title: Recurrent hyponatremia in a patient with chronic kidney disease.
abstract: Hyponatremia, albeit common in chronic renal insufficiency, necessitates a detailed search of the underlying hidden causes. We report on a 67-year-old woman with chronic kidney disease (creatinine 230 micromol/L) and hypertension who suffered from general fatigue, dizziness, nausea, vomiting and abdominal fullness off and on for 6 months. Hyponatremia (plasma Na(+) 106-125 mmol/L) on 4 occasions during the past 6 months was noticed. Her extracellular volume status was apparently normal. Plasma Na(+) concentration 110 mmol/L was the most striking laboratory abnormality with mild metabolic acidosis (HCO(3)- 19.8 mmol/L). Her urine Na(+) concentration and osmolality were inappropriately high. Her hyponatremia was refractory to normal saline, hypertonic NaHCO(3) and 0.1-microg 9 alfa-fludrocortisone. Despite normal plasma cortisol and thyroid hormone concentrations, a provocation test with cosyntropin (250 microg) showed a blunted cortisol (<579 nmol/L) but intact aldosterone response. Magnetic resonance imaging of her brain displayed a normal pituitary gland and hypothalamus. A history of intermittent intravenous steroid therapy to treat her allergic rhinitis for 3 years was uncovered. Steroid supplements induced water diuresis and corrected hyponatremia to 135 mmol/L in 5 days. With nonspecific clinical symptoms, glucocorticoid insufficiency must be kept in mind as a cause of hyponatremia even in patients with impaired renal function and normal plasma cortisol concentration.
authors.affiliation: Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Chin-Sheng
authors.initials: CS
authors.lastname: Lin
authors.forename: Chih-Jen
authors.initials: CJ
authors.lastname: Cheng
authors.forename: Kuang-Chung
authors.initials: KC
authors.lastname: Shih
authors.forename: Shih-Hua
authors.initials: SH
authors.lastname: Lin
mesh_terms: D000368:Aged; D002908:Chronic Disease; D005260:Female; D005938:Glucocorticoids / Q000172:deficiency*; D006801:Humans; D007010:Hyponatremia / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D007674:Kidney Diseases / Q000150:complications*; D012008:Recurrence
chemical_list: D005938:Glucocorticoids