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

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 >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<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<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 >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.

Download Full-text

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

Scanning ◽

10.1155/2021/1834556 ◽

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.

Download Full-text

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

International Journal of Endocrinology ◽

10.1155/2021/2395212 ◽

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.

Download Full-text

THYROID FUNCTION TESTS: A REVIEW

10.36106/ijsr/2502260 ◽

2021 ◽

pp. 73-76

Author(s):

Vasudev Sankhla ◽

Aman Deep

Keyword(s):

Thyroid Function ◽

Thyroid Dysfunction ◽

Radioactive Iodine ◽

Thyroid Stimulating Hormone ◽

Thyroid Function Tests ◽

Function Tests ◽

Tsh Secretion ◽

Line Test ◽

Radioactive Iodine Uptake

Thyroid function tests are one of the most common endocrine panels in general practice because a good understanding of when to order them, indications for treatment are important for the optimal treatment of thyroid dysfunction. Thyroid-stimulating hormone (TSH) should be the rst test to be performed on any patient with suspected thyroid dysfunction and in follow-up of individuals on treatment. It is useful as a rst-line test because even small changes in thyroid function are sufcient to cause a signicant increase in TSH secretion. Thyroxine levels may be assessed in a patient with hyperthyroidism, to determine the severity of hyperthyroxinemia. Antithyroid peroxidase measurements should be considered while evaluating patients with subclinical hypothyroidism and can facilitate the identication of autoimmune thyroiditis during the evaluation of nodular thyroid disease. The measurement of TSH receptor antibody must be considered when conrmation of Graves’ disease is needed and radioactive iodine uptake cannot be done.

Download Full-text

The Effect of Hypolipidemic Agents on Thyroid Autoimmunity in Women with Hashimoto’s Thyroiditis Treated with Levothyroxine and Selenomethionine

Experimental and Clinical Endocrinology & Diabetes ◽

10.1055/s-0043-120342 ◽

2017 ◽

Vol 126 (05) ◽

pp. 321-326 ◽

Cited By ~ 1

Author(s):

Robert Krysiak ◽

Witold Szkróbka ◽

Bogusław Okopień

Keyword(s):

Hashimoto’S Thyroiditis ◽

Plasma Lipids ◽

Thyroid Autoimmunity ◽

Hdl Cholesterol ◽

Hashimoto's Thyroiditis ◽

Thyroid Peroxidase ◽

Free Triiodothyronine ◽

Hypolipidemic Agents ◽

Antibody Titers ◽

Group B

Abstract Background Levothyroxine and selenomethionine were found to reduce thyroid antibody titers in patients with Hashimoto’s thyroiditis. The same effect was produced by intensive statin therapy. The aim of the present study was to assess whether hypolipidemic agents modulate the impact of thyroid hormone supplementation and selenomethionine on thyroid autoimmunity. Methods The study included 62 women with Hashimoto's thyroiditis treated for at least 6 months with levothyroxine and selenomethionine. On the basis of plasma lipids, women were divided into three groups: women with isolated hypercholesterolemia (group A; n=20), women with isolated hypertriglyceridemia (group B; n=17), and women with normal plasma lipids (group C; n=25). Group A were then treated with atorvastatin (20 mg daily), while group B received micronized fenofibrate (200 mg daily). Serum titers of thyroid peroxidase and thyroglobulin antibodies, as well as serum levels of thyrotropin, free thyroxine and free triiodothyronine were measured at the beginning of the study and 6 months later. Results Fenofibrate decreased triglycerides and increased HDL cholesterol, while simvastatin decreased total and LDL cholesterol. Fenofibrate reduced titers of thyroid peroxidase and, to a lesser extent, thyroglobulin antibodies. Atorvastatin tended to increase thyroid peroxidase antibodies. No changes in thyrotropin, free thyroxine and free triiodothyronine were observed in any treatment group. Fenofibrate-induced changes in thyroid antibody titers correlated with baseline antibody titers, as well as with treatment-induced changes in HDL cholesterol and insulin sensitivity. Conclusions The obtained results indicate that only fibrates may potentiate the effect of selenomethionine and levothyroxine on thyroid autoimmunity in women.

Download Full-text

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

Acta Endocrinologica ◽

10.1530/eje-10-1021 ◽

2011 ◽

Vol 164 (3) ◽

pp. 317-323 ◽

Cited By ~ 44

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.

Download Full-text

Lyme Disease: An Autoimmunity-Based “Destructive Thyroiditis” or Just Another “Non-Thyroidal Illness”?

Journal of the Endocrine Society ◽

10.1210/jendso/bvab048.1922 ◽

2021 ◽

Vol 5 (Supplement_1) ◽

pp. A940-A941

Author(s):

Nyembezi Dhliwayo ◽

Rana Wajahat ◽

Andriy Havrylyan ◽

Alvia Moid ◽

Walid Khayr ◽

...

Keyword(s):

Lyme Disease ◽

Thyroid Function ◽

Paranoid Schizophrenia ◽

Thyroid Autoimmunity ◽

Thyroid Peroxidase ◽

Thyroid Function Tests ◽

Free T4 ◽

Radioiodine Uptake ◽

Function Tests ◽

Antigenic Properties

Abstract There is considerable evidence that some Borrelial (Lyme spirochetal) proteins share significant antigenic properties with several thyroid-related proteins (e.g. TSH receptor, thyroglobulin, thyroid peroxidase) and can induce thyroid autoimmunity, sometimes associated with Hashimoto’s thyroiditis and perhaps also a “destructive thyroiditis” such as “silent” thyroiditis or “Hashitoxicosis.” As an acute illness, Lyme disease may also constitute a “non-thyroidal illness” capable of perturbing thyroid function tests without causing thyroid dysfunction. We report a 22-year old woman admitted with an acute paranoid schizophrenia, thyroid function tests consistent with autoimmunity, transient thyrotoxicosis (tachycardia, lid-lag, brisk DTR’s) and a greatly reduced radioiodine uptake. The thyroid was not palpably enlarged, nodular or tender. On screening assay, reactivity was demonstrated to 4 of 13 Borrelial proteins. Anti-Lyme IgM but not IgG, antibodies, were positive. This was consistent with recent Lyme disease infection. Serum TSH (NL: 0.358-3.74 mcU/ml), Free T4 (NL: 0.76-1.46 ng/dl), and Free T3 (NL: 2.18-3.98 pg/ml) were, respectively: Day1: 0.087 mcU/ml (suppressed), 1.52 ng/dl (slightly elevated), 2.07 pg/ml (slightly reduced); Day2: 0.148 (suppressed), 1.18 (normal), no FT3; Day4: 0.827 (normal), no FT4 or FT3; Day5: 1.66 (normal), 0.89 (normal), 1.77 (low). Anti-Tg and Anti-Peroxidase antibodies were both moderately elevated. Thyroid Stimulating Immunoglobulins were not elevated. The radioactive iodine uptake on Day4 was 2.8% (NL: 15-30% at 24 hr). Thyroid ultrasonogram was normal. An attractive explanation is that Lyme disease triggered a “destructive thyroiditis,” perhaps but not necessarily mediated by thyroid autoimmunity. This would account for the brief interval of thyrotoxicosis accompanied by a very low radioiodine uptake. Alternatively, Lyme disease, as an acute process, would expectedly be capable of eliciting the thyroid function abnormalities of “non-thyroidal illnesses” in general, as would acute psychosis, well-known to often resemble Graves’ disease at admission.

Download Full-text

Management of Thyrotoxicosis Induced by PD1 or PD-L1 Blockade

Journal of the Endocrine Society ◽

10.1210/jendso/bvab048.1716 ◽

2021 ◽

Vol 5 (Supplement_1) ◽

pp. A841-A841

Author(s):

Alessandro Brancatella ◽

Isabella Lupi ◽

Lucia Montanelli ◽

Debora Ricci ◽

Nicola Viola ◽

...

Keyword(s):

Thyroid Function ◽

Checkpoint Inhibitors ◽

Thyroid Volume ◽

Clinical Severity ◽

Response To Treatment ◽

Thyroid Function Tests ◽

Thyroid Ultrasound ◽

Normal Thyroid ◽

Normal Thyroid Function

Abstract Context: Thyrotoxicosis is a common immune-related adverse event in patients treated with PD1 or PD-L1 checkpoint inhibitors. A detailed endocrinological assessment, including thyroid ultrasound and scintigraphy is missing, as are data on response to treatment and follow-up. Objectives: To better characterize the thyrotoxicosis secondary to immune checkpoint inhibitors, gaining insights into pathogenesis and informing management. Methods: We conducted a prospective cohort study of 20 consecutive patients who had normal thyroid function before starting immunotherapy and then experienced thyrotoxicosis upon PD1 or PD-L1 blockade. Clinical assessment was combined with thyroid ultrasound, scintigraphy, and longitudinal thyroid function tests. Results: Five patients had normal scintigraphic uptake (Sci+), no serum antibodies against the TSH receptor, and remained hyperthyroid throughout follow-up. The other 15 patients had no scintigraphic uptake (Sci-) and experienced destructive thyrotoxicosis followed by hypothyroidism (N= 9) or euthyroidism (N= 6). Hypothyroidism was more readily seen in those with normal thyroid volume than in those with goiter (P= 0.04). Among Sci- subjects, a larger thyroid volume was associated to a longer time to remission (P<0.05). Methimazole (MMI) was effective only in Sci+ subjects (P<0.05). Conclusions: Administration of PD1 or PD-L1 blocking antibodies may induce two different forms of thyrotoxicosis that appear similar in clinical severity at onset: a type 1 characterized by persistent hyperthyroidism that requires treatment with MMI, and a type 2 characterized by destructive and transient thyrotoxicosis that evolves to hypo- or eu-thyroidism. Thyroid scintigraphy and ultrasound help differentiating and managing these two forms of iatrogenic thyrotoxicosis

Download Full-text

SAT-440 Phthalates Expose and Thyroid Parameters in Euthyroid Patient with Type 2 Diabetes: Sex Specific Associations

Journal of the Endocrine Society ◽

10.1210/jendso/bvaa046.1026 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

Author(s):

Yi Chen ◽

Chi Chen ◽

Jingsi Chen ◽

Wen Zhang ◽

Yuying Wang ◽

...

Keyword(s):

Thyroid Function ◽

Smoking Status ◽

Thyroid Autoimmunity ◽

Mediating Effect ◽

Thyroid Peroxidase ◽

Endocrine Disorders ◽

Free Triiodothyronine ◽

Men And Women ◽

Phthalate Metabolites ◽

Negatively Associated

Abstract Phthalates are ubiquitous in different environmental exposure media around the world. Recent years, issues on the relationships of phthalates and endocrine disorders raise attention. Evidence of thyroid disruption as a result of phthalates expose among euthyroid participants with diabetes is very limited. We aimed to evaluate the association between phthalate and thyroid function, and to explore whether thyroid autoimmunity mediated this association. Concurrent urine and blood samples were collected from 538 participant in METAL study. We measured urinary concentrations of ten phthalate metabolites (urinary creatinine adjusted), along with serum levels of thyroid-stimulating hormone (TSH), free thyroxin (FT4), free triiodothyronine (FT3), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb). Euthyroidism was defined as TSH within normal range. After adjusting for age, sex (only with the entire sample), BMI and smoking status, linear regression analyses showed exactly opposite directional results among men and women. TSH levels were negatively associated with mono-2-ethyl-5-carboxypentylphthalate (MECPP), mono-2-ethyl-5-hydroxyhexylphthalate (MEHHP), mono-2-ethyl-5-oxohexylphthalate (MEOHP), mono-2-carboxymethyl-hexyl phthalate (MCMHP) and sum of di (2-ethylhexyl) phthalate metabolites (ΣDEHPm) in men, but positively associated with monoisobutylphthalate (MiBP) and mono-n-butylphthalate (MnBP) in women. Meanwhile, FT4 was positively associated with mono-2-ethylhexylphthalate percentage (%MEHP) in men, but negatively associated with MnBP, MEOHP and MCMHP in women. Further, in women, TPOAb was increasing along with the increased level of MEHP and %MEHP. In the mediation analysis, TPOAb demonstrated a mediating effect whereby MEHP or %MEHP had a positive effect on TSH and a negative effect on FT4 only in women (all P<0.05). We got a conclusion that among euthyroid participants with diabetes, urinary phthalate metabolites maybe associated with altered TSH, FT4 and TPOAb levels in different direction in men and women. Further, our present study maybe the first to suggest that TPOAb might be a potential mediator of the association between phthalate metabolites and thyroid function in women.

Download Full-text

The clinical value of regular thyroid function tests during amiodarone treatment

Acta Endocrinologica ◽

10.1530/eje-17-0018 ◽

2017 ◽

Vol 177 (1) ◽

pp. 9-14 ◽

Cited By ~ 14

Author(s):

Stan Benjamens ◽

Robin P F Dullaart ◽

Wim J Sluiter ◽

Michiel Rienstra ◽

Isabelle C van Gelder ◽

...

Keyword(s):

Thyroid Function ◽

Thyroid Dysfunction ◽

Common Adverse Effect ◽

Considerable Proportion ◽

Thyroid Function Tests ◽

Clinical Value ◽

Function Tests ◽

Amiodarone Treatment

Objective Amiodarone is used for the maintenance of sinus rhythm in patients with arrhythmias, but thyroid dysfunction (amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH)) is a common adverse effect. As the onset of AIT and AIH may be unpredictable, the value of long-term regular monitoring of amiodarone treated patients for thyroid dysfunction is still uncertain. Design We retrospectively documented the frequency at which overt thyroid dysfunction was preceded by subclinical thyroid dysfunction. Methods We included 303 patients treated with amiodarone between 1984 and 2007. AIT was defined as a lowered TSH level with an elevated free thyroxine (FT4) and AIH was defined as an elevated TSH level with a decreased or subnormal FT4. Subclinical AIT was defined as a lowered TSH level with a normal FT4 and subclinical AIH as an elevated TSH level with a normal FT4. Results 200 men and 103 women, aged 62 ± 12.0 years, suffering from atrial (260) or ventricular (43) arrhythmias, were evaluated. During a median follow-up of 2.8 (1.0–25) years, 44 patients developed AIT and 33 AIH. In 42 (55%) patients who developed AIT/AIH, earlier thyroid function tests showed no subclinical AIT or subclinical AIH. In 35 (45%) patients, AIT/AIH was preceded by subclinical AIT or subclinical AIH (16/44 for AIT and 19/33 for AIH). Conclusions In a considerable proportion of patients who developed AIT/AIH, earlier thyroid function tests showed no subclinical AIT/AIH. Less than half of the patients with a subclinical event subsequently developed overt AIT/AIH. This study provides data to reconsider the yield of regular testing of thyroid function to predict overt thyroid dysfunction in amiodarone treated patients.

Download Full-text

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

Endocrinology Diabetes and Metabolism Case Reports ◽

10.1530/edm-19-0097 ◽

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.

Download Full-text