Rare coexistence of aldosterone resistance and adrenal insufficiency in asymptomatic infant with persistent hyperkalaemia: A case report

BACKGROUND: Hyperkalaemia is a potentially life-threatening electrolyte disturbance, most commonly encountered in neonates and infants with renal or endocrine abnormalities. Persistent hyperkalaemia in an otherwise clinically well child is unusual and warrants careful investigation. This case illustrates a rare coexistence of pseudohypoaldosteronism and adrenal insufficiency in an otherwise well infant, presenting solely with persistent hyperkalaemia. CASE SUMMARY: We report a 6-month-old male infant who was incidentally found to have persistent hyperkalaemia during hospitalisation for acute bronchiolitis. He remained asymptomatic, with no clinical or electrocardiographic features of hyperkalaemia. Laboratory investigations revealed persistent hyperkalaemia with normal serum sodium and chloride levels, low serum bicarbonate, elevated serum aldosterone, and suppressed plasma renin activity which consistent with features of aldosterone resistance. Further testing demonstrated low basal serum cortisol with inadequate response to synacthen stimulation, while serum 17-hydroxyprogesterone levels were normal, excluding congenital adrenal hyperplasia. The child was managed with hydrocortisone, high-dose fludrocortisone, and potassium-binding resins, with subsequent improvement. CONCLUSION: This case illustrates a rare coexistence of aldosterone resistance and adrenal insufficiency in an otherwise well infant, presenting solely with persistent hyperkalaemia. It emphasises the importance of considering overlapping endocrine pathologies and highlights the need for early hormonal profiling in infants with unexplained electrolyte disturbances.