Renal handling of salt and water in myxedema

The response to acute water ingestion was determined in 10 patients with untreated myxedema and another 10 control subjects. Comparison of the results in the two groups indicated an abnormality in water excretion in the myxedematous patients. The imparied water diuresis in patients with myxedema including those with significant hyponatremia appeared to be multifactorial in origin. Impaired sodium transport, altered antiduiretic hormone metabolism and diminished volume delivery to the distal diluting segments are all present in hypothyroidism and may operate in combination in the pathogenesis of the impaired renal handling of salt and water in this disorder