Fetal pseudohypoaldosteronism: another cause of hydramnios.

Pseudohypoaldosteronism (PHA) is a rare hereditary salt-wasting syndrome which is caused by decreased renal tubular responsiveness to aldosterone. The syndrome consists of hyponatremia, hyperkalemia, dehydration, failure to thrive and increased urinary salt loss. A case of PHA was previously described where fetal polyuria was the probable cause of hydramnios. We present four new cases of PHA, from two families, who were born after pregnancies complicated by severe hydramnios and premature labor. We suggest that PHA should be included in the differential diagnosis of hydramnios, since appropriate investigations might lead to the early diagnosis and treatment of a life-threatening disease.