Restoration Of Euthyroid State Research Articles

Postpartum thyroid dysfunction in women with autoimmune thyroiditis

Introduction: Autoimmune thyroiditis (AIT) is a predisposing factor for developing postpartum thyroid dysfunction (PPTD).Aim: To study the characteristics of PPTD in women with AIT.Methods: Thirty-eight women with pre-existing AIT were included in the study. Thyroid-stimulating hormone, free triiodthyronine, free thyroxine, thyroid peroxidase antibodies, thyroglobulin antibodies were measured and ultrasound evaluation of the thyroid gland was performed in the first trimester of pregnancy and during the first year following delivery.Results: Thyroid dysfunction was recognized in 68.4% of the patients – 28.9% presented with hypothyroidism and 39.5 % with thyrotoxicosis. The immunological and morphological parameters did not differ between euthyroid women and those with thyroid dysfunction. At the end of the postpartum period restoration of euthyroid state (being on the treatment before pregnancy) was observed in 15.4% of patients with PPTD, while 84.6% required increase of the levothyroxine dose. The analysis found a significantly lower volume of the thyroid gland, shorter duration of the disease, a lower dose of levothyroxine before and during gestation in patients with impaired thyroid function at the end of the postpartum period.Conclusion: The risk of PPTD in women with AIT predating pregnancy is higher among women with preserved thyroid functional capacity motivating a thorough assessment of thyroid hormone levels and close follow-up of those women during the postpartum period.

Remission of Graves’ disease is not related to early restoration of euthyroidism with high-dose methimazole therapy

Introduction and aims: The most recent hypothesis postulated that early restoration of euthyroid state in patients with Graves’ disease changes the course of the disease and leads to better disease control. Therefore, we analyzed the efficacy of methimazole therapy and the course of disease in patients with restored euthyroidism and in patients with active disease on first control visit. Patients and methods: We included 63 patients with total T4 level >190 nmol/L or T3 >7 nmol/L and diffuse goiter with no previous episodes of hyperthyroidism. All patients received initially high doses of methimazole (60–80 mg) followed by a rapid dose reduction. Results: Ten percent of patients were excluded from the study due to side effects. Two different groups emerged after 5 weeks of treatment with same dose of methimazole: group 1 with active disease (48%) and group 2 with restored euthyroidism. Further controls on 12th, 24th and 68th weeks of treatment showed no difference in remission rates, number of iatrogenic hypothyroid episodes, and number of exacerbations between the two groups, regardless of methimazole dose. There was no association between age, gender, thyroid hormone levels, and remission and exacerbation rates. Conclusions: Initially, higher methimazole doses with rapid progressive decrease to maintenance dose result in similar remission rates and are followed by similar incidence of adverse side-effect as fixed low dose therapy. Our results indicate that neither an early restoration of euthyroidism nor the difference in methimazole doses influence the course of Graves’ disease.

Ovarian Cysts in Young Girls with Hypothyroidism: Follow-up and Effect of Treatment

Ovarian cysts have been reported in girls with longstanding uncompensated primary hypothyroidism. Restoration of euthyroid state has been associated with resolution of these cysts; long-term follow-up of these patients is however lacking. We evaluated the outcome in ten girls with ovarian cysts and hypothyroidism managed at our hospital with special emphasis on subsequent pubertal development and ovarian imaging. Patients were diagnosed at the age of 8.6 +/- 2.3 years (mean +/- SD) with severe uncompensated primary hypothyroidism (TSH levels >100 mIU/l in all; 509.3 +/- 651 mIU/l) and growth retardation (height SDS -4.1 +/- 1.8). Nine girls had vaginal bleeding at diagnosis; five also had thelarche. LH and FSH levels were prepubertal in all patients. Ovarian cysts were bilateral in eight girls (80%); internal septation was noted in six. Thyroxine replacement (4.1 +/- 0.7 microg/kg/day) led to normalization of TSH levels with reversal of pubertal changes and regression of ovarian cysts in all patients 2.2 +/- 1.0 months after treatment. At last follow-up 3.5 +/- 2.6 years after initiation of treatment at the age of 12.0 +/- 2.3 years, all patients had normal ovarian size in ultrasound evaluation with six girls progressing to normal puberty. Our study emphasizes the need to exclude hypothyroidism in young girls with ovarian cysts. Identification of hypothyroidism in these girls obviates the need for extensive investigations.

The effects of thyroid status on plasma leptin levels in women.

Leptin, the product of the adipose specific ob gene, regulates food intake and energy expenditure. However, little is known about the effects of thyroid status on plasma leptin levels in women. We determined fasting plasma leptin levels before and 1 month after restoration of euthyroidism in 20 female patients with hypothyroidism, 20 female patients with hyperthyroidism and 20 age and BMI-matched female controls. To restore the normal thyroid function patients with hypothyroidism were treated with levothyroxine, whereas patients with hyperthyroidism were treated with propylthiouracil. Plasma leptin levels were measured by a RIA method with a sensitivity of 0.5 microgram/l. Leptin levels were significantly lower in patients with hypothyroidism before treatment (4.17 +/- 2.58 micrograms/l) than in patients with hyperthyroidism (6.80 +/- 4.3 micrograms/l; z = -2.06, p = 0.037). Leptin levels were significantly higher in hyperthyroid patients than in the control group (3.71 +/- 1.69 micrograms/l, z = -2.44, p = 0.014) whereas leptin levels in the hypothyroid patients were not significantly different from those in control subjects (z = -0.16, p = 0.87). Restoration of euthyroid state was not associated with a significant change in leptin levels either in the hypothyroid (from 4.17 +/- 2.58 to 5.22 +/- 3.4 micrograms/l; z = -1.74, p = 0.08) or in the hyperthyroid group (from 6.80 +/- 4.37 micrograms/l to 7.93 +/- 6.25 micrograms/l z = -0.89, p = 0.37), although a tendency for leptin to increase was observed in both groups. There was no correlation between plasma leptin and FT3, FT4, TSH, or BMI either before or after therapy in both groups. Leptin levels were significantly correlated with BMI in the control group (r = -0.53, p = 0.018). We conclude that plasma leptin levels are increased in hyperthyroidism and unchanged in hypothyroidism. Furthermore, our study demonstrates that mean plasma leptin levels are not influenced by short term restoration of euthyroidism in both hypothyroidism and hyperthyroidism, although an effect of long-term treatment may not be excluded.

Plasma concentration of gonadotrophins, oestrogens and progesterone in thyrotoxic women.

Plasma levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), oestrogen and progesterone were measured daily in 15 thyrotoxic women in the reproductive age for 28 to 30 consecutive days before commencement of therapy and for a similar period following restoration of the euthyroid state. Five of these patients had secondary amenorrhoea whilst the other 10 had hypomenorrhoea. Twelve healthy volunteer eythyroid women of similar age and parity, with no history of menstrual abnormality, served as controls. The levels of both gonadotrophins (LH and FSH) and oestrogen were found to be significantly raised in all thyrotoxic patients in comparison with levels in the euthyroid female controls (P less than 0.001). "Mid cycle" LH and FSH peaks were present in thyrotoxic patients who were still menstruating whilst they were absent in those who developed amenorrhoea. Plasma oestrogen concentration rose to a peak on the day before the surge of LH (and FSH) in all euthyroid frmale controls as well as in thyrotoxic patients who were still menstruating. In contrast, oestrogen peaks occurred without ensuing LH (and FSH) peaks in thyrotoxic patients who had developed amenorrhoea, suggesting a failure of the positive feed-back mechanism. The levels and patterns of plasma progesterone in thyrotoxic subjects who were still menstruating were similar to those of euthyroid controls. However, no significant circulating plasma progesterone was detected in thyrotoxic subjects who were amenorrhoeic. The levels and patterns of all of these hormones (gonadotrophins, oestrogen and progesterone) became normal after restoration of euthyroid state and normal menstruation.