COVID-induced thyroid autoimmunity.

Breakdown of self-tolerance to thyroid antigens (thyroperoxidase, thyroglobulin and the thyrotropin-receptor) is the driver of thyroid autoimmunity. It has been suggested that infectious disease might trigger autoimmune thyroid disease (AITD). Involvement of the thyroid has been reported during severe acute respiratory syndrome virus 2 (SARS-CoV-2) infection, in the form of subacute thyroiditis in subjects with mild coronavirus disease 19 disease (COVID-19) and of painless, destructive thyroiditis in hospitalized patients with severe infection. In addition, cases of AITD, both Graves' disease (GD) and Hashimoto's thyroiditis (HT), have been reported in association with (SARS-CoV-2) infection. In this review, we focus on the relationship between SARS-CoV-2 infection and occurrence of AITD. Nine cases of GD strictly related to SARS-CoV-2 infection and only three cases of HT associated to COVID-19 infection have been reported. No study has demonstrated a role of AITD as a risk factor for a poor prognosis of COVID-19 infection.

Autoimmune encephalitis associated with COVID-19: A systematic review.

INTRODUCTION: There are increasing reports of COVID-19 related neurological complications which may be due to direct viral invasion, or immune mediated inflammatory diseases such as autoimmune encephalitis and ADEM (acute demyelinating encephalomyelitis). In this study, a systematic review is presented of the reported cases infected by the COVID-19 who were diagnosed with various forms of autoimmune encephalitis (AE). METHODS: The authors searched three databases including PubMed, Scopus, and Web of science for extracting original articles on coronavirus/ COVID-19 and AE. RESULTS: Eighteen articles were considered in this study, including 15 case reports, and three case series with a total of 81 patients. Among the studies, 19 cases were reported with AE including 7 (37%) cases of limbic encephalitis, 5 (26%) patients with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis, 2 (11%) with AE presenting as new-onset refractory status epilepticus (NORSE), 1 (5%) case of steroid-responsive encephalitis, and 4 (21%) cases with an unknown type of AE. CONCLUSION: Our systematic review revealed evidence on AE development in patients infected with the COVID-19. Clinicians should be aware of the possible diagnosis of AE when considering other neurological differential diagnosis in SARS-CoV-2 infected patients.

Systematic review of COVID-19 and autoimmune thyroiditis.

COVID-19 is a severe acute respiratory syndrome. Recent reports showed that autoimmune thyroiditis might occur following COVID-19 infection. We aimed to review the literature to assess the prevalence, clinical features and outcome of autoimmune thyroid disorders triggered by COVID-19. We reviewed case reports, case series, and observational studies of autoimmune thyroiditis including Graves' disease, Hashimoto thyroiditis, and silent thyroiditis developed in COVID-19 patients by searching PubMed, SCOPUS and Web of Science and included in the systematic review. Our search yielded no prevalence study. We noted 20 reported cases: Fourteen cases of Graves' disease, 5 cases of hypothyroidism due to Hashimoto's thyroiditis and one case of postpartum thyroiditis. The majority (16/20, 80%) were middle-aged (mean age: 40 years) female patients. Autoimmune thyroiditis was diagnosed either concomitantly or 7-90 days after the COVID-19 infection. Eight out of 14 cases with Graves' disease had a known thyroid disorder and they were stable in remission. One out of 5 cases with Hashimoto's thyroiditis had known prior hypothyroidism. The majority of the patients achieved remission within 3 months. One patient with thyroid storm due to Graves' disease and one patient with myxedema coma have died. Current data suggest that COVID-19 may cause autoimmune thyroid disease or exacerbate the underlying thyroid disease in remission. It is reasonable to routinely assess the thyroid functions both in the acute phase and during the convalescence so as not to overlook a thyroid disorder and not to delay treatment especially in patients with preexisting autoimmune thyroid diseases.

Olfactory impairment in autoimmune encephalitis: another piece of the puzzle.

BACKGROUND: Despite being long neglected, olfaction has recently become a focus of intense research in neuroscience, as smell impairment has been consistently documented in both neurodegenerative and neuroinflammatory diseases. Considering the close anatomo-functional correlations between the limbic system and the central olfactory structures, we investigated olfaction in a population of patients with autoimmune encephalitis (AE). METHODS: Nineteen adult subjects (14 males, median age 64 years) diagnosed with definite (14/19) or possible (5/19) AE and followed for ≥ 6 months were enrolled. The Brief Smell Identification Test (B-SIT), a 12-item, forced-choice, scratch-and-sniff measure, was used to assess the patients' olfactory function in comparison with a group of sex- and age-matched healthy controls (HC). According to the B-SIT score, subjects were classified as anosmic (< 6), hyposmic (6-8) and normal (≥ 9). Electro-clinical, laboratory and neuroimaging findings were reviewed. RESULTS: Smell impairment was revealed in 15/19 patients (9 hyposmic, 6 anosmic), compared with 5/19 HC (p = 0.0029). Age, gender and smoking habits did not affect the participants' performance at B-SIT. Olfactory dysfunction appeared more common among patients with definite AE (p = 0.0374), regardless of autoantibody status. Subjects with higher modified Rankin Scale (mRS) scores at AE onset more likely presented hyposmia/anosmia (p = 0.033), and so did those with bilateral ictal/interictal EEG abnormalities (p = 0.006). CONCLUSIONS: We found olfaction to be impaired in a significantly large proportion of AE cases. Smell deficits appeared more common in subjects with severe AE (as indicated by both definite diagnosis and higher mRS score), and might represent an additional feature of immune-mediated encephalitis.

Autoimmune hepatitis after SARS-CoV-2 vaccine: New-onset or flare-up?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been reported to trigger several autoimmune diseases. There are also recent reports of autoimmune diseases that develop after SARS-CoV-2 vaccines. Autoimmune hepatitis is a polygenic multifactorial disease, which is diagnosed using a scoring system. A 61-year-old woman presented with malaise, fatigue, loss of appetite, nausea and yellow eyes. She had a Pfizer/BioNTech BNT162b2 mRNA vaccine a month ago. Her physical examination revealed jaundice all over the body, especially in the sclera. The laboratory tests showed elevated liver enzymes and bilirubin levels. Antinuclear antibody and anti-smooth muscle antibody were positive and immunoglobulin G was markedly elevated. The liver biopsy revealed histopathological findings consistent with autoimmune hepatitis (AIH). The patient was diagnosed with AIH and initiated on steroid therapy. She rapidly responded to steroid therapy. A few cases of AIH have been reported after the COVID-19 vaccine so far. Although the exact cause of autoimmune reactions is unknown, an abnormal immune response and bystander activation induced by molecular mimicry is considered a potential mechanism, especially in susceptible individuals. As intensive vaccination against SARS-CoV-2 continues, we would like to emphasize that clinicians should be cautious and consider AIH in patients presenting with similar signs and symptoms.

Autoimmune Encephalitis After SARS-CoV-2 Infection: Case Frequency, Findings, and Outcomes.

BACKGROUND AND OBJECTIVES: Autoimmune encephalitis (AE) cases after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been reported, but the frequency is unknown. We aimed to determine the frequency and diagnostic features of coronavirus disease 2019 (COVID-19)-related AE. METHODS: Residual sera from 556 consecutive Mayo Clinic Rochester patients (laboratory cohort) who underwent autoimmune encephalopathy neural immunoglobulin G (IgG) evaluation were tested for total antibodies against the SARS-CoV-2 spike glycoprotein using a Food and Drug Administration-authorized chemiluminescence assay (October 2019-December 2020). Clinical records from patients with a positive SARS-CoV-2 antibody result and available research consent were reviewed. This laboratory cohort was cross-referenced with the Department of Neurology's COVID-19-related consultative experience (encephalopathy cohort, n = 31). RESULTS: Eighteen of the laboratory cohort (3%) were SARS-CoV-2 antibody positive (April-December 2020). Diagnoses were as follows: AE, 2; postacute sequelae of SARS CoV-2 infection (PASC), 3; toxic-metabolic encephalopathy during COVID-19 pneumonia, 2; diverse non-COVID-19 relatable neurologic diagnoses, 9; unavailable, 2. Five of the encephalopathy cohort had AE (16%, including the 2 laboratory cohort cases that overlapped), representing 0.05% of 10,384 patients diagnosed and cared for with any COVID-19 illness at Mayo Clinic Rochester in 2020. The 5 patients met definite (n = 1), probable (n = 1), or possible (n = 3) AE diagnostic criteria; median symptom onset age was 61 years (range, 46-63); 3 were women. All 5 were neural IgG negative and 4 tested were SARS-CoV-2 PCR/IgG index negative in CSF. Phenotypes (and accompanying MRI and EEG findings) were diverse (delirium [n = 5], seizures [n = 2], rhombencephalitis [n = 1], aphasia [n = 1], and ataxia [n = 1]). No acute disseminated encephalomyelitis cases were encountered. The 3 patients with possible AE had spontaneously resolving syndromes. One with definite limbic encephalitis was immune therapy responsive but had residual mood and memory problems. One patient with probable autoimmune rhombencephalitis died despite immune therapy. The remaining 26 encephalopathy cohort patients had toxic-metabolic diagnoses. DISCUSSION: We encountered occasional cases of AE in our 2020 COVID-19 experience. Consistent with sporadic reports and small case series during the COVID-19 pandemic, and prior experience of postinfectious AE, our cases had diverse clinical presentations and were neural IgG and CSF viral particle negative. Application of diagnostic criteria assists in differentiation of AE from toxic-metabolic causes arising in the setting of systemic infection.

Hashimoto's thyroiditis following SARS-CoV-2 infection.

Infectious diseases have long been considered one of the triggers for autoimmune and autoinflammatory diseases. Since the appearance of the new coronavirus in December 2019 in the city of Wuhan, China, there have been many reports suggesting that infection with coronavirus 2 (SARS-CoV-2) precedes the appearance of several autoimmune and autoinflammatory diseases. We describe a case report of a patient who was infected with the SARS-CoV-2 virus and later developed a picture of Hashimoto's thyroiditis.

Autoimmune hepatitis triggered by SARS-CoV-2 vaccination.

The development of autoimmune diseases has been reported after SARS-CoV-2 infection. Vaccination against SARS-CoV-2 could also trigger auto-immunity, as it has been described with other vaccines. An aberrant immune response induced by molecular mimicry and bystander activation, especially in predisposed individuals, is a potential mechanism. We report the case of a 76-year-old woman with Hashimoto thyroiditis and prior COVID-19 infection who developed severe autoimmune hepatitis (with typical features including strongly positive anti-smooth muscle antibody and markedly elevated immunoglobulins G, as well as typical histological findings) following SARS-CoV-2 vaccination (mRNA-1273 SARS-CoV-2 vaccine, Moderna®). The link between SARS-CoV-2 vaccination and the development of autoimmune diseases needs to be further investigated. Although a causality relationship cannot be proven, caution may be warranted when vaccinating individuals with known autoimmune diseases.

Autoimmune Encephalitis Concomitant with SARS-CoV-2 Infection: Insight from 18F-FDG PET Imaging and Neuronal Autoantibodies.

We report the case of a 72-y-old man with concomitant autoimmune encephalitis and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The patient presented with subacute cerebellar syndrome and myoclonus several days after general infectious symptoms began. Methods: Clinical examination, CT, PET, MRI, and autoantibody testing were performed. Results: The oropharyngeal swab test was positive for SARS-CoV-2. The brain MRI results were normal. Cerebrospinal fluid testing showed normal cell counts, a negative result on reverse-transcription polymerase chain reaction testing, and no oligoclonal banding. Brain 18F-FDG PET showed diffuse cortical hypometabolism associated with putaminal and cerebellum hypermetabolism, compatible with encephalitis and especially cerebellitis. The immunologic study revealed high titers of IgG autoantibodies in serum and cerebrospinal fluid directed against the nuclei of Purkinje cells, striatal neurons, and hippocampal neurons. Whole-body 18F-FDG PET and CT scans did not show neoplasia. Treatment with steroids allowed a rapid improvement in symptoms. Conclusion: This clinical case argues for a possible relationship between SARS-CoV-2 infection and autoimmune encephalitis and for the use of 18F-FDG PET in such a context.