Cardiac arrest in a newborn: A case of pseudohypoaldosteronism.

Pseudohypoaldosteronism (PHA) is a rare disease that can cause life-threatening hyperkalemia, which could lead to cardiac arrest and death if not recognized and treated quickly. We report a case of a neonate who was diagnosed with PHA type 1 and found to have a novel variant gene mutation on the NR3C2 gene. A 5-day-old newborn presented in cardiac arrest with severe hyperkalemia, hyponatremia, and metabolic acidosis. Hypothermia treatment was initiated due to suspected hypoxic-ischemic encephalopathy as well as electrolyte management with IV fluids and bicarbonate for the metabolic acidosis. Clinical suspicion and subsequent diagnostic testing led to a diagnosis of the renal form of PHA type 1. Genetic testing revealed a novel mutation on the NR3C2 gene of unknown significance (c.2891_2893dup plle964dup). The baby was discharged home on supplemental sodium and high-calorie formula for catch-up growth. Outpatient follow-up is ongoing, and the dose of sodium supplement was slowly decreased and discontinued at 2 years. There is evidence for developmental delays which is likely secondary to the cardiac arrest although the MRI during hospitalization was noted to be within normal limits. Having a high clinical suspicion for pseudohypoaldosteronism is paramount to initiating treatment and preventing potential cardiac arrest and death in these patients. Novel mutations such as this one need to be further explored to determine their significance with this disease.