In the neonatal period, hydro electrolytic disorders with dehydration and metabolic acidosis can cause admission to an intensive care unit and become a diagnostic challenge. Among such disorders, hyponatremia and hyperkalemia become diagnostic challenges with hormonal involvement, including aldosterone. Pseudohypoaldosteronism (PHA) resulting from the lack of response to aldosterone in target cells can be classified into three types and its suspected diagnosis in cases of hyponatremia, hyperkalemia with an elevation of serum aldosterone, can be confirmed by exome sequencing with identification of a potentially pathogenic. This study was based on the case report of a newborn of consanguineous parents who, after birth, evolved in the first week of life with shock, hyponatremia, hyperkalemia, and metabolic acidosis. An initial investigation ruled out congenital adrenal hyperplasia. The presence of hyperaldosteronism with increased plasma renin activity, associated with hyperkalemia and hyponatremia difficult to control with electrolyte replacement, led to a molecular investigation that confirmed PHA type 1 by a mutation in the SCCN1A gene. In neonates with severe hyponatremia that is difficult to resolve with conventional treatment and elevation of serum aldosterone, this pathology must be remembered and investigated, avoiding high morbidity and mortality.