TSH Suppression Benefits and Adverse Effects by Jeffrey Dach MD
At a recent medical meeting I attended, “the danger of TSH suppression” was mentioned. The listening audience of doctors was advised not to suppress TSH with thyroid medication. We were advised to make sure the TSH always stays within the lab reference range.
Thyroid Excess and Thyrotoxicosis
Of course, we would all agree that too much thyroid medication causing thyroid excess and thyrotoxicosis is to be avoided, as this clearly is the most significant adverse effect of taking thyroid hormone pills. Taking too many pills is not a good thing, as this will cause a clinical syndrome known as thyrotoxicosis characterized by tachycardia, palpitations, insomnia, anxiety, panic attacks etc. The arrythmia, atrial fibrillation is the dreaded complication to be avoided.
Take the Time to Go Over Thyroid Excess List of Symptoms
We actually spend 5 or 10 minutes with each patient in the office talking about Thyroid excess signs and symptoms to look for, and we give each patient a print out of this list to take home and post on their bulletin board to read every day. If the patient experiences any symptoms of thyroid excess they are instructed to stop the thyroid pills. Patient selection is also a factor here, as a patient with early dementia could not be expected to have the cognitive function to recognize thyroid excess and stop their pill. The patient must be able and willing to play a role in their health care. Otherwise, they are not a candidate for natural thyroid treatment, and instead are referred to your local friendly endocrinologist for levothyroxine dosage and TSH in range.
Stop the Thyroid Pills
Thyroid excess is easily avoided by simply stopping the thyroid medication should signs of rapid resting heart rate occur. Symptoms will resolve within hours after stopping the natural thyroid pill. For T4 only levothyroxine, which has a longer half life, it takes longer for symptoms to resolve.
Is a low TSH indicative of Thyroid Excess ?
Mainstream endocrinology makes the assumption that a suppressed TSH indicates thyroid excess, and by definition, thyrotoxicosis. This is true for Graves disease and Toxic Nodular Goiter. In Graves disease with thyrotoxicosis, hypercalcemia from rapid bone turnover has been reported. (21,22)
However, for the vast majority of hypothyroid patients taking natural dessicated thyroid (Nature-throid- RLC labs) a suppressed TSH merely indicates adequate treatment dosage with full clinical benefit, and does not correspond with the clinical signs and symptoms (or laboratory findings) of thyroid excess.
Monitoring the Other Labs and the Patient
Of course, we always monitor Free T3, Free T4, and Thyroid antibody levels, as well as monitor the patients clinical status. If the patient has a Free T3 and Free T4 in the normal range, and has no tachycardia at rest or any other symptoms of thyroid excess, then a suppressed TSH indicates adequate thyroid treatment, and by no stretch of the imagination could the patient possibly be in a state of thyroid excess or thyrotoxiciosis.(6)
Adverse Health Effects of TSH Suppression
Another point mentioned at the medical meeting to persuade us clinicians not to suppress the TSH with thyroid medication was the idea that there are adverse health consequences when the TSH is suppressed. The major one being loss of bone density, osteoporosis which is a real finding in long standing Graves Disease patients.(21-22)
However numerous studies have examined this idea in hypothyroid patients treated with thyroid pills and found this to be a medical myth.(24) In our patient population we see bone density improving, especially in women receiving bioidentical hormone replacement and bone supplements such as Vitamin D3, K2, magnesium and calcium.(9-16)
As to the idea that there must be some adverse health effects of a suppressed TSH, this has also been examined in two groups of patients on long term TSH suppressive doses of thyroid medication, and this idea found to be false.
TSH Suppression after Thyroidectomy for Thyroid Cancer
In patients after thyroidectomy for papillary thyroid cancer who are commonly treated with TSH suppressive doses of thyroxine, there have been no adverse effects noted in many long term studies.(2) (16-18)
Here is a quote from Dr.Chen 2004 who studied bone mineral density in women post-thyroidectomy for thyroid CA treated with suppressive doses of T4 (2) : “Women with differentiated thyroid cancer who had long-term (7 +/- 3 years) T4 therapy and suppressed TSH levels had no evidence of lower Bone Mineral Density.”(2)
Shrinking Thyroid Nodules With TSH Suppression
Similarly in patients with thyroid nodules treated with TSH suppression, there have no ill effects of TSH suppression.(4-5)(7) Here is a quote from Dr Zelmanovitz 2013 who treated thyroid nodules with suppressive therapy and found no change in bone mineral density after one year. “The data obtained in this study do not suggest any significant decrease in BMD after 1 yr of treatment with suppressive doses of T4.”(7)
No Adverse Effects from Low TSH below Reference Range in Large Scale Study
In 2010, Drs Graham Leese and Robert Flynn from University of Dundee, UK published their large scale study showing no adverse effect of a low TSH in the (.03-.40) range.(24)
See this article: Is it safe for patients taking thyroxine to have a low but not suppressed serum TSH concentration? .
Japan to the Rescue – Suppressive Doses of Thyroid Hormone Needed
Dr Mitsuru Iti from Japan reported in 2012 that TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy. Dr Ito found in the post-thyrodiectomy patient, moderately suppressive doses of thyroxine are required to reproduce Free T3 levels found pre-operatively.(25) In his discussion, Dr Ito quotes Dr Maria Alevizaki Maria who reported in 2005 that “TSH may not be a good marker for adequate thyroid hormone replacement therapy.”(25)
Dr Thierry Hertoghe, possibly the most recognized thyroid expert on the planet, suppresses TSH in about 30% of his patients. (personal communication)
Left Image courtesy of Thierry Hertoghe.
Thyroid Receptor Mutation Requires TSH Suppressive doses of Thyroid Hormone
Another patient population are those patients with mutations in the Thyroid hormone receptor genes. The syndrome of peripheral thyroid hormone resistance was predicted and hypothesized twenty years ago, but only recently in 2013 was the genetic defect in the receptor gene identified. Patients with peripheral thyroid hormone resistance may require higher Free T3 levels to overcome the receptor defects.(23) Higher Free T3 may be accompanied by suppressed TSH in these cases.
Normal Pregnant Women May Have a Suppressed TSH
During pregnancy, HCG levels rise to very high levels, and there is associated suppression of TSH, not indicative of a hyperthyroid state. “In up to 10–20% of normal pregnant women, serum TSH concentrations are transiently low or undetectable.” (26)
Suppression of TSH during the first trimester is due to elevated HCG.(Brotherton 1990). “This suppression of maternal pituitary TSH levels during pregnancy was considered to be due to the central feedback inhibitory thyrotrophic activity of HCG,”
There are many drugs which suppress TSH.
Hypothalamic Dysfunction in the Chronic Fatigue Fibromyalgia – Central Hypothyroidism.(27-31)
Both Drs Kent Holtorf and Dr Jacob Teitelbaum have devoted much of their careers to the study and treatment of the chronic fatigue fibromyalgia patient. One of the keys to understanding the patho-physiology in this disorder is hypothalamic dysfunction which may lead to central hypothyroidism. One of the pituitary hormones affected by hypothalamic dysfunction is the TSH (thyroid stimulating hormone) which may be paradoxically low, even though the patient is in a hypothyroid state with chronic fatigue. Thus, according to both Drs. Kent Holtorf (42,43) and JacobTeitelbaum (32), the chronic fatigue patient may have central hypothyroidism with a suppressed TSH. Again, it would be a clinical error to withhold thyroid hormone treatment from this patient because of a lab finding of a low or “suppressed” TSH. (27-32) Left Image courtesy of Jacob Teitelbaum MD.
Chemotherapy during cancer treatment may cause hypothalamic dysfunction in cancer-survivors. The TSH may be paradoxically low and unreliable in these cases.(39-41)
Hashimoto’s Thyroiditis Auto-Immune Thyroid Disease
It is common practice among endocrinologist to treat “euthyroid” Hashimotos’ patients with thyroxine (T4). The definition of “Euthyroid” means the TSH is in the lab reference range. Studies show benefit with thyroid hormone treatment to reduce anti-TPO and anti-Thyroglobulin Antibody levels even though the TSH is in the normal range. Obviously, such treatment may on occasion result in suppressed TSH. Such treatment with thyroid hormone is thought beneficial in stabilizing the Hashimotos autoimmune process, and is recommended as soon as the diagnosis is established.(33-38)
Conclusion: Long term TSH suppression in the thyroid nodule and thyroid cancer patient is a common practice of mainstream endocrinology with no adverse effects reported in many published studies. The TSH laboratory test may not always accurately reflect of peripheral thyroid levels, and may in fact be unreliable in a variety of medical conditions such as chronic fatigue, fibromyalgia, pregnancy, post chemotherapy, autoimmune thyroid disease, and hypothalamic dysfunction.
Finally, a quote from Kent Holtorf MD 2014 (42):
“extreme caution should be used in relying on TSH or serum thyroid levels to rule out hypothyroidism in the presence of a wide range of conditions, including physiologic and emotional stress, depression, dieting, obesity, leptin insulin resistance, diabetes, chronic fatigue syndrome, fibromyalgia, inflammation, autoimmune disease, or systemic illness, as TSH levels will often be normal despite the presence of significant hypothyroidism.”(42) End Quote.
A Quote from Dr. Rudolf Hoermann:
“(our) data reveal disjoints between FT4–TSH feedback and T3 production that persist even when sufficient T4 apparently restores euthyroidism” Quoted from “Is pituitary TSH an adequate measure of thyroid hormone-controlled homoeostasis during thyroxine treatment?.” Eur J Endo 2013.
Update 2020: TSH suppression is safe in men and pre-menopausal women. However, TSH Suppression in Post Menopausal women is associated with loss of bone density. However, this is negated by concurrent use of estrogen. (11)(48-49)
See: Schneider, Diane L., Elizabeth L. Barrett-Connor, and Deborah J. Morton. “Thyroid hormone use and bone mineral density in elderly women: effects of estrogen.“ Jama 271.16 (1994): 1245-1249.
Why Natural Thyroid is Better Than Synthetic
Why Natural Thyroid is Better than Synthetic Part Two
Above Left Image: Radionuclide Thyroid Scan showing diffuse goiter in patient with TSH receptor mutation and resistance to thyroid hormone courtesy of KIM.
Jeffrey Dach MD
7450 Griffin road Suite 190
Davie, Fl 33314
Links and References
J Clin Endocrinol Metab. 1996 Dec;81(12):4278-89.
Effects on bone mass of long term treatment with thyroid hormones: a meta-analysis. Uzzan B1, Campos J, Cucherat M, Nony P, Boissel JP, Perret GY.
1Hôpital Avicenne, Centre Hospitale Universitaire Paris Nord, France.
Osteoporosis is the main cause of spine and hip fractures. Morbidity, mortality, and costs arising from hip fractures have been well documented. Thyroid hormones (TH) are widely prescribed, mainly in the elderly. Some studies (but not all) found a deleterious effect of suppressive TH therapy on bone mass. These conflicting data raised a controversy as to the safety of current prescribing and follow-up habits, which, in turn, raised major health-care issues. To look for a detrimental effect on bone of TH therapy, we performed a meta-analysis (by pooling standardized differences, using a fixed effect model) of all published controlled cross-sectional studies (41, including about 1250 patients) concerning the impact of TH therapy on bone mineral density (BMD). Studies with women receiving estrogen therapy were excluded a priori, as were studies with a high percentage of patients with postoperative hypoparathyroidism, when no separate data were available. We decided to stratify the data according to anatomical site, menopausal status, and suppressive or replacement TH therapy, resulting in 25 meta-analysis on 138 homogeneous subsets of data. The main sources of heterogensity between studies that we could identify were replacement or suppressive TH therapy, menopausal status, site (lumbar spine, femoral neck, Ward’s triangle, greater trochanter, midshaft and distal radius, with various percentages of cortical bone), and history of hyperthyroidism, which has recently been found to impair bone mass in a large epidemiological survey. To improve homogeneity, we excluded a posteriori 102 patients from 3 studies, who had a past history of hyperthyroidism and separate BMD data, thus allowing assessment of the TH effect in almost all 25 subset meta-analyses. However, controls were usually not matched with cases for many factors influencing bone mass, such as body weight, age at menarche and at menopause, calcium dietary intake, smoking habits, alcohol intake, exercise, etc. For lumbar spine and hip (as for all other sites), suppressive TH therapy was associated with significant bone loss in postmenopausal women (but not in premenopausal women), whereas, conversely, replacement therapy was associated with bone loss in premenopausal women (spine and hip), but not in postmenopausal women. The detrimental effect of TH appeared more marked on cortical bone than on trabecular bone. Only a large long term prospective placebo-controlled trial of TH therapy (e.g. in benign nodules) evaluating BMD (and ideally fracture rate) would provide further insight into these issues.
Most patients with well-differentiated thyroid carcinoma have an excellent prognosis and are likely to live long enough to be subjected to osteoporosis. The purpose of this study was to investigate the consequences of treatment with a supraphysiological dose of levothyroxine (l-T4) on bone mineral density (BMD) in Taiwanese women with differentiated thyroid cancer.
METHODS:A total of 69 (44 premenopausal, 25 postmenopausal) Taiwanese women with differentiated thyroid cancer were included in this retrospective study. These patients were free of disease recurrence after initial near-total thyroidectomy and I-131 radioablation, and had undergone regular l-T4 suppressive therapy for more than 3 years (mean, 7.3 +/- 3.0 years; range, 3 to 15 years). The degree of thyroid-stimulating hormone (TSH) suppression was determined based on the mean TSH score for each patient which was determined by analysis of all available follow-up TSH data, where 1 = undetectable TSH (< 0.2 mIU/mL); 2 = subnormal TSH (0.2 to 0.39 mIU/mL); 3 = normal TSH (0.4 to 4.0 mIU/mL); and 4 = elevated TSH (> 4.0 mIU/mL). The patients were divided into a full TSH suppression group with a mean TSH score in the range 1.0 to 1.99, and a partial TSH suppression group with a mean TSH score in the range 2.0 to 2.99. BMD was measured by dual-energy X-ray absorptiometry at the lumbar spine, femoral neck, Ward’s triangle and total hip. Comparisons between subgroups of patients and controls were performed by unpaired t test. Correlation between BMD and other clinical variables was assessed by Pearson’s correlation analysis.
RESULTS:Postmenopausal patients (aged 57.7 +/- 6.9 years) had significantly higher serum calcium levels and decreased BMD at all sites of the spine and hip as compared with premenopausal patients (aged 38.6 +/- 6.7 years) with similar BMI and duration of TSH suppression. Comparison of BMD between postmenopausal patients and BMI- and age-matched controls revealed that the patient group had decreased BMD at all sites of measurement, although this difference was not significant. This phenomenon was not observed in the premenopausal patients. Furthermore, when BMD was compared between patients categorized as having full and partial suppression of TSH, only patients with full suppression in the postmenopausal group showed a tendency to lower BMD. There was a strong correlation of BMD with age, BMI and serum calcium level. However, no correlation was found between BMD and degree of TSH suppression or duration of l-T4 suppression therapy.
CONCLUSION: Women with differentiated thyroid cancer who had long-term (mean, 7.3 +/- 3.0 years) l-T4 therapy and suppressed TSH levels had no evidence of lower BMD. However, patients with full suppression in the postmenopausal group showed a tendency towards lower BMD. Therefore, careful monitoring of BMD in postmenopausal women during suppression therapy is mandatory.
Endocr Regul. 2010 Apr;44(2):57-63.
Thyrotropin versus thyroid hormone in regulating bone density and turnover in premenopausal women. Baqi L1, Payer J, Killinger Z, Hruzikova P, Cierny D, Susienkova K, Langer P.
This cross-sectional study aimed to evaluate the interrelations between endogenous TSH level on one side and the status of bone mineral density (BMD) and bone metabolic turnover (BMT) on the other in pooled four groups of premenopausal women either without or with a long-term L-thyroxine treatment.
METHODS:Serum levels of free thyroxine (FT4), thyrotropin (TSH), calcium (Ca), alkaline phosphatase (ALP), osteocalcin OC) and cross linked N-telopeptide of type 1 collagen (NTx) as well as urinary calcium (U-Ca/24h), bone mineral density of lumbar spine L 1-4 (BMD-L) and femoral hip (BMD-F) were estimated in a cohort of 151 premenopausal women (median 36 years) consisting of four groups: Group 1, 40 healthy untreated women, while three other groups consisted of patients previously treated for about 5 years; Group 2, 41 patients with genuine hypothyroidism treated by L-thyroxine (50-100 microg daily); Group 3, 40 patients with genuine hyperthyroidism treated by Carbimazol (10-15 mg daily); Group 4, 30 patients treated by suppressive doses of L-thyroxine (100-150 microg daily) after thyroidectomy for thyroid cancer (n=10) or because of progressively growing benign goitre (n=20).
RESULTS:When using multiple correlation analysis (Pearson’s r) in pooled 151 women, TSH showed significant positive correlation with BMD-L (p<0.01) and BMD-F (p<0.001) and, at the same time, significant negative correlation with serum level of BMT markers such as ALP (p<0.05), OC (p<0.05) and NTx (p<0.01), while the correlation of FT4 with BMD-L, BMD-F was significantly negative (p<0.001 for both) and that with all BMT markers was significantly positive (p<0.05 to <0.001). Thus, it appeared that higher TSH level was associated with increased bone mineral density and, at the same, with decreased bone metabolic turnover. These interrelations were further supported by the findings of significantly lower BMD-F (p<0.01), BMD-L (p<0.001) and significantly higher ALP, OC and NTX (all at p<0.001) in the group of 36 women with TSH level<0.3 mU/l as compared to the group of 115 women with TSH level range of 0.35-6.3 mU/l).
CONCLUSIONS:Irrespectively of thyroid diagnosis and/or previous long term thyroxine treatment in some groups, this cross sectional study showed that, after the pooled group of 151 women has been redistributed according to the actual TSH level, the bone mineral density and the level of bone turnover markers was significantly more favorable in 115 subjects with TSH level range of 0.35-6.3 mU/l than these in 36 women with TSH<0.3 mU/l.
N Engl J Med. 1987 Jul 9;317(2):70-5.
Suppressive therapy with levothyroxine for solitary thyroid nodules. A double-blind controlled clinical study. Gharib H, James EM, Charboneau JW, Naessens JM, Offord KP, Gorman CA.
Thyroid nodules are present in up to 50 percent of adults in the fifth decade of life. Patients are often treated with thyroxine in order to reduce the size of the nodule, but the efficacy of thyrotropin-suppressive therapy with thyroxine remains uncertain. In this study, 53 patients with a colloid solitary thyroid nodule confirmed by biopsy were randomly assigned in a double-blind manner to receive placebo (n = 25) or levothyroxine (n = 28) for six months. Before treatment, pertechnetate-99m thyroid scanning showed that 22 percent of the nodules were functional, 25 percent hypofunctional, and 53 percent nonfunctional. High-resolution (10-MHz) sonography was used to measure the size of the nodules before and after treatment. Suppression of thyrotropin release was confirmed in the levothyroxine-treated group by the administration of thyrotropin-releasing hormone; thyrotropin release was normal in the placebo group. Six months of therapy did not significantly decrease the diameter or volume of the nodules in the levothyroxine group as compared with the placebo group. We conclude that the efficacy of levothyroxine therapy in reducing the size of colloid thyroid nodules is not apparent within six months, despite effective suppression of thyrotropin.
J Clin Endocrinol Metab. 2002 Nov;87(11):4928-34.
Effects of thyroid-stimulating hormone suppression with levothyroxine in reducing the volume of solitary thyroid nodules and improving extranodular nonpalpable changes: a randomized, double-blind, placebo-controlled trial by the French Thyroid Research Group. Wémeau JL1, Caron P, Schvartz C, Schlienger JL, Orgiazzi J, Cousty C, Vlaeminck-Guillem V.
The efficacy of suppressing TSH secretion with levothyroxine (L-T(4)) in reducing solitary thyroid nodule growth is still controversial. In this prospective multicenter, randomized, double-blind, placebo-controlled trial, 123 patients with a single palpable benign nodule were included and randomly allocated to an 18-month treatment with L-T(4) or placebo. Individual dose was adjusted to allow a serum TSH level below 0.3 mIU/liter. Clinical and ultrasonographic nodule characteristics were assessed before treatment and 3, 6, 12, and 18 months thereafter. The largest mean nodule size assessed on palpation and largest volume, assessed by ultrasonography, decreased in the L-T(4) group and increased slightly in the placebo group [size, -3.5 +/- 7 mm vs. +0.5 +/- 6 mm (P = 0.006); volume, -0.36 +/- 1.71 ml vs. +0.62 +/- 3.67 ml (P = 0.01), respectively]. The proportion of clinically relevant volume reduction (> or =50%) rose significantly in the L-T(4) group [26.6% vs. 16.9% (P = 0.04)]. The proportion of patients with a reduced number of infraclinical additional nodules was significantly higher in the L-T(4) group [9.4% vs. 0 (P = 0.04)]. It is concluded from this study that suppressive L-T(4) therapy is effective in reducing solitary thyroid nodule volume and improving infraclinical extranodular changes.
Ir J Med Sci. 1992 Dec;161(12):684-6. TSH as an index of L-thyroxine replacement and suppression therapy. Igoe D1, Duffy MJ, McKenna TJ.
When hypothalamic-pituitary function is normal, serum TSH levels measured by ultrasensitive assay yield bioassays of endogenous thyroid action and thus provide an ideal index of thyroid secretion and its relationship to fluctuating endogenous thyroid levels. It is theoretically possible that patients receiving exogenous L-thyroxine for primary hypothyroidism should have suppressed TSH levels if physiological needs are constantly met. To examine this possibility free thyroxine, FT4 and TSH were measured in 90 clinically euthyroid patients receiving treatment with L-thyroxine for primary hypothyroidism. TSH levels were normal in 44, suppressed in 16 and elevated in 30 patients. FT4 levels were normal in 68, elevated in 13 and suppressed in 9 patients. Normal TSH levels were associated with normal FT4 levels in 79.5% of patients, elevated FT4 levels in 13.6% and low FT4 in 6.8%. Suppressed TSH levels were associated with elevated FT4 levels in 37.5% of patients and normal FT4 levels in 62.5%. When FT4 levels were normal, however, TSH levels were normal in only 51.5% and abnormal in 48.5%. We also examined the possibility that FT4 levels may remain within normal range when TSH is suppressed during L-thyroxine treatment for goitre or cancer. FT4 and TSH were measured in 45 patients on L-thyroxine as TSH suppression treatment. TSH was suppressed in 23 patients (51.1%), normal in 20 (44.4%) and elevated in 2 (4.5%). When TSH was suppressed, FT4 was elevated in 30.4% but normal in 69.6% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Suppressive Therapy with Levothyroxine for Solitary Thyroid Nodules: A Double-blind Controlled Clinical Study and Cumulative Meta-analyses
Flávio Zelmanovitz 2 , Sandra Genro, and Jorge L. Gross
JCEM July 01, 2013
The data obtained in this study do not suggest any significant decrease in BMD after 1 yr of treatment with suppressive doses of T4. However, a meta-analysis of related studies, performed by Uzzan et al., demonstrated that suppressive therapy decreased the BMD in 409 postmenopausal patients after an average of 9.6 yr (11).
Ann Intern Med. 2001 Apr 3;134(7):561-8.
Risk for fracture in women with low serum levels of thyroid-stimulating hormone.
Bauer DC1, Ettinger B, Nevitt MC, Stone KL; Study of Osteoporotic Fractures Research Group.
Biochemical evidence of hyperthyroidism may be associated with low bone mass, particularly in older postmenopausal women, but no prospective studies of thyroid function and subsequent fracture risk have been done.
OBJECTIVE:To examine the association between low levels of thyroid-stimulating hormone (TSH) and fracture in older women.
DESIGN:Prospective cohort study with case-cohort sampling.
SETTING:Four clinical centers in the United States.
PATIENTS:686 women older than 65 years of age from a cohort of 9704 women recruited from population-based listings between 1986 and 1988.
MEASUREMENTS:Baseline assessment of calcaneal bone mass, spine radiography, and history of thyroid disease. Spine radiography was repeated after a mean follow-up of 3.7 years; nonspine fractures were centrally adjudicated. Thyroid-stimulating hormone was measured in sera obtained at baseline from 148 women with new hip fractures, 149 women with new vertebral fractures, and a subsample of 398 women randomly selected from the cohort.
RESULTS:After adjustment for age, history of previous hyperthyroidism, self-rated health, and use of estrogen and thyroid hormone, women with a low TSH level (0.1 mU/L) had a threefold increased risk for hip fracture (relative hazard, 3.6 [95% CI, 1.0 to 12.9]) and a fourfold increased risk for vertebral fracture (odds ratio, 4.5 [CI, 1.3 to 15.6]) compared with women who had normal TSH levels (0.5 to 5.5 mU/L). After adjustment for TSH level, a history of hyperthyroidism was associated with a twofold increase in hip fracture (relative hazard, 2.2 [CI, 1.0 to 4.4]), but use of thyroid hormone itself was not associated with increased risk for hip fracture (relative hazard, 0.5 [CI, 0.2 to 1.3]).
CONCLUSIONS:Women older than 65 years of age who have low serum TSH levels, indicating physiologic hyperthyroidism, are at increased risk for new hip and vertebral fractures. Use of thyroid hormone itself does not increase risk for fracture if TSH levels are normal.
Clin Endocrinol (Oxf). 1992 Dec;37(6):500-3.
Morbidity in patients on L-thyroxine: a comparison of those with a normal TSH to those with a suppressed TSH. Leese GP1, Jung RT, Guthrie C, Waugh N, Browning MC.
Patients on L-thyroxine with a ‘suppressed’ TSH (< 0.05 mU/l) were compared to those in whom TSH was detectable but not elevated (0.05-4.0 mU/l), with regard to morbidity data.
DESIGN:Biochemical data from Tayside Thyroid Register was matched to hospital admissions data obtained from Health Board Statistics.
PATIENTS:The patients were identified from those registered on the computerized Tayside Register.
MEASUREMENTS:Serum T4 and TSH assays, clinical assessment scores, and admission records with regard to ischaemic heart disease, overall fractures, fractured neck of femur and breast carcinoma.
RESULTS:Over one year, 1180 patients on thyroxine replacement had clinical and biochemical assessment; 59% had a suppressed TSH and 38% ‘normal’ TSH. Patients with a suppressed TSH exhibited higher median serum thyroxine levels (146 nmol/l, range 77-252 vs 119 nmol/l, 58-224; P < 0.001). Patients under the age of 65 years on L-thyroxine had an increased risk of ischaemic heart disease compared to the general population (female 2.7 vs 0.7%, P < 0.001; male 6.4 vs 1.7%, P < 0.01), but the risk was no different between those with suppressed and normal TSH. There was no increase in risk for overall fracture, fractured neck of femur or breast carcinoma in those on thyroxine with suppressed or normal TSH.
CONCLUSION:Patients under the age of 65 years on L-thyroxine had an increased risk of ischaemic heart disease. There was no excess of fractures in patients on L-thyroxine even if the TSH is suppressed.
J Clin Endocrinol Metab. 1997 Sep;82(9):2931-6.
Low thyrotropin levels are not associated with bone loss in older women: a prospective study. Bauer DC1, Nevitt MC, Ettinger B, Stone K.
The relationship between excess thyroid hormone and bone loss is controversial. To determine whether low TSH levels, indicating excessive thyroid hormone, are associated with low bone mass or accelerated bone loss in older women, we performed a prospective cohort study of 458 women over age 65 yr participating in the multicenter Study of Osteoporotic Fractures. Three hundred and twenty-three women were randomly selected from the entire cohort of 9704; an additional 135 randomly selected thyroid hormone users were studied. Medical history, medication use, and calcaneal bone mineral density (BMD) were assessed at the baseline visit. Serum was collected and stored at -190 C. Hip and spine BMD were measured approximately 2 yr later, and follow-up calcaneal and hip BMD measurements were obtained after mean follow-up periods of 5.7 and 3.5 yr, respectively. TSH levels were determined in baseline serum samples using a third generation chemiluminescent assay. After adjustment for age, weight, previous hyperthyroidism, and use of estrogen, bone loss over 4-6 yr was similar in women with low, normal, or high TSH. For example, femoral neck bone loss was -0.3%/yr (95% confidence interval, -0.8%, 0.3%) among women with low TSH (< or = 0.1 mU/L) and -0.5%/yr (95% confidence interval, -0.7%, -0.3%) in those with normal TSH (0.1-5.5 mU/L). There were no statistically significant differences in baseline bone mass of the calcaneus, spine, or femoral neck or trochanteric hip subregions. Baseline total hip BMD was 6% lower (P = 0.01) in women with low TSH. Similar results were obtained in analyses confined to women not taking estrogens. We found no consistent evidence that low TSH, a sensitive biochemical marker of excess thyroid hormone, was associated with low BMD or accelerated bone loss in older ambulatory women.
conclusion, in this prospective study of thyroid function and skeletal health in older women, we found no consistent evidence that low TSH was associated with low bone mass or accelerated bone loss.
Effects of Estrogen
JAMA. 1994 Apr 27;271(16):1245-9.
Thyroid hormone use and bone mineral density in elderly women. Effects of estrogen. Schneider DL1, Barrett-Connor EL, Morton DJ.
To determine the effect of long-term use of thyroid hormone on bone mineral density (BMD) in elderly women and the potential mitigating effects of estrogen replacement therapy.
DESIGN:Cross-sectional, community-based study.
SETTING:Rancho Bernardo, Calif.
PARTICIPANTS:A total of 991 white women aged 50 to 98 years who participated in a study of osteoporosis.
MAIN OUTCOME MEASURES:Bone mineral density at the ultradistal radius and midshaft radius using single-photon absorptiometry and at the hip and lumbar spine using dual-energy x-ray absorptiometry.
RESULTS:A total of 196 women taking thyroid hormone for a mean duration of 20.4 years were compared with 795 women who were not using thyroid hormone.
Women taking daily thyroxine-equivalent doses of 200 micrograms or more had significantly lower BMD levels at the midshaft radius and hip compared with those taking less than 200 micrograms. Daily doses of 1.6 micrograms/kg and greater were associated with lower bone mass at all four sites compared with nonuse, whereas doses less than 1.6 micrograms/kg were not associated with lower BMD levels. These associations were independent of age, body mass index, smoking status, and use of thiazides, corticosteroids, and estrogen.
Women taking both estrogen and a thyroid hormone dose of 1.6 micrograms/kg or greater had significantly higher BMD levels at all four sites than women taking the same thyroid hormone dose alone. Women taking both thyroid hormone and estrogen had BMD levels comparable with those observed in women taking only estrogen.
CONCLUSIONS: Long-term thyroid hormone use at thyroxine-equivalent doses of 1.6 micrograms/kg or greater was associated with significant osteopenia at the ultradistal radius, midshaft radius, hip, and lumbar spine. Estrogen use appears to negate thyroid hormone-associated loss of bone density in postmenopausal women. Women taking both thyroid hormone and estrogen had BMD levels comparable with those observed in women taking only estrogen.
J Bone Miner Res. 1997 Jan;12(1):72-7.
Skeletal integrity in men chronically treated with suppressive doses of L-thyroxine. Marcocci C1, Golia F, Vignali E, Pinchera A.
We measured bone mineral density (BMD) (lumbar spine, femoral neck, Ward’s triangle, and trochanter) in 34 men given suppressive doses of levothyroxine (L-T4) for a mean of 10.2 years. Indications for treatment were nontoxic goiter (n = 5) or thyroidectomy for differentiated thyroid cancer (n = 6) or nontoxic goiter (n = 3). Patients were followed at our institution and treated with the minimal amount of L-T4 able to suppress thyroid-stimulating hormone (TSH). At the time of evaluation, free T3 was normal in all cases, whereas free T4 was increased in 14 men (41.2%). The mean daily dose of L-T4 was 172 +/- 6 microg, and the cumulative dose of L-T4 was 673 +/- 71 mg. We found no significant difference between patients and age- and weight-matched controls in BMD (g/cm2) at any site of measurement (lumbar spine 1.144 +/- 0.12 vs. 1.168 +/- 0.15; femoral neck 0.979 +/- 0.13 vs. 1.001 +/- 0.13; Ward’s triangle 0.854 +/- 0.17 vs. 0.887 +/- 0.15; and trocanther 0.852 +/- 0.13 vs. 0.861 +/- 0.13). BMD was not correlated with the duration of therapy, cumulative or mean daily dose of L-T4, serum levels of free T4, free T3, osteocalcin, and bone alkaline phosphatase. Serum calcium and osteocalcin were slightly but significantly elevated in patients compared with controls, whereas there was no difference in intact parathyroid hormone, bone alkaline phosphatase, and sex hormone-binding globulin (marker of thyroid hormone action). Our data suggest that L-T4 suppressive therapy, if carefully carried out and monitored, using the smallest dose necessary to suppress TSH secretion, has no significant effects on bone metabolism and bone mass in men.
Carefully monitored levothyroxine suppressive therapy is not associated with bone loss in premenopausal women. Marcocci C, et al. J Clin Endocrinol Metab. 1994.
We measured total body and regional (lumbar spine, femoral neck, Ward’s triangle, and trochanter) bone mineral density (BMD) in 47 premenopausal women chronically treated with suppressive doses of levothyroxine (L-T4). Treatment was administered to 7 patients with nontoxic goiter or, after thyroidectomy, to 38 patients with differentiated thyroid cancer and 2 with nontoxic goiter. Patients were followed at our institution and treated with the minimal amount of L-T4 necessary to suppress TSH. At the time of evaluation, free T3 was normal in all cases, whereas free T4 was increased in 17 (36.2%). The mean daily dose of L-T4 was 154.3 +/- 5 micrograms, and the mean duration of treatment was 10.1 yr. We found no significant difference between patients and age- and weight-matched controls in BMD at any site of measurement. BMD was not correlated with duration of therapy, cumulative or mean daily dose of L-T4, serum levels of free T4, free T3, and osteocalcin. There was no difference between patients and controls in serum total calcium, intact PTH, osteocalcin, or carboxy-terminal cross-linked telopeptide of type I collagen or in the concentrations of two markers of thyroid hormone action (sex hormone-binding globulin and amino-terminal propeptide of type III procollagen). Our data suggest that L-T4 suppressive therapy, if carefully carried out and monitored, using the smallest dose necessary to suppress TSH secretion has no significant effect on bone metabolism or bone mass.
Thyroid. 1995 Apr;5(2):81-7. Possible limited bone loss with suppressive thyroxine therapy is unlikely to have clinical relevance. Müller CG1, Bayley TA, Harrison JE, Tsang R.
To determine the effect of suppressive doses of thyroxine (T4) on bone mass, we studied 50 women on suppressive doses of T4 for 3-27 years (mean of 11 years). Twenty-five had nontoxic goiter and 25 had well-differentiated thyroid carcinoma. Fifty controls were matched for age, menopausal status, and body mass index. Bone mineral density (BMD) was measured in the lumbar spine (LS), femoral neck (FN), trunk (TK), and extremities (EXT) by dual-energy X-ray absorptiometry (DXA). In addition, the trunk area was measured by neutron activation analysis and recorded as a calcium bone index (CaBI). Twenty-one patients were restudied with DXA measurements at a mean of 1.5 +/- 0.5 (1 SD) years. The total population of 50 patients showed no difference in bone mass from controls. In patients with nontoxic goiter, there was no evidence of any loss in bone mass. Cancer patients showed insignificant reductions of 2-5% in BMD of LS, FN, and TK and a significant 5% reduction in BMD of EXT, compared to controls, and a 12% reduction in CaBI compared to goiter patients. Cancer patients had a slightly higher (p < 0.001) mean daily dose of T4 than goiter patients (0.23 vs 0.15 mg/day) but had a similar degree of TSH suppression. BMD and CaBI values did not correlate with free T4 index) with the daily T4 dose, accumulative dose, or with duration of T4 therapy. There were no significant changes in bone mass in either goiter or cancer patients restudied after a mean of 1.5 years.
Thyroid. 1995 Feb;5(1):13-7.Suppressive doses of thyroxine do not accelerate age-related bone loss in late postmenopausal women.
Fujiyama K1, Kiriyama T, Ito M, Kimura H, Ashizawa K, Tsuruta M, Nagayama Y, Villadolid MC, Yokoyama N, Nagataki S.
To examine whether suppressive doses of thyroxine have any adverse effects on bone, we evaluated various bone metabolic markers (lectin-precipitated alkaline phosphatase, osteocalcin, carboxyl-terminal region of type I collagen propeptide, tartrate-resistant alkaline phosphatase, and urinary excretion of hydroxyproline and pyridinium crosslinks), incidence of vertebral deformity, total body and regional (lumbar spine and radius) bone mineral densities (BMDs), and rates of bone loss in 24 late postmenopausal (more than 5 years after menopause) women who were treated with levothyroxine (L-T4) after total thyroidectomy for differentiated carcinoma. Depending on the clinical records, including serum TSH levels measured by immunoradiometric assay, these patients were divided into two groups. One group of patients was given suppressive doses of L-T4 (TSH < 0.1 mU/L, n = 12) and the other group was given nonsuppressive doses of L-T4 (TSH > 0.1 mU/L, n = 12). There was no difference in bone metabolic markers and incidence of vertebral deformity between the groups. In patients with TSH suppression, Z-scores of BMDs calculated from age-matched healthy women (n = 179, aged 55 to 80) were nearly in the zero range of values (0.077 at total body, 0.228 at lumbar spine, and -0.117 at trabecular region of lumbar spine). The rate of bone loss in TSH-suppressed patients (-0.849 +/- 0.605%/year) was not significantly different from that of nonsuppressed patients (-0.669 +/- 0.659). These prospective and cross-sectional data suggest that long-term levothyroxine therapy using suppressive doses has no significant adverse effects on bone.
Clin Endocrinol (Oxf). 1993 Nov;39(5):529-33.
Suppressed TSH levels secondary to thyroxine replacement therapy are not associated with osteoporosis. Grant DJ1, McMurdo ME, Mole PA, Paterson CR, Davies RR.
Recent studies have suggested that patients receiving thyroxine are at increased risk of osteoporosis. We set out to measure bone mineral densities in two groups of post-menopausal women receiving thyroxine replacement therapy (those with serum TSH levels persistently suppressed or non-suppressed) and to compare the results in both groups with those of the local control population.
PATIENTS:Seventy-eight post-menopausal women who had been treated with thyroxine for primary autoimmune or idiopathic hypothyroidism for a minimum of 5 years, 44 with TSH persistently suppressed and 34 non-suppressed. One hundred and two control subjects.
MEASUREMENTS:Forearm bone mineral density at proximal and distal sites as measured by single-photon absorptiometry.
RESULTS:Results were expressed as Z-scores, i.e. number of standard deviations from the mean of a 5-year age-band from the local control population. Mean Z-scores at proximal and distal sites for the non-suppressed patients were -0.03 and -0.07 and for the suppressed patients were -0.20 and -0.25, representing a decrease in bone mineral density of at most 5% in the suppressed patients. The differences between the three groups were not statistically significant.
CONCLUSION:In this patient population, the reduction in bone mineral density due to thyroxine is small. It is unlikely to be of clinical significance and should not on its own be an indication for reduction of thyroxine dose in patients who are clinically euthyroid.
Lack of deleterious effect on bone mineral density of long-term thyroxine suppressive therapy for differentiated thyroid carcinoma
J L Reverter, S Holgado1, N Alonso, I Salinas, M L Granada2 and A Sanmartí
Department of Endocrinology and Nutrition, Germans Trias i Pujol Hospital, Carretera de Canyet s/n. 08916, Badalona, Barcelona, Spain
1Department of Rheumatology, Germans Trias i Pujol Hospital, Badalona, Barcelona, Spain
2Hormone Laboratory, Germans Trias i Pujol Hospital, Badalona, Barcelona, Spain
The effect of subclinical hyperthyroidism on bone mineral density is controversial and could be significant in patients with differentiated thyroid carcinoma who receive suppressive doses of levothyroxine (LT4). To ascertain whether prolonged treatment with LT4 to suppress thyrotropin had a deleterious effect on bone mineral density and/or calcium metabolism in patients thyroidectomized for differentiated thyroid cancer we have performed a cross-sectional study in a group of 88 women (mean ± SD age: 51 ± 12 years) treated with LT4 after near-total thyroidectomy and in a control group of 88 healthy women (51 ± 11 years) matched for body mass index and menopausal status. We determined calcium metabolism parameters, bone turnover marker N-telopeptide and bone mass density by dual-energy X-ray absorptiometry. No differences were found between patients and controls in calcium metabolism parameters or N-telopeptide except for PTH, which was significantly increased in controls. No differences were found between groups in bone mineral density in femoral neck (0.971 ± 0.148 gr/cm2 vs 0.956 ± 0.130 gr/cm2 in patients and controls respectively, P = 0.5). In lumbar spine, bone mineral density values were lower in controls than in patients (1.058 ± 0.329 gr/cm2 vs 1.155 ± 0.224 gr/cm2 respectively, P<0.05). When premenopausal (n = 44) and postmenopausal (n = 44) patients were compared with their respective controls, bone mineral density was similar both in femoral neck and lumbar spine. The proportion of women with normal bone mass density, osteopenia and osteoporosis in patient and control groups was similar in pre- and postmenopausal women. In conclusion, long-term suppressive LT4 treatment does not appear to affect skeletal integrity in women with differentiated thyroid carcinoma.
Endocrinol Nutr. 2011 Feb;58(2):75-83. doi: 10.1016/j.endonu.2010.09.007. Epub 2011 Jan 17.
[Potential risks of the adverse effects of thyrotropin suppression in differentiated thyroid carcinoma].
[Article in Spanish]
Reverter JL1, Colomé E.
In patients with differentiated thyroid carcinoma, long-term inhibition of thyrotropin (TSH) secretion through levothyroxine administration is required when there is evidence of persistent or recurrent disease. In these cases, levothyroxine doses should be monitored to achieve the objectives of inhibiting TSH and avoiding clinical hyperthyroidism. The possibility that suppressive therapy may produce deleterious effects is still controversial, mainly in elderly patients. There are many studies on the potential harmful effects of suppressive therapy on various organs and systems with discrepant results. However, there is no scientific evidence that the clinical impact of these effects is significant.
Endocrinol Nutr. 2010 Oct;57(8):350-6. doi: 10.1016/j.endonu.2010.03.015. Epub 2010 May 24.
[Clinical endocrinologists’ perception of the deleterious effects of TSH suppressive therapy in patients with differentiated thyroid carcinoma].
[Article in Spanish]
Reverter JL1, Colomé E, Puig Domingo M, Julián T, Halperin I, Sanmartí A.
To explore the opinion of clinical endocrinologists as to the deleterious effects of thyrotropin (TSH) suppressive therapy in patients with differentiated thyroid carcinoma (DTC).
MATERIALS AND METHODS:
A self-administered survey was sent by e-mail to a group of endocrinologists with expertise in the treatment of patients with differentiated thyroid carcinoma. The questionnaire consisted of three questions related to: 1) the possible adverse effects of this therapy on different organ systems, 2) the clinical significance of these effects and 3) the usefulness of treatment guidelines for DTC.
RESULTS:A total of 91 endocrinologists responded with a wide divergence of opinions. No question had more than 80% of answers in a particular option. Of the possible side effects of suppressive therapy, a high degree of ignorance to three of them (increased left ventricular mass, reentrant tachycardia and diastolic dysfunction). Most respondents felt that the seven items, dementia and Alzheimer, decreased quality of life, decreased bone mineral density (BMD) in premenopausal women and men, thromboembolic disease, signs and symptoms of hyperthyroidism and increased risk of fractures were not affected by suppressive therapy, while most responded positively to two items (increased heart rate and decreased BMD in postmenopausal women). Eighty percent of the respondents felt that in any case these effects were not clinically significant and 33% considered that treatment guidelines should be reviewed.
CONCLUSIONS:Clinical endocrinologists seem to have a very heterogeneous opinion regarding the potential harmful effects of TSH-suppressive therapy for DTC.
Criminalizing Doctors Who Diagnose Hypothyroidism
The State of Oregon v. John E. Gambee, MD
John Gambee, MD is a physician practicing in Eugene, Oregon,
Letter from the Publisher
by Jonathan Collin, MD
Dr. Derry Medical License Suspended
21) Case Reports in Endocrinology Volume 2015 (2015), Article ID 684648, 5 Life-Threatening Hypercalcemia due to Graves’ Disease and Concomitant Adrenal Failure: A Case Report and Review of the Literature
Hande Mefkure Ozkaya, Fatma Ela Keskin, Ozlem Asmaz Haliloglu, Tugba Elif Senel, and Pinar Kadioglu Endocrinology and Metabolism, Cerrahpasa Medical School, University of Istanbul, 34098 Istanbul, Turkey
22) Hyperthyroidism an overlooked cause of severe hypercalcaemia Clark 2010 Abdul Mohammedb, Anita Pillaib, Angelos Klotsasb,
Paul Mastersa and Nigel Lawsona Grand Rounds Volume 10 2010
23) Biochim Biophys Acta. 2013 Jul;1830(7):3987-4003.
The syndromes of reduced sensitivity to thyroid hormone.
Dumitrescu AM1, Refetoff S. Department of Medicine, The University of Chicago, Chicago, IL, USA.
24) Endocrine Abstracts (2010) 21 OC5.6
Is it safe for patients taking thyroxine to have a low but not suppressed serum TSH concentration? Graham Leese & Robert Flynn
University of Dundee, Tayside, UK.
We aimed to examine the safety of having a TSH which was either suppressed (≤0.03 mU/l), low (0.04–0.4 mU/l), ‘normal’ (0.4–4.0 mU/l) or raised (>4.0 mU/l) in a population-based cohort of patients all of whom were treated with thyroxine.
There were a total of 16 426 patients on thyroxine replacement (86% female, mean age 60 years) with a total follow-up of 74 586 years. Cardiovascular disease, dysrhythmias and fractures were increased in patients with a high TSH (adjusted hazards ratio 1.95 (1.73–2.21), 1.80 (1.33–2.44) and 1.83 (1.41–2.37) respectively), and patients with a suppressed TSH (1.37 (1.17–1.6), 1.6 (1.1–2.33) and 2.02 (1.55–2.62) respectively), when compared to patients with a TSH in the laboratory reference range. Patients with a low TSH did not have an increased risk of any of these outcomes (HR: 1.1 (0.99–1.123), 1.13 (0.88–1.47) and 1.13 (0.92–1.39) respectively.
25) Ito, Mitsuru, et al. “TSH-suppressive doses of levothyroxine are required to achieve preoperative native serum triiodothyronine levels in patients who have undergone total thyroidectomy.” European Journal of Endocrinology 167.3 (2012): 373-378.
26) Soldin, Offie P., Sarah H. Chung, and Christine Colie. “The Use of TSH in Determining Thyroid Disease: How Does It Impact the Practice of Medicine in Pregnancy?” Journal of Thyroid Research 2013 (2013): 148157. PMC. Web. 21 May 2015.
(27) Effective Treatment of Chronic Fatigue Syndrome and Fibromyalgia: A Comprehensive Medicine Approach by Jacob Teitelbaum, MD Townsend Letter December 2011
28) Chronic Fatigue Syndrome Fibromyalgia Jacob Teitelbaum 2001
29) Effective Treatment of Chronic Fatigue Syndrome and
Fibromyalgia—A Randomized, Double-Blind, Placebo-
Controlled, Intent to Treat Study Jacob E. Teitelbaum, MD*1; Barbara Bird, M.T.,C.L.S.*; Robert M. Greenfield, MD1; Alan Weiss, MD1; Larry Muenz, Ph.D2; Laurie Gould, BS*3 Published in the Journal of Chronic Fatigue Syndrome Vol. 8, No. 2, 2001. PP3-28.
30) treating-thyroid-despite-normal-labs Kent Holtorf JAcob Teitelbaum
31) Holtorf, Kent. “Diagnosis and treatment of hypothalamic-pituitary-adrenal (HPA) axis dysfunction in patients with chronic fatigue syndrome (CFS) and fibromyalgia (FM).” Journal of Chronic Fatigue Syndrome 14.3 (2007): 59-88. hypothalamic-pituitary-adrenal HPA dysfunction chronic fatigue syndrome fibromyalgia Holtorf 2007
32) Effective Treatment of Chronic Fatigue Syndrome JAcob Teitelbaum 2005 Integrative Medicine
33) Nuklearmedizin. 1999;38(5):144-9.
[Effect of iodine and thyroid hormones in the induction and therapy of Hashimoto’s thyroiditis]. [Article in German] Rink T1, Schroth HJ, Holle LH, Garth H.
The effect of an iodine prophylaxis on the induction of Hashimoto’s thyroiditis as well as the influence of various therapeutic approaches on the course of antithyroglobulin (TgAb) and antiperoxidase (TPOAb) antibodies in manifest diseases are evaluated.
METHOD: A collective of 375 euthyroid subjects without relevant goiter received daily doses of 200 micrograms iodide, weekly doses of 1.53 milligrams iodide, or no medication. A second group of 377 patients suffering from Hashimoto’s thyroiditis was treated with a non-suppressive hormone medication, a suppressive hormone administration, a combination of a non-suppressive hormone therapy with low dose iodide (50-150 micrograms/day), mere iodide in doses of 200 micrograms/day, or received no therapy. The mean observation period in these two groups was 860 and 848 days, respectively.
There was no significant increase of the antibody levels in the subgroup with 200 micrograms iodide/day and in the non-treated subjects of the first collective. However, the group that received 1.53 milligrams iodide/week presented a distinct increase of the TgAb as well as the TPOAb, and the incidence of Hashimoto’s thyroiditis was 4-fold higher than in the two other subgroups. The patients of the second collective revealed a significant decrease of the TgAb in the subgroups treated with up to 200 micrograms iodide/day, while the reduction of the TPOAb depended on the thyrotropin level(TSH) and was most significant in the suppressed group (p < 0.0001).
To lower the incidence of autoimmune thyroid diseases in predisposed subjects, a daily iodine supplementation seems to be superior to high-dose weekly administrations. A hormone therapy combined with a daily, low-dose iodine medication is able to reduce the TgAb and the TPOAb levels even in patients with Hashimoto’s thyroiditis.
34) Effects of prophylactic thyroid hormone replacement in euthyroid Hashimoto’s thyroiditis Aksoy DY, Kerimoglu U, Okur H, Canpinar H, Karaağaoğlu E, Yetgin S, Kansu E, Gedik O Section of Endocrinology and Metabolism, Department of Internal Medicine, Hacettepe University, Ankara, Turkey.
Endocrine Journal [2005, 52(3):337-343]
Hashimoto’s thyroiditis is the most frequent autoimmune thyroid disease. L-thyroxine therapy can reduce the incidence and alleviate the symptoms of this disease. The aim of this study was to evaluate the effects of prophylactic L-thyroxine treatment on clinical and laboratory findings of patients who were euthyroid at the time of diagnosis.
Thirty-three patients who had diagnosis of euthyroid Hashimoto’s thyroiditis were randomized to two groups, one group received prophylactic L-thyroxine treatment and the other was followed-up without treatment. Initial thyroid function tests, autoantibodies, ultrasonography, fine needle aspiration biopsy and peripheral blood lymphocyte subsets were similar in the two study groups. After 15 months of L-thyroxine treatment, there was a significant increase in free T4 and a significant decrease in TSH and anti-thyroglobulin antibody anti-thyroid peroxidase antibody levels. CD8+ cell counts increased in both groups, CD4/CD8 levels decreased significantly because of the increase in CD8+ cell count levels. Though there was no change in cytological findings, ultrasonography showed a decrease in thyroid volume in L-thyroxine receiving patients whereas an increase was detected in patients who were followed without treatment. In conclusion, prophylactic thyroid hormone therapy can be used in patients with Hashimoto’s thyroiditis even if they are euthyroid.
35) One-year prophylactic treatment of euthyroid Hashimoto’s thyroiditis patients with levothyroxine: is there a benefit?
Padberg, Heller K, Usadel KH, Schumm-Draeger PM
Medica Clinic l, Endocrinology, Center of Internal Medicine, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany. Thyroid : Official Journal of the American Thyroid Association [2001, 11(3):249-255]
Studies in animal models of spontaneous Hashimoto’s autoimmune thyroiditis (HT) show that prophylactic treatment with levothyroxine (LT4) can reduce incidence and degree of lymphocytic infiltration in HT. The aim of the present study was to clarify whether there is a benefit of prophylactic treatment with LT4 in patients with euthyroid HT with respect to the progression of the autoimmune process. Twenty-one patients with euthyroid HT were checked for thyroid function (thyrotropin [TSH], free triiodothyronine [FT3], free thyroxine [FT4]), thyroid volume, antibodies (thyroglobulin [Tg-Ab], thyroid peroxidase [TPO-Ab]), and lymphocyte subsets. Peripheral (PBL) and thyroid-derived lymphocytes (TL) were analyzed by triple color flow cytometry. One-half of the patients with euthyroid HT were treated with LT4 for 1 year (n = 10). The other half (n = 11) were never treated with LT4. TL were obtained by fine-needle aspiration biopsy (FNAB). Thirteen healthy subjects (C) without medical history of thyroid disease served as controls concerning PBL, and patients with non-toxic nodular goiter (NG; n = 10) served as controls concerning TL. Thyroid-derived T-helper cells were found more frequently in euthyroid patients with HT compared to patients with NG (p < 0.01). After 1 year of therapy with LT4, TPO-Abs and B lymphocytes decreased significantly only in the treated group of euthyroid patients with HT (p < 0.05). In contrast, TPO-Abs levels did not change or even increased in untreated euthyroid patients with HT. Thyroid volume did not differ before and after therapy. Prophylactic treatment of euthyroid patients with HT reduced both serological and cellular markers of autoimmune thyroiditis. Therefore, prophylactic LT4 treatment might be useful to stop the progression or even manifestation of the disease. However, the long-term clinical benefit of prophylactic LT4 therapy in euthyroid patients with HT is yet to be established.
Schmidt, Matthias, et al. “Long-term follow-up of antithyroid peroxidase antibodies in patients with chronic autoimmune thyroiditis (Hashimoto’s thyroiditis) treated with levothyroxine.” Thyroid 18.7 (2008): 755-760.
Thyroid. 2008 Jul;18(7):755-60. doi: 10.1089/thy.2008.0008.
Long-term follow-up of antithyroid peroxidase antibodies in patients with chronic autoimmune thyroiditis (Hashimoto’s thyroiditis) treated with levothyroxine.
Schmidt M1, Voell M, Rahlff I, Dietlein M, Kobe C, Faust M, Schicha H.
A number of studies show that the serum levels of antithyroid peroxidase antibodies (TPO-Ab) in patients with Hashimoto’s thyroiditis decline during levothyroxine treatment, but do not provide quantitative data or report the fraction of patients in whom test for TPO-Ab became negative (“normalization percentage”). The objective of the present study was to provide this information.
This was a retrospective study of TPO-Ab concentrations in 36 women and 2 men (mean age 51 +/- 16 years; range 19-81 years) with Hashimoto’s thyroiditis as defined by the following criteria: elevated plasma TPO-Ab and typical hypoechogenicity of the thyroid in high-resolution sonography at first presentation or during follow-up and low pertechnetate uptake in thyroid scintigraphy. When first studied 17 women and 1 man were not yet taking levothyroxine. The remaining 20 patients were receiving levothyroxine. At initial examination 18 patients had serum thyroid-stimulating hormone (TSH) concentrations above normal. Results of up to eight (mean = 5.8) measurements obtained over a mean period of 50 months while patients were receiving levothyroxine were analyzed. In addition, serum TSH, free triiodothyronine (fT3), and free thyroxine (fT4) were measured, and ultrasound of the neck was performed at each follow-up examination.
RESULTS: In terms of TPO-Ab levels, 35 of 38 patients (92%) had a decrease, 2 patients had undulating levels, and 1 patient had an inverse hyperbolic increase in her TPO-Ab levels. In the 35 patients in whom there were decreasing TPO-Ab values, the mean of the first value was 4779 IU/mL with an SD of 4099 IU/mL. The mean decrease after 3 months was 8%, and after 1 year it was 45%. Five years after the first value, TPO-Ab levels were 1456 +/- 1219 IU/mL, a decrease of 70%. TPO-Ab levels became negative, < 100 IU/mL, in only six patients, a normalization percentage of 16%. There were no correlations between changes in thyroid volume and changes in TPO-Ab.
Serum TPO-Ab levels decline in most patients with Hashimoto’s thyroiditis who are taking levothyroxine, but after a mean of 50 months, TPO-Ab became negative in only a minority of patients.
37) Clin Endocrinol (Oxf). 1991 Sep;35(3):235-8.
Influence of thyroxine treatment on thyroid size and anti-thyroid peroxidase antibodies in Hashimoto’s thyroiditis.
Hegedüs L1, Hansen JM, Feldt-Rasmussen U, Hansen BM, Høier-Madsen M.
It has been postulated that a decrease in thyroid size can be achieved by thyroxine treatment in patients with goitrous Hashimoto’s thyroiditis but no objective data are available. We have therefore investigated the influence of thyroxine treatment on ultrasonically determined thyroid size. We also measured serum antithyroid peroxidase antibodies.
DESIGN: Consecutive patients with goitrous Hashimoto’s thyroiditis was studied.
PATIENTS: Thirteen women participated; all had goitrous thyroiditis.
TREATMENT: To render them euthyroid thyroxine was given for 24 months.
MEASUREMENTS: Thyroid size was measured ultrasonically and antithyroid peroxidase antibodies were measured using a commercial radioimmunological method.
RESULT: Concomitant with the gradual increase in serum free thyroxine and free triiodothyronine index values and a fall in serum thyrotrophin level, a gradual decrease in thyroid volume from 50.4 +/- 6.8 ml (mean +/- SEM) to 34.1 +/- 5.7 ml (32%), P less than 0.001 was demonstrated. Antithyroid peroxidase antibodies were present in high concentrations in all subjects but the mean serum level was not significantly changed at 24 months after initiation of treatment.
CONCLUSION: A clinically significant reduction in thyroid volume related to normalization of thyroid function but unrelated to changes in antithyroid peroxidase antibody can be achieved during L-thyroxine treatment of hypothyroid goitrous Hashimoto’s thyroiditis.
38) Exp Clin Endocrinol Diabetes. 1999;107 Suppl 3:S84-7.
Prophylactic levothyroxine therapy in patients with Hashimoto’s thyroiditis.
Schumm-Draeger PM1, Padberg S, Heller K.
1Medical Clinic I, Endocrinology, Center of Internal Medicine, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany. Schumm-Draeger@em.uni-frankfurt.de
39) Breast Cancer Res Treat. 2007 Jul;103(3):303-11. Epub 2006 Sep 29.
Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5-10 years after chemotherapy.
Silverman DH1, Dy CJ, Castellon SA, Lai J, Pio BS, Abraham L, Waddell K, Petersen L, Phelps ME, Ganz PA.
Purpose To explore the relationship of regional cerebral blood flow and metabolism with cognitive function and past exposure to chemotherapy for breast cancer.
Patients and methods Subjects treated for breast cancer with adjuvant chemotherapy remotely (5–10 years previously) were studied with neuropsychologic testing and positron emission tomography (PET), and were compared with control subjects who had never received chemotherapy. [O-15] water PET scans was acquired during performance of control and memory-related tasks to evaluate cognition-related cerebral blood flow, and [F-18] fluorodeoxyglucose (FDG) PET scans were acquired to evaluate resting cerebral metabolism. PET scans were analyzed by statistical parametric mapping and region of interest methods of analysis.
Results During performance of a short-term recall task, modulation of cerebral blood flow in specific regions of frontal cortex and cerebellum was significantly altered in chemotherapy-treated subjects. Cerebral activation in chemotherapy-treated subjects differed most significantly from untreated subjects in inferior frontal gyrus, and resting metabolism in this area correlated with performance on a short-term memory task previously found to be particularly impaired in chemotherapy-treated subjects. In examining drug-class specific effects, metabolism of the basal ganglia was significantly decreased in tamoxifen + chemotherapy-treated patients compared with chemotherapy-only breast cancer subjects or with subjects who had not received chemotherapy, while chemotherapy alone was not associated with decreased basal ganglia activity relative to untreated subjects.
Conclusion Specific alterations in activity of frontal cortex, cerebellum, and basal ganglia in breast cancer survivors were documented by functional neuroimaging 5–10 years after completion of chemotherapy.
40) Hum Brain Mapp. 2011 Aug;32(8):1206-19. Cerebral hyporesponsiveness and cognitive impairment 10 years after chemotherapy for breast cancer.
de Ruiter MB1, Reneman L, Boogerd W, Veltman DJ, van Dam FS, Nederveen AJ, Boven E, Schagen SB.
Chemotherapy is associated with cognitive impairment in a subgroup of breast cancer survivors, but the neural circuitry underlying this side effect is largely unknown. Moreover, long-term impairment has not been studied well. In the present study, functional magnetic resonance imaging (fMRI) and neuropsychological testing were performed in breast cancer survivors almost 10 years after high-dose adjuvant chemotherapy (chemo group, n = 19) and in breast cancer survivors for whom chemotherapy had not been indicated (control group, n = 15). BOLD activation and performance were measured during an executive function task involving planning abilities (Tower of London) and a paired associates task for assessment of episodic memory. For the chemo group versus the control group, we found hyporesponsiveness of dorsolateral prefrontal cortex in the Tower of London, and of parahippocampal gyrus in the paired associates task. Also, the chemo group showed significantly impaired planning performance and borderline significantly impaired recognition memory as compared to findings in the control group. Whole-brain analyses demonstrated hyporesponsiveness of the chemo versus the control group in very similar regions of bilateral posterior parietal cortex during both the Tower of London and the paired associates task. Neuropsychological testing showed a relatively stable pattern of cognitive impairment in the chemo group over time. These results indicate that high-dose adjuvant chemotherapy is associated with long-term cognitive impairments. These impairments are underpinned by (a) task-specific hyporesponsiveness of dorsolateral prefrontal cortex and parahippocampal gyrus, and (b) a generalized hyporesponsiveness of lateral posterior parietal cortex encompassing attentional processing.
41) Hum Brain Mapp. 2011 Mar;32(3):480-93. doi: 10.1002/hbm.21033.
Chemotherapy-induced structural changes in cerebral white matter and its correlation with impaired cognitive functioning in breast cancer patients.
Deprez S1, Amant F, Yigit R, Porke K, Verhoeven J, Van den Stock J, Smeets A, Christiaens MR, Leemans A, Van Hecke W, Vandenberghe J, Vandenbulcke M, Sunaert S.
A subgroup of patients with breast cancer suffers from mild cognitive impairment after chemotherapy. To uncover the neural substrate of these mental complaints, we examined cerebral white matter (WM) integrity after chemotherapy using magnetic resonance diffusion tensor imaging (DTI) in combination with detailed cognitive assessment. Postchemotherapy breast cancer patients (n = 17) and matched healthy controls (n = 18) were recruited for DTI and neuropsychological testing, including the self-report cognitive failure questionnaire (CFQ). Differences in DTI WM integrity parameters [fractional anisotropy (FA) and mean diffusivity (MD)] between patients and healthy controls were assessed using a voxel-based two-sample-t-test. In comparison with healthy controls, the patient group demonstrated decreased FA in frontal and temporal WM tracts and increased MD in frontal WM. These differences were also confirmed when comparing this patient group with an additional control group of nonchemotherapy-treated breast cancer patients (n = 10). To address the heterogeneity observed in cognitive function after chemotherapy, we performed a voxel-based correlation analysis between FA values and individual neuropsychological test scores. Significant correlations of FA with neuropsychological tests covering the domain of attention and processing/psychomotor speed were found in temporal and parietal WM tracts. Furthermore, CFQ scores correlated negatively in frontal and parietal WM. These studies show that chemotherapy seems to affect WM integrity and that parameters derived from DTI have the required sensitivity to quantify neural changes related to chemotherapy-induced mild cognitive impairment.
42) Peripheral Thyroid Hormone Conversion Impact on TSH Holtorf J Restorative Medicine 2014 Holtorf, Kent. “Peripheral Thyroid Hormone Conversion and Its Impact on TSH and Metabolic Activity.” Journal of Restorative Medicine 3.1 (2014): 30-52.
43) Holtorf, Kent. “Thyroid hormone transport into cellular tissue.” Journal of Restorative Medicine 3.1 (2014): 53-68. Link to article on Ingentaconnect.
“A retrospective study by Pujol et al4 suggested that a suppressed serum TSH to undetectable levels was associated with an increased relapse-free survival in patients with differentiated thyroid cancer.”
44) Hoermann, Rudolf, et al. “Is pituitary TSH an adequate measure of thyroid hormone-controlled homoeostasis during thyroxine treatment?.” European Journal of Endocrinology 168.2 (2013): 271-280.
45) Cooper, David S. “TSH suppressive therapy: an overview of long-term clinical consequences.” Hormones (Athens) 9.1 (2010): 57-59. TSH suppressive therapy long-term clinical consequences Cooper David S Hormones 2010
46) Abo-Touk, Niveen A., and Dalia H. Zayed. “The Efficacy of Thyrotropin Suppression Therapy in Treatment of Differentiated Thyroid Cancer after Total Thyroidectomy.” Forum of Clinical Oncology. Vol. 6. No. 2. 2015.
47) Pujol, P. A. S. C. A. L., et al. “Degree of thyrotropin suppression as a prognostic determinant in differentiated thyroid cancer.” The Journal of Clinical Endocrinology & Metabolism 81.12 (1996): 4318-4323.Thyrotropin suppression as prognostic determinant in thyroid cancer Pujol Journal Clinical Endo1996
This study shows that a lesser degree of TSH suppression is associated with an increased incidence of relapse, supporting the hypothesis that a high level of TSH suppression is required for the endocrine management of thyroid cancer.
48) Thyroid. 2010 Feb;20(2):135-46. doi: 10.1089/thy.2009.0311.
Benefits of thyrotropin suppression versus the risks of adverse effects in differentiated thyroid cancer. Biondi B1, Cooper DS.
Despite clinical practice guidelines for the management of differentiated thyroid cancer (DTC), there are no recommendations on the optimal serum thyrotropin (TSH) concentration to reduce tumor recurrences and improve survival, while ensuring an optimal quality of life with minimal adverse effects. The aim of this review was to provide a risk-adapted management scheme for levothyroxine (L-T4) therapy in patients with DTC. The objective was to establish which patients require complete suppression of serum TSH levels, given their risk of recurrent or metastatic DTC, and how potential adverse effects on the heart and skeleton, induced by subclinical hyperthyroidism, in concert with advanced age and comorbidities, may influence the degree of TSH suppression.
SUMMARY:A risk-stratified approach to predict the rate of recurrence and death from thyroid cancer was based on the recently revised American Thyroid Association guidelines. A stratified approach to predict the risk from the adverse effects of L-T4 was devised, taking into account the age of the patient, as well as the presence of preexisting cardiovascular and skeletal risk factors that might predispose to the development of long-term adverse cardiovascular or skeletal outcomes, particularly increased heart rate and left ventricular mass, atrial fibrillation, and osteoporosis. Nine potential patient categories can be defined, with differing TSH targets for both initial and long-term L-T4 therapy.
CONCLUSION:Before deciding on the degree of TSH suppression during initial and long-term L-T4 treatment in patients with DTC, it is necessary to consider the aggressiveness of DTC, as well as the potential for adverse effects induced by iatrogenic subclinical hyperthyroidism. More aggressive TSH suppression is indicated in patients with high-risk disease or recurrent tumor, whereas less aggressive TSH suppression is reasonable in low-risk patients. In patients with high-risk DTC and an equally high risk of adverse effects, long-term treatment with L-T4 therapy should be individualized and balanced against the potential for adverse effects. In patients with an intermediate risk for thyroid cancer recurrence and a high risk of adverse effects of therapy, the degree of TSH suppression should be reevaluated during the follow-up period. Normalization of serum TSH is advisable for long-term treatment of disease-free elderly patients with DTC and significant comorbidities.
47) Samuels, M. H., et al. “Effects of Altering Levothyroxine (L-T4) Doses on Quality of Life, Mood, and Cognition in L-T4 Treated Subjects.” The Journal of clinical endocrinology and metabolism 103.5 (2018): 1997.
Background: The brain is a critical target organ for thyroid hormone, but it is unclear whether variations in thyroid function within and near the reference range affect quality of life, mood, or cognition.
Methods: A total of 138 subjects with levothyroxine (L-T4)-treated hypothyroidism and normal thyrotropin (TSH) levels underwent measures of quality of life (36-Item Short Form Health Survey, Underactive Thyroid-Dependent Quality of Life Questionnaire), mood (Profile of Mood States, Affective Lability Scale), and cognition (executive function, memory). They were then randomly assigned to receive an unchanged, higher, or lower L-T4 dose in double-blind fashion, targeting one of three TSH ranges (0.34 to 2.50, 2.51 to 5.60, or 5.61 to 12.0 mU/L). Doses were adjusted every 6 weeks based on TSH levels. Baseline measures were reassessed at 6 months.
Results: At the end of the study, by intention to treat, mean L-T4 doses were 1.50 ± 0.07, 1.32 ± 0.07, and 0.78 ± 0.08 μg/kg (P < 0.001), and mean TSH levels were 1.85 ± 0.25, 3.93 ± 0.38, and 9.49 ± 0.80 mU/L (P < 0.001), respectively, in the three arms. There were minor differences in a few outcomes between the three arms, which were no longer significant after correction for multiple comparisons. Subjects could not ascertain how their L-T4 doses had been adjusted (P = 0.55) but preferred L-T4 doses they perceived to be higher (P < 0.001).
Conclusions: Altering L-T4 doses in hypothyroid subjects to vary TSH levels in and near the reference range does not affect quality of life, mood, or cognition. L-T4-treated subjects prefer perceived higher L-T4 doses despite a lack of objective benefit. Adjusting L-T4 doses in hypothyroid patients based on symptoms in these areas may not result in significant clinical improvement.
2020 post menopausal women
48) Brancatella, Alessandro, and Claudio Marcocci. “TSH suppressive therapy and bone.” Endocrine Connections 9.7 (2020): R158-R172.
In this review we will discuss the current indication of TSH suppressive therapy in patients with DTC, the potential adverse effects on bones and their prevention.
Thyroid hormones stimulate bone turnover in adults by increasing osteoclastic bone resorption. TSH suppressive therapy is usually applied in patients with differentiated thyroid cancer (DTC) to improve the disease outcome. Over the last decades several authors have closely monitored the potential harm suffered by the skeletal system. Several studies and meta-analyses have shown that chronic TSH suppressive therapy is safe in premenopausal women and men.
Conversely, in postmenopausal women TSH suppressive therapy is associated with a decrease of bone mineral density, deterioration of bone architecture (quantitative CT, QCT; trabecular bone score, TBS), and, possibly, an increased risk of fractures.
The TSH receptor is expressed in bone cells and the results of experimental studies in TSH receptor knockout mice and humans on whether low TSH levels, as opposed to solely high thyroid hormone levels, might contribute to bone loss in endogenous or exogenous thyrotoxicosis remain controversial. Recent guidelines on the use of TSH suppressive therapy in patients with DTC give value not only to its benefit on the outcome of the disease, but also to the risks associated with exogenous thyrotoxicosis, namely menopause, osteopenia or osteoporosis, age >60 years, and history of atrial fibrillation. Bone health (BMD and/or preferably TBS) should be evaluated in postmenopausal women under chronic TSH suppressive therapy or in those patients planning to be treated for several years. Antiresorptive therapy could also be considered in selected cases (increased risk of fracture or significant decline of BMD/TBS during therapy) to prevent bone loss.
In an historical study by Ross et al., radial BMD was measured by single photon absorptiometry in 28 white premenopausal females who received TSH suppressive therapy (TSH <0.1 mU/mL) for 5 years or more. A significant BMD reduction (about 10% vs normal controls) was observed in women receiving LT4 therapy for 10 years or more
TSH-suppressive therapy was deleterious on BMD in postmenopausal but safe in premenopausal women and men (26, 27, 28, 29, 30).
Finally, women taking LT4 and estrogen had BMD values similar to those of women taking only estrogens (32).
In conclusion, whether and to what extent low TSH levels, as opposed to solely high thyroid hormone levels, contribute to bone loss in endogenous or exogenous thyrotoxicosis remains to be defined.
49) Ross DS, Neer RM, Ridgway EC, Daniels GH. Subclinical hyperthyroidism and reduced bone density as a possible result of prolonged suppression of the pituitary-thyroid axis with L-thyroxine. American Journal of Medicine 1987 82 1167–1170.
Spontaneous hyperthyroidism and that due to excessive administration of thyroid hormone result in osteopenia. Bone density was measured in 28 white premenopausal female patients who were taking commonly prescribed suppressive doses of L-thyroxine (mean dose 0.171 +/- 0.035 g) for five or more years. The thyroxine level was 13.5 +/- 2.6 micrograms/dl (normal 8.0 +/- 2.4 micrograms/dl), the free thyroxine index was 4.4 +/- 1.0 (normal 2.4 +/- 0.8), and the triiodothyronine value was 154 +/- 26 ng/dl (normal 132 +/- 32 ng/dl). Basal thyrotropin was undetectable (less than 0.08 microIU/ml) in 23 patients, and thyrotropin measured 20 minutes after thyrotropin-releasing hormone administration was not demonstrable in 13 patients and subnormal in 10 patients. Women who had taken L-thyroxine for 10 or more years (n = 12, age 37 +/- 4 years) had a 9 percent reduction in bone density (0.667 +/- 0.044 g/cm2, p less than 0.01) compared with normal premenopausal age-matched control subjects (n = 56, age 35 +/- 6 years, bone density 0.733 +/- 0.055 g/cm2). It is concluded that prolonged suppressive L-thyroxine treatment may result in mild subclinical hyperthyroidism with adverse effects on bone. Patients requiring suppression of the pituitary-thyroid axis should be given the smallest dose of L-thyroxine necessary to achieve a satisfactory clinical response.
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Another group of patients who may be given thyroxine or NDT when euthyroid are the Hashimotos patients.
Mark Darby from Alberta Canada says:
Dear Dr. Dach,
I am in my 3rd year of running a BHRT clinic in Calgary, Alberta. I do
this 1 day per week and family medicine the rest of the week. I have
found great success – most especially with thyroid treatment. I have
appreciated the valuable information and insights you have shared on
your website (and chapter in Stop the thyroid madness II).
I agree that when a correct dosage is clinically found, the TSH is typically suppressed. I have 2 questions stemming from this I hope you might be able to answer:
1) free t3 I agree seems to be the most reliable
test. Problem is, it is very dependent on the interval of time between
their last pill and the blood test. I can always tell when a patient
didn’t read the instruction sheet properly and does the blood work an
hour after their thyroid pills! What time interval do you recommend?
2) which organization do you recommend for education? I have done a few symposium with the A4M, (and will go again this June as Dr Hertoghe is coming!), but Dr Pam Smith who runs the education for hormones at the
A4M, teaches that one must NEVER see a suppressed TSH with thyroid
Thanks so Much!
We usually do labs first thing in the AM, and the patient is instructed to hold meds until after the blood draw. For thyroid educational meetings, I would recommend David Brownstein MD, Mark Starr MD, and Neal Rozier MD, Their books are all excellent. They also speak at various meeting during the year.
regards jeffrey dach md
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I had radioactive iodine treatment for Graves in my twenties, 1980. I ended up with a damaged parathyroid because of the RAI and had surgery for hyperparathyroidism 5 years ago. Since then, I’ve been in a constant state of fatigue and a low TSH. No matter what dose of Naturethroid I’m on, my TSH is always around .3, my T4 is always 1, my T3 always 3.3. My doctors have chased my thyroid dose down and eventually my TSH jumps up to 7 because both my T3 and T4 go below normal, usually in the cold winter months. My problem is, I can’t find one doctor in Boston who will look past the TSH numbers. Any help?
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I am trying to find a doctor to treat my thyroid. My PCP keeps changing my meds and I feel like death warmed over. He just recently dropped my Synthroid from 100 to 25 mcg and my Cytomel from 5 to 25MCG. Too much too fast. The TSH is suppressed. .03 And the truth is I felt great when it was in the .01 to .03 levels but my PCP is freaking out. Help me find a doctor.