased ADH secretion has been reported in adults with acute respiratory infection. Therefore, we concluded that polydipsia caused by the throat inflammation, plus increased ADH secretion, resulted in hyponatremia in this patient. We should pay attention to the behavior of drinking extra fluid in patients with acute respiratory infections.

Hyponatremia: clinical diagnosis and management

Hyponatremia is a common clinical problem in hospitalized patients and nursing home residents. It also may occur in healthy athletes after endurance exercise. The majority of patients with hyponatremia are asymptomatic and do not require immediate correction of hyponatremia. Symptomatic hyponatremia is a medical emergency requiring rapid correction to prevent the worsening of brain edema. How fast we should increase the serum sodium levels depends on the onset of hyponatremia and still remains controversial. If the serum sodium levels are corrected too rapidly, patients may develop central pontine myelinolysis, but if they are corrected too slowly, patients may die of brain herniation. We review the epidemiology and mechanisms of hyponatremia, the sensitivity of women to hyponatremic injury, the adaptation and maladaptation of brain cells to hyponatremia and its correction, and the practical ways of managing hyponatremia. Because the majority of hyponatremia is caused by the non-osmotic release of vasopressin, the recent approval of the vasopressin receptor antagonist conivaptan for euvolemic hyponatremia may simplify hyponatremia management. However, physicians should be aware of the risk of rapid correction of hyponatremia, hypotension, and excessive fluid intake.

Body water and plasma volume in severe community-acquired pneumonia: implications for fluid therapy

OBJECTIVES

To determine changes in total and extracellular body water, plasma volume and sodium in children with severe and very severe pneumonia, and examine the association between these changes and oxygenation.

DESIGN

Prospective, observational.

SUBJECTS

Fifty children aged 2-59 mths with severe and very severe pneumonia.

METHODS

Serum sodium (SNa), plasma osmolality (Posm), urinary sodium (UNa) and osmolality, total body water (TBW), extracellular water (ECW) and plasma volume (PV) were estimated during the acute phase of pneumonia (within 3-6 hrs of presentation) and after recovery. These were correlated with oxygen saturation (SpO(2)) recorded on presentation.

RESULTS

All children had cough, fever, tachypnoea and chest-wall indrawing; 70% had inability to feed and 90% were hypoxaemic (SpO(2) < or = 90%). During the acute phase of illness, among the survivors (n=46), mean (SD) ECW and PV were significantly higher than that after recovery [ECW 318 (45) vs 308 (49) ml/kg, PV 53.2 (2.3) vs 52.1 (2.3) ml/kg, p<0.05]. SNa < or = 135 mmol/L was significantly correlated with ECW and PV excess. SpO(2) showed a significant linear relationship with TBW, ECW and PV (r=0.43, 0.46 and 0.42, respectively, p<0.005) and SNa (r= or <0.33, p=0.02). On multiple regression analysis, ECW, blood urea and PV were significant predictors of SpO(2) (combined r=0.63). The four patients who died had significantly higher Posm and blood urea and lower SpO(2) but in a logistic regression model SpO(2) was the only significant predictor of death (odds ratio 0.54, 95% CI 0.32-0.9, p=0.02).

CONCLUSION

ECW and PV were moderately increased in severe and very severe pneumonia and the increase correlated with better oxygenation. These findings suggest that fluid retention in response to hypoxaemia is directed towards improving circulating volume. The current practice of fluid restriction in hypoxaemic patients with severe pneumonia might be logical only after correction of hypoxaemia.

Advising patients to increase fluid intake for treating acute respiratory infections

BACKGROUND

Acute respiratory infection is a common reason for people to present for medical care. Advice to increase fluid intake is a frequent treatment recommendation. Attributed benefits of fluids include replacing increased insensible fluid losses, correcting dehydration from reduced intake and reducing the viscosity of mucus. However, there are theoretical reasons for increased fluid intake to cause harm. Anti-diuretic hormone secretion is increased in lower respiratory tract infections of various aetiologies. This systematic examination of the evidence sought to determine the benefit versus harm from increasing fluid intake.

OBJECTIVES

To answer the following questions. (1) Does recommending increased fluid intake as a treatment for acute respiratory infections improve duration and severity of symptoms? (2) Are there adverse effects from recommending increased fluids in people with acute respiratory infections? (3) Are any benefits or harms related to site of infection (upper or lower respiratory tract) or a different severity of illness?

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2005), MEDLINE (1966 to July Week 1, 2005), EMBASE (1974 to Week 29, 2005), Current Contents (current 5 years) and CINAHL (1982 to July week 3 2005). Reference lists of articles identified were searched, and experts in the relevant disciplines were contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that examined the effect of increasing fluid intake in people with acute respiratory infections.

DATA COLLECTION AND ANALYSIS

Each author assessed the identified studies to determine eligibility for inclusion.

MAIN RESULTS

No RCTs assessing the effect of increasing fluid intake in acute respiratory infections were found.

AUTHORS' CONCLUSIONS

There is currently no evidence for or against the recommendation to increase fluids in acute respiratory infections. The implications for fluid management in acute respiratory infections have not been studied in any RCTs to date. Some non-experimental (observational) studies report that increasing fluid intake in acute respiratory infections may cause harm. RCTs need to be done to determine the true effect of this very common medical advice.

Atrial natriuretic peptide in children with pneumonia

Atrial natriuretic peptide (ANP) has known natriuretic, diuretic, and vasodilatatory effects. It is synthesized and stored in the atrial cells. Stretching of the atrial muscle fibers during an increase in venous return sets a response of ANP release into the blood stream. High levels of ANP were measured in a number of lung diseases. Pneumonia in children is frequently accompanied by the hyponatremia of the syndrome of inappropriate antidiuretic hormone (ADH) secretion (SIADH). High levels of ANP were found among patients with SIADH. Our objective was to determine if ANP plasma levels are altered in children with pneumonia, and to evaluate a possible correlation between severity of pneumonia and ANP levels. Blood samples from 28 children diagnosed with pneumonia were collected. Plasma ANP levels were determined by radioimmunoassay and compared to levels in 25 children without pneumonia. ANP levels in the pneumonia group (mean +/- SD, 16.02 +/- 11.69 pg/ml) increased significantly (P < 0.01) compared to levels in the control group (mean +/- SD, 7.44 +/- 9.29 pg/ml). Children in the pneumonia group also exhibited low levels of plasma sodium (mean +/- SD, 134.88 +/- 2.5 mmol/l) compared to levels in children without pneumonia (mean +/- SD, 139.77 +/- 4.15 mmol/l) (P < 0.01). There was no correlation between ANP plasma levels and severity of pneumonia. In conclusion, ANP levels in children with pneumonia, as in other lung diseases, are increased. High ANP levels may play a role in maintaining water and electrolyte equilibrium during a state of inappropriate ADH secretion accompanying pneumonia.

Neonatal pneumonia in developing countries

Pneumonia contributes to between 750,000 and 1.2 million neonatal deaths and an unknown number of stillbirths each year world wide. The aetiology depends on time of onset. Gram negative bacilli predominate in the first week of life, and Gram positive bacteria after that. Streptococcus pneumoniae probably causes about 25% of neonatal pneumonia. Interventions that would reduce mortality from this condition would have a large range of beneficial effects: improved maternal health, better management of other common neonatal conditions, and reduced long term childhood and adult morbidity.

Hyponatremia in hospitalized critically ill children: current concepts

Hyponatremia (serum sodium to < 136 mEq/l) is the most common electrolyte abnormality in critically ill children. It could result from a deficit of sodium, or surplus of water. Impaired water excretion, 'inappropriate' release of vasopressin, use of hypotonic fluids, redistribution of sodium and water, sick cell syndrome, several drugs and primary illness all may contribute to hyponatremia. Acute hyponatremia, defined as a fall in serum sodium to ~ 120 mEq/l within 48 hours may result in acute cerebral edema and brain stem herniation particularly in children. However, there is paucity of data on hyponatremia in hospitalized critically ill patients. Studies addressing incidence, cause and outcome of hyponatremia in critically ill patients are needed to plan rational fluid therapy protocols, and resolve the current debate, which calls for abandonment of N/5 saline in 5% dextrose solution as maintenance intravenous fluid in favour of normal saline to prevent hyponatremia. At present it is not fully correct to assume that isotonic maintenance fluids would be superior to current maintenance fluids. Reducing the volume of maintenance fluid to about 75% of normal maintenance volume may be more appropriate way to prevent hyponatremia in view of water retaining effect of high ADH and reduced renal free water clearance in critically ill children.