Thyroid Function and Anti-thyroid Antibodies in Pediatric Anti-NMDAR Encephalitis

Objective: Recent studies found that changes of thyroid antibodies (ATAbs), thyroid hormone, and non-thyroidal illness syndrome (NTIS) characterized by thyroid hormone inactivation with low triiodothyronine and high reverse triiodothyronine followed by suppressed thyroid-stimulating hormone (TSH) in adult anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis were associated with disease severity. This study aimed to explore thyroid function and ATAbs in pediatric anti-NMDAR encephalitis and their clinical association.Methods: We retrospectively analyzed the clinical data of 51 pediatric cases with anti-NMDAR encephalitis hospitalized in Guangzhou Women and Children's Medical Center from August 2016 to 2019.Results: A percentage of 52.9% of patients belonged to the ATAb (+) group, with 26 cases both positive for anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TGAb), and one patient only positive for TPOAb. A percentage of 62.7% of patients had at least one abnormality in terms of FT3, free thyroxin (FT4), or TSH levels. Meanwhile, 45.1% of patients were diagnosed with NTIS. Among 25 cases retested for thyroid function 2 months after the initial test, the respectively decreased FT3 and FT4 in 13 and 11 cases on admission returned to normal or closer normal than before; TPOAb in eight cases and TGAb in 12 cases were changed from positivity to negativity. Compared with onset, the level of TPOAb and TGAb at relapse remained stable or significantly decreased, respectively. Compared with the ATAb (–) group, the ATAb (+) group had an older onset age, a higher ratio of movement disorders, elevated rate of sleep disorders, increased anti-nuclear antibody positivity rate, and higher ratio of more than one course of intravenous immunoglobulin treatment. There were no significant differences between the NTIS and non-NTIS groups in clinical characteristics.Conclusion: Anti-thyroid antibody positivity, abnormality of FT3, FT4, or TSH levels and NTIS are frequent in pediatric anti-NMDAR encephalitis. Thyroid antibody and thyroid hormone abnormalities could be improved through the course of treatment of anti-NMDAR encephalitis. Cases with ATAbs (+) are at older onset ages and more likely to be treated by intravenous immunoglobulin therapy more than once. Unlike adult anti-NMDAR encephalitis, NTIS might not be associated with the clinical characteristics of anti-NMDAR encephalitis in pediatric patients.

Relationship of the platelet distribution width/platelet count ratio with thyroid antibody levels in patients with Hashimoto's thyroiditis

Objective I investigated whether the platelet distribution width/platelet count (PDW/PC) ratio, which is an inexpensive and simple test performed for almost all patients, is applicable in the follow-up of patients with Hashimoto’s thyroiditis and examined the relationship of this ratio with thyroperoxidase and thyroglobulin antibody levels. Materials and methods The study groups consisted of 67 patients with Hashimoto’s thyroiditis and 17 controls. All participants were aged 20 to 75 and treated the Internal Medicine outpatient clinic of my institution. The PDW/PC ratio and thyroid antibody levels were retrospectively evaluated in patients with normal liver and renal function and normal white blood cell counts, hemoglobin levels, and hematocrit levels. Results Thyroid antibody levels were significantly higher in patients with Hashimoto’s thyroiditis than in controls. PC was higher in patients with Hashimoto’s thyroiditis, whereas the PDW/PC ratio was lower. However, these differences were not statistically significant. Conclusion In this study, I did not find a statistically significant relationship between thyroid antibody levels and PDW/PC. However, a weak correlation between these variables was identified.

Insights From Prospective Follow-up of Thyroid Function and Autoimmunity Among Covid-19 Survivors

Objective: Occurrence of Graves’ disease and Hashimoto’s thyroiditis after coronavirus disease 2019 (COVID-19) raised the concern about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggering thyroid autoimmunity. Uncertainties remain regarding incident thyroid dysfunction and autoimmunity among COVID-19 survivors. We carried out a prospective study to characterize the evolution of thyroid function and autoimmunity among COVID-19 survivors. Method: Consecutive adult patients, without known thyroid disorders, admitted to Queen Mary Hospital for confirmed COVID-19 from 21 July to 21 September 2020 were included. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3) and anti-thyroid antibodies were measured on admission and at 3 months. Positive anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) was defined by >100 units. Results: Among 200 COVID-19 survivors, 122 had reassessment thyroid function tests (TFTs) (median age: 57.5 years; 49.2% men). Baseline characteristics of patients who did and did not have reassessment were comparable. Among the 20 patients with baseline abnormal TFTs on admission, mostly low fT3, 15 recovered. Of the 102 patients with normal TFTs on admission, two (2.0%) had new onset abnormal TFTs, which may represent TFTs in different phases of thyroiditis (one had mildly elevated TSH 5.8 mIU/L, with normal fT4 [16 pmol/L] and fT3 [4.3 pmol/L], the other had mildly raised fT4 25 pmol/L with normal TSH [1.1 mIU/L] and fT3 [4.7 pmol/L]). Among 104 patients with anti-thyroid antibody titers reassessed, we observed increases in anti-TPO (baseline: 28.3 units [IQR 14.0-67.4] vs reassessment: 35.0 units [IQR: 18.8-99.0]; p<0.001) and anti-Tg titers (baseline: 6.6 units [IQR 4.9-15.6] vs reassessment: 8.7 units [IQR: 6.6-15.4]; p<0.001), but no change in anti-TSHR titer (baseline: 1.0 IU/L [IQR: 0.8-1.2] vs reassessment: 1.0 IU/L [IQR: 0.8-1.3]; p=0.486). Of the 82 patients with negative anti-TPO at baseline, 16 had significant interval increase in anti-TPO titer by >12 units (2×6 [precision of the anti-TPO assay in normal range being 6 units per SD]), of these, four became anti-TPO positive. Factors associated a significant increase in anti-TPO titer included worse baseline clinical severity (p=0.018), elevated C-reactive protein during hospitalization (p=0.033), and higher baseline anti-TPO titer (p=0.005). Conclusion: Majority of thyroid dysfunction on admission recovered during convalescence. Abnormal TFTs suggestive of thyroiditis could occur during convalescence, though uncommon. Importantly, we provided the novel observation of an increase in anti-thyroid antibody titers post-COVID-19, suggesting the potential of SARS-CoV-2 in triggering thyroid autoimmunity, which warrants further follow-up for incident thyroid dysfunction among COVID-19 survivors.

Impact of thyroid cancer treatment on assisted reproductive technology outcomes in women with infertility

Purpose We investigated the effect of different surgical procedures and radioactive iodine treatment (RAIT) on in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes and evaluated whether possible risk factors, including age, thyroid-stimulating hormone (TSH) levels, and thyroid antibody positivity, were associated with adverse IVF/ICSI outcomes. Methods This retrospective study included 76 women with infertility who had received thyroid cancer (TC) treatment among 137,698 infertile women who underwent IVF/ICSI cycles at the Peking University Third Hospital between 2010 and 2019. Clinical pregnancy and live birth rates were assessed. Results We found that the clinical pregnancy and live birth rates in women who underwent partial thyroidectomy were 7- and 6-fold higher, respectively, than those in women who underwent total thyroidectomy. We observed no significant differences in the clinical pregnancy and live birth rates between the RAIT and non-RAIT groups, even after adjusting for age, TSH levels, surgical treatment, and thyroid antibody positivity. Multivariate logistic regression analysis showed that age and TSH levels were not associated with decreased clinical pregnancy and live birth rates. Women with thyroid antibody positivity had significantly lower clinical pregnancy and live birth rates than women without thyroid antibody positivity. Conclusion Our study showed lower clinical pregnancy and live birth rates in women who underwent total thyroidectomy than in women who underwent partial thyroidectomy. Thyroid antibody positivity is an important risk factor for adverse IVF/ICSI outcomes in women who have received TC treatment.

Association between albuminuria and thyroid function in patients with chronic kidney disease

Purpose The relationship between proteinuria and thyroid function remains controversial in patients with chronic kidney disease (CKD). We prospectively investigated the association between kidney and thyroid function in thyroid antibody-negative patients through all CKD stages. Methods We enrolled 184 nondialysis patients (mean age: 63.1 ± 16.9 years) without previous thyroid disease or thyroid-specific antibodies. Kidney function was assessed by estimating the glomerular filtration rate (eGFR) classified according KDIGO (CKD G1–5). Kidney damage was assessed by albuminuria (albumin-to-creatinine ratio, ACR) and classified as mild, moderate, or severe (ACR1: <300, ACR2: 300–3000, and ACR3: 3000 mg/g). To evaluate thyroid function, TSH, T4, fT4, T3, fT3, reverse T3 (rT3), and thyroxine-binding globulin (TBG) were measured. Results rT3 concentrations correlated negatively with albuminuria (r = −0.286, p < 0.001) and were significantly lower in patients with severe albuminuria than in those with mild or moderate albuminuria (ACR3: 0.28 vs. ACR2: 0.32 vs. ACR1: 0.36 nmol/l, p < 0.001). The severity of albuminuria revealed no impact on TSH, fT4, T3, fT3, and TBG. EGFR correlated with increasing T4, fT4, T3, fT3, and TBG (T4: r = 0.289, p < 0.01; fT4: r = 0.196, p < 0.01; T3: r = 0.408, p < 0.01; fT3: r = 0.390, p < 0.01) but not with rT3. Conclusions In thyroid antibody-negative patients presenting advanced CKD (stages 4 and 5), even severe kidney protein loss failed to influence thyroid hormone status. However, albuminuria severity correlated negatively with rT3, which was significantly lower in patients with albuminuria in the nephrotic range.

Adequate Animal Protein Intake Maintains Normal Thyroid Antibody Levels in Pregnant Women With Mild Iodine Deficiency

Background: Both of the iodine and animal protein may affect thyroid function. We explored the association between animal protein intake and thyroid antibody status in pregnant women after universal salt iodization.Method: Pregnant women were enrolled by using a multistage, stratified random sampling method. 4,646 eligible participants were interviewed in person with questionnaires physical examination and thyroid antibody test. Results: Only thyrotropin receptor antibodies (TR-Ab) positive rates were different among different animal protein intake groups. The median of urinary iodine concentration (UIC) in thyroid peroxidase antibodies (TPO-Ab) positive groups was higher than the negative group. The median of total protein intake, animal protein intake and UIC in TR-Ab positive group was higher than the negative group. The medians of total protein intake and UIC in TPO-Ab/TG-Ab/TR-Ab positive group were higher than the negative group. The above differences were statistically significant (P < 0.05). The multivariable logistic regression results showed that insufficient iodine had a negative correlation with TPO-Ab positive and TR-Ab positive (P < 0.05). The middle third and top third animal protein intakes served as protective factors for TR-Ab (coefficient = 0.559, 95% CI = 0.415–0.752; coefficient = 0.0.406, 95% CI = 0.266–0.621) and positive TPO-Ab/TR-Ab/TG-Ab (coefficient = 0.817, 95% CI = 0.687–0.971; coefficient = 0.805, 95% CI= 0.672–0.964). Conclusions: Adequate animal protein intake protects against elevated anti-thyroid antibody levels in pregnant women with mild iodine deficiency.

Brain dysfunction and thyroid antibodies: autoimmune diagnosis and misdiagnosis

Hashimoto encephalopathy, also known as steroid-responsive encephalopathy associated with autoimmune thyroiditis, has been defined by subacute onset encephalopathy, with elevated thyroid antibodies, and immunotherapy responsiveness, in the absence of specific neural autoantibodies. We aimed to retrospectively review cases referred with suspected Hashimoto encephalopathy over a 13 year period, and to determine the clinical utility of thyroid antibodies in the course of evaluation of those patients. One hundred and forty-four patients (all thyroid antibody positive) were included; 72% were women. Median age of symptom onset was 44.5 years (range, 10-87). After Mayo Clinic evaluation, 39 patients (27%) were diagnosed with an autoimmune CNS disorder (autoimmune encephalopathy [36], dementia [2] or epilepsy [1]). Three of those 39 patients had neural-IgGs detected (high glutamic acid decarboxylase-65, AMPA-receptor and neural-restricted unclassified antibody), and 36 were seronegative. Diagnoses among the remaining 105 patients (73%) were functional neurological disorder (n = 20), neurodegenerative disorder (n = 18), subjective cognitive complaints (n = 14), chronic pain syndrome (n = 12), primary psychiatric (n = 11), sleep disorder (n = 10), genetic/developmental (n = 8), non-autoimmune seizure disorders (n = 2), and other (n = 10). More patients with autoimmune CNS disorders presented with subacute symptom onset (p &lt; 0.001), seizures (p = 0.008), stroke-like episodes (p = 0.007), aphasia (p = 0.04) and ataxia (p = 0.02), and had a prior autoimmune history (p = 0.04). Abnormal brain MRI (p = 0.003), abnormal EEG (p = 0.007), CSF inflammatory findings (p = 0.002) were also more frequent in the autoimmune CNS patients. Patients with an alternative diagnosis had more depressive symptoms (p = 0.008), anxiety (p = 0.003), and chronic pain (p = 0.002). Thyoperoxidase antibody titer was not different between the groups (median 312.7 vs 259.4 IU/mL, p = 0.44, normal range &lt;9 IU/mL). None of the non-autoimmune group and all but three of the CNS autoimmune group (two with insidious dementia presentation, one with seizures only) fulfilled the autoimmune encephalopathy criteria proposed by Graus et al (sensitivity 92%, specificity 100%). Among patients who received an immunotherapy trial at our institution and had objective post-treatment evaluations, the 16 responders with autoimmune CNS disorders more frequently had inflammatory CSF, compared to 12 non-responders, all eventually given an alternative diagnosis (p = 0.02). Seventy-three percent of patients referred with suspected Hashimoto encephalopathy had an alternative non-immune mediated diagnosis, and more than half had no evidence of a primary neurological disorder. Thyroid antibody prevalence is high in the general population, and does not support a diagnosis of autoimmune encephalopathy in the absence of objective neurological and CNS-specific immunological abnormalities. Thyroid antibody testing is of little value in the contemporary evaluation and diagnosis of autoimmune encephalopathies.