Thyroid suppression test with a single oral dose of levothyroxine in the diagnosis of functional thyroid autonomy

OBJECTIVE

To propose a modified form of thyroid suppression test with use of a single oral dose of levothyroxine (35 mg/kg).

METHODS

After a baseline scintigram, 23 patients with nodular goiter suspected of autonomous function (warm or hot nodules, subnormal or undetectable thyrotropin levels, or both findings) and 14 normal subjects underwent a repeated scintigram 4 days after administration of levothyroxine. We evaluated triiodothyronine (T(3)), free thyroxine, and thyrotropin before and on the first, second, third, fourth, and seventh days after administration of the individualized dose of levothyroxine.

RESULTS

The 99th percentile of postsuppression uptake in normal subjects was determined, and an uptake >12.4%, a 131 I concentration restricted to the nodule, or both factors were adopted as the criteria for diagnosis of an autonomously functioning thyroid nodule. Twelve patients were considered to have autonomously functioning nodules, and 11 patients were considered to have nonautonomous nodules. Baseline thyrotropin levels in patients with autonomous nodules did not differ significantly from those in patients with nonautonomous nodules. No signs or symptoms of toxicity were detected during the test, but all study subjects had increased free thyroxine values, and seven had high levels of T(3).

CONCLUSION

The thyroid suppression test with 35 mg/kg of levothyroxine is an effective method for the diagnosis of an autonomously functioning thyroid nodule, is nontoxic, and avoids the inaccurate use of the medication occasionally observed with T(3). Even sensitive methods of thyrotropin determination cannot replace this test in the evaluation of autonomous thyroid function.

Pentoxifylline (PTX)--an alternative treatment in Graves' ophthalmopathy (inactive phase): assessment by a disease specific quality of life questionnaire and by exophthalmometry in a prospective randomized trial

PURPOSE

To investigate the effect of pentoxifylline (PTX) in subjects with inactive Graves' ophthalmopathy (GO) through a specific quality of life (QOL) questionnaire and exophthalmometry readings.

METHODS

Eighteen females were randomly divided in two groups. Group A (n=9) was treated with PTX 1200 mg orally/day for 6 months. Group B (n=9) received placebo during the initial 6 months and then PTX for another 6 months. Proptosis measurements were carried out every 3 months and a questionnaire graded from 0 to 10 according to the severity of the symptoms was performed at baseline and after placebo and PTX administration.

RESULTS

At baseline, Group A questionnaire score values were 5.5 (median; range 3.5 to 8.0), and 5.0 after 6 months (3.0 to 6.0; p=0.01). In Group B, baseline values were not significantly different after 6 months of placebo: 6.0 (4.5 to 7.0) and 5.5 (4.5 to 7.0), respectively. However, a significant change was observed 6 months after PTX: 4.0 (2.0 to 5.0; p<0.001). Patients in Group A had a progressive improvement of proptosis during PTX: at baseline, 23 mm (median; range 20 to 32); after 3 months, 23 mm (18 to 30; p=0.02); and after 6 months, 23 mm (18 to 30; p=0.005). In Group B, proptosis remained stable during placebo: at baseline, 23 mm (21 to 25); after 3 months, 23 mm (20 to 25); and after 6 months, 23.5 mm (20 to 25). A significant change was observed after 3 and 6 months of PTX: 22 mm (19 to 24; p=0.0006) and 20.8 mm (17 to 25; p=0.0003), respectively.

CONCLUSIONS

Pentoxifylline seems to improve the QOL of patients in the inactive phase of GO. The objective findings of the proptosis readings corroborate to suggest that PTX may be an effective and promising drug in the inactive phase of GO.

Pentoxifylline (PTX): an alternative treatment in Graves ophthalmopathy (inactive phase): assessment by a disease specific quality of life questionnaire and by exophthalmometry in a prospective randomized trial

PURPOSE

To investigate the effect of pentoxifylline (PTX) in subjects with inactive Graves ophthalmopathy (GO) through a specific quality of life (QOL) questionnaire and exophthalmometry readings.

METHODS

Eighteen females were randomly divided in two groups. Group A (n=9) was treated with PTX 1200 mg orally/day for 6 months. Group B (n=9) received placebo during the initial 6 months and then PTX for another 6 months. Proptosis measurements were carried out every 3 months and a questionnaire graded from 0 to 10 according to the severity of the symptoms was performed at baseline and after placebo and PTX administration.

RESULTS

At baseline, Group A questionnaire score values were 5.5 (median; range 3.5 to 8.0), and 5.0 after 6 months (3.0 to 6.0; p=0.01). In Group B, baseline values were not significantly different after 6 months of placebo: 6.0 (4.5 to 7.0) and 5.5 (4.5 to 7.0), respectively. However, a significant change was observed 6 months after PTX: 4.0 (2.0 to 5.0; p<0.001). Patients in Group A had a progressive improvement of proptosis during PTX: at baseline, 23 mm (median; range 20 to 32); after 3 months, 23 mm (18 to 30; p=0.02); and after 6 months, 23 mm (18 to 30; p=0.005). In Group B, proptosis remained stable during placebo: at baseline, 23 mm (21 to 25); after 3 months, 23 mm (20 to 25); and after 6 months, 23.5 mm (20 to 25). A significant change was observed after 3 and 6 months of PTX: 22 mm (19 to 24; p=0.0006) and 20.8 mm (17 to 25; p=0.0003), respectively.

CONCLUSIONS

Pentoxifylline seems to improve the QOL of patients in the inactive phase of GO. The objective findings of the proptosis readings corroborate to suggest that PTX may be an effective and promising drug in the inactive phase of GO. (Eur J Ophthalmol 2004; 14: 277-83).

Effect of combined treatment with calcitonin on bone densitometry of patients with treated hypothyroidism

INTRODUCTION

Thyroid hormones (TH) may affect bone metabolism and turnover, inducing a loss of bone mass among hyperthyroid and in hypothyroid patients under hormone replacement treatment. Thyroid dysfunction leads to changes in the dynamics of parathyroid hormone (PTH) and calcitonin (CT) secretion.

OBJECTIVE

The objective of the study was to determine the usefulness of CT as adjuvant therapy in the prevention of bone loss during the treatment of hypothyroidism.

MATERIAL AND METHODS

We studied 16 female patients with recently diagnosed primary hypothyroidism, divided into two groups: group G1 (n = 8) submitted to treatment with thyroxine (L-T4), and Group 2 (n = 8) that, in addition to being treated with L-T4, received a nasal CT spray. All patients were submitted to determination of TSH, free T4, bone mineral densitometry (BMD) and total bone calcium (TBC) at the time of diagnosis, after 6 to 9 months of treatment, and after 12 months of treatment.

RESULTS

No statistical significant differences were detected in either group between the total BMD values obtained for the femur and lumbar spine before and after treatment. However, group G1 presented a statistical significant TBC loss after 12 months of treatment compared to initial values. In contrast, no TBC loss was observed in the group treated with LT-4 in combination with CT, a fact that may suggest that CT was responsible for the lower bone reabsorption during treatment of hypothyroidism.

Prospective and controlled study of ophthalmopathy after radioiodine therapy for Graves' hyperthyroidism

The effects of radioiodine (131I) therapy for hyperthyroidism on the ocular process of Graves' disease is controversial. In order to evaluate the outcome of ophthalmopathy after radioiodine therapy for thyrotoxicosis we studied prospectively 30 Graves' hyperthyroid patients, 22 submitted to radioiodine (131I) treatment (group A) and 8 treated with antithyroid drugs (group B). All patients were evaluated by clinical ophthalmologic examination, and ocular proptosis (OP) was measured with both a Hertel exophthalmometer (HE) and computed tomography (CT) before and 4 to 7 months after therapy. No statistical difference was obtained between pre- and post-treatment OP measurements in each eye in either group, and we did not observe worsening in the ophthalmopathy of patients treated with drugs or radioiodine. After therapy, there was an improvement in the clinical signs of ophthalmopathy in 59% of group A and in 37.5% of group B patients. We found a significant correlation between OP measured by HE and by CT. CT findings showed an increase in orbital fat and/or muscle thickening in all patients at baseline, proving to be a useful procedure for ophthalmologic diagnosis in doubtful cases. No patient in either group developed hypothyroidism or elevated TSH levels during the study period; this may explain our good results in the evolution of Graves' ophthalmopathy after treatment with 131I and antithyroid drugs. Euthyroidism seems to be an important factor in the outcome of ophthalmopathy after therapy, whatever the mode of treatment chosen to achieve it.

Persistent hyperactivity of the parathyroid glands in treated hypothyroid patients

Twelve untreated hypothyroid patients were submitted to EDTA infusion and the parathyroid hormone response to the induced hypocalcemia was studied with an amino-terminal specific assay. Eight of these patients were retested 6 months after achieving clinical and laboratory euthyroidism. The PTH response in the pretreatment condition was significantly higher than that obtained in a group of 10 normal individuals; this increased response had not normalized after 6 months of euthyroidism. This persisting hyperresponsiveness can be a contributory factor to the bone hypersensitivity to thyroid hormone replacement seen in hypothyroid patients.