TSH receptor antibody-associated thyroid dysfunction following subacute thyroiditis

Comparison of two different TSH-receptor antibody assays: A clinical practice study

Background

Graves' disease (GD) is caused by the production of TSH-receptor (TSHR) stimulating auto-antibodies. Over the years various TSHR-antibody (TRAb) detection assays have been developed. Most clinical laboratories use competitive TSH-binding inhibitory immunoglobulin (TBII) assays, which measure the total amount of stimulating and blocking auto-antibodies. Selective detection of TSHR stimulating auto-antibodies (TSI) was previously only possible with functional cell-based bioassays. However, more recently an automated bridge-based binding assay to more specifically measure TSI has become available. The aim of our study was to compare the third-generation automated competitive immunoassay (TBII) with the automated bridge immunoassay (TSI) in clinical practice in an academic thyroid expert center.

Methods

A retrospective study in 356 patients with Graves' disease, Graves orbitopathy (GO), and other (thyroid) disease treated in an academic thyroid center was performed. All samples were analyzed for TBII and TSI. For both assays, sensitivity, specificity, positive predictive value (PVV), negative predictive value (NPV) and diagnostic odds ratios were calculated using different cut-offs for negativity.

Results

Using the provided cut-off, the overall sensitivity appeared similar between TBII and TSI, but TSI showed higher overall specificity, PPV, NPV and diagnostic odds ratio. Using two or three times the cut-off for negativity resulted in a decrease in sensitivity, but an increase in specificity and PPV, which was most pronounced for the TBII-assay. Analysis in a subgroup of newly diagnosed treatment naïve GD/GO patients also revealed overall favorable results for the TSI-assay. Increasing the cut-off for negativity resulted in increased specificity for both assays, with similar results using two or three times the cut-off. Most patients with concordant positive results for TBII and TSI suffered from GD or GD + GO (n = 110, 95.6 %), while patients negative for both TBII and TSI mostly suffered from other (thyroid) disease (n = 143, 77.3 %). From patients with positive TBII but negative TSI only 42.1 % had GD/GO (n = 16), whereas 57.9 % (n = 22) had other (thyroid) disease. In contrast, 88.9 % of patients with positive TSI but negative TBII had GD/GO (n = 16), whereas 11.1 % (n = 2) had other (thyroid) disease.

Conclusion

In our academic thyroid center, the diagnostic performance of the TSI-assay outperformed the TBII-assay. Using a higher cut-off value for negativity can be helpful in assessing clinical relevance.

COVID-19 vaccination and thyroiditis

At the end of 2019, the world began to fight the coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2. Many vaccines have quickly been developed to control the epidemic, and with the widespread use of vaccines globally, several vaccine-related adverse events have been reported. This review mainly focused on COVID-19 vaccination-associated thyroiditis and summarized the current evidence regarding vaccine-induced subacute thyroiditis, silent thyroiditis, Graves' disease, and Graves' orbitopathy. The main clinical characteristics of each specific disease were outlined, and possible pathophysiological mechanisms were discussed. Finally, areas lacking evidence were specified, and a research agenda was proposed.

HLA typing of patients who developed subacute thyroiditis and Graves' disease after SARS-CoV-2 vaccination: a case report

BACKGROUND

Cases of subacute thyroiditis (SAT) after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination have been reported. A human leukocyte antigen (HLA) allele, HLA-B*35, appears to be involved in the pathogenesis of SAT.

CASE PRESENTATION

We conducted HLA typing of one patient with SAT and another with both SAT and Graves' disease (GD), which developed after SARS-CoV-2 vaccination. Patient 1, a 58-year-old Japanese man, was inoculated with a SARS-CoV-2 vaccine (BNT162b2; Pfizer, New York, NY, USA). He developed fever (38 °C), cervical pain, palpitations, and fatigue on day 10 after vaccination. Blood chemistry tests revealed thyrotoxicosis and elevated serum C-reactive protein (CRP) and slightly increased serum antithyroid-stimulating antibody (TSAb) levels. Thyroid ultrasonography revealed the characteristic findings of SAT. Patient 2, a 36-year-old Japanese woman, was inoculated twice with a SARS-CoV-2 vaccine (mRNA-1273; Moderna, Cambridge, MA, USA). She developed fever (37.8 °C) and thyroid gland pain on day 3 after the second vaccination. Blood chemistry tests revealed thyrotoxicosis and elevated serum CRP, TSAb, and antithyroid-stimulating hormone receptor antibody levels. Fever and thyroid gland pain persisted. Thyroid ultrasonography revealed the characteristic findings of SAT (i.e., slight swelling and a focal hypoechoic area with decreased blood flow). Prednisolone treatment was effective for SAT. However, thyrotoxicosis causing palpitations relapsed thereafter, for which thyroid scintigraphy with ^99mtechnetium pertechnetate was conducted, and the patient was diagnosed with GD. Thiamazole treatment was then initiated, which led to improvement in symptoms.

CONCLUSION

HLA typing revealed that both patients had the HLA-B*35:01, -C*04:01, and -DPB1*05:01 alleles. Only patient 2 had the HLA-DRB1*11:01 and HLA-DQB1*03:01 alleles. The HLA-B*35:01 and HLA-C*04:01 alleles appeared to be involved in the pathogenesis of SAT after SARS-CoV-2 vaccination, and the HLA-DRB1*11:01 and HLA-DQB1*03:01 alleles were speculated to be involved in the postvaccination pathogenesis of GD.

Recurrent Subacute Thyroiditis in a Patient With Human Leukocyte Antigen-associated Predisposition to Graves Disease

Background

Subacute thyroiditis (SAT) followed by Graves disease (GD) is a rare condition. We report the case of a patient with recurrent SAT with human leukocyte antigen (HLA)-associated predisposition to GD.

Case Report

A 28-year-old Japanese woman presented with neck pain and hyperthyroidism symptoms. We observed elevated C-reactive protein and thyroid hormone levels, along with a high erythrocyte sedimentation rate. Further, anti-thyroid-stimulating hormone receptor antibody was undetected, and thyroid glands were heterogeneous and hypoechoic. These findings confirmed a diagnosis of SAT. The patient was treated with prednisone (starting dose, 30 mg), and clinical and laboratory data suggested an improvement. Six months later, the patient presented with recurrent clinical and biochemical features of hyperthyroidism (thyroid-stimulating hormone level, 0.003 mIU/mL; free thyroxine level, 3.14 ng/dL; and TSH receptor-stimulating autoantibodies, 220%). The patient was diagnosed with GD and was successfully treated with methimazole. Eleven years later, the patient was diagnosed with simultaneous SAT and GD. HLA-typing revealed that the patient possessed characteristic alleles associated with susceptibility to GD, such as HLA-DRB1∗04:03 and ∗15:01, DQB1∗03:02:01 and 06:02:01, and HLA DPB1∗05:01 alleles.

Discussion

The occurrence of SAT may trigger thyroid antigen release and lead to the onset of GD in patients who are genetically predisposed to this autoimmune disorder.

Conclusion

For certain patients, the diagnosis of GD should be considered in case of recurrent hyperthyroidism and history of resolved SAT.

SARS-CoV-2 Vaccine-induced Thyroiditis: Safety of Revaccinations and Clinical Follow-up

CONTEXT

The number of reported cases with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccine-induced subacute thyroiditis (SAT) and Graves' disease (GD) is growing. However, active debate continues about managing such side effects and the safety of repeat or booster doses of the vaccines in such cases.

OBJECTIVES

This study aims to present long-term clinical follow-up of SARS-CoV-2 vaccine-induced SAT or GD cases and provide data regarding the safety of revaccinations.

METHODS

Patients diagnosed with SARS-CoV-2 vaccine-induced SAT or GD were included. Data regarding the long-term clinical follow-up of SARS-CoV-2 vaccine-induced SAT and GD cases and outcomes of repeat or booster SARS-CoV-2 vaccinations were documented. The literature, including cases of SARS-CoV-2 vaccine-induced SAT or GD, was reviewed.

RESULTS

Fifteen patients with SARS-CoV-2 vaccine-induced SAT and 4 with GD were included. Pfizer/BioNTech COVID-19 vaccine (BNT162b2) was associated with symptoms in a majority of cases with SAT and all with GD. Median time from vaccination to symptom onset was 7 and 11.5 days, respectively, while 7 and 2 patients required medical treatment in SAT and GD groups, respectively. Remission was documented in 10 SAT patients, with a median time to remission of 11.5 weeks. No exacerbation/recurrence of SAT occurred in 7 of 9 patients who received a repeat vaccination dose, while symptoms of SAT worsened following the second vaccination in 2 cases. None of the patients experienced severe side effects that could be associated with revaccinations.

CONCLUSIONS

Revaccinations appear to be safe in patients with SARS-CoV-2 vaccine-induced SAT cases, while more evidence is needed regarding SARS-CoV-2 vaccine-induced GD.

Elevated Graves' Disease-Specific Thyroid-Stimulating Immunoglobulin and Thyroid Stimulating Hormone Receptor Antibody in a Patient With Subacute Thyroiditis

Subacute thyroiditis can be rarely associated with autoimmune thyroid disorders. It includes Graves' disease which is characterized by the presence of a highly specific antibody known as thyroid-stimulating hormone (TSH) receptor antibody (TRAb). There are three types of TRAb: TSH receptor stimulating antibody (TSAb) which stimulates the TSH receptor causing Graves' disease, TSH receptor blocking antibody (TBAb) which blocks the TSH receptor causing hypothyroidism, and a neutralizing antibody which does not alter the thyroid function. There are two assays used to check the TRAb: the thyroid-stimulating immunoglobulin (TSI) assay and the TSH receptor-binding inhibitor immunoglobulin (TBII) assay out of which the TSI assay measures the stimulating antibody which is specific for graves' disease. Although autoimmune thyroid disorders can rarely occur following subacute thyroiditis, their clinical presentation is usually compatible with the type of antibody detected in the patient’s serum.

We present a unique case of a 44-year-old patient who presented with subacute thyroiditis followed by the development of persistent hypothyroidism even in the presence of elevated Graves' disease-specific TSI and TRAb.

Graves Disease Following Subacute Thyroiditis in a Chinese Man

Background/Objective

The development of Graves disease (GD) after subacute thyroiditis (SAT) is rare, with approximately 31 reported cases, of which only 5 occurred in men. We describe a case of GD diagnosed based on newly elevated thyroid-stimulating immunoglobulin (TSI) and thyroid-stimulating hormone (TSH) receptor autoantibody (TRAb) levels after SAT.

Case Report

A 32-year-old Chinese man presented with right anterior neck pain, swelling, sore throat, cough, and fever. He had a diffuse tender goiter but no proptosis, lid lag, or stare. His TSH level was 0.03 mIU/mL (normal range [NR] 0.45-5.33 mIU/mL), serum free thyroxine (FT4) level was 2.40 ng/dL (NR 0.61-1.44 ng/dL), total triiodothyronine (TT3) level was 113 ng/dL (NR 87-178 ng/dL), TSI level was <0.10 IU/L (NR < 0.10 IU/L), and erythrocyte sedimentation rate was 21 mm/h (NR < 15 mm/h). After 7 weeks of prednisone, the symptoms resolved, FT4 level was 0.95 ng/dL, and TT3 level was 91 ng/dL. At 11 weeks after SAT onset, the TSH level was <0.01 mIU/mL, TT3 level was 257 ng/dL, FT4 level was 3.03 ng/dL, TSI level was 1.94 IU/L, then 3.42 IU/L 2 weeks later, TRAb level was 8.72 IU/L (NR < 2 IU/L), and erythrocyte sedimentation rate was 4 mm/h. After 1 month of methimazole, the FT4 level was 1.32 ng/dL and TT3 level was 110 ng/dL. Genetic testing revealed human leukocyte antigen-B35 and DRB1∗15:01 positivity.

Discussion

GD after SAT is thought to be due to the activation of thyroid autoimmunity induced by SAT in genetically susceptible individuals.

Conclusions

This case illustrates the induction of thyroid autoimmunity after SAT, resulting in GD, supporting TSI and/or TRAb testing if hyperthyroidism recurs. The presence of HLA alleles associated with SAT and GD suggests a genetic contribution to the development of thyroid autoimmunity.

C-reactive protein and thyroid-stimulating hormone levels as risk factors for hypothyroidism in patients with subacute thyroiditis

OBJECTIVE

This study was designed to explore the relationships between the clinical characteristics and outcomes of patients with subacute thyroiditis (SAT).

DESIGN

This is a single-center retrospective study.

PATIENTS

Eighty-nine patients with SAT who were hospitalized in the Sir Run Run Shaw Hospital in Zhejiang, China, from October 2014 to September 2020 were included.

METHODS

The Mann-Whitney U-test, chi-square test, and Cox regression analysis were conducted to identify the relationships between clinical characteristics and outcomes. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff levels of C-reactive protein (CRP) and thyroid-stimulating hormone (TSH).

RESULTS

The hypothyroidism and recurrence rates were 15.7 and 16.9%, respectively. CRP (≥72.0 mg/L), TSH (<0.02 mIU/L), and free triiodothyronine (fT3) (≥4.10 pg/mL) were associated with hypothyroidism. The cutoff level was 97.80 mg/L for CRP (area under the curve (AUC), 0.717, P = 0.014; sensitivity, 57.1%; specificity, 84.0%) and 0.10 mIU/L for TSH (AUC, 0.752, P = 0.004; sensitivity, 100%; specificity, 46.0%) by ROC curve analysis for hypothyroidism. The factors under study were not associated with recurrence.

CONCLUSION

CRP and TSH were risk factors for hypothyroidism in SAT. Thyroid functions should be monitored closely for the early detection of hypothyroidism, especially in patients with CRP levels of more than 97.80 mg/L and TSH levels of less than 0.10 mIU/L.

Strong Correlation between HLA and Clinical Course of Subacute Thyroiditis-A Report of the Three Siblings

Subacute thyroiditis (SAT) is a thyroid inflammatory disease with susceptibility associated with the presence of human leukocyte antigen (HLA)-B*35, -B*18:01, -DRB1*01 and -C*04:01. Previous viral infection is considered as a triggering factor in genetically predisposed individuals. The influence of HLA on the SAT course was previously suggested. We aim to present the three siblings-female twins and their brother-with very close onset but different clinical courses of SAT, which appeared to be HLA-dependent. The HLA profile in the reported three siblings is strongly correlated with both SAT and Graves' disease (GD), however the coexistence of particular sets of high risk and protective alleles seems to be crucial for the GD development and the SAT course. The co-occurrence of HLA-DRB1*15:01 and/or -B*07:02, possibly together with the lack of HLA-A*01:01 and -B*41:01 seems to be key factors protecting against the development of GD with high TRAb levels, as well as against the recurrent SAT course and steroid dependence.

The Detection of Serum IgMs to Thyroglobulin in Subacute Thyroiditis Suggests a Protective Role of IgMs in Thyroid Autoimmunity

CONTEXT

The role of serum immunoglobulin (Ig)Ms in autoimmune thyroid diseases is uncertain.

OBJECTIVE

We looked for IgMs to thyroglobulin (Tg) in patients with subacute thyroiditis (SAT), which is characterized by high serum Tg levels, the possible de novo appearance of IgGs to Tg (TgAb-IgGs), and no autoimmune sequelae.

MAIN OUTCOME MEASURES

TgAb-IgMs and TgAb-IgGs were detected by binding to Tg using the enzyme-linked immunosorbent assay (ELISA). The upper reference limit of TgAb-IgMs and TgAb-IgGs was established in 40 normal subjects. We looked for TgAb-IgMs in 16 patients with SAT, 11 with Hashimoto's thyroiditis (HT), and 8 with Graves' disease (GD) who were all positive for TgAb-IgGs. IgM binding to bovine serum albumin (BSA), keyhole limpet hemocyanin (KLH), and glucagon in ELISA was measured. Inhibition of TgAb-IgMs binding to coated Tg was evaluated by preincubating serum samples or IgG-depleted samples with soluble Tg.

RESULTS

TgAb-IgMs were positive in 10/16 patients with SAT, 2/11 with HT, and 1/8 with GD. TgAb-IgMs were higher in SAT (0.95; 0.42-1.13) (median; 25th-75th percentiles) than in HT (0.47; 0.45-0.51) and GD patients (0.35; 0.33-0.40) (P < .005 for both). IgM binding of SAT sera to BSA, KLH, and glucagon was significantly lower than Tg. Preincubation with soluble Tg reduced the binding of IgMs to coated Tg by 18.2% for serum samples and by 35.0% and 42.1% for 2 IgG-depleted samples. TgAb-IgM levels were inversely, although nonsignificantly, correlated with Tg concentrations.

CONCLUSIONS

Tg leak associated with thyroid injury induces the production of specific TgAb-IgMs, which, in turn, increases the clearance of Tg and might prevent the establishment of a persistent thyroid autoimmune response.

Two-Years Prospective Follow-Up Study of Subacute Thyroiditis

Purpose: The aim of the present prospective follow-up study was to explore the early indicators of hypothyroidism and the final changes in thyroid volume in subacute thyroiditis (SAT) patients. Methods: We enrolled 61 SAT patients and followed them up for 2 years to assess the incidence of hypothyroidism and changes in thyroid volume. Binary logistic regression and receiver operating characteristic (ROC) curves were used for data analysis. Results: During the 2 years follow-up period, we found that the volumes of the thyroid gland in SAT patients at 1 and 2 years were significantly smaller than those in the healthy control group, which were significantly smaller compared to the initial thyroid volumes after SAT onset (p < 0.001). Also, the thyroid volumes of SAT patients with hypothyroidism were significantly smaller than those of SAT patients without hypothyroidism. The early maximum thyroid-stimulating hormone (TSH) values (within 3 months after SAT onset) were closely related to the incidence of hypothyroidism at 2 years. The OR value was 1.18 (95% CI = 1.01-1.38, p = 0.032). The early maximum TSH value had a maximum area under the ROC curve (AUC) of 0.866 for the development of hypothyroidism 2 years after SAT onset vs. euthyroidism (p < 0.001). Conclusions: The thyroid volumes of patients increased significantly after the onset of SAT, while during the follow-up these volumes decreased; the thyroid volumes at 1 and 2 years were significantly smaller than those of normal healthy subjects, especially in SAT patients with hypothyroidism. Furthermore, the early maximum TSH value could be used as an effective indicator of the development of hypothyroidism 2 years after the onset of SAT.

Thyroid primary and metastatic malignant tumours of poor prognosis may mimic subacute thyroiditis - time to change the diagnostic criteria: case reports and a review of the literature

BACKGROUND

The diagnosis of subacute thyroiditis (SAT) is based mainly on the presence of painful thyroid goitre and a significant increase in erythrocyte sedimentation rate (ESR). Proceeding according to these diagnostic criteria may lead to an incorrect diagnosis and treatment. Extremely dangerous is the situation when the diagnosis of SAT is erroneously made based on criteria other than ultrasound (US) image and fine needle aspiration biopsy (FNAB), which leads to delayed diagnosis of malignant tumour with poor prognosis.

CASE PRESENTATION

Five patients with typical SAT symptoms are presented. In all of them, anaplastic thyroid cancer or metastatic thyroid tumours were finally diagnosed as the cause of the initial symptoms resembling SAT. Most of the patients were initially misdiagnosed and the proper diagnosis of malignancy was delayed.

CONCLUSIONS

The authors have proposed the new diagnostic criteria for SAT, and strongly suggest that thyroid gland US should be included in the main criteria of SAT diagnosis, together with FNAB result excluding the presence of malignant tumour.

Hyperthyroidism After Radiation Therapy for Childhood Cancer: A Report from the Childhood Cancer Survivor Study

PURPOSE

The association of hyperthyroidism with exposure to ionizing radiation is poorly understood. This study addresses the risk of hyperthyroidism in relation to incidental therapeutic radiation dose to the thyroid and pituitary glands in a large cohort of survivors of childhood cancer.

METHODS AND MATERIALS

Using the Childhood Cancer Survivor Study's cohort of 5-year survivors of childhood cancer diagnosed at hospitals in the United States and Canada between 1970 and 1986, the occurrence of hyperthyroidism through 2009 was ascertained among 12,183 survivors who responded to serial questionnaires. Radiation doses to the thyroid and pituitary glands were estimated from radiation therapy records, and chemotherapy exposures were abstracted from medical records. Binary outcome regression was used to estimate prevalence odds ratios (ORs) for hyperthyroidism at 5 years from diagnosis of childhood cancer and Poisson regression to estimate incidence rate ratios (RRs) after the first 5 years.

RESULTS

Survivors reported 179 cases of hyperthyroidism, of which 148 were diagnosed 5 or more years after their cancer diagnosis. The cumulative proportion of survivors diagnosed with hyperthyroidism by 30 years after the cancer diagnosis was 2.5% (95% confidence interval [CI], 2.0%-2.9%) among those who received radiation therapy. A linear relation adequately described the thyroid radiation dose response for prevalence of self-reported hyperthyroidism 5 years after cancer diagnosis (excess OR/Gy, 0.24; 95% CI, 0.06-0.95) and incidence rate thereafter (excess RR/Gy, 0.06; 95% CI, 0.03-0.14) over the dose range of 0 to 63 Gy. Neither radiation dose to the pituitary gland nor chemotherapy was associated significantly with hyperthyroidism. Radiation-associated risk remained elevated >25 years after exposure.

CONCLUSIONS

Risk of hyperthyroidism after radiation therapy during childhood is positively associated with external radiation dose to the thyroid gland, with radiation-related excess risk persisting for >25 years. Neither radiation dose to the pituitary gland nor chemotherapy exposures were associated with hyperthyroidism among childhood cancer survivors through early adulthood.

A Case of Thyrotoxicosis due to Simultaneous Occurrence of Subacute Thyroiditis and Graves' Disease

Subacute thyroiditis is an inflammatory disorder of the thyroid. Graves' disease is an autoimmune thyroid disease in which thyroid hormones are overproduced. Here we present a rare case of thyrotoxicosis due to the simultaneous occurrence of both diseases. Prompt diagnosis and therapy are required to prevent complications in patients with thyrotoxicosis.

Unexpected cause of fever in a patient with untreated HIV

We report a case of a 27-year-old man with a history of untreated HIV who presented with fever, rash and leg cramps. Initial suspicion was high for an infectious process; however, after an exhaustive evaluation, thyrotoxicosis was revealed as the aetiology of his symptoms. Recent intravenous contrast administration complicated his workup to determine the exact cause of hyperthyroidism. Differentiation between spontaneously resolving thyroiditis and autonomous hyperfunction was paramount in the setting of existing neutropenia and the need for judicious use of antithyroid therapy. The inability to enlist a nuclear scan in the setting of recent iodinated contrast administration prompted alternative testing, including thyroid antibodies and thyroid ultrasound. In this case, we will discuss the diagnostic challenges of thyrotoxicosis in a complex patient, the sequelae of iodine contrast administration, effects of iodine on the thyroid and the predictive value of other available tests.

Presence of Thyroid-Stimulating Hormone Receptor Antibodies in a Patient with Subacute Thyroiditis followed by Hypothyroidism and Later Graves' Disease with Ophthalmopathy: A Case Report

BACKGROUND

The development of Graves' disease (GD) after subacute thyroiditis (SAT) is very rare and only a limited number of cases have been reported.

OBJECTIVES

Here, we report a patient with SAT followed by hypothyroidism and later GD, with ophthalmopathy, occurring 11 years after SAT.

CONCLUSION

This case illustrates the appearance of thyroid-stimulating hormone (TSH) receptor antibodies in a female 1 year after SAT, the development of hypothyroidism requiring thyroxine, and later the occurrence of GD with severe ophthalmopathy, 11 years after SAT. The occurrence of SAT and GD may be coincidental but SAT may have induced the appearance of TSH-receptor antibodies, with the bioactivity changing from blocking, leading to hypothyroidism, and later to a stimulating activity that led to GD in a genetically susceptible patient.

Subacute thyroiditis: clinical presentation and long term outcome

Few studies have been reported from the Kingdom of Saudi Arabia (SA) to describe the clinical presentation and long term outcomes of subacute thyroiditis (SAT). Our aim was to review the demographic, anthropometric, clinical presentation, laboratory results, treatment, and disease outcome in Riyadh region and to compare those with results from different regions of the Kingdom and different parts of the world. We reviewed the medical files of patients who underwent thyroid uptake scan during an 8-year period in King Khalid University Hospital. Only 25 patients had confirmed diagnosis of thyroiditis. Age and gender distribution were similar to other studies. Most patients presented with palpitation, goiter, and weight change. Elevated thyroid hormones, suppressed thyroid-stimulating hormone, and elevated ESR were reported. Among those, 7 cases of SAT were recorded. β -Blockers were prescribed to 57% and nonsteroidal anti-inflammatory drugs to 29% of SAT. Long follow-up demonstrated that 85.7% of SAT cases recovered, while 14.3% developed permanent hypothyroidism. In conclusion, SAT is uncommon in the central region of SA. Compared to the western region, corticosteroid is not commonly prescribed, and permanent hypothyroidism is not uncommon. A nation-wide epidemiological study to explain these interprovincial differences is warranted.

Follow-up of a case of subacute thyroiditis with uncommon thyroid (99m)Tc uptake

Thyroidal 99mTc uptake in the acute thyrotoxic phase of subacute thyroiditis (SAT) is always inhibited. However, a patient with SAT had signs in the right-side thyroid gland with transient thyrotoxicosis and slightly high 99mTc uptake levels in the right lobe, low 99mTc uptake in the left lobe, and normal overall uptake. Histological examination showed cellular destruction and granulomatous inflammatory changes in the right lobe, with marked interstitial fibrosis in the left lobe. The patient was thyrotrophin-receptor antibody (TRAb) positive. After a short course of prednisolone, SAT-like symptoms and signs improved. TRAb-positivity resolved spontaneously after 22 months, and TSH levels were slightly low for 22 months. Levels then kept normal in the following four years. In conclusion, high 99mTc uptake by the right lobe was due to the combined effects of TRAb and left thyroid gland fibrosis.

Thyroglobulin autoantibodies of patients with subacute thyroiditis are restricted to a major B cell epitope

BACKGROUND

Thyroglobulin autoantibodies (TgAb) can develop in patients with subacute thyroiditis (SAT).

AIM

Comparison of the epitope pattern of TgAb of patients with SAT, Hashimoto's thyroiditis (HT) [autoimmune thyroid disease (AITD)] and non-toxic multinodular goiter (NTMG) (non-AITD).

SUBJECTS AND METHODS

Serum TgAb from 10 patients with SAT, 45 with HT, and 19 with NTMG were evaluated. Serum TgAb binding to Tg was inhibited by 4 recombinant human TgAb-Fab, recognizing Tg epitope regions A, B, C, and D. The ability of single TgAb-Fab to inhibit the binding of serum TgAb to Tg was evaluated in enzymelinked immunosorbent assay.

RESULTS

Levels of inhibition were different for all TgAb-Fab in the 3 groups of patients. Inhibition by region A TgAb-Fab in SAT [50.5 (30.3-62.5)%] (median and 25th to 75th percentiles) was similar to HT [49.0 (38.0-69.5)%] and significantly higher than in NTMG [25.0 (14.0-37.0)%]; by region B TgAb-Fab in SAT [0.0 (0.0-12.5)%] was significantly lower than in HT [28.0 (9.5-48.0)%] and similar to NTMG [9.0 (4.8-20.5)%]; by region C TgAb-Fab in SAT [9.5 (0.0-25.8)%] were similar to HT [23.0 (9.5-41)%] and NTMG [6.5 (1.7-21.5)%]; and by region D TgAb-Fab in SAT [0.0 (0.0-8.0)%] were lower than in HT [12.0 (1.0-28.5)%] and similar to NTMG [1.0 (0.0-5.0)%].

CONCLUSIONS

The epitope pattern of TgAb of SAT is restricted to the A region that is immunodominant in AITD and non-AITD. In the majority of patients with SAT, the autoimmune phenomena represent a non-specific and transient response to the release of thyroid antigens, rather than the expression of thyroid autoimmunity.

Graves' disease following subacute thyroiditis

Subacute thyroiditis is a painful, inflammatory disease frequently accompanied with fever. It is suspected to be a viral infectious disease, while Graves' disease is an autoimmune disease. Thus, there appears to be no etiological relationship between the two diseases. A total of 25,267 thyroid disease patients made their first visits to our thyroid clinic during a period of 24 years between 1985 and 2008. Among them, subacute thyroiditis and Graves' disease accounted for 918 patients (3.6%) and 4,617 patients (18.2%), respectively. We have encountered 7 patients (one male and six female) with subacute thyroiditis followed by Graves' disease in this period (0.15% of the 4,617 patients with Graves' disease and 0.76% of the 918 patients with subacute thyroiditis). The age ranges were 40~66 years (mean 48.7 years) at the onset of subacute thyroiditis. The intervals between the onsets of subacute thyroiditis and Graves' disease were 1~8 months (mean 4.7 months). Because Graves' disease was preceded by subacute thyroiditis, the signs and symptoms of both diseases were evident together in the intervening period. The diagnosis of Graves' disease in those patients is always difficult because of atypical signs and symptoms and an unclear onset time. The causes of the Graves'disease that followed subacute thyroiditis are still unknown. However, the inflammatory nature of subacute thyroiditis may lead to the activation of the autoimmune response in susceptible subjects, resulting in the onset of Graves' disease. Graves' disease should be suspected when a high blood level of thyroid hormone persists after subacute thyroiditis.

Eponym : de Quervain thyroiditis

de Quervain thyroiditis is a self-limited inflammatory disorder of the thyroid gland. It is an uncommon disease in adults and very rare in children. Fritz de Quervain, a Swiss surgeon, who was an authority on thyroid disease, described the unique pathology of this disease. Granulomatous changes with giant cells in thyroid tissue are the pathological findings. Viral infection in genetically predisposed individuals has been proposed as the pathogenesis of the disease. Clinical hallmarks for the diagnosis are painful thyroid enlargement, elevated erythrocyte sedimentation rate, and C-reactive protein as well as decreased uptake of the thyroid gland on thyroid scintigraphy. In addition, thyrotoxicosis is present in about 50% of cases in early phase of the disease. Serum thyroglobulin level is usually elevated. Only symptomatic treatment with analgesics is usually required for pain relief. Glucocorticoid therapy may be used in severely ill patients. de Quervain thyroiditis is generally completely resolved without complications in 6-12 months. However, permanent hypothyroidism and recurrent disease have been reported in some patients.

Pathogenesis of thyroid-associated ophthalmopathy: does autoimmunity against calsequestrin and collagen XIII play a role?

Thyroid-associated ophthalmopathy (TAO), or thyroid eye disease, is a complex inflammatory disorder of the eye that, as its name implies, is associated with thyroid disease. TAO can be divided into three subtypes: ocular myopathy, congestive myopathy and mixed congestive and myopathic ophthalmopathy. Although the precise pathophysiology of TAO remains unclear it is likely to reflect an autoimmune reaction involving sensitized T-cells and autoantibodies directed against a thyroid and orbital tissue shared antigen. One well studied candidate in this immune reaction is the thyroid-stimulating hormone receptor (TSH-r), expressed in the orbital fibroblast and pre adipocyte. In our studies of TAO, we have investigated the nature and significance of antibodies targeting other eye muscle and orbital connective tissue (OCT) antigens. Our findings suggest that autoimmunity against the eye muscle antigen calsequestrin and the OCT antigen collagen XIII plays a role in the pathogenesis of TAO. We propose that ocular myopathy and chronic eyelid retraction are due to autoimmunity against skeletal muscle calsequestrin in the extraocular and eyelid muscles, respectively. This may be initiated in the thyroid where calsequestrin expression is upregulated, possibly due to a stimulatory effect of TSH-r antibodies. We also propose that congestive ophthalmopathy results from a reaction against the TSH-r or collagen XIII in orbital fibroblast cell membranes. Further insight into the role of eye muscle and OCT antigens in the pathogenesis of TAO may allow for the development of new therapies to treat the eye disorder and reduce patient morbidity.

Viruses and thyroiditis: an update

Viral infections are frequently cited as a major environmental factor involved in subacute thyroiditis and autoimmune thyroid diseases This review examines the data related to the role of viruses in the development of thyroiditis.

Our research has been focused on human data. We have reviewed virological data for each type of thyroiditis at different levels of evidence; epidemiological data, serological data or research on circulating viruses, direct evidence of thyroid tissue infection. Interpretation of epidemiological and serological data must be cautious as they don't prove that this pathogen is responsible for the disease. However, direct evidence of the presence of viruses or their components in the organ are available for retroviruses (HFV) and mumps in subacute thyroiditis, for retroviruses (HTLV-1, HFV, HIV and SV40) in Graves's disease and for HTLV-1, enterovirus, rubella, mumps virus, HSV, EBV and parvovirus in Hashimoto's thyroiditis. However, it remains to determine whether they are responsible for thyroid diseases or whether they are just innocent bystanders. Further studies are needed to clarify the relationship between viruses and thyroid diseases, in order to develop new strategies for prevention and/or treatment.

Extent of hypoechogenic area in the thyroid is related with thyroid dysfunction after subacute thyroiditis

OBJECTIVE

To gain an insight into risk factors for hypothyroidism after subacute thyroiditis (SAT), we examined the correlation between initial laboratory and ultrasonographic findings and sequential thyroid dysfunction among treatment modalities.

PATIENTS

We reviewed retrospectively the medical records of 252 patients (26 men and 226 women) with SAT who consecutively visited our thyroid clinic at Kuma Hospital for at least 6 months from 1996 through 2004.

RESULTS

Throughout the course, 135 patients (53.6%) developed transient or permanent hypothyroidism. Levels of TSH were most often elevated (greater than 5 IU/ml) 2 months after SAT onset regardless of treatment, and 97.0% of patients who showed transient or permanent hypothyroidism clustered within 6 months from onset. During follow-up, patients treated with prednisone (PSL) were more likely to have normal thyroid function than patients not treated or those receiving anti-inflammatory drug therapy. In patients who developed hypothyroidism with PSL treatment or without treatment, the rates of bilateral hypoechogenic areas (HEA) were 6-fold higher than those of unilateral HEA. Moreover, permanent hypothyroidism occurred in 5.9% of patients, and all patients with permanent hypothyroidism presented initially with bilateral HEA and had consequently small thyroid size with or without abnormal autoimmunity.

CONCLUSIONS

The rates of thyroid dysfunction after SAT were significantly lower in patients receiving PSL. Extent of HEA in the thyroid, but not laboratory findings, may be a possible marker for developing thyroid dysfunction after SAT.

Association of the ultrasonographic findings of subacute thyroiditis with thyroid pain and laboratory findings

We aimed to determine whether ultrasonography is a useful diagnostic tool by correlating its findings with biological data of patients with subacute thyroiditis (SAT). Thirty-two SAT patients were evaluated in a retrospective study. Thirty-one patients (96.9%) had tenderness, 14 (43.8%) had localized pain, and 11 patients (34.4%) had radiating pain during a state of SAT. With ultrasonography, we found 51 hypoechoic areas in 32 patients. The hypoechoic volume per unilateral thyroid gland (%) was significantly larger in areas accompanied with pain (P<0.001). Out of 27 patients measured, 18 (67%) were positive for thyroglobulin antibodies (TgAb), of whom all were females. TgAb levels ranged from 0.3 to 13.8 U/ml. During therapy, TgAb levels gradually increased in 2 of the 7 patients who were measured several times. Both thyroglobulin antigen (TgAg) and free thyroxine (FT4) correlated well with total hypoechoic volume (cm (3) ), and the TgAg level showed a strong correlation with the FT4 level (r = 0.7; P<0.0001). The area (%) that the hypoechoic volume occupied in the total thyroid gland, even if the area was over half, was not related to the need of L-T4 replacement therapy. Also, none of the other variables (age, days from onset until diagnosis, serum levels of FT4, TgAg, CRP, autoantibodies, therapies, treatment) differed between the patients with and without replacement therapy. In summary, we found that the hypoechoic area in patients with SAT reflected the degree of inflammation and thyroid hormone levels, though it was difficult to predict continuous hypothyroidism.

Two cases of subacute thyroiditis presenting in pregnancy

Subacute thyroiditis (SAT) is an extremely rare cause of thyrotoxicosis in pregnant women. Untreated, thyrotoxicosis may result in complications, such as prematurity and congenital malformations in the fetus. We report two cases of first trimester subacute thyroiditis, one mild and one severe. The severe case, as demonstrated by laboratory and ultrasound findings, was successfully treated with prednisolone. In this case, it was thought that the benefits of pharmacological therapy outweighed the risk of potential teratogenesis by the medication. In contrast, the milder case was managed conservatively and resolved without treatment. These cases illustrate how laboratory and ultrasound findings can be used to determine whether treatment should be initiated and, once begun, if medication levels need to be adjusted. In both cases, the pregnancies resulted in healthy full-term infants.

Four cases of Graves' disease which developed after painful Hashimoto's thyroiditis

We report four cases of Graves' disease that developed after painful Hashimoto's thyroiditis. All were middle-aged women, who had high titers of anti-thyroid antibodies and thyrotoxicosis at the onset of painful Hashimoto's thyroiditis. After 2 to 7 years, they developed Graves' disease with positive antibody against the thyrotropin receptor. Their clinical courses of Graves' disease went favorably due to the treatment with antithyroid drug or radioactive iodine therapy. Painful Hashimoto's thyroiditis is an atypical variant of Hashimoto's thyroiditis and is one form of destructive thyroiditis. Thyroid damage due to painful Hashimoto's thyroiditis may be associated with the development of Graves' disease.

[Pharyngitis, massive ESR elevation and hyperthyroidism in a 71-year-old female patient]

We present a 71-year-old female patient suffering from a sore throat with unilateral neck swelling, pain on swallowing, subfebrile temperatures and general fatigue persisting for several weeks without any clinical signs of hyperthyroidism, although laboratory findings show high concentrations of T(3) and T(4) and a low TSH. A massive ESR elevation is found as well. Ultrasound reveals an inhomogeneous pattern of the thyroid gland with low echogenicity. (99m)Tc pertechnetate uptake is suppressed. The diagnosis of acute/subacute thyroiditis de Quervain is concluded. Therapeutic application of prednisone leads to a swift improvement, yet two weeks later asymptomatic hypothyroidism is diagnosed, requiring substitution of thyroxine. We discuss de Quervain's thyroiditis and the differential diagnosis of inflammatory disorders of the thyroid gland.

Stimulation of thyroid-stimulating hormone (TSH) receptor antibody production following painless thyroiditis

OBJECTIVE

Development or recurrence of Graves' disease (GD) following painless thyroiditis (PT) has been documented. Therefore, we measured titres of TSH receptor antibodies (TSHR Ab) using a novel sensitive TSHR Ab assay in patients with PT to determine whether PT enhances TSHR Ab production, possibly triggering the development or recurrence of GD.

DESIGN AND MEASUREMENTS

Ninety-two patients who developed PT were studied. Group G consisted of 40 patients with a history of GD (19 patients in remission, 21 who had stopped taking antithyroid drugs during pregnancy). Group P consisted of 52 patients with no history of GD. Serum thyroid hormone levels, thyroid autoantibodies including TSHR Ab, and 123I uptake at 24 h (RAIU) were measured in these patients at the time of PT onset. TSHR Abs were measured by radioreceptor assay using porcine TSH receptors (pTBII) or human TSH receptors (hTBII).

RESULTS

There were no significant differences in serum thyroid hormone levels or pTBII values between groups G and P. Nor was there any significant difference between p- and h-TBII values in group P. There was also no significant difference in pTBII levels before, compared to at the time of PT onset in group G patients. However, hTBII values at the PT onset were significantly higher in the group G than in the group P (7.7 +/- 9.8%vs. 1.4 +/- 5.4%, P = 0.0014). The rate of hTBII positivity was also significantly higher in group G than in group P (12/40 vs. 3/52, P = 0.002). Furthermore, the RAIU in group G patients was significantly higher than that in group P patients (2.8 +/- 2.4%vs. 1.3 +/- 0.9%, P = 0.0002). GD recurrence was observed in seven patients in group G, whose hTBII levels were significantly higher than those of other patients in this group (17.0 +/- 11.8%vs. 5.7 +/- 8.2%, P = 0.02). Of these seven with relapses, five had hTBII values exceeding 15%.

CONCLUSIONS

TBII elevation at the onset of PT in patients with a history of GD was detected by a sensitive hTBII assay. Destruction of the thyroid by PT may trigger GD recurrence in patients with a history of GD.

Clinical features and outcome of subacute thyroiditis in an incidence cohort: Olmsted County, Minnesota, study

Subacute thyroiditis (SAT), or granulomatous thyroiditis, is an inflammatory thyroid condition associated with pain and systemic symptoms. Few community studies are available. We studied the 160 patients with SAT in Olmsted County, Minnesota, seen between January 1, 1960, and December 30, 1997. Subjects were identified through the medical diagnostic index of the Rochester Epidemiology Project. The overall age- and sex-adjusted incidence from 1960 through 1997 was 4.9 cases per 100,000/yr. In the most recent 28-yr period (1970-1997), 94 patients were identified. In this group, pain was the presenting symptom in 96%. SAT recurred in 4% of the patients 6-21 yr after the initial episode. Corticosteroid therapy was given to 36%. Early-onset hypothyroidism occurred both in patients receiving corticosteroid therapy (29%) and in those not receiving corticosteroid therapy (37%). At latest follow-up, significantly more patients who had received corticosteroid therapy had a diagnosis of hypothyroidism than the group without corticosteroid therapy (25% vs. 10%, P < 0.05; overall rate of hypothyroidism, 15%). Early transient hypothyroidism is common in SAT. Permanent hypothyroidism is less common, and only 15% of the patients are receiving T(4) therapy after 28 yr of follow-up. Symptomatic relief is achieved with corticosteroid therapy, but such therapy does not prevent early- and late-onset thyroid dysfunction.

[Subacute thyroiditis with cell destruction and temporary hyperthyroidism in Graves'disease--case report]

We present the case of a 60-year old woman with painful swelling of the thyroid gland and temporary thyrotoxicosis. 30 years ago she had experienced a period of hyperthyroidism because of Graves' disease. This time thyrotropin-receptor-antibodies were negative, Tc-99 m scan revealed decreased uptake in both lobes (this pattern normalised later on) and fine needle aspiration presented leucocyte infiltration of the thyroid. Three months later hypothyroidism was observed requiring treatment with levothyroxine. The development of subacute thyroiditis and Graves' disease in the same person is rare, autoimmune factors and a possible relationship are discussed.

Subacute thyroiditis in an immunosuppressed patient

Subacute thyroiditis is a well-recognized cause of transient thyrotoxicosis, resulting from a destruction injury to the thyroid. The pathogenesis of this condition is not completely understood and there is debate regarding the extent of the contribution of autoimmunity and external agents, such as infections, to this process. We present the first reported case of subacute thyroiditis in a patient who had been on chronic lithium therapy as well as long-term immunosuppression, with cyclosporin and prednisolone, following an allogeneic bone marrow transplant. We speculate that this case suggests a minimal role of autoimmunity in the development of subacute thyroiditis.

Anti-TSH receptor antibodies in clinical practice

Anti-thyroid stimulating hormone receptor antibodies are pathophysiologic and clinical indicators in autoimmune thyroid diseases, not only in Graves' disease. The detection of these antibodies is useful for diagnostic and management purposes. The presence and titers of anti-TSH receptor antibodies, however, have to be interpreted in light of the clinical and other biological characteristics of each patient. Newer, more sensitive assays of anti-TSH receptor antibodies may increase their significance in the diagnosis and management of autoimmune thyroid diseases and Graves' disease.