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Hypertension and low serum potassium caused by excess salt-retaining hormone activity in hypothyroidism
The background of the study. Hypothyroidism is characterized by an increase in blood pressure, and a few patients have hypertension that is responsive to treatment with thyroxine (T4). This report describes a patient with hypothyroidism who had hypertension and low serum potassium thought to be caused by excess adrenal salt-retaining hormone activity.
Case report. The patient was an 84-year-old woman with a history of hypertension and peripheral vascular disease who was referred for evaluation of increasing hypertension and low serum potassium. Her blood pressure was 180/80 to 180/90 mm Hg. Her serum sodium concentration was slightly high and her serum potassium low. The patient’s serum thyrotropin (TSH) concentration was very high and her serum free T4 concentration was low.
The ratio of cortisol (which can cause slat retention and hypertension) to cortisone (which does have either action) in serum was 10 to 12 (normal average, 4.0). The patient was treated with a drug to block the kidney action of cortisol and potassium supplements for approximately two weeks, and T4. Her blood pressure decreased, and her serum potassium increased. Her serum cortisol:cortisone ratio gradually decreased to normal.
The conclusions of the study. Hypothyroidism can result in a decrease in the conversion of cortisol to cortisone that is sufficient to cause hypertension and low serum potassium.
The original article. Inagaki K, Otsuka F, Otani H, Sato C, Miyoshi T, Ogura T, Makino H. Apparent mineralocorticoid excess manifested in an elderly patient with hypothyroidism. Am J Hypertens 2007;20:104-7.
Next Article: Serum insulin-like growth factor I increases in response to thyroxine in patients with hypothyroidism |
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| Thyroid Digest Index | | | March 2007 Thyroid Digest |
