A 76-year-old man was admitted because of general
fatigue and
lumbago. Two years before admission,
hyponatremia and
hyperkalemia were pointed out, subsequently
hydrocortisone (20 mg/day) was given under the diagnosis of
panhypopituitarism. The marked improvement was found in the
electrolytes abnormality. On examination at admission, there was no abnormality of anterior pituitary function. In addition to the extremely low level of plasma
renin activity and
aldosterone concentration, the persistent microhematuria and
hyperuricemia were found, however, renal histology only showed the benign
arteriosclerosis but no significant alteration in juxtaglomerular apparatus and glomeruli. The urinary
prostacyclin metabolite output was rather increased compared to that of normal subject, suggesting that
prostaglandins may not be responsible for the defect of
renin secretion. Although, the cause was still unknown, small dose of
dexamethasone was extremely effective to resolve
electrolytes abnormality and
hematuria.