scholarly journals Increased Epoxyeicosatrienoic Acids and Hydroxyeicosatetraenoic Acids After Treatment of Iodide Intake Adjustment and 1,25-Dihydroxy-Vitamin D3 Supplementation in High Iodide Intake–Induced Hypothyroid Offspring Rats

2021 ◽  
Vol 12 ◽  
Author(s):  
Qing Liu ◽  
Yue Zhang ◽  
Hailing Zhao ◽  
Xiaomei Yao
Keyword(s):  
Fatty Acids ◽  
Thyroid Function ◽  
Vitamin D3 ◽  
Cardiac Dysfunction ◽  
Density Lipoprotein ◽  
Thyroid Peroxidase ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Pregnant Rats ◽  
Hydroxyeicosatetraenoic Acids

Aim: This study aimed to investigate the potential role of fatty acids in high iodide intake–induced hypothyroidism and its complications and also in the intervention of iodide intake adjustment and 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] supplementation.Methods: Pregnant rats were allocated to two groups, namely, normal iodide (NI, 7.5 μg/day) intake and 100 times higher-than-normal iodide (100 HI, 750 μg/day) intake. The offspring were continuously administered potassium iodide from weaning [i.e., postnatal day 21 (PN21)] to PN90. After PN90, the offspring were either administered iodide intake adjustment (7.5 μg/day) or 1,25(OH)2D3 supplementation (5 μg·kg−1·day−1), or both, for 4 weeks. Thyroid function tests (free triiodothyronine, free thyroxine, thyrotropin, thyroid peroxidase antibody, and thyroglobulin antibody), blood lipids (triglyceride, total cholesterol, free fatty acid, and low-density lipoprotein cholesterol), and vitamin D3 (VD3) levels were detected by ELISA. Cardiac function was measured by echocardiography. Blood pressure was measured using a non-invasive tail-cuff system. The serum fatty acids profile was analyzed by liquid chromatography–mass spectrometry.Results: In the offspring rats with continued 100 HI administration, the levels of 8,9-dihydroxyeicosatrienoic acid (8,9-DHET) and thromboxane B2 (TXB2) were decreased, while those of prostaglandin J2 (PGJ2), prostaglandin B2 (PGB2), 4-hydroxydocosahexaenoic acid (4-HDoHE), 7-HDoHE, 8-HDoHE, and 20-HDoHE were increased. Significant correlations were found between PGB2, 8,9-DHET, 7-HDoHE levels and thyroid dysfunction, between PGJ2, 20-HDoHE, PGB2, 8,9-DHET levels and cardiac dysfunction, between PGJ2, 20-HDoHE levels and hypertension, between 4-HDoHE, 8-HDoHE, TXB2 levels and dyslipidemia, and between PGB2 and decreased VD3 level. After the treatment of iodide intake adjustment and 1,25(OH)2D3 supplementation, the levels of 16-hydroxyeicosatetraenoic acids (16-HETE), 18-HETE, 5,6-epoxyeicosatrienoic acid (5,6-EET), 8,9-EET, 11,12-EET, 14,15-EET, PGE2, 5-oxo-ETE, and 15-oxo-ETE were increased. The significant associations between PGE2, 16-HETE, 18-HETE and improved thyroid function and also between 5,6-EET, 11,12-EET, 14,15-EET, 16-HETE, 15-oxo-ETE and attenuated dyslipidemia were detected.Conclusion: Increased levels of prostaglandins (PGs) and HDoHEs and decreased levels of 8,9-DHET and TXB2 might occur in the progression of cardiac dysfunction, hypertension, and dyslipidemia in high iodide intake–induced hypothyroidism. The increased levels of EETs and HETEs might help to ameliorate these complications after iodide intake adjustment and 1,25(OH)2D3 supplementation.

scholarly journals Relationship between Different Psoriasis Types and Thyroid Dysfunction: A Retrospective Analysis

Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Juan Du ◽  
Chunyue Ma ◽  
Runnan Wang ◽  
Lanmei Lin ◽  
Luhui Gao ◽  
...  
Keyword(s):  
Psoriatic Arthritis ◽  
Thyroid Function ◽  
Thyroid Dysfunction ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Peroxidase ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Hormone Levels ◽  
Significant Difference ◽  
Total Thyroxine

Objective. The aim of this study was to investigate the relationship between different psoriasis types and thyroid dysfunction. Methods. The data of patients diagnosed with psoriasis between January 2013 and October 2018 who underwent thyroid function tests were collected. Free triiodothyronine (FT3), free thyroxine (FT4), total triiodothyronine (TT3), total thyroxine (TT4), thyroid-stimulating hormone (TSH), thyroglobulin antibody (TGAb), and thyroid peroxidase antibody (TPOAb) were measured. The thyroid function of patients with psoriasis vulgaris, pustular psoriasis, erythrodermic psoriasis, and psoriatic arthritis was evaluated, and the differences in hormone levels and antibodies in the pituitary-thyroid axis with psoriasis type were analyzed. Results. The data of a total of 468 patients were analyzed in this study. The proportion of normal hormone levels was higher among vulgaris patients ( P < 0.001 ), while the erythrodermic patients were more likely to have decreased FT3 or FT4 but normal TSH ( P < 0.001 ). FT3 levels were lower in pustular patients ( P < 0.05 ), FT4 levels were lower in erythrodermic patients ( P < 0.05 ), and TSH levels were higher in patients with psoriatic arthritis ( P < 0.05 ). TPOAb levels were higher than normal in all patients, but there was no significant difference in the levels of TPOAb and TGAb among 4 types of the patients. Conclusion. Psoriasis is related to thyroid dysfunction, especially in patients with atypical psoriasis types. The possibility of complications should be considered in erythrodermic patients.

scholarly journals Pure T3 thyrotoxicosis from a Struma Ovarii characterised by a paradoxical rise in thyroxine on treatment

2020 ◽  
Vol 2020 ◽  
Author(s):  
James Prentice ◽  
Kate Panter ◽  
Ayoma Attygalle ◽  
Thomas Ind ◽  
Malcolm Prentice
Keyword(s):  
Blood Flow ◽  
Thyroid Function ◽  
Follicular Carcinoma ◽  
Thyroid Peroxidase ◽  
List Type ◽  
Thyroid Function Tests ◽  
Thyroid Ultrasound ◽  
Struma Ovarii ◽  
Free Triiodothyronine ◽  
Initial Surgery

Summary A 33-year-old female presented with a right 11.6 cm ovarian cyst. Routine pre-operative thyroid function tests showed thyroid stimulating hormone (TSH) of less than 0.02 mU/L (0.3–3.05) and a free thyroxine (FT4) of 5.5 pmol/L (10–28.2) suggesting either assay interference, triiodothyronine (T3) ingestion or hypopituitary hypothyroidism. A free triiodothyronine (FT3) level was requested which was high normal 6.9 pmol/L (3.1–8.1). Parallel assays on a different platform were similar but with a raised FT3 of 7.2 pmol/L (3.1–6.8). TSH receptor stimulating antibody (TSHAb) and thyroid peroxidase antibodies (TPO) were negative. Antithyroglobulin antibody (TgAb) was positive at 155.6 IU/mL (0–115). She was clinically euthyroid. Thyroid ultrasound showed a normal sized mildly heterogeneous gland with low blood flow and a solitary 1.5 cm U3 (BTA) nodule with higher blood flow. Thyroid Tc99m uptake was very low 0.2% (0.6–3.0) with no nodule uptake. These results demonstrated an extrathyroidal source of excessive autonomous T3 production resulting in the low thyroxine (T4). With carbimazole her TSH rose to 11.9 mU/L, FT4 rose to 7.7 pmol/L and FT3 reduced to 3.6 pmol/L. Histological diagnosis was Struma Ovarii. Her TSH, FT4 and FT3 remained normal thereafter. In conclusion, an extrathyroidal source of high T3 secretion was diagnosed using routine thyroid tests and scans. We believe this is the first description of a Struma Ovarii exclusively secreting T3 hormone characterised by the paradoxical rise of a low FT4 to normal with treatment. Two years later she developed non-secreting peritoneal deposits of highly differentiated follicular carcinoma. Learning points: Abnormally low TSH and FT4 levels suggestive of possible T3 ingestion, or less likely, hypopituitary hypothyroidism should always be followed by an assay of FT3. The diagnosis of an extrathyroidal source of T3 can be made using conventional thyroid tests, thyroid ultrasound scanning and technetium thyroid uptake and scan imaging. In a pre-menopausal patient this avoids a radiation dose to the pelvis. Pelvic radioisotope scanning of a suspected Struma Ovarii causing thyrotoxicosis can be reserved for patients whose thyroid function remains abnormal after initial surgery. Carbimazole is effective in the treatment of extrathyroidal autonomous T3 hormone production from a Struma Ovarii. The pathological appearance of a Struma Ovarii is not a guide to its malignancy. Even with a benign appearance they can disseminate to peritoneum, as highly differentiated follicular carcinoma (previously known as peritoneal strumosis). Hyperthyroid secretion by a Struma Ovarii may not be replicated in the metastatic follicular carcinoma in the peritoneum.

scholarly journals The Association of Thyroid Hormone Changes with Inflammatory Status and Prognosis in COVID-19

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ceyda Dincer Yazan ◽  
Can Ilgin ◽  
Onur Elbasan ◽  
Tugce Apaydin ◽  
Saida Dashdamirova ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Thyroid Autoimmunity ◽  
Oxygen Demand ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Peroxidase ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Icu Admission ◽  
Inflammatory Status ◽  
Length Of Hospitalization

Background. COVID-19 infection may have multiorgan effects in addition to effects on the lungs and immune system. Recently, studies have found thyroid function abnormalities in COVID-19 cases which were interpreted as euthyroid sick syndrome (ESS) or destructive thyroiditis. Therefore, in this study, we aimed to evaluate the thyroid function status and thyroid autoimmunity in COVID-19 patients. Material and Method. 205 patients were included. The medical history and laboratory parameters at admission were collected from medical records. Serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroid peroxidase antibody, and thyroglobulin antibody were measured, and patients were classified according to thyroid function status. Results. 34.1% of the patients were euthyroid. Length of hospitalization ( p < 0.001 ), rate of oxygen demand ( p < 0.001 ), and intensive care unit (ICU) admission ( p = 0.022 ) were lower, and none of the euthyroid patients died. 108 (52.6%) patients were classified to have ESS, 57 were classified as mild, and 51 were moderate. The inflammatory parameters were higher in patients with moderate ESS. In cluster analysis, a high-risk group with a lower median FT3 value (median = 2.34 ng/L; IQR = 0.86), a higher median FT4 value (median = 1.04 ng/dL; IQR = 0.33), and a lower median TSH value (median = 0.62 mIU/L; IQR = 0.59) included 8 of 9 died patients and 25 of the 31 patients that were admitted to ICU. Discussion. Length of hospitalization, oxygen demand, ICU admission, and mortality were lower in euthyroid patients. Moreover, none of the euthyroid patients died. In conclusion, evaluation of thyroid function tests during COVID-19 infection may give information about the prognosis of disease.

scholarly journals Insights From Prospective Follow-up of Thyroid Function and Autoimmunity Among Covid-19 Survivors

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A840-A841
Author(s):  
David T W Lui ◽  
Chi Ho Lee ◽  
Wing Sun Chow ◽  
Alan C H Lee ◽  
Anthony Raymond Tam ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Thyroid Dysfunction ◽  
Thyroid Autoimmunity ◽  
Clinical Severity ◽  
Thyroid Peroxidase ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Thyroid Antibody ◽  
Antibody Titers

Abstract Objective: Occurrence of Graves’ disease and Hashimoto’s thyroiditis after coronavirus disease 2019 (COVID-19) raised the concern about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggering thyroid autoimmunity. Uncertainties remain regarding incident thyroid dysfunction and autoimmunity among COVID-19 survivors. We carried out a prospective study to characterize the evolution of thyroid function and autoimmunity among COVID-19 survivors. Method: Consecutive adult patients, without known thyroid disorders, admitted to Queen Mary Hospital for confirmed COVID-19 from 21 July to 21 September 2020 were included. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3) and anti-thyroid antibodies were measured on admission and at 3 months. Positive anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) was defined by &gt;100 units. Results: Among 200 COVID-19 survivors, 122 had reassessment thyroid function tests (TFTs) (median age: 57.5 years; 49.2% men). Baseline characteristics of patients who did and did not have reassessment were comparable. Among the 20 patients with baseline abnormal TFTs on admission, mostly low fT3, 15 recovered. Of the 102 patients with normal TFTs on admission, two (2.0%) had new onset abnormal TFTs, which may represent TFTs in different phases of thyroiditis (one had mildly elevated TSH 5.8 mIU/L, with normal fT4 [16 pmol/L] and fT3 [4.3 pmol/L], the other had mildly raised fT4 25 pmol/L with normal TSH [1.1 mIU/L] and fT3 [4.7 pmol/L]). Among 104 patients with anti-thyroid antibody titers reassessed, we observed increases in anti-TPO (baseline: 28.3 units [IQR 14.0-67.4] vs reassessment: 35.0 units [IQR: 18.8-99.0]; p&lt;0.001) and anti-Tg titers (baseline: 6.6 units [IQR 4.9-15.6] vs reassessment: 8.7 units [IQR: 6.6-15.4]; p&lt;0.001), but no change in anti-TSHR titer (baseline: 1.0 IU/L [IQR: 0.8-1.2] vs reassessment: 1.0 IU/L [IQR: 0.8-1.3]; p=0.486). Of the 82 patients with negative anti-TPO at baseline, 16 had significant interval increase in anti-TPO titer by &gt;12 units (2×6 [precision of the anti-TPO assay in normal range being 6 units per SD]), of these, four became anti-TPO positive. Factors associated a significant increase in anti-TPO titer included worse baseline clinical severity (p=0.018), elevated C-reactive protein during hospitalization (p=0.033), and higher baseline anti-TPO titer (p=0.005). Conclusion: Majority of thyroid dysfunction on admission recovered during convalescence. Abnormal TFTs suggestive of thyroiditis could occur during convalescence, though uncommon. Importantly, we provided the novel observation of an increase in anti-thyroid antibody titers post-COVID-19, suggesting the potential of SARS-CoV-2 in triggering thyroid autoimmunity, which warrants further follow-up for incident thyroid dysfunction among COVID-19 survivors.

Subclinical hypothyroidism

2011 ◽  
pp. 543-547
Author(s):  
Jayne A. Franklyn
Keyword(s):  
Thyroid Function ◽  
Subclinical Hypothyroidism ◽  
Expert Panel ◽  
Elevated Serum ◽  
Thyroid Stimulating Hormone ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Function Tests ◽  
Serum Tsh

Subclinical hypothyroidism is defined biochemically as the association of a raised serum thyroid-stimulating hormone (TSH) concentration with normal circulating concentrations of free thyroxine (T4) and free triiodothyronine (T3). The term subclinical hypothyroidism implies that patients should be asymptomatic, although symptoms are difficult to assess, especially in patients in whom thyroid function tests have been checked because of nonspecific complaints such as tiredness. An expert panel has recently classified individuals with subclinical hypothyroidism into two groups (1): (1) those with mildly elevated serum TSH (typically TSH in the range 4.5–10.0 mU/l) and (2) those with more marked TSH elevation (serum TSH >10.0 mU/l).

scholarly journals SAT-576 Possible Involvement of Thyroid Function in PCSK9 Inhibitor Therapy

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Masayasu Iwabuchi
Keyword(s):  
Thyroid Function ◽  
Ldl Cholesterol ◽  
Inhibitor Therapy ◽  
Thyroid Peroxidase ◽  
Thyroid Function Tests ◽  
Pcsk9 Inhibitors ◽  
Free T4 ◽  
Hyperthyroid Patient ◽  
Pcsk9 Inhibitor ◽  
The Impact

Abstract INTRODUCTION Proprotein convertase subtilisin kexin type 9 (PCSK9) inhibition is an effective strategy for lowering plasma LDL-cholesterol and enhancing the LDL-cholesterol lowering ability of statins. PCSK9, a serine protease that binds to the LDL receptor promoting its degradation, is an important regulator of LDL metabolism. In addition, LDL-cholesterol is also controlled by TSH and thyroid hormones via PCSK9. TSH has received increasing attention as being closely associated with increased LDL-cholesterol level and higher atherosclerotic risks. In vitro study, the effects of TSH on hepatic PCSK9 expression in HepG2 cells were reported (1). I here report a case of transient hyperthyroidism secondary to PCSK9 inhibitor therapy. This case highlights the involvement of thyroid function in PCSK9 Inhibitor therapy. CLINICAL CASE A 65-year-old man had a weight loss of 6 kg (13 lbs.) in 4 months, accompanied with fatigue. He had a past history of myocardial infarction and his LDL was 83 mg/dL by 2.5mg of rosuvastatin and heart rate was controlled by 10mg of carvedilol. Six months ago, he started a PCSK9 Inhibitor therapy with 140mg of evolocumab every 2 weeks for 6 weeks. He had no preceding viral illness and denied anterior neck pain or tenderness. His height was 1.53 m, weight 52.6 kg (115 lbs.), and body mass index (BMI) 22.46 kg/m2. His thyroid was not enlarged and non-tender without clear palpable thyroid nodules or neck lymph nodes. Hyperthyroidism was suspected and confirmed by thyroid function tests: TSH was less than 0.0005 μIU/mL (normal 0.35–4.94), and free T4 1.830 ng/dL (0.70–1.48). Graves’ disease was considered, and thyroid antibody tests performed. Thyroid peroxidase (TPO) antibody titer was less than 9 IU/mL (&lt;9), and TSI 141% (&lt;120%). To confirm the diagnosis of this hyperthyroid patient, Technetium-99m uptake and scan was done which showed uptake of 0.8% (0.5–7%). After careful observation for 2 months with 5mg of carvedilol, he turned asymptomatic and free T4 lowered to 1.480 ng/dL and TSH remained less than 0.0005 μIU/mL. CLINICAL LESSONS I here report a case of transient hyperthyroidism secondary to PCSK9 inhibitor therapy. There has been no report of hyperthyroidism induced by PCSK9 inhibitors. Immunological influence of anti-PCSK9 therapy on thyroid is unknown. In this case, the decrease of TSH due to hyperthyroidism was considered to reduce hepatic PCSK9 expression, leading to additive effect to PCSK9 inhibitor. PCSK9 inhibitors may modify the effects of hyperlipidemia treatment by causing changes in thyroid function. When using PCSK9 inhibitors, follow-up of thyroid function should be considered. This case highlights the involvement of thyroid function in PCSK9 inhibitor therapy. Reference (1) Gong, Y., Ma, Y., et al. Thyroid stimulating hormone exhibits the impact on LDLR/LDL-c via up-regulating hepatic PCSK9 expression. Metabolism. 2017;76;32–41

Thyroid function in neonates with severe respiratory failure on extracorporeal membrane oxygenation

Perfusion ◽  
2001 ◽  
Vol 16 (6) ◽  
pp. 469-475 ◽  
Author(s):  
Dan L Stewart ◽  
Noah Ssemakula ◽  
Duncan R MacMillan ◽  
L Jane Goldsmith ◽  
Larry N Cook
Keyword(s):  
Respiratory Failure ◽  
Extracorporeal Membrane Oxygenation ◽  
Thyroid Function ◽  
Newborn Infants ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Function Tests ◽  
Severe Respiratory Failure ◽  
Serum Concentrations ◽  
Free Triiodothyronine ◽  
Membrane Oxygenation

The object was to study thyroid function in neonates with severe respiratory failure on extracorporeal membrane oxygenation (ECMO) and determine whether abnormal thyroid function correlates with prognosis. Total and free thyroxine (T4, FT4), total and free triiodothyronine (T3, FT3), reverse triiodothyronine (rT3), thyroid-stimulating hormone, and thyroxine binding globulin were measured in 14 newborn infants with severe respiratory failure (age 1-30 days) from samples collected before anesthesia for cannula placement, at 30, 60, and 360 min after initiation of ECMO, and on days 2, 4, 6, and 8. The patients were divided into survivors and non-survivors for statistical analyses. No differences were noted between survivors and non-survivors in the pre-ECMO mean serum concentrations of the thyroid function tests analyzed. In nine survivors, mean serum T4, FT4, T3, FT3, and rT3 all declined significantly within 30-60 min after initiation of ECMO, compared to baseline values. The values for all mean serum concentrations recovered completely and exceeded baseline between days 2 and 8. In five non-survivors, the decline of all mean serum values was not statistically significant and recovery to baseline was not achieved. The ratios of mean serum concentration of rT3/FT3were significantly different between survivors and non-survivors across all times during the ECMO course ( p λ 0.0005). These findings indicate that abnormalities in thyroid function occur in neonates with severe respiratory failure on ECMO and that the rT3/FT3 ratio correlates with prognosis over the ECMO course. Survival was associated with a significant reduction of serum thyroid hormone concentrations followed by recovery. We speculate that, in neonates with respiratory failure on ECMO, adaptive mechanisms which enhance survival include the capacity to down-regulate the pituitary-thyroid axis.

scholarly journals Erythrocyte zinc in hospital patients

2005 ◽  
Vol 42 (6) ◽  
pp. 448-452 ◽  
Author(s):  
L Batchat ◽  
S Vaja ◽  
D Treacher ◽  
M Kinerons ◽  
R Swaminathan
Keyword(s):  
Critically Ill ◽  
Thyroid Function ◽  
Critically Ill Patients ◽  
Geriatric Patients ◽  
Tissue Level ◽  
Hospitalized Patients ◽  
Thyroid Function Tests ◽  
Thyroid Status ◽  
Free Triiodothyronine ◽  
Hospital Patients

Background: Abnormal thyroid function tests (serum thyrotropin [TSH], free thyroxine [T4] and free triiodothyronine [T3]) are frequently seen in hospitalized patients. Assessment of thyroid function in these patients is difficult. It has been suggested that acutely ill patients may be hypothyroid at the tissue level. Erythrocyte zinc (EZn) has been shown to be increased in hypothyroidism. The aim of this study was to examine EZn as an index of thyroid status of hospital patients. Methods: In order to assess the thyroid status at tissue level, we measured EZn in 26 healthy subjects, 39 critically ill patients and 19 hospitalized geriatric patients. EZn was measured in young cells, as the effect of illness is likely to be seen in the newly formed cells. Result: TSH and free T3 were lower in critically ill patients and serum free T3 was lower in geriatric patients. EZn in young cells was higher in both patient groups (by 13% and 23%, respectively). EZn in old cells was also higher in the geriatric group. Conclusion: We conclude that EZn is higher in hospitalized patients, suggesting that these patients may be hypothyroid at the tissue level.

scholarly journals Report of the IFCC Working Group for Standardization of Thyroid Function Tests; Part 2: Free Thyroxine and Free Triiodothyronine

2010 ◽  
Vol 56 (6) ◽  
pp. 912-920 ◽  
Author(s):  
L. M. Thienpont ◽  
K. Van Uytfanghe ◽  
G. Beastall ◽  
J. D. Faix ◽  
T. Ieiri ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Working Group ◽  
Free Thyroxine ◽  
Thyroid Function Tests ◽  
Free Triiodothyronine ◽  
Function Tests

scholarly journals Variation in thyroid function in subclinical hypothyroidism: importance of clinical follow-up and therapy

2011 ◽  
Vol 164 (3) ◽  
pp. 317-323 ◽  
Author(s):  
Jesper Karmisholt ◽  
Stig Andersen ◽  
Peter Laurberg
Keyword(s):  
Thyroid Function ◽  
Subclinical Hypothyroidism ◽  
Repeated Measurements ◽  
Thyroid Peroxidase ◽  
Biochemical Tests ◽  
Free Triiodothyronine ◽  
Significant Difference ◽  
Hypothyroid Patients ◽  
Symptoms And Signs

Subclinical hypothyroidism (SCH) is a common condition that is often observed without therapy. However, no evidence-based recommendation exists with regards to how patients with untreated SCH should be monitored.Monitoring involves regular assessment of symptoms and signs of hypothyroidism (HYPO) and biochemical tests of thyroid function. An important question when repeated tests of thyroid function are performed is how large a difference in test results is needed to be confident that the change is real and not just due to chance variation.Recent data show that the least significant difference between two tests in SCH is 40% for TSH and 15% for free thyroxine and free triiodothyronine, with 90% confidence. Furthermore, monitoring has to be based on biochemical function testing because serial evaluation of symptoms and signs related to HYPO is rather insensitive in detecting worsening of thyroid insufficiency.When the presence of thyroid peroxidase auto-antibodies (TPO-Ab) in serum has been demonstrated, repeated measurements do not add much useful information in the monitoring of individual subclinical hypothyroid patients, as levels of TPO-Ab vary in parallel with TSH in these patients.Lastly, we discuss how differences in the monitoring procedure influence the diagnostic outcome, and we suggest a follow-up approach for untreated subclinical hypothyroid patients.

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