[An elderly fludrocortison-responsive woman with hyponatoremia].

An 89-years-old woman had anorexia for at least 1 month, and had been given symptomatic treatment at a nearby hospital. She was admitted to our hospital on August 22, 2003, for thorough examination and appropriate treatment for lack of spontaneity and appetite loss. On admission, laboratory data revealed hyponatremia (125 mEq/L) and hypoaldosteronism (0.7 ng/mL). Since hyponatremia did not improve by intravenous drip with saline, we identified the major cause of her complaint as hypoaldosteronism. She was treated with fludrocortisone (0.05 mg/day) and her condition improved immediately. Although she was discharged at that time, her condition shortly deteriorated. She was referred to our hospital on February 10, 2004 for medical treatment. On admission, inadequate oral intake, lack of spontaneity and weakness in her lower legs were noted. The plasma Na concentration was 127 mEq/L. Nasogastric tube feeding was started to prevent aspiration pneumonia because of her dysphagia. Fludrocortisone was given (0.2 mg/day), and she was able to swallow food without nasal feeding tube during the second month of therapy. Laboratory data including plasma natrium concentration were normal. Also she could perform bed-to-wheelchair transfer independently. This is a rare case of a critically ill elderly patient with hyponatremia caused by hypoaldosteronism possibly due to mineral corticoid-responsive hyponatremia of the elderly.