Prevalence, diagnosis, and management of secondary pseudohypoaldosteronism

Hyponatremia in babies: a 11-year single-center study

Introduction

Hyponatremia is one of the most prevalent water-electrolyte disturbances encountered in clinical practice in pediatrics and can arise from various conditions. However, there are limited reports on hyponatremia in hospitalized infants. The objective of this study was to provide an overview of the incidence, etiologies, and clinical characteristics of hyponatremia in hospitalized babies (from birth to 3 years old) at a tertiary hospital.

Method

Computer records of all hospitalized babies (from birth to 3 years old) with hyponatremia were extracted from the First Affiliated Hospital of Guangxi Medical University's clinical databases.

Results

801 patients from 39,019 hospital admissions were found to have hyponatremia and the overall prevalence of this condition was 2.05% in babies. Patients with hyponatremia due to aldosterone signaling abnormalities, neurological disorders, and liver diseases exhibited more severe outcomes than those with other etiologies.

Conclusions

Various conditions can result in hyponatremia in hospitalized babies. Aldosterone signaling abnormalities were not that uncommon and it could lead to severe hyponatremia in babies.

Pseudo-hypoaldosteronism secondary to infantile urinary tract infections: role of ultrasound

Background

The biochemical hallmarks of transient pseudo-hypoaldosteronism associated with a pyelonephritis include hyponatremia, hyperkalemia, and acidosis. We tested if the kidney-urinary tract ultrasound helps in predicting the diagnosis of overt pseudo-hypoaldosteronism in infants with a pyelonephritis.

Cases presentation

Between 2013 and 2020, we managed 71 previously healthy infants 4 weeks to 24 months of age with a pyelonephritis (42 males and 29 females) and made the biochemical diagnosis of pseudo-hypoaldosteronism in 17 (24%). Infants with and without pseudo-hypoaldosteronism did not significantly differ with respect to the prevalence of kidney-urinary tract ultrasound abnormalities, graded by means of the UTD classification system of urinary tract abnormalities.

Conclusions

Kidney-urinary tract ultrasound is almost routinely obtained in children with a febrile urinary tract infection. Our experience does not support the hypothesis that ultrasound might be relevant for the diagnosis of overt transient pseudo-hypoaldosteronism in babies affected by a urinary tract infection. Our data confirm the assumption that negative studies may be important for advancing clinical practice.

A Unique Genotype of Pseudohypoaldosteronism Type 1b in a Highly Consanguineous Population

Context

Pseudohypoaldosteronism (PHA) is a condition in which serum aldosterone level is normal or elevated but its action is deficient.

Objective

This study describes the molecular genetics of PHA 1b in the highly consanguineous population of 2 Arabian Gulf countries, Saudi Arabia and Oman.

Methods

This study enrolled 22 patients from 13 unrelated families (2 families with 5 patients from Oman and 11 families with 17 patients from Saudi Arabia). All of these patients had presented within the first 10 days of life with nausea and vomiting, hyponatremia, hyperkalemia, and hypotension. We isolated DNA from peripheral blood and PCR-sequenced all exons and exon-intron boundaries of SCNN1A and, if negative, SCNN1B and SCNN1G using the Dideoxy Chain termination method.

Results

We found a total of 8 mutations in 13 families as follows: 6 mutations in SCNN1A, 1 in SCNN1B, and 1 in SCNN1G. All of these mutations were novel except one. SCNN1A mutations were: c.1496A>G, p.Q499R (novel) in 1 patient; c.1453C>T, p.Q485X (novel) in 1 patient; c.1322_1322delA, p.N441Tfs*41 (novel) in 2 patients of 1 family; c.876 + 2 delGAGT (novel) in 3 patients of 1 family; c.203_204 delTC, p.I68Tfs*76 (a known mutation) in 8 patients of 5 families; and whole SCNN1A gene deletion (novel) in 2 patients of 2 families. In addition, a nonsense SCNN1B mutation c.1694C>A, p.S565X (novel) was found in 3 siblings from 1 Omani family, and an SCNN1G deletion mutation c.527_528 delCA, p.T176Rfs*9 (novel) in 2 siblings from another Omani family.

Conclusion

We characterized a unique genotype of PHA 1b with several novel gene structure-disrupting mutations in SCNN1A, SCNN1B, and SCNN1G in a highly consanguineous population.

Hyponatremia in childhood urinary tract infection

Acute urinary tract infection (UTI) is the most common bacterial infection in childhood. Although hyponatremia was described in ~ 2/3 of these children, its clinical significance is still unclear. Herein, we evaluated the prevalence and clinical implications of hyponatremia in children hospitalized with a UTI. Medical records of previously healthy children hospitalized between January 2011 and December 2016 with UTI were retrospectively reviewed. Patients (median age 5.5 months) were divided into two groups according to their sodium levels: normonatremia (Na ≥ 135 mEq/L) and hyponatremia (Na < 135 mEq/L). Hyponatremia diagnosed on admission was found in 114/219 children (49%). Hyponatremic patients experienced a more severe disease manifested by a longer hospital stay (3.8 vs 3.4 days, p = 0.003), a higher prevalence of abnormal findings on renal ultrasound (10 vs 2, p = 0.01), higher C-reactive protein (CRP) levels (8.6 vs 3.4 mg/dl, p = <0.001), and a negative correlation between sodium levels and CRP (r = - 0.38, p < 0.001).Conclusion:Hyponatremia occurs frequently in children hospitalized with UTI and is associated with elevated inflammatory markers and a more severe disease course. What is Known: • Hyponatremia, one of the most common electrolyte abnormalities, occurs in approximately 1/3 of hospitalized children and in 2/3 of children with pyelonephritis. • In certain cases of various medical conditions, hyponatremia has been shown to correlate with disease severity. What is New: • Hyponatremia in hospitalized children with UTI correlates with elevated inflammatory markers and a more severe disease course.

Case Report: Severe Hyponatremia in Infants With Urinary Tract Infection

Introduction: Many reports on investigations and treatments in UTI, however little, have been mentioned with regard to electrolyte abnormalities. Secondary pseudohypoaldosteronism (PHA) in UTI, though less common, is a known association. Features include hyponatremia and concomitant hyperkalemia. Objectives: We aim to highlight these uncommon sequelae in UTI to avoid incorrect diagnosis and unnecessary investigations. Study Design: Clinical data of patients admitted and referred to a pediatric nephrologist at the University Malaya Medical Center between May 2019 and October 2020 were collated and elaborated. Results and Discussion: We report three infants with hyponatremia and hyperkalemia during UTI episodes. Two infants were known to have posterior urethral valve (PUV) before the onset of UTI and one infant had UTI, which led to investigations confirming the diagnosis of bladder vaginal fistula. The electrolyte derangements were temporary and resolved within 48 to 72 h of treatment with intravenous fluid and appropriate antibiotic therapy. Out of three, only one had a hormonal study, which confirms PHA. Reduced aldosterone activity could be due to absolute reduction in aldosterone titer or lack of aldosterone responsiveness at tubular (other tissues) level. In the latter, aldosterone titer is elevated. The infant in our cohort who had hormonal evaluation had the mentioned electrolyte abnormalities with a markedly elevated aldosterone titer. This demonstrated defective action of the hormone at the level of mineralocorticoid receptor. Although the remaining two infants had no confirmatory hormonal study, all of them recovered within 48 h of hospital admission, after receiving appropriate management for the primary problem, which was UTI. We observed a slower recovery of hyponatremia in relation to hyperkalemia, but none of these infants required salt replacement upon discharge. Conclusion: Infants with severe UTI and deranged electrolytes should be screened for structural abnormality and vice versa. Not all infants require hormonal screening, but those who required prolonged salt replacement or showed involvement of other systems warrant further evaluation.