Transient pseudohypoaldosteronism masquerading as congenital adrenal hyperplasia

Analysis of patients presenting with serum electrolyte imbalance in terms of the differential diagnosis of pseudohypoaldosteronism

OBJECTIVE

The aim of this study was to contribute to the differential diagnosis of transient pseudohypoaldosteronism (t-PHA).

METHODS

Twenty-nine infants, younger than 24 weeks, and with high aldosterone levels were included in the study. The patients were divided into two groups as t-PHA and other diagnoses group. Of 29 patients, 18 were in the t-PHA group and 11 were in other diagnoses group.

RESULTS

The means aldosterone, plasma renin activities (PRA), adrenocorticotropic hormone (ACTH), cortisol, and 17-hydroxyprogesterone (17-OHP) of those with t-PHA were 138±92.8 ng/dL, 8.39±10.57 ng/mL/h, 26.86±19.56 ng/L, 19.44±21.84 μg/dL, and 7.66±10.71 ng/mL, respectively. In other diagnoses group, the mean level of aldosterone, PRA, ACTH, cortisol, and 17-OHP levels was 100.9±70 ng/dL, 5.49±8.41 ng/mL/h, 408.28±491.9 ng/L, 19.99±14.43 μg/dL, and 11.99±12.21 ng/mL, respectively. In the t-PHA group, the number of patients with high PRA was eight (50%), while the number of patients with high levels was two (18.1%) in other diagnoses group. In the t-PHA group, although the average serum K levels were the same in both groups, serum aldosterone/K ratios were higher.

CONCLUSION

When an infant younger than 24 weeks, with urinary tract infection and/or urinary tract malformation has electrolyte abnormalities, pediatricians should primarily consider the diagnosis of t-PHA. Thus, many unnecessary investigations and inappropriate treatments can be avoided.

A Five-Month-Old Boy With Hypotonia, Electrolyte Derangements, and Failure to Thrive

Failure to thrive in the setting of profound hypotonia and multiple electrolyte derangements is a challenging constellation of findings that offers a broad differential diagnosis for providers to consider. Initial management should focus on the stabilization of the patient and correction of potential life-threatening electrolyte derangements. Once completed, the diagnosis should be sought, and in this case, many were considered and ultimately ruled out with thorough history and physical examination. Laboratory abnormalities revealed the final diagnosis of pseudohypoaldosteronism and connected the case. With proper treatment, our patient had a resolution of laboratory anomalies along with improved growth and tone.

Challenges of Diagnosing Pseudohypoaldosteronism (PHA) in an Infant

Background. Pseudohypoaldosteronism (PHA) is characterized by renal tubular resistance to aldosterone. As a result, the symptoms typically involve hyperkalemia and hyponatremia. The aim of this clinical case report is to highlight the severe electrolyte imbalance PHA can present within an infant, as well as difficulties in diagnosing the condition. Case Presentation. A 5-week-old male arrived at the ER with episodes of emesis, lethargy, and difficulty in feeding. He had significant electrolyte abnormalities and was being treated by his PCP for failure to thrive. He presented with urinary sodium wasting, indicated by hyponatremia, hyperkalemia, low chloride, and hypercalcemia. Patient was treated with IVF and NaCl supplementation to normalize the electrolytes. The patient showed heterozygosity for a variant in the WNK1 gene, which typically causes Gordon syndrome; however, our patient had a normal blood pressure. The electrolyte imbalance self-resolved during several months of follow-up, and currently, the patient is not on any treatment.

Novel SCNN1A gene splicing-site mutation causing autosomal recessive pseudohypoaldosteronism type 1 (PHA1) in two Italian patients belonging to the same small town

INTRODUCTION

Pseudohypoaldosteronism type 1 (PHA1) is a rare genetic disease due to the peripheral resistance to aldosterone. Its clinical spectrum includes neonatal salt loss syndrome with hyponatremia and hypochloraemia, hyperkalemia, metabolic acidosis and increased plasmatic levels of aldosterone. Two genetically distinct forms of disease, renal and systemic, have been described, showing a wide clinical expressivity. Mutations in the genes encoding for the subunits of the epithelial sodium channels (ENaC) are responsible for generalized PHA1.

PATIENTS' PRESENTATION

We hereby report on two Italian patients with generalized PHA1, coming from the same small town in the center of Sicily. The first patient is a male child, born from the first pregnancy of healthy consanguineous Sicilian parents. A novel SCNN1A (sodium channel epithelial subunit alpha) gene mutation, inherited from both heterozygous parents, was identified by next generation sequencing (NGS) in the homozygous child (and later, also in the heterozygous maternal aunt). A more detailed family history disclosed a possible related twenty-year-old girl, belonging to the same Sicilian small town, with referred neonatal salt loss syndrome associated to hyperkalemia, and subsequent normal growth and neurodevelopment. This second patient had a PHA1 clinical diagnosis when she was about 1 year old. The genetic investigation was, then, extended to her and to her family, revealing the same mutation in the homozygous girl and in the heterozygous parents.

CONCLUSIONS

The neonatologist should consider PHA1 diagnosis in newborns showing hyponatremia, hyperkalemia and metabolic acidosis, after the exclusion of a salting-loss form of adrenogenital syndrome. The increased plasmatic levels of aldosterone and aldosterone/renin ratio, associated to a poor response to steroid administration, confirmed the diagnosis in the first present patient. An accurate family history may be decisive to identify the clinical picture. A multidisciplinary approach and close follow-up evaluations are requested, in view of optimal management, adequate growth and development of patients. Next generation sequencing (NGS) techniques allowed the identification of the SCNN1A gene mutation either in both patients or in other heterozygous family members, enabling also primary prevention of disease. Our report may broaden the knowledge of the genetic and molecular bases of PHA1, improving its clinical characterization and providing useful indications for the treatment of patients. Clinical approach must be personalized, also in relation to long-term survival and potential multiorgan complications.

A rare cause of salt-wasting in early infancy: Transient pseudohypoaldosteronism

Three infants aged between 38 days and 43 days all presented with poor weight gain, hyponatremia, hyperkalemia, and were diagnosed as having urinary tract infections, which were accompanied by urinary tract malformations in our cases. Hydration and infection treatments were given. A few days after admission, hormonal studies revealed normal cortisol and 17-hydroxy progesterone levels and markedly high aldosterone levels, thus the patients were diagnosed as having transient pseudohypoaldosteronism. After the proper treatment was given, the transient pseudohypoaldosteronism resolved. In conclusion, when an infant with urinary tract infection or malformation has electrolyte abnormalities, pediatricians should consider the diagnosis of transient pseudohypoaldosteronism.

Systemic Pseudohypoaldosteronism Type 1 due to 3 Novel Mutations in SCNN1Aand SCNN1BGenes

OBJECTIVE

The systemic form of pseudohypoaldosteronism type 1 (PHA1) is an autosomal recessive disorder characterized by defective sodium transport in multi-organ systems. Mutations in the genes encoding the amiloride-sensitive epithelial sodium channel, ENaC, account for genetic causes of systemic PHA1. We describe systemic PHA1 due to 4 novel variants detected in SCNN1A and SCNN1B in 3 cases from 3 unrelated consanguineous families.

PATIENTS AND METHODS

We evaluated the clinical presentations, biochemical and hormonal characteristics, and molecular genetic analysis results of 3 patients from 3 unrelated consanguineous families and parents from whom samples were available.

RESULTS

The ages at presentation were postnatal days 9, 10, and 5. The main presentation symptoms were vomiting, poor feeding, weakness, weight loss, and skin rash. All patients exhibited laboratory characteristics including severe hyponatremia, hyperkalemia, metabolic acidosis, elevated plasma renin, elevated aldosterone, and positive sweat tests, suggesting a diagnosis of systemic PHA1. Molecular genetic analysis revealed 2 novel pathogenic variants [c.87C>A(p.Tyr29*)/IVS9 + 1G>A (c.1346 + 1G>A)] in SCNN1Bin case 1, a novel homozygous pathogenic variant [p.His69Arg(c.206A>G] in SCNN1Ain case 2, and a homozygous one-base duplication, p.A200Gfs*6 (c.598dupG), in SCNN1A in case 3.

CONCLUSION

PHA1 should be considered at differential diagnosis in patients presenting with hyponatremia, hyperkalemia, and metabolic acidosis. The cases in this report involving 4 novel variants will add valuable insights into the phenotype-genotype relationship and will expand the mutation database.

Transient pseudohypoaldosteronism: a potentially severe condition affecting infants with urinary tract malformation

BACKGROUND

Secondary pseudohypoaldosteronism (S-PHA) is a life-threatening condition affecting young children with urinary tract malformation (UTM).

OBJECTIVE

The aim of the study was to highlight the diagnosis of S-PHA in children with UTM and propose appropriate management.

STUDY DESIGN

The authors retrospectively reviewed cases of S-PHA related to UTM observed at the institution and searched the PubMed® database to review the literature.

RESULTS

A total of 116 cases of S-PHA associated with UTM, including the four cases from the institution, were reviewed. One hundred six cases (92.2%) were younger than 6 months, and 95 cases (81.9%) occurred in boys. Urinary tract infection was associated in 105 cases (90.5%). All types of UTM were observed. In the absence of urinary tract infection, S-PHA was related to bilateral UTM or solitary kidney. In 89 cases (76.5%), S-PHA resolved with medical treatment only. In cases of UTM requiring immediate surgery, electrolyte imbalance related to S-PHA also resolved after surgery. Children with associated urinary tract infection and bilateral UTM are at higher risk of developing S-PHA.

DISCUSSION

The pathogenesis of S-PHA has not been fully elucidated. Renal tubular immaturity may be one of the factors involved, in view of the young age of the population being affected. A high rate of bilateral UTM (or UTM on solitary kidney) was observed (50.9%), suggesting an association with S-PHA. In the absence of urinary tract infection (UTI), S-PHA appeared to occur more frequently in the presence of bilateral UTM. Although the indication for early surgery remains unclear, it may have a role in the prevention of UTI and prevention of recurrence of S-PHA. Serum electrolytes should be checked in children with UTM before urological surgery, and/or presenting urinary tract infection, before the age of 6 months. The results of this study must be interpreted cautiously because of its retrospective nature and the fact that data were derived from various articles. Few articles on S-PHA related to UTM have been published in the literature. To the best of the authors' knowledge, the study constitutes the largest series published to date.

CONCLUSIONS

S-PHA results in potentially severe electrolyte imbalance and affects children younger than 6 months with UTI and/or UTM. Electrolyte abnormalities related to S-PHA often resolve after administration of appropriate intravenous electrolyte solution and treatment of UTI and/or surgery.

High aldosterone and cortisol levels in salt wasting congenital adrenal hyperplasia: a clinical conundrum

BACKGROUND

Salt wasting syndrome (hyponatremia, hyperkalemia, dehydration, metabolic acidosis) in early infancy could be caused by either mineralocorticoid deficiency as in congenital adrenal hyperplasia (CAH) and adrenal insufficiency or mineralocorticoid resistance as in pseudohypoaldosteronism (PHA). In salt wasting CAH, serum aldosterone and cortisol levels are expected to be low. Cross reactivity between high levels of adrenal steroid precursors and aldosterone has recently been reported resulting in elevated aldosterone levels in CAH, leading to difficulty in differentiating between CAH and PHA.

CASE PRESENTATION

We report four such cases of salt wasting CAH, where high aldosterone levels and high normal cortisol levels led to initial diagnostic confusion with PHA. Diagnosis of CAH was later established on the basis of significantly elevated adrenocorticotropic hormone (ACTH) stimulated 17-hydroxyprogesterone (17-OHP) values.

CONCLUSIONS

By reporting these cases we draw attention to the possibility that high levels of adrenal steroid precursors can cross react with aldosterone and cortisol, and underscore the significance of ACTH stimulated 17-OHP values in differentiating CAH and PHA.

Secondary or Transient Pseudohypoaldosteronism Associated With Urinary Tract Anomaly and Urinary Infection: A Case Report

Hyponatremia with hyperkalemia in infancy is a rare presentation, but may be due to aldosterone deficiency or end organ resistance to its action. There are few cases associating this condition with urinary tract infections or anatomic abnormalities that predispose to infection. Clinicians should have a high index of suspicion in diagnosing secondary pseudohypoaldosteronism (PHA) due to its often atypical presentation. We describe ten month-old infant who presented with this condition and was found to have urinary tract infection complicating unilateral urinary tract anomaly, which may have strong association with renal tubular resistance to aldosterone.

Novel mutations in the SCNN1A gene causing Pseudohypoaldosteronism type 1

Pseudohypoaldosteronism type 1 (PHA1) is a rare inherited disease characterized by resistance to the actions of aldosterone. Mutations in the subunit genes (SCNN1A, SCNN1B, SCNN1G) of the epithelial sodium channel (ENaC) and the NR3C2 gene encoding the mineralocorticoid receptor, result in systemic PHA1 and renal PHA1 respectively. Common clinical manifestations of PHA1 include salt wasting, hyperkalaemia, metabolic acidosis and elevated plasma aldosterone levels in the neonatal period. In this study, we describe the clinical and biochemical manifestations in two Chinese patients with systemic PHA1. Sequence analysis of the SCNN1A gene revealed a compound heterozygous mutation (c.1311delG and c.1439+1G>C) in one patient and a homozygous mutation (c.814_815insG) in another patient, all three variants are novel. Further analysis of the splicing pattern in a minigene construct showed that the c.1439+1G>C mutation can lead to the retainment of intron 9 as the 5′-donor splice site disappears during post-transcriptional processing of mRNA. In conclusion, our study identified three novel SCNN1A gene mutations in two Chinese patients with systemic PHA1.