Hyponatremia in children with respiratory tract infection

Abstract

Sirs,We read with great interest the article entitled "Hyponatremia in pediatric community-acquired pneumonia" by Don et al. in the latest issue of this journal [1], and we congratulate their elegant study.They concluded that hyponatremia (HN) is common (present in 45.4% of children with community-acquired pneumonia) and seems to be associated with the severity, assessed by fever, need of hospitalization and serum nonspecific inflammatory markers.We would like to add a comment based on our retrospective analysis. In 2004 we encountered serial patients with HN who had ben admitted to our hospital because of respiratory tract infection (RTI). This experience prompted us to investigate the prevalence of HN in children with RTI: the medical records of 138 children with RTIs admitted in 2004 (mean age 2.2 years, range 0.1-11.6 years) were reviewed retrospectively. These children had been previously healthy and did not have any underlying illness which predisposed them to HN, such as renal, thyroidal, adrenal or hypophyseal insufficiency.As shown in the table, there were 40 children (28.9%) with RTIs showing HN (serum sodium <136 mmol/L). There were no significant differences in age or duration of hospital stay between children with HN and those without HN: age 2.72± 2.55 years (mean ± standard deviation) for the former and 2.03±2.09 years for the latter; duration of hospital stay 7.00± 3.38 days (mean ± standard deviation) for the former and 6.04± 3.82 days for the latter (P>0.05 by unpaired Student's t-test). Furthermore, the 138 patients with RTIs were divided into three groups according to the site of inflammation, based on the clinical and radiological findings (Table 1). Interestingly enough, the deeper the site of inflammation, the higher the prevalence of HN.There have been several reports regarding HN in children with pneumonia [1][2][3][4], including the study by Don et al. In those studies the authors speculated that the mechanism of HN in pneumonia is due to the syndrome of inappropriate antidiuretic hormone (ADH) secretion and found that HN was associated with the severity in pneumonia. In addition, we here would like to suggest that the deeper the site of inflammation in the respiratory tract, the higher the prevalence of HN in children with RTIs.

Hyponatremia as a marker of invasiveness of pediatric respiratory tract infections

“…The interesting observations of Kaneko and Kaneko on the association between the depth of respiratory tract infection (RTI) and hyponatremia markedly supplement our findings on hyponatremia in pediatric pneumonia [1,2]. This association is in line with our finding, that the disease severity, assessed by fever and serum non-specific inflammatory markers, thus reflecting the invasiveness of infection, was associated with the occurrence of hyponatremia in children with pneumonia.…”

“…The frequency of hyponatremia was surprisingly similar in the Italian (45.4%; serum sodium <135 mmol/l) and Japanese (38.7%; serum sodium <136 mmol/l) children with pneumonia. Kaneko and Kaneko did not report how many patients had severe hyponatremia [1]. Among our patients, only 7/97(7%) had serum sodium levels <130 mmol/l, and none had symptoms induced by hyponatremia [2].…”

“…This association is in line with our finding, that the disease severity, assessed by fever and serum non-specific inflammatory markers, thus reflecting the invasiveness of infection, was associated with the occurrence of hyponatremia in children with pneumonia. In the study by Kaneko and Kaneko [1], the prevalence of hyponatremia was 13.3% in upper (pharyngitis or laryngitis), 22.9% in middle (bronchiolitis or bronchitis) and 38.7% in lower (pneumonia) respiratory tract infection. Owing to the small number of patients in the group with upper respiratory tract infection, the differences were statistically significant only when the children with pharyngitis, laryngitis, bronchiolitis or bronchitis were jointly compared with children suffering from pneumonia (hyponatremia in 16/76 vs 24/62; P=0.018).…”

“…Moreover, the mechanisms may be different in children in developing and developed countries. Despite this, currently available data suggest that hyponatremia may be common in children with different respiratory tract infections, and attention should be paid to sufficient but not excessive drinking [6] and, if based on these two recent studies, also on appropriate supply of sodium [1,2]. Both dehydration and hyponatremia are common in children with acute intestinal infections, and, in these conditions, preventive therapy with small amounts of oral rehydration solutions (ORS; sodium 60 mmol/l in Italy), consumed daily during the symptomatic days, has been successful [7].…”

Prevalence of Hyponatremia in Children with Pneumonia -CrossSectional Study

“…The resultant cerebral edema is associated with high mortality. Hyponatremia has also been documented as a marker of severe illness and increases mortality (7,8). It's therefore paramount for clinicians to understand common electrolyte abnormalities, have a high index of suspicion and timely recognize them.…”