Bone mineral density in postmenopausal women treated with L-thyroxine.

PURPOSE: To determine if bone mineral density is decreased in postmenopausal women treated with 1-thyroxine, and, if any decrease is observed, whether it is related to overtreatment with thyroid hormone, to deficiency of calcitonin, or to other factors. PATIENTS AND METHODS: The study consisted of 19 postmenopausal women between 50 and 75 years of age treated with 1-thyroxine for 5 years or longer, and 19 matching control subjects with no thyroid disease. Bone mineral density of the spine and hip was measured by dual-photon absorptiometry. Plasma calcitonin concentrations and serum thyroid hormone levels were determined by radioimmunoassays. RESULTS: The 1-thyroxine-treated women had lower bone density in the lumbar spine (1.013 g/cm2 [95% confidence interval, 0.945 to 1.081] versus 1.134 g/cm2 [1.026 to 1.242], p = 0.043); in the femoral neck (0.736 g/cm2 [0.694 to 0.778] versus 0.809 g/cm2 [0.747 to 0.872], p = 0.040); in Ward's triangle (0.576 g/cm2 [0.530 to 0.623] versus 0.694 g/cm2 [0.617 to 0.770], p = 0.011); and in the trochanteric area (0.626 g/cm2 [0.581 to 0.672] versus 0.722 g/cm2 [0.651 to 0.794], p = 0.027). The maximal increase in calcitonin following calcium infusion was 1.37 ng/L (95% confidence interval, -0.44 to 3.17) in the 1-thyroxine-treated patients versus 18.8 ng/L (95% confidence interval, 10.0 to 27.5) in normal women, p less than 0.001. The average dose of 1-thyroxine was 120 micrograms/day; 16 of the 19 patients had normal serum thyroxine levels. However, TSH levels were low in 13 of the 19, suggesting that 1-thyroxine treatment was supraphysiologic. Seven of the 19 patients had a history of hyperthyroidism in the distant past; these patients, considered separately, had significantly reduced bone density in the hip. The other 12 patients, considered separately, did not have a statistically significant loss of bone density. CONCLUSIONS: Long-term 1-thyroxine therapy is associated with decreased density of the spine and hip. Since subclinical hyperthyroidism, decreased calcitonin responsiveness, and a history of hyperthyroidism were demonstrated in some or all of these patients, these factors must be considered as possible causes of the decreased bone density.

Oral clonidine for rapid control of accelerated hypertension.

Thirty emergency-room patients, 15 men and 15 women, from 27 to 64 years old with diastolic blood pressures (DBP) greater than 115 mm Hg, were admitted to an open-label, oral loading trial of clonidine. At this time, their supine mean arterial pressures (MAP) averaged 150 +/- 2 mm Hg. An initial clonidine dose of 0.1 to 0.2 mg was to be followed every hour by another 0.1 mg until the DBP had been lowered to a level allowing treatment to be continued on an ambulatory basis or until a total of 0.5 mg had been given. A satisfactory response--defined as a reduction of the supine DBP to 105 mm Hg or lower if the baseline was between 115 and 135 mm Hg, or reduction of a baseline DBP greater than 135 mm Hg by at least 30 mm Hg--was achieved in all but one of the patients in an average of 118 minutes; the mean dose required was 0.26 mg. The mean reduction from the baseline MAP was 23.1 +/- 0.9%. Drug-related adverse experiences comprised drowsiness and dry mouth in 13 patients. Thereafter, 28 of the patients were chronically treated with clonidine for an average of 73 days. In 24 patients treated for at least 80 days, the daily clonidine dose averaged 0.375 mg. All the patients required concurrent diuretic therapy. A satisfactory response (as defined above) to this maintenance treatment was shown by 85% of the patients, and full blood-pressure control (supine DBP less than 95 mm Hg) was attained in 78%.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic thyroiditis and mitral valve prolapse.

Mitral valve prolapse is more prevalent in patients with autoimmune diffuse toxic goiter, suggesting a possible etiologic association. The prevalence of mitral valve prolapse was determined in 75 patients with chronic lymphocytic thyroiditis, another autoimmune thyroid disorder, and in 50 healthy control subjects. Mitral valve prolapse was found in 31 of 75 (41%) patients with chronic lymphocytic thyroiditis and in 4 of 50 (8%) controls (odds ratio, 8.10; 95% confidence interval, 2.64 to 24.83; p less than 0.0005). The age-race adjusted odds ratio was 9.26 (95% confidence interval, 2.83 to 30.26; p less than 0.0005). No correlation between the prevalence of mitral valve prolapse and the presence of hypothyroidism, serum antithyroid antibodies, or the duration of chronic lymphocytic thyroiditis was found. The prevalence of mitral valve prolapse is substantially increased in patients with the autoimmune thyroid disorders.

Long-term follow-up of patients with Grave's disease treated by subtotal thyroidectomy.

This long-term follow-up study of 83 patients with Grave's disease who were treated by subtotal thyroidectomy reemphasizes the fact that postoperative hypothyroidism occurs primarily in the first postoperative year (27 percent of the study patients). In addition, there was no evidence of progressive increase in the incidence of hypothyroidism in subsequent years. Patients treated with radioactive iodine have a reported incidence of hypothyroidism of 70 percent 10 years postoperatively [4]. The 6 percent incidence of recurrent hyperthyroidism is much less than a reported incidence of 90 percent in patients treated with long-term antithyroid drugs [7]. Subtotal thyroidectomy continues to be an excellent method of treatment for patients with Grave's disease and compared favorably with both radioactive iodine and long-term antithyroid drugs.

Racial difference in salivary sodium-potassium ratio in low renin essential hypertension.

We have studied the relationship between plasma renin activity (PRA) and the salivary sodium-potassium (Na-K) ratio, an index of mineralocorticoid effect, in 223 patients with essential hypertension. In 24 white patients with low PRA, the median Na-K ratio was 0.74, which was significantly lower than the ratio of 1.40 in 54 normal white subjects and the ratio of 1.10 in 34 white hypertensive patients with normal PRA. The Na-K ratio in 71 black patients with low PRA was 1.06, which was not significantly lower than the ratio of 1.50 in 38 black normal subjects or the ratio of 1.56 in 94 black hypertensive patients with normal PRA. These findings indicate a difference in salivary Na-K ratios between white and black patients with low renin essential hypertension and suggest a racial difference in the pathophysiology of this form of hypertension.

The salivary sodium/potassium ratio in hypertension: relation to race and plasma renin activity.

We have studied the relationship between plasma renin activity (PRA) and the salivary Na:K ratio, an index of mineralocorticoid effect, in 223 patients with essential hypertension. In 24 white patients with low PRA the median Na:K ratio was 0.74, which was significantly lower than the ratio of 1.40 in 54 normal white subjects (P less than .005) and the ratio of 1.10 in 34 white hypertensive patients with normal PRA (P less than .005). The Na:K ratio in 71 black patients with low PRA was 1.06, which was not significantly lower than the ratio of 1.50 in 38 black normal subjects or the ratio of 1.56 in 94 black hypertensive patients with normal PRA. These findings indicate a difference in salivary Na:K ratios between white and black patients with low renin essential hypertension, and suggest that mineralocorticoid excess may be a more frequent cause of low renin essential hypertension in white than in black patients.