During the first year of life, and especially in the first 6 months, urinary tract infections, congenital anomalies of the kidney and urinary tract (CAKUT)-particularly obstructive types-and the coexistence of both factors may lead to transient resistance to aldosterone. This condition is characterized by fluid and salt loss despite significant activation of the renin-angiotensin-aldosterone system, and by electrolyte disturbance featuring hyponatremia, hyperkalemia, and metabolic acidosis with a normal anion gap. Transient resistance to aldosterone is not widely recognized by clinicians. Our objective was to describe the clinical presentations and management strategies in order to propose a comprehensive diagnostic approach. We conducted a 13-year retrospective study involving 35 children from eight centers across France, as well as one child from Switzerland. Most of the children in our cohort were under 6 months of age (68.6% male). The clinical presentation of pseudohypoaldosteronism was variable and often similar to that of adrenal insufficiency. The pyelonephritis diagnosis was retained in 94.3% of the cases and uropathy was present in 85.7% of the children. Treatment was primarily symptomatic, and included intravenous hydration, salt supplementation, correction of potassium levels, and antibiotic therapy when pyelonephritis was diagnosed.  Transient type I pseudohypoaldosteronism should be promptly considered in any infant presenting with a deteriorating general condition and fluid and electrolyte imbalances, particularly hyponatremia and hyperkalemia, in the context of acute pyelonephritis and/or uropathy. • Transient type I pseudohypoaldosteronism affects infants under 1 year of age with congenital anomalies of the kidney and urinary tract during acute pyelonephritis. • Treatment mostly consists of antibiotics and parenteral fluids. • This is the first article to report on 34 cases from a single country. • The importance of renal ultrasound in the context of urinary tract infection with salt wasting symptoms in infants without known congenital anomalies the kidney and urinary tract. • The importance of assessing hydro-electrolytic status in cases of urinary tract infection in infants under 6 months with or without known congenital anomalies of the kidney and urinary tract. • A decision tree for the diagnostic approach of transient type I pseudohypoaldosteronism.

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

The aim of the study was to evaluate whether serum aldosterone levels or plasmatic renin activity (PRA) measured early in life (1-3 months) could predict a future surgical intervention for obstructive congenital anomalies of kidney and urinary tract (CAKUT). Twenty babies aged 1-3 months of life with suspected obstructive CAKUT were prospectively enrolled. The patients underwent a 2-year follow-up and were classified as patients needing or not needing surgery. In all of the enrolled patients, PRA and serum aldosterone levels were measured at 1-3 months of life and were evaluated as predictors of surgery by receiver-operating characteristic (ROC) curve analysis. Patients undergoing surgery during follow-up showed significantly higher levels of aldosterone at 1-3 months of life compared to those who did not require surgery (p = 0.006). The ROC curve analysis of the aldosterone for obstructive CAKUT needing surgery showed an area under the ROC curve of 0.88 (95%CI = 0.71-0.95; p = 0.001). The aldosterone cut-off of 100 ng/dL presented 100% sensitivity and 64.3% specificity and predicted surgery in 100% of cases. The PRA at 1-3 months of life was not a predictor of surgery. In conclusion, serum aldosterone levels at 1-3 months could predict the need for surgery during obstructive CAKUT follow-up.

Transient Pseudohypoaldosteronism (TPHA) is a very rare condition usually secondary to urinary tract malformations (UTM) and/or urinary tract infection (UTI). It is characterized by hyperkalemia, hyponatremia, metabolic acidosis, and elevated plasma aldosterone levels. Given that the predominant manifestations of TPHA patients are digestive tract symptoms, such as poor appetite, vomiting, and weight gain, it is easily misdiagnosed as digestive tract diseases. Two children with poor appetite and vomiting were admitted to the Department of Gastroenterology, Children's Hospital of Nanjing Medical University, from 2020 to 2021. Laboratory test results of these two children revealed hyponatremia (< 135.00 mmol/L), hyperkalemia (> 5.50 mmol/L), and hyperaldosteronism (> 180.00 ng/L). Moreover, genetic tests demonstrated no genetic variants highly associated with the phenotype in both cases. The two patients were subsequently treated with electrolyte correction. One of them also treated with antibiotics and one of them underwent surgery. They were followed for 8 and 4 months, respectively. No complications were observed during the follow-up period. This review aimed to outline both cases with parental consent. Transient pseudohypoaldosteronism should be considered in children younger than 6 months, presenting with vomiting, poor appetite, unexplained hyponatremia, hyperkalemia, elevated aldosterone levels, and urethral malformation or urinary tract infection. Furthermore, attention should be paid to whether salt supplementation or anti-infection therapy is effective.