Subacute thyroiditis: a rare presentation in pregnancy.

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Subacute thyroiditis during pregnancy: clinical characteristics of seven cases.

Objective: There are few reports of subacute thyroiditis (SAT) during pregnancy. This study aimed to clarify the clinical characteristics of SAT in pregnant patients. Methods and results: Seven patients diagnosed with SAT during pregnancy at our institution from January 2004 to December 2021 were identified, and their clinical findings were retrospectively examined. At SAT diagnosis, the median age was 34 (range: 31-42) years, the median duration of pregnancy was 5 (4-24) weeks, and all patients had neck pain but no fever. On laboratory examination, median (range) free thyroxine, free triiodothyronine, and C-reactive protein levels were 2.66 (1.14-7.77) ng/dL, 7.1 (3.3-16.1) pg/mL, and 2.22 (0.42-5.79) mg/dL, respectively, and all patients had a hypoechoic lesion of the thyroid gland. Three patients (43%) were treated with steroids, and three patients (43%) received replacement therapy with levothyroxine for hypothyroidism following destructive thyroiditis. There were no pregnancy complications in any of the cases. These seven patients (pregnancy group) were compared with 217 non-pregnant female patients (non-pregnancy group) aged 31 to 42 years who were diagnosed with SAT at our institution from 2016 to 2019. The frequency of body temperatures above 37°C was lower in the pregnancy group than in the non-pregnancy group (0% vs 65%). Conclusion: Patients who develop SAT during pregnancy may have less fever than non-pregnant patients with SAT. There were no pregnancy complications in the pregnancy group in this study. This suggests that adverse pregnancy outcomes may be avoided by the appropriate management of SAT, including hypothyroidism after destructive thyroiditis.

The role of severity and duration of inflammation and hematological parameters on the outcome of subacute thyroiditis.

Background: The role of severity and duration of inflammatory findings on the development of persistent hypothyroidism and anemia has not been clarified in subacute thyroiditis (SAT). Methods: Demographic data and laboratory parameters of patients with SAT were analyzed retrospectively. Results: Permanent hypothyroidism was observed in 28.1% of patients. Baseline elevated erythrocyte sedimentation rate as defined >74.5 mm/h was found to be associated with permanent hypothyroidism, but the duration of inflammation was not different between the recovered and hypothyroid patients. Baseline hemoglobin values improved without specific therapy in 3.5 months. Conclusion: The initial severity but not the duration of inflammation increases the risk for the development of permanent thyroid dysfunction, and anemia improves with the resolution of inflammation.

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Subacute thyroiditis in the SARS-CoV-2 era: a multicentre prospective study.

Objective: Many cases of subacute thyroiditis (SAT) have been described related to SARS-CoV-2 infection, but no prospective data about follow-up are known. This prospective, longitudinal, 3-year, multicentre study aims to explore the clinical peculiarities and outcome of SAT in relation to SARS-CoV-2 infection, ascertained with antibody dosage. Methods: All patients receiving SAT diagnosis from November 2020 to May 2022 were enrolled. Data on anamnesis, physical examination, blood tests (TSH, freeT4, freeT3, thyroglobulin, anti-thyroid antibodies, C-reactive protein, erythrocyte sedimentation rate, complete blood count), and thyroid ultrasound were collected. At baseline, the presence of IgG against the SARS-CoV-2 spike protein or nucleocapsid was investigated. Patients were evaluated after 1, 3, 6, and 12 months. Results: Sixty-six subjects were enrolled. At baseline, 54 presented with pain, 36 (67%) for at least 15 days. Serum SARS-CoV-2 IgG measurements documented that 7 out of 52 subjects (13.5%) had infection before SAT diagnosis (COVID+). No significant differences between the COVID+ and COVID- groups were found at baseline, except for respiratory symptoms and fever, which were more common in COVID+ (P = 0.039 and P = 0.021, respectively). Among the 41 subjects who completed follow-up, COVID+ and COVID- did not differ for therapeutic approach to SAT or outcome, all having an improvement in neck pain, inflammation parameters, and ultrasound features. Conclusion: This is the first prospective study investigating any difference both at diagnosis and at follow-up between SAT presentation in patients with previous SARS-CoV-2 infection and those without. Our data demonstrate that SARS-CoV-2 does not impact on SAT onset, evolution, and outcome.

[A Case of Thyroid Gland Abscess Caused by Brucella melitensis]. / Brucella melitensis'in Neden Oldugu Bir Tiroid Bezi Apsesi Olgusu.

Brucellosis is a zoonotic disease endemic in many developing countries, including Türkiye. Among the species that are pathogenic for humans; Brucella melitensis is isolated from livestock animals like sheep and goats, Brucella abortus from cattle and Brucella suis from pigs. Laboratory diagnosis of infection caused by Brucella species with gram-negative coccobacillus morphology; can be made through characteristic culture features, serological tests and molecular methods. Brucellosis, which has a wide distribution of clinical signs and symptoms; can cause various complications by affecting many organs and systems. Among all complications, the probability of thyroid abscess is less than 1%. In this case report; an example of thyroid abscess, one of the rare complications of brucellosis that is not frequently encountered in the literature, was presented. During the physical examination of a 45-year-old female patient who admitted with the complaint of pain in the neck area, fever, neck swelling, redness and pain that increased with palpation were detected. Leukocytosis, lymphopenia, high sedimentation and CRP, low TSH and high T4 values were detected in laboratory tests and subacute thyroiditis was considered as the preliminary diagnosis. Surgical abscess drainage was planned as the patient's clinical findings progressed during follow-up and spontaneous pus discharged from the midline of the neck. The abscess aspirate sample taken during surgical intervention and the blood culture samples taken before were evaluated microbiologically. Microorganisms that did not grow on EMB agar but grew on 5% sheep blood and chocolate agar at the 72-96th hour of incubation of culture plates; were detected to have gram-negative coccobacillus morphology and positive for catalase, oxidase and urease. Although the Wright test was negative with a titer of 1/20, the Rose Bengal test was positive, Coombs test was positive with a titer of 1/160 and the Brucellacapt test was positive with a titer of >1/5120. Microorganisms growing on culture plates were identified as B.melitensis at the species level with specific antisera. As a result of antibiotic susceptibility tests evaluated according to the European Committee on Antimicrobial Susceptibility Testing version 14.0 (EUCAST v14.0), the isolate was susceptible to rifampicin, doxycycline, gentamicin and trimethoprim-sulfamethoxazole at standart dosing regimen and susceptible to ciprofloxacin and levofloxacin at increased exposure. The patient, who was started on doxycycline and rifampicin combination treatment, was discharged without any complaints. In the diagnosis of infection due to Brucella species, which is one of the pathogens that early diagnosis and initiation of treatment greatly affects the prognosis; in addition to culture, which is the gold standard method, serological tests are also very important. If diagnosis is delayed, complications may develop due to involvement in almost every part of the body, depending on the affected organs and systems. In areas where brucellosis is endemic, patients with symptoms such as neck swelling, shortness of breath and difficulty in swallowing, thyroid tissue involvement due to brucellosis should definitely be considered etiologically.

The association of subacute thyroiditis with viral diseases: a comprehensive review of literature

Introduction: Subacute thyroiditis (SAT), also known as de Quatrain's thyroiditis or granulomatous thyroiditis, is an inflammatory disease of the thyroid. Most of the time, it manifests in the thirties to fifties and is more common in women. SAT can have either viral or post-viral origin. Some viruses, like influenza, COVID-19, Epstein-Barr virus, cytomegalovirus, hepatitis, coxsackievirus 16, and mumps virus, have been linked to SAT development. The COVID-19 pandemic has affected people's lives all around the world and has changed our attitude toward the treatment of many diseases. It has also made us look deeper into the subject in a way that we would be able to treat this sort of disease with a newer insight. Objective: Regarding the importance of this issue, we decided to summarize our extensive searches from online databases, including PubMed, Google Scholar, Medline, Web of Science, and Scopus until February 2023, which we found effective in elucidating the association of subacute thyroiditis and viral diseases. Method: Different online databases were searched for narrative review articles, systemic review articles, and original articles, which were published until February 2023. Result: According to the included studies, we found that there is a correlation between SAT and several viruses such as Epstein-Barr virus, influenza virus, human immunodeficiency virus, cytomegalovirus, oral and cervical virus, hepatitis, dengue virus, and SARS-COV-2. The effect of each of the viral diseases mentioned in the SAT is given in the text. Conclusions: According to the results mentioned in the text, because SAT may be challenging for early diagnosis, due to the potential of classic symptoms as well as the interference of similar clinical symptoms between thyrotoxicosis and viral reactions, the correlation between SAT and viral diseases should be considered so that we can avoid misdiagnosis and lateness.

Subacute thyroiditis following COVID-19 vaccination: Case presentation.

Background: Subacute thyroiditis (SAT) is an organ-specific disease that various drugs, including COVID-19 vaccines, can trigger. COVID-19 infection has been associated with thyroid gland damage and disease SARS-CoV-2 direct action, euthyroid sick syndrome, and immune-mediated mechanisms are all potential mechanisms of thyroid damage. It denotes thyroid gland inflammation, most commonly of viral origin, and belongs to the transitory, self-limiting thyroid gland diseases group, causing complications in approximately 15% of patients in the form of permanent hypothyroidism. Some authors say SAT is the most common thyroid disease associated with COVID-19.Purpose: The occurrence of SAT many weeks after administering the second COVID-19 vaccine is rare and has limited documentation in academic literature. This study aims to present the occurrence of SAT after administering the COVID-19 vaccine. We present the case of a 37-year-old man who developed SAT 23 days after receiving the second dose of Pfizer BioNTech's COVID-19 mRNA vaccine.Research design and study sample: Due to neck pain and an elevated body temperature (up to 38.2°C), a 37-year-old male subject presented for examination 23 days after receiving the second Pfizer BioNTech mRNA vaccine against SARS-CoV-2 viral infection. The patient denied ever having an autoimmune disease or any other disease. Painful neck palpation and a firm, slightly enlarged thyroid gland with no surrounding lymphadenopathy were identified during the exam. The heart rate was 104 beats per minute. All of the remaining physical findings were normal.Data collection and/or Analysis: Data collected during the disease are integral to the medical record.Results: Hematology and biochemistry analyses at the initial and follow-up visits revealed minor leukocytosis, normocytic anaemia, and thrombocytosis, followed by a mild increase in lactate dehydrogenase and decreased iron levels. The patient's thyroid function and morphology had recovered entirely from post-vaccine SAT.Conclusions: Results from this study emphasise the need for healthcare professionals to promptly report any case of SAT related to COVID-19 vaccination. Further investigation is warranted to understand the immunopathogenesis of COVID-19-associated thyroiditis and the impact of COVID-19 immunization on this condition.

Characteristics of patients with subacute thyroiditis.

INTRODUCTION: The diagnosis and management of subacute thyroiditis (SAT) may be challenging, and more evidence on patient and disease characteristics is warranted. METHODS: This was a retrospective cohort study of all patients in the North Denmark Region with a SAT diagnosis in the Danish National Patient Registry, 2016-2018. The medical records and biochemical results prior to the diagnosis and during a two-year follow-up period were reviewed. RESULTS: A total of 71 patients with a SAT diagnosis were identified, and the diagnosis was verified in 44 (62.0%) cases with an incidence rate of 2.4/100,000/year. Patients with verified SAT were predominantly females (72.7%) with a median age of 50.7 years. Biochemical results showed thyrotoxicosis at the initial examination in 69.8% and elevated C-reactive protein in 86.5% of patients. Longitudinal biochemical assessment showed a biphasic response (median thyroid-stimulating hormone, initially: 0.02 mIU/l, at three months: 4.7 mIU/l and 2.4 mIU/l after two years). Treatment with non-steroidal anti-inflammatory drugs, beta-blockers and/or prednisolone was initiated in 23 of the 38 patients (60.5%) evaluated, and ten of 33 patients (30.3%) with follow-up data received thyroid hormone replacement therapy. CONCLUSION: In the North Denmark Region, a hospital diagnosis of SAT was verified in less than two thirds of cases. Further large studies are warranted to extend the findings concerning the treatment and outcome of SAT. FUNDING: None. TRIAL REGISTRATION: Not relevant.

Beyond Acute COVID-19: Investigating the Incidence of Subacute Thyroiditis in Long COVID-19 in Korea.

BACKGRUOUND: The correlation between acute coronavirus disease 2019 (COVID-19) and subacute thyroiditis (SAT) has not been clearly investigated in "long COVID" patients. We aimed to investigate the incidence of SAT during convalescence and after the acute phase of COVID-19, comparing with that of the general population. METHODS: Data from a total of 422,779 COVID-19 patients and a control group of 2,113,895 individuals were analyzed. The index date was defined as the date 3 months after confirmation of COVID-19. The incidence rate (IR) of SAT and hazard ratios (HRs) were calculated per 100,000 persons. Subgroup analysis included analysis of HRs 90-179 and 180 days post-COVID-19 diagnosis; and additional analysis was conducted according to hospitalization status, sex, and age group. RESULTS: The IR of SAT was 17.28 per 100,000 persons (95% confidence interval [CI], 12.56 to 23.20) in the COVID-19 group and 8.63 (95% CI, 6.37 to 11.45) in the control group. The HR of COVID-19 patients was 1.76 (95% CI, 1.01 to 3.06; P=0.045). The HR of SAT was 1.39 (95% CI, 0.82 to 2.34; P=0.220) up to 6 months after the index date and 2.30 (95% CI, 1.60 to 3.30; P<0.001) beyond 6 months. The HR for SAT among COVID-19 patients was 2.00 (95% CI, 1.41 to 2.83) in hospitalized patients and 1.76 (95% CI, 1.01 to 3.06) in non-hospitalized patients compared to the control group. The IR of SAT was 27.09 (95% CI, 20.04 to 35.82) for females and 6.47 (95% CI, 3.34 to 11.30) for males. In the 19 to 64 age group, the IR of SAT was 18.19 (95% CI, 13.70 to 23.67), while the IR was 9.18 (95% CI, 7.72 to 10.84) in the 65 to 69 age group. CONCLUSION: SAT could be a potential long-term complication of COVID-19. Long-term surveillance for thyroid dysfunction is needed especially in hospitalized, female and young-aged subjects.

The value of FT4/TSH ratio in the differential diagnosis of Graves' disease and subacute thyroiditis.

Objective: To explore the value of the FT4/TSH ratio in the etiological diagnosis of newly diagnosed patients with thyrotoxicosis. Methods: The retrospective study was conducted on 287 patients with thyrotoxicosis (122 patients with subacute thyroiditis and 165 patients with Graves' disease) and 415 healthy people on their first visit to our hospital. All patients underwent thyroid function tests including the measurement of T3, T4, FT3, FT4, TSH, T3/TSH, and T4/TSH. The receiver operating characteristic (ROC) curve was employed to evaluate the value of FT4/TSH in the differential diagnosis of Graves' disease and subacute thyroiditis, and compared with other related indicators. Results: The area under the curve of FT4/TSH for diagnosing Graves' disease and thyroiditis was 0.846, which was significantly larger than the area under the curve of T3/T4 ratio (P< 0.05) and FT3/FT4 ratio (P< 0.05). When the cut-off value of the FT4/TSH ratio was 5731.286 pmol/mIU, the sensitivity was 71.52%, the specificity was 90.16%, the positive predictive value was 90.77% and the negative predictive value was 70.06%. The diagnostic accuracy was 79.44%. Conclusion: FT4/TSH ratio can be used as a new reference index for the differential diagnosis of thyrotoxicosis.

Subacute thyroiditis following recovery from COVID-19 infection: novel clinical findings from an Eastern Indian cohort.

OBJECTIVE: Recent reports have suggested a link between COVID-19 infection and subacute thyroiditis (SAT). We aimed to describe variations in clinical and biochemical parameters in patients developing post-COVID SAT. DESIGN: Ours was a combined retrospective-prospective study on patients presenting with SAT within 3 months of recovery from COVID-19 infection, who were subsequently followed up for a further 6 months since diagnosis of SAT. RESULTS: Out of 670 patients with COVID-19, 11 patients presented with post-COVID-19 SAT (6.8%). Those with painless SAT (PLSAT, n = 5) presented earlier, had more severe thyrotoxic manifestations and exhibited higher C-reactive protein, interleukin 6 (IL-6), neutrophil-lymphocyte ratio and lower absolute lymphocyte count than those with painful SAT (PFSAT, n = 6). There were significant correlations of total and free T4 and total and free T3 levels with serum IL-6 levels (pall <0.04). No differences were observed between patients with post-COVID SAT presenting during the first and second waves. Oral glucocorticoids were needed for symptomatic relief in 66.67% of patients with PFSAT. At 6 months of follow-up, majority (n = 9, 82%) achieved euthyroidism, while subclinical and overt hypothyroidism were found in one patient each. CONCLUSIONS: Ours is the largest single-centre cohort of post-COVID-19 SAT reported until, demonstrating two distinct clinical presentations-without and with neck pain-depending on time elapsed since COVID-19 diagnosis. Persistent lymphopaenia during the immediate post-COVID recovery period could be a key driver of early,painless SAT. Close monitoring of thyroid functions for at least 6 months is warranted in all cases.

Concurrent Subacute Thyroiditis and Graves' Disease After COVID-19: A Case Report.

There are many reports of subacute thyroiditis (SAT) that occurred after the coronavirus disease 2019 (COVID-19), but no such case has been reported in Korea. Moreover, the simultaneous occurrence of SAT and Graves' disease (GD) is rare. Here, we describe a patient who developed SAT and GD after the second episode of COVID-19. A 27-year-old woman with no known history of thyroid disease presented with fever, upper respiratory tract symptoms, and painful neck swelling. Thyroid function tests revealed thyrotoxicosis, and thyroid ultrasound showed heterogeneous echogenicity of enlarged thyroid glands. Her initial clinical presentation was consistent with SAT after viral infection, with typical neck tenderness and spontaneous improvement of thyrotoxicosis without antithyroid drug use. However, this case had some atypical features, such as an elevated thyroid-stimulating immunoglobulin level, relapse of thyrotoxicosis in short-term follow-up, and increased Tc-99m pertechnetate uptake, suggesting the coexistence of GD. About two months after methimazole (15 mg/day) was prescribed, she was lost to follow up again. We report the first case of unusual co-occurrence of SAT and GD following COVID-19.

A Rare Case of Painless Destructive Thyroiditis Resulting in Thyroid Storm.

Thyroid storm is a life-threatening clinical condition that is usually triggered by untreated or interrupted treatment of Graves' disease, leading to the sudden onset of severe thyrotoxicosis, which requires an immediate diagnosis and treatment based on diagnostic criteria. Cases of thyroid storm caused by painless/painless subacute thyroiditis are very rare. We herein report an 85-year-old man with features of severe thyrotoxicosis caused by painless/painless subacute thyroiditis who had no uptake of 99mTcO4 and was negative for thyroid-stimulating hormone receptor antibodies. In thyroid storm patients in whom the findings are inconsistent with Graves' disease, careful follow-up and management are necessary, assuming the possibility of painless or painless subacute thyroiditis.

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.

Subacute thyroiditis presenting as simple acute headache was misdiagnosed as meningitis: case report and literature review.

BACKGROUND: The relationship between headache and thyrotoxicosis has been occasionally mentioned in case reports, but there are few related reports. Thus, the relationship cannot be determined. Few cases of subacute thyroiditis (SAT) presenting as simple headache have been reported. CASE PRESENTATION: This case report describes a middle-aged male patient who came to our hospital with acute headache for 10 days. He was initially misdiagnosed as meningitis due to headache, fever, and increased C-reactive protein. Routine antibacterial and antiviral therapy did not improve his symptoms. Blood test suggested thyrotoxicosis, and color ultrasound suggested SAT sonography. He was diagnosed with SAT. With the treatment of SAT, the headache was relieved after the thyrotoxicosis improved. CONCLUSION: This patient is the first detailed report of SAT presenting with simple headache, which is helpful for clinicians to differentiate and diagnose atypical SAT.

Takotsubo cardiomyopathy with left ventricle thrombus caused by subacute thyroiditis.

We report a rare case of takotsubo cardiomyopathy caused by subacute thyroiditis in a man in his 50s. He went to the doctor with complaints of loss of appetite, diarrhoea, chills and general malaise. He had consciousness disturbance, thyrotoxicosis and thyroid-stimulating hormone (TSH) suppression. Thyroglobulin and C reactive protein levels in the blood were elevated, but TSH receptor antibody, thyroid-stimulating antibody, antithyroglobulin antibody and antithyroid peroxidase antibody were not. We began treatment with prednisolone and propranolol after he was diagnosed with thyroid storm caused by subacute thyroiditis. The ECG revealed inverted T waves on the fifth day after admission. He was newly diagnosed with takotsubo cardiomyopathy on the day. A large thrombus was detected in the left ventricle, requiring anticoagulation therapy. Thus, even if there are no findings of takotsubo cardiomyopathy or thrombus at the onset of thyroid storm, appropriate monitoring is required because they can develop during the treatment course.

A Case of Thyroid Storm Caused by Thyroiditis.

Thyroid storm occurs when thyroid hormones are released causing a hyperadrenergic state resulting in potentially life-threatening cardio-respiratory effects. The most common cause of thyroid storm is thyrotoxicosis secondary to Graves disease. Alternatively, subacute thyroiditis (SAT) is usually a self-limited condition consisting of painful inflammation of thyroid gland, often associated with viral illness. Transient hyperthyroidism is a common finding in SAT; however, thyroid storm is an extremely rare complication of SAT. We report the sixth recorded case of SAT associated with thyroid storm.

Incidence of Subacute Thyroiditis During the COVID-19 Pandemic in South Korea Using the National Health Insurance Service Database.

Background: Subacute thyroiditis (SAT) is a thyroid disease initiated by viral infection. Whether severe acute respiratory syndrome coronavirus 2 infection can cause SAT is unclear. This study investigated changes in the nationwide incidence of SAT during the coronavirus disease 2019 (COVID-19) pandemic. Methods: This is a retrospective, cross-sectional population-based study. Data regarding SAT and related viral diseases, including COVID-19, from 2017 to 2020 were collected from the National Health Insurance Service and Korea Disease Control and Prevention Agency databases. Results: In a total of 15,447 patients, 2484 men and 12,963 women diagnosed with SAT from 2017 to 2020 were included in this study. The incidence of SAT was significantly higher in 2020 than in 2017-2019 (8.30 vs. 7.27 per 100,000 persons, p < 0.001), while the incidence of SAT-related respiratory viral diseases, except for COVID-19, markedly decreased in 2020. The peak age of SAT incidence in 2020 was 50-59 years, and the women-to-men ratio was 5.4 (similar to that in 2017-2019). Corticosteroids were prescribed more often (72% vs. 58%, p < 0.001), and the prescription rate exceeding 1 month was significantly higher (45% vs. 40%, p < 0.01) in 2020 than in 2017-2019. Conclusions: The incidence of SAT increased in 2020 in association with COVID-19. A diagnostic approach to COVID-19 needs to be considered in patients with SAT during the COVID-19 pandemic.

Subacute Thyroiditis after COVID-19: A Literature Review.

Subacute thyroiditis (SAT), potentially caused by severe acute respiratory syndrome coronavirus 2 infection, has been reported as a complication of COVID-19 since 2020. The clinical characteristics and outcomes of SAT after COVID-19 remain incompletely defined. Therefore, we aimed to collect and survey case reports of SAT after COVID-19. We performed a systematic search of PubMed/MEDLINE, Web of Science, and Google Scholar. The keywords and MeSH terms used for the searches were "subacute thyroiditis" and "COVID-19." A total of 38 patients from 26 case reports, case series, and letters on SAT associated with COVID-19 were included and analyzed. The most frequent SAT symptom was neck pain (27 cases), followed by fever (22 cases). Of the 25 cases with information on the duration between onset of COVID-19 symptoms and onset of SAT symptoms, the shortest was simultaneous occurrence, and the longest was 4 months. In most cases, patients developed SAT at several days or weeks after the onset of COVID-19. All patients with SAT recovered with no severe complications or sequelae. Clinicians should be aware of the possibility of SAT development in patients with neck pain and fever following COVID-19. Further research is necessary to determine the relationship between SAT and COVID-19.