COVID-19 emerged in December 2019 and rapidly became a global pandemic. It has since been associated with the progression of various endocrine disorders, including thyroid disease. The long-term effects of this interplay have yet to be explored. This review explores the relationship between COVID-19 and thyroid diseases, emphasizing thyroid gland function and the clinical implications for managing thyroid disorders in infected individuals.

This narrative review intends to provide insight into the scope of research that future clinical studies may aim to address regarding the long-term effects of COVID-19 infection on thyroid health.

Keywords including "thyroid disease", "COVID-19", and "long-term" were used to search PubMed and Google Scholar for updated and relevant clinical research.

COVID-19 affects the thyroid gland multifacetedly and includes direct viral invasion, immune-mediated damage, and hypothalamic-pituitary-thyroid axis disruption. Approximately 15% of COVID-19 patients experience thyroid dysfunction, which can present as thyrotoxicosis, hypothyroidism, or non-thyroidal illness syndrome (NTI). Noteworthy findings include inflammatory thyroiditis. Long-term effects, including those observed in children, include persistent hypothyroidism and exacerbated pre-existing thyroid-autoimmune conditions. Management of thyroid disorders in COVID-19 patients requires consideration: anti-thyroid drug (ATD) therapy used to treat hyperthyroidism in COVID-19 patients may need adjustment to prevent immunosuppression. Radioactive iodine (ROI) alternatives and interleukin-6 (IL-6) receptor antagonists could offer potential benefits and should be further explored.

Longitudinal follow-ups post-COVID-19 for patients with new and pre-existing thyroid disorders can improve disease outcomes. In addition, pathophysiological research on thyroid dysfunction in COVID-19 may help develop strategies to prevent and alleviate thyroid gland abnormalities post-COVID-19.

The COVID-19 pandemic has affected over 772 million people globally. While lung damage is the major contributor to the morbidity and mortality of this disease, the involvement of multiple organs, including the endocrine glands, has been reported. This Review aims to provide an updated summary of evidence regarding COVID-19 and thyroid dysfunction, incorporating highlights of recent advances in the field, particularly in relation to long COVID and COVID-19 vaccination. Since subacute thyroiditis following COVID-19 was first reported in May 2020, thyroid dysfunction associated with COVID-19 has been increasingly recognized, secondary to direct and indirect effects on the hypothalamic-pituitary-thyroid axis. Here, we summarize the epidemiological evidence, pattern and clinical course of thyroid dysfunction following COVID-19 and examine radiological, molecular and histological evidence of thyroid involvement in SARS-CoV-2 infection. Beyond acute SARS-CoV-2 infection, it is also timely to examine the course and implication of thyroid dysfunction in the context of long COVID owing to the large population of survivors of COVID-19 worldwide. This Review also analyses the latest evidence on the relationship between the therapeutics and vaccination for COVID-19 and thyroid dysfunction. To conclude, evidence-based practice recommendations for thyroid function testing during and following COVID-19 and concerning COVID-19 vaccination are proposed.

Subacute thyroiditis (SAT) is a self-limiting inflammatory condition of the thyroid gland with distinct symptoms and a predictable outcome. During the current COVID-19 pandemic, there have been multiple isolated reports of SAT either during the active viral illness or following recovery. Here, we report two such cases of COVID-19 infection presenting with SAT. A 65-year-old male presented with a two-week history of anterior neck pain, odynophagia, high-grade fever (38.9°C), sweating, palpitations, and tremulousness. At physical examination, the patient presented with a slightly increased heart rate and a tender and enlarged thyroid on palpation. Laboratory examination showed high C-reactive protein levels, with elevated erythrocyte sedimentation rate, and thyroid function tests were suggestive of thyrotoxicosis. Ultrasonography showed a heterogeneous thyroid gland with ill-defined hypoechoic areas, and thyroid scintigraphy showed reduced uptake, confirming the diagnosis of SAT. In another case, a 52-year-old male presented with fever, cough, and myalgias, and was diagnosed with mild COVID-19 pneumonia, and managed conservatively. After two weeks, the patient had a recurrence of high-grade fever, odynophagia, palpitations, and tremors. Examination revealed tachycardia, hyperhidrosis, and a tender and enlarged thyroid on palpation. Thyroid function tests revealed low thyroid-stimulating hormone, with normal total T4 and total T3. Ultrasonography examination showed a heterogeneous thyroid gland with bilateral ill-defined hypoechoic areas. In our systematic review, including 103 SAT cases, it has been suggested that SAT should be recognized as an uncommon extra-pulmonary clinical manifestation of COVID-19 infection and clinicians need to be aware of the association. Pending larger multicentric studies, management of the condition has to be on a case-by-case basis.

The coronavirus disease 2019 (COVID-19) is a major public health problem threatening human health. It can lead to multiple system complications, among which liver damage is also a common complication of COVID-19. The pathogenesis of liver injury is complex and involves the interaction of multiple factors. This study aims to investigate the incidence and risk factors of liver injury in COVID-19 patients and analyze the impact of liver injury on clinical prognosis of patients, so as to provide corresponding basis for clinical diagnosis and treatment.

PubMed and Cochrane Library were searched in computer to collect original studies on liver injury cases, laboratory indicators and clinical outcomes in COVID-19 patients. Articles were screened according to inclusion and exclusion criteria, and data were meta-analyzed using Stata12.0 software.

A total of 49 studies, including 23,611 patients with COVID-19, had a prevalence of liver injury of 39.63%. Subgroup analysis found that patients in the Americas had the highest incidence of liver injury at 43.7% and lowest in Africa (25.99%). The vast majority of liver injury is manifested by aminotransferase or bilirubin levels greater than 1 times the upper limit of normal (49.16%). The older the age, the male, the associated chronic liver disease, and the higher the levels of white blood cells, neutrophils, and C-reactive protein, the higher the risk of liver injury. The use of hormones, hydroxychloroquine, and tocilizumab increases the risk of liver injury. Patients with concurrent liver injury have longer hospital stays, are more likely to progress to severe cases, and have a higher risk of death than patients without liver injury.

The incidence of liver injury in COVID-19 patients was high, affected by age, gender, chronic liver disease, inflammatory state and medication, and patients with liver injury were hospitalized longer and were more likely to have a poor prognosis. Therefore, clinical attention should be paid to early intervention.

Despite the significant research and development of COVID-19 diagnostic and therapeutic approaches, the virus still poses a concern, particularly to groups that are already vulnerable. Several individuals experienced cardiac problems like myocardial infarction, arrhythmia, heart failure, cardiomyopathy, myocarditis, and pericarditis after they had recovered from the infection. Early diagnosis and timely management of sequelae are part of the therapy. However, there are gaps in the knowledge of the diagnostic and definitive treatment options for COVID-19 myocarditis. This review focuses on myocarditis associated with COVID-19.

This systemic review provides the most recent overview of myocarditis caused by COVID-19, including clinical manifestations, diagnostic techniques, available treatments, and outcomes.

The PubMed, Google Scholar, and ScienceDirect servers were used to conduct a systematic search in compliance with the PRISMA guidelines. Boolean search terms included "(COVID-19)" OR "(COVID19)" OR "(COVID-19 VIRUS INFECTION)" AND "(MYOCARDITIS)". The results were tabulated and analyzed.

A total of 32 studies, including 26 case reports and 6 case series, were included in the final analysis, and 38 cases of COVID-19-associated myocarditis were analyzed. Middle-aged men constituted the most affected population (60.52%). Dyspnoea (63.15%), chest pain or discomfort (44.73%), and fever (42.10%) were the prevalent presentations. ST-segment abnormalities were reported in 48.38% of cases on electrocardiography testing. Leucocytic infiltration (60%) was the frequent finding obtained on endomyocardial biopsy. Cardiac magnetic resonance imaging yielded myocardial oedema (63.63%), and late gadolinium enhancement (54.54%) as the most common findings. Reduced ejection fraction (75%) was the frequent result obtained on echocardiography. Corticosteroids (76.31%) and immunomodulators (42.10%) were the well-established in-hospital medications. Veno-arterial extracorporeal membrane oxygenation (35%) was the most common intervention used to support the treatment. The frequent in-hospital complications were cardiogenic shock (30.76%), followed by pneumonia (23.07%). The mortality rate was 7.9%.

Early detection and timely management of myocarditis are essential to reduce the risk of developing further complications. It is crucial to emphasize the need to evaluate COVID-19 as a possible cause of myocarditis in populations that are young and healthy to avoid fatal consequences.

Subacute thyroiditis (SAT) is a self-limiting thyroid inflammatory disease occurring specifically after upper respiratory tract infections. Since COVID-19 is a respiratory disease leading to multi-organ involvements, we aimed to systematically review the literature regarding SAT secondary to COVID-19.

We searched Scopus, PubMed/MEDLINE, Cochrane, Web of Science, ProQuest, and LitCovid databases using the terms "subacute thyroiditis" and "COVID-19" and their synonyms from inception to November 3, 2022. We included the original articles of the patients with SAT secondary to COVID-19. Studies reporting SAT secondary to COVID-19 vaccination or SAT symptoms' manifestation before the COVID-19 infection were not included.

Totally, 820 articles were retained. Having removed the duplicates, 250 articles remained, out of which 43 articles (40 case reports and three case series) with a total of 100 patients, were eventually selected. The patients aged 18-85 years (Mean: 42.70, SD: 11.85) and 68 (68%) were women. The time from the onset of COVID-19 to the onset of SAT symptoms varied from zero to 168 days (Mean: 28.31, SD: 36.92). The most common symptoms of SAT were neck pain in 69 patients (69%), fever in 54 (54%), fatigue and weakness in 34 (34%), and persistent palpitations in 31 (31%). The most common ultrasonographic findings were hypoechoic regions in 73 (79%), enlarged thyroid in 46 (50%), and changes in thyroid vascularity in 14 (15%). Thirty-one patients (31%) were hospitalized, and 68 (68%) were treated as outpatients. Corticosteroids were the preferred treatment in both the inpatient and outpatient settings (25 inpatients (81%) and 44 outpatients (65%)). Other preferred treatments were nonsteroidal anti-inflammatory drugs (nine inpatients (29%) and 17 outpatients (25%)) and beta-blockers (four inpatients (13%) and seven outpatients (10%)). After a mean duration of 61.59 days (SD: 67.07), 21 patients (23%) developed hypothyroidism and thus, levothyroxine-based treatment was used in six of these patients and the rest of these patients did not receive levothyroxine.

SAT secondary to COVID-19 seems to manifest almost similarly to the conventional SAT. However, except for the case reports and case series, lack of studies has limited the quality of the data at hand.

Following the rapidly increasing number of multisystem inflammatory syndromes in children (MIS-C), a similar clinical scenario has been observed in adult patients. Although its prevalence is low and probably related to underdiagnosis, its development can be associated with high mortality. Multisystem inflammatory syndrome in adults (MIS-A) can develop following both asymptomatic and symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and in previously healthy people. Like MIS-C, MIS-A is a multisystem disease that can involve the cardiovascular, respiratory, gastrointestinal, dermatologic, hematologic, and neurologic systems. In addition to the clinical manifestations, the diagnosis of MIS-A requires laboratory evidence of inflammation and SARS-CoV-2 infection. The appropriate treatment for MIS-A remains unclear; anti-inflammatory agents, including intravenous immunoglobulin and corticosteroids, are commonly used. However, there are still many unknowns regarding MIS-A. Further studies are needed to determine the true prevalence, pathogenesis, and effective treatment for MIS-A.

As COVID-19 was uncovered, it became evident that specific individuals could experience multi-organ complications for quite a while after infection. Among them, there were several cardiovascular complications. Myocardial perfusion imaging single photon emission computed tomography (MPI SPECT) can be utilized to detect and evaluate cardiac problems regardless of whether COVID caused them. By examining all publications relevant to the impacts of the pandemic on SPECT MPI imaging, we aimed to understand how the COVID pandemic affected different aspects of the MPI, how intense these effects were, and what the consequences were.

On the 6th of June, 2022, a four-domain search strategy was developed and implemented by searching the following databases: PubMed, SCOPUS, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials. The retrieved records have been put through two levels of screening. The search for forward and backward citations provided more results.

This study contained 32 papers, divided into the following three categories: 1. Case reports and series; 2. A comparison of the number of MPIs conducted before and after the pandemic; and 3. SPECT MPI findings.

We observed through the article review that CT scans performed in combination with MPI are crucial and should be interpreted within the context of COVID, especially during outbreaks. Moreover, we discovered that in the initial months of the pandemic, the number of SPECT MPIs performed globally decreased, with the fall being more significant in some countries, primarily in low- to middle-income regions. Lastly, we found that individuals with a history of COVID-19 may be more prone to having MPIs that demonstrate abnormalities, such as ischemia.

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.

This is a review of full-length articles strictly concerning subacute thyroiditis (SAT) in relation to the SARS-CoV-2 virus infection (SVI) and COVID-19 vaccine (COV) that were published between the 1st of March 2020 and the 21st of March 2022 in PubMed-indexed journals. A total of 161 cases were reported as follows: 81 cases of SAT-SVI (2 retrospective studies, 5 case series, and 29 case reports), 80 respective cases of SAT-COV (1 longitudinal study, 14 case series, 17 case reports; also, 1 prospective study included 12 patients, with 6 patients in each category). To our knowledge, this represents the largest cohort of reported cases until the present time. SAT-SVI was detected in adults aged between 18 and 85 years, mostly in middle-aged females. SAT-COVID-19 timing classifies SAT as viral (synchronous with infection, which is an original feature of SATs that usually follow a viral infection) and post-viral (during the recovery period or after infection, usually within 6 to 8 weeks, up to a maximum 24 weeks). The clinical spectrum has two patterns: either that accompanying a severe COVID-19 infection with multi-organ spreading (most frequent with lung involvement) or as an asymptomatic infection, with SAT being the single manifestation or the first presentation. Either way, SAT may remain unrecognized. Some data suggest that more intense neck pain, more frequent fever, and more frequent hypothyroidism at 3 months are identified when compared with non-SAT-SVI, but other authors have identified similar presentations and outcomes. Post-COVID-19 fatigue may be due to residual post-SAT hypothyroidism. The practical importance of SAT-SVI derives from the fact that thyroid hormone anomalies aggravate the general status of severe infections (particular concerns being tachycardia/arrhythmias, cardiac insufficiency, and ischemic events). If misdiagnosed, SAT results in unnecessary treatment with anti-thyroid drugs or even antibiotics for fever of unknown cause. Once recognized, SAT does not seem to require a particular approach when compared with non-COVID-19 cases, including the need for glucocorticoid therapy and the rate of permanent hypothyroidism. A complete resolution of thyroid hormone anomalies and inflammation is expected, except for cases with persistent hypothyroidism. SAT-COV follows within a few hours to a few weeks, with an average of 2 weeks (no particular pattern is related to the first or second vaccine dose). Pathogenesis includes molecular mimicry and immunoinflammatory anomalies, and some have suggested that this is part of ASIA syndrome (autoimmune/inflammatory syndrome induced by adjuvants). An alternative hypothesis to vaccine-related increased autoimmunity is vaccine-induced hyperviscosity; however, this is supported by incomplete evidence. From what we know so far concerning the risk factors, a prior episode of non-SVI-SAT is not associated with a higher risk of SAT-COV, nor is a previous history of coronavirus infection by itself. Post-vaccine SAT usually has a less severe presentation and a good outcome. Generally, the female sex is prone to developing any type of SAT. HLA susceptibility is probably related to both new types of SATs. The current low level of statistical evidence is expected to change in the future. Practitioners should be aware of SAT-COV, which does not restrict immunization protocols in any case.

Myopericarditis is an inflammatory heart condition involving the pericardium and myocardium. It can lead to heart failure, dilated cardiomyopathy, arrhythmia and sudden death. Its pathogenesis is mainly mediated by viral infections but also can be induced by bacterial infections, toxic substances and immune mediated disorders. All these conditions can produce severe inflammation and myocardial injury, often associated with a poor prognosis. The specific roles of these different pathogens (in particular viruses), the interaction with the host, the interplay with gut microbiota, and the immune system responses to them are still not completely clear and under investigation. Interestingly, some research has demonstrated the contribution of the gut microbiota, and its related metabolites (some of which can mimic the cardiac myosin), in cardiac inflammation and in the progression of this disease. They can stimulate a continuous and inadequate immune response, with a subsequent myocardial inflammatory damage. The aim of our review is to investigate the role of gut microbiota in myopericarditis, especially for the cardiovascular implications of COVID-19 viral infection, based on the idea that the modulation of gut microbiota can be a new frontier in the cardiological field to prevent or treat inflammatory cardiomyopathies.