Clinical significance of thyroid disease in patients with inflammatory myopathy

Discovery of new myositis genetic associations through leveraging other immune-mediated diseases

Genome-wide association studies (GWASs) have been successful at finding associations between genetic variants and human traits, including the immune-mediated diseases (IMDs). However, the requirement of large sample sizes for discovery poses a challenge for learning about less common diseases, where increasing volunteer numbers might not be feasible. An example of this is myositis (or idiopathic inflammatory myopathies [IIM]s), a group of rare, heterogeneous autoimmune diseases affecting skeletal muscle and other organs, severely impairing life quality. Here, we applied a feature engineering method to borrow information from larger IMD GWASs to find new genetic associations with IIM and its subgroups. Combining this approach with two clustering methods, we found 17 IMDs genetically close to IIM, including some common comorbid conditions, such as systemic sclerosis and Sjögren's syndrome, as well as hypo- and hyperthyroidism. All IIM subtypes were genetically similar within this framework. Next, we colocalized IIM signals that overlapped IMD signals, and found seven potentially novel myositis associations mapped to immune-related genes, including BLK, IRF5/TNPO3, and ITK/HAVCR2, implicating a role for both B and T cells in IIM. This work proposes a new paradigm of genetic discovery in rarer diseases by leveraging information from more common IMD, and can be expanded to other conditions and traits beyond IMD.

Adult-Onset Still's Disease Associated with Thyroid Dysfunction: Case Report and Review of the Literature

To our knowledge, the possible unveiled interaction between adult-onset Still’s disease (AOSD) with autoimmune thyroid disease (AITD) has never been reported although it is well established that systemic autoimmune disease may usually occur in relation to AITD. As increasingly clear links of AITD with other autoimmune disease such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and primary Sjögren’s syndrome (pSS) have been reported, and the incidence of AOSD concurrent AITD draws our attention rapidly. In this study, we searched relevant literatures published in the past 30 years to explore that condition.

Dermatomyositis related to autoimmune thyroiditis

BACKGROUND AND OBJECTIVE

Reports on the coexistence of dermatomyositis (DM) with autoimmune thyroiditis (AIT) are very few. Our aim is to define the relationship of the two conditions, identify clinical, laboratory, electromyographic and pathologic features of coexistent DM and AIT.

METHODS

We underwent a MEDLINE search to identify relevant literature published in the past 30 years. Concurrently, we analysed retrospectively medical records of five patients diagnosed with DM and AIT from our hospital.

RESULTS

Eleven cases were included. 90.9% of patients were female with a mean (SD) age of 44.18 (13.11) years for DM at diagnosis, and 39.00 (7.81) years for AIT. AIT can precede or parallel the diagnosis of DM. The most common comorbidities included hypothyroidism (90.9%), cardiopulmonary diseases (63.7%) and overlap syndrome (27.3%), while only one case had malignancy. The most common clinical manifestations were: muscle weakness (100%), polyarthralgia (45.5%), heliotrope rash (45.5%), myalgia (36.4%), and Raynaud's phenomenon (27.3%). The abnormalities on electromyography and muscle/skin biopsy of DM related to AIT did not differ from those findings of DM, while none of these reports were normal. All patients received both the treatment of corticosteroids and levothyroxine, and only 27.3% of patients had a good prognosis.

CONCLUSION

Prevalence of cancer in coexistent DM and AIT may be very low. Also, it is reasonable to suggest that DM patients with AIT should be routinely evaluated for thyroid function and the emergence of comorbidities. Moreover, corticosteroids combined with levothyroxine may be useful for these patients as a standard treatment.

Polymyositis associated with hypothyroidism or hyperthyroidism: two cases and review of the literature

Studies confirming a possible relationship of polymyositis within thyroid dysfunction, either hypothyroidism or hyperthyroidism, are hardly available. To define the association, identify clinical, laboratory, electromyographic, and pathologic features in polymyositis (PM) patients with hypothyroidism or hyperthyroidism, we conducted a MEDLINE and Chinese biomedicine database search to identify relevant literature published in the past 25 years. Seventeen cases were included. All patients were female (10 hypothyroidism patients, seven hyperthyroidism patients). The mean (SD) age of PM, hypothyroidism, and hyperthyroidism at diagnosis was 54.8 (16.7), 55.5 (16.5), and 32.7 years (10.2), respectively. PM diagnosis can precede or parallel hypothyroidism while PM may occur following the diagnosis of hyperthyroidism. The most common comorbidities were malignant tumors in these disorders, including thymoma, colon cancer, and thyroid cancer. Muscle weakness was described in 100% of patients. Other common manifestations included muscles' atrophy and pain, deep tendon reflexes, polyarthralgia, and dysphagia. Most patients had markedly elevated creatine kinase and the presence of anti-Sjogren's syndrome A (SSA) antibodies was also found in two cases. Malignancy associated with PM may more frequently occur in hypothyroidism than in hyperthyroidism. The abnormalities on electromyography and biopsy did not differ from those findings of PM. Therapy consisting of corticosteroids, thyroid hormone, or anti-thyroid drugs was administrated; however, poor prognosis seemed to be associated with malignant tumors as well as older age and the presence of anti-SSA antibodies. It is reasonable to suggest that those patients should be routinely evaluated for thyroid function, especially in older female and patients suffering from cancers.

Hashimoto's encephalopathy

Hashimoto's encephalopathy (HE) is a controversial neurological disorder that comprises a heterogenous group of neurological symptoms that manifest in patients with high titers of antithyroid antibodies. Clinical manifestations of HE may include encephalopathic features such as seizures, behavioral and psychiatric manifestations, movement disorders, and coma. Although it has been linked to cases of Hashimoto's thyroiditis or thyroid dysfunction, the most common immunological feature of HE is the presence of high titers of antithyroglobulin or anti-TPO (antimicrosomal) antibodies. At present, it is unclear whether antithyroid antibodies represent an immune epiphenomenon in a subset of patients with encephalopathic processes or they are really associated with pathogenic mechanisms of the disorder. The significance of classifying encephalopathies under the term HE will be determined in the future once the relevance of the role of antithyroid antibodies is demonstrated or dismissed by more detailed experimental and immunopathological studies. The responsiveness of HE to steroids or other therapies such as plasmapheresis supports the hypothesis that this is a disorder that involves immune pathogenic mechanisms. Further controlled studies of the use of steroids, plasmapheresis, or immunosuppressant medications are needed in the future to prove the concept of the pathogenic role of antithyroid antibodies in HE.