Sporadic pseudohypoaldosteronism: A challenging diagnosis

Abstract

Introduction: Pseudohypoaldosteronism (PHA) is a rare form of salt-wasting syndrome, caused by peripheral resistance to aldosterone. PHA is of three types: PHA type 1, 2, 3. Pseudohypoaldosteronism type 1 (PHA_1) is further differentiated into, (i) hereditary forms, autosomal recessive and dominant, which are caused by epithelial sodium channel and mineralocorticoid receptor mutations respectively and (ii) secondary form which is associated with urological problems. Case Report: We present a case of a male infant who presented with failure to thrive, vomiting, mild dehydration and reflux. Evaluation revealed hyperkalemia with normal glucose and carbon dioxide levels. A preliminary diagnosis of CAH (congenital adrenal hyperplasia) was made. Further workup showed high serum aldosterone and renin levels with normal renal and adrenocortical functions. In line with the investigations the diagnosis of pseudohypoaldosteronism was made. The patient was treated with sodium supplementation, which normalized his clinical state and serum electrolytes. Follow-up revealed weight gain and improved status. Conclusion: Diagnosis of PHA_1 is based on plasma electrolyte assessment, elevated renin activity and aldosterone levels with normal renal function. PHA_1 results from a renal or systemic resistance to aldosterone. In our reported patient we suspected a renal form of PHA_1, which is a milder form and responded well to treatment with salt supplements. Infants who present with electrolyte imbalance like hyperkalemia, hyponatremia and weight loss should be evaluated for adrenocortical function and need careful management. Though PHA is a group of rare syndromes, a high degree of suspicion along with extensive laboratory workup should be pursued in cases with electrolyte imbalances.