Insights into Current Management Strategies for Dysthyroid Optic Neuropathy: A Review

White Matter Alterations of Visual Pathway in Thyroid Eye Disease: A Fixel-Based Analysis

BACKGROUND

Thyroid eye disease (TED), particularly its sight-threatening complication, dysthyroid optic neuropathy (DON), profoundly impacts patients' visual health. The pathological changes in the white matter (WM) fibers within the intracranial visual pathway in TED have been infrequently studied. Understanding these changes holds crucial importance for exploring the pathogenesis and prognosis of TED.

PURPOSE

To utilize fixel-based analysis (FBA) to clarify the type of microstructural damage occurring in the visual pathway in TED.

STUDY TYPE

Prospective.

SUBJECTS

28 TED with DON patients (11 males and 17 females), 28 TED without DON (non-DON) patients (12 males and 16 females), and 28 healthy controls (HCs) (12 males and 16 females).

FIELD STRENGTH/SEQUENCE

3 T; multishell diffusion MRI using echo planar imaging.

ASSESSMENT

Fiber density (FD) and fiber-bundle cross-section (FC) were calculated to characterize WM microstructural alteration in TED visual pathway. The correlations between FBA metrics and visual field index and mean deviation were examined.

STATISTICAL TESTS

One-way analysis of variance, Kruskal-Wallis, t-tests, Mann-Whitney U, Chi-square, and Pearson correlation, were conducted with false discovery rate and family wise error corrections. Significance was set at P < 0.05.

RESULTS

Both DON and non-DON groups showed significant FD loss in the right optic tract compared with HCs, with DON patients experiencing more severe FD loss. Only DON patients had FD loss in the right optic radiation (OR) compared with the non-DON patients and HCs, with no FC difference across groups. FD in DON patients' ORs significantly correlated with visual field index (r = 0.857) and mean deviation (r = 0.751).

DATA CONCLUSION

Both DON and non-DON affect the WM microstructure of the visual pathway to varying extents. Visual field metrics can reflect the severity of FD damage to the OR in the visual pathway of DON patients.

EVIDENCE LEVEL

2.

TECHNICAL EFFICACY

Stage 3.

Dysthyroid Optic Neuropathy Dramatically Improved by Sheath-Guided Triamcinolone Orbital Injection: A Case Report

Thyroid eye disease is an autoimmune disorder caused by thyroid-stimulating hormone receptor autoantibodies stimulating the thyroid-stimulating hormone receptor, resulting in proptosis, extraocular muscle dysfunction, diplopia, retro-orbital pain, optic nerve compression, and visual impairment. Dysthyroid optic neuropathy (DON), believed to result from direct compression by enlarged extraocular muscles, represents a severe complication with the potential for irreversible vision loss. Currently, the treatment options for DON are limited to highly invasive procedures, such as orbital decompression surgery and systemic steroid pulse therapy. There are consequently significant challenges in the management of this condition. This report presents a case where a significant improvement in DON was achieved solely through the novel technique of sheath-guided orbital triamcinolone injection, which was utilized with the aim of reaching the deeper part of the orbit under sheath guidance. In this case, the best corrected visual acuity improved from 20/32 (decimal visual acuity: 0.7) to 20/20 (1.2) in the right eye and from 20/500 (0.04) to 20/20 (1.2) in the left eye. Critical flicker frequency values also improved, from 20.3 Hz to 35.0 Hz in the right eye and from 9.3 Hz to 31.5 Hz in the left eye. The cross-sectional areas of the extraocular muscles decreased by an average of 55.5%.

Balanced medial-lateral wall vs selective 3-wall orbital decompression for sight-threatening Graves's orbitopathy: a clinical retrospective cohort study from 2016 to 2022

PURPOSE

Although urgent orbital decompression surgery for sight-threatening Graves' orbitopathy unresponsive to available medical treatments continues to evolve, post-operative new-onset or worsened pre-operative strabismus or diplopia remains a significant complication. At present, the optimal surgical technique remains debatable. Here, we sought to compare long-term outcomes after balanced medial-lateral wall versus selective 3-wall decompression as an urgent treatment for unresponsive sight-threatening GO.

METHODS

This retrospective study examined the post-operative outcome of 102 eyes (57 patients) that underwent urgent orbital decompression for sight-threatening GO. Treatment effectiveness was measured by visual acuity, proptosis, perimetry, and strabismus/diplopia, while fundus findings were detected by fundus color photography and optical coherence tomography and followed up for more than 12 months.

RESULTS

Fifty-seven patients (102 orbits) with an average age of 52.7 ± 10.2 years were evaluated. Balanced medial-lateral wall (BMLW-OD) or selective 3-wall decompression(S3W-OD) were performed in 54 and 48 eyes, respectively. Twelve months after orbital decompression, all parameters significantly improved in both groups, including best-corrected visual acuity (BCVA), mean defect of visual field (VF-MD), pattern standard deviation of visual field (VF-PSD), and proptosis (all P < 0.01). However, new-onset esotropia occurred in 25.8% and 3.8% of patients who underwent BMLW-OD surgery or S3W-OD, respectively. Moreover, 6.5% and 38.5% of patients improved after decompression in the medial-lateral wall decompression group and the selective 3-wall decompression group, respectively.

CONCLUSIONS

We demonstrated that S3W-OD provides a lower rate of new-onset strabismus/diplopia as compared with BMLW-OD surgery, while still allowing for satisfactory visual outcomes.

TRIAL REGISTRATION NUMBER

 : NCT05627401. Date of registration: November 25, 2022.

Altered Static and Dynamic Brain Functional Topological Organization in Patients With Dysthyroid Optic Neuropathy

CONTEXT

Dysthyroid optic neuropathy (DON) is a serious vision-threatening complication of thyroid-associated ophthalmopathy (TAO). Exploration of the underlying mechanisms of DON is critical for its timely clinical diagnosis.

OBJECTIVE

We hypothesized that TAO patients with DON may have altered brain functional networks. We aimed to explore the alterations of static and dynamic functional connectomes in patients with and without DON using resting-state functional magnetic resonance imaging with the graph theory method.

METHODS

A cross-sectional study was conducted at a grade A tertiary hospital with 66 TAO patients (28 DON and 38 non-DON) and 30 healthy controls (HCs). Main outcome measures included topological properties of functional networks.

RESULTS

For static properties, DON patients exhibited lower global efficiency (Eg), local efficiency, normalized clustering coefficient, small-worldness (σ), and higher characteristic path length (Lp) than HCs. DON and non-DON patients both exhibited varying degrees of abnormalities in nodal properties. Meanwhile, compared with non-DON, DON patients exhibited abnormalities in nodal properties in the orbitofrontal cortex and visual network (VN). For dynamic properties, the DON group exhibited higher variance in Eg and Lp than non-DON and HC groups. A strengthened subnetwork with VN as the core was identified in the DON cohort. Significant correlations were found between network properties and clinical variables. For distinguishing DON, the combination of static and dynamic network properties exhibited optimal diagnostic performance.

CONCLUSION

Functional network alterations were observed both in DON and non-DON patients, providing novel insights into the underlying neural mechanisms of disease. Functional network properties may be potential biomarkers for reflecting the progression of TAO from non-DON to DON.

Efficiency and Safety of Tocilizumab for the Treatment of Thyroid Eye Disease: A Systematic Review

PURPOSE

To review existing literature concerning the effectiveness and safety of tocilizumab (TCZ) for managing thyroid eye disease.

METHODS

A systematic search was conducted across the PubMed and Embase databases to identify studies on TCZ therapy, from inception to May 2023. The search included the keywords "Graves orbitopathy," "thyroid ophthalmopathy," "thyroid eye disease," "thyroid-associated orbitopathy," "thyroid-associated ophthalmopathy," "Graves ophthalmopathy," "endocrine ophthalmopathy," and "Tocilizumab." Only articles written in English, Spanish, or French were considered.

RESULTS

Among the 1,013 articles initially screened, a total of 29 fulfilled the eligibility criteria and were selected. Most studies were case reports or case series, and only one randomized clinical trial was found. TCZ has been used mainly in glucocorticoid-resistant or relapsing cases, with a dosage ranging from 4 or 8 mg/kg every 4 weeks when intravenous or a weekly subcutaneous dose of 162 mg. Treatment duration is usually adjusted to the clinical response. TCZ is mostly effective in reducing inflammatory signs during the active phase of thyroid eye disease, with an improvement of at least 3 points in clinical activity score and an overall relapsing rate of 8.2%. Numerous studies have shown marked reductions in proptosis; although the only available randomized controlled trial reported a nonstatistically significant improvement 6 months after treatment, a recent meta-analysis indicated that TCZ seems to be the most effective treatment for reducing proptosis. No severe side effects related to intravenous or subcutaneous TCZ administration were reported.

DISCUSSION

Despite these promising findings, randomized clinical trials to directly compare the efficacy and safety of TCZ and other currently available therapeutic options are needed.

Optic nerve compression associated with visual cortex functional alteration in dysthyroid optic neuropathy: A combined orbital and brain imaging study

AIMS

To investigate the alterations of the optic nerve and visual cortex in dysthyroid optic neuropathy (DON), a subgroup of thyroid eye disease (TED).

METHODS

Multiple orbital imaging biomarkers related to optic nerve compression and the amplitude of low-frequency fluctuations (ALFF) of the brain were obtained from 47 patients with DON, 56 TED patients without DON (nDON), and 37 healthy controls (HC). Correlation analyses and diagnostic tests were implemented.

RESULTS

Compared with HC, the nDON group showed alterations in orbital imaging biomarkers related to optic nerve compression in posterior segments, as well as ALFF of the right inferior temporal gyrus and left fusiform gyrus. DON differed from nDON group mainly in the modified muscle index of the posterior segment of optic nerve, and ALFF of orbital part of right superior frontal gyrus, right hippocampus, and right superior temporal gyrus. Orbital and brain imaging biomarkers were significantly correlated with each other. Diagnostic models attained an area under a curve of 0.80 for the detection of DON.

CONCLUSION

The combined orbital and brain imaging study revealed alterations of the visual pathway in patients with TED and DON as well as provided diagnostic value. The initiation of alterations in the visual cortex in TED may precede the onset of DON.

Three-dimensional soft tissue reconstruction and volume measurement used for the diagnosis of dysthyroid optic neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) leads to vision loss. This study aimed to investigate a new method that can directly evaluate the change in muscle cone inner volume (MCIV) and distinguish DON orbits from non-DONs.

MATERIALS AND METHODS

This study included 54 patients (108 orbits) who were diagnosed with thyroid eye disease and treated at the Beijing Tongren Hospital between December 2019 and September 2021. The extraocular muscle volume (EOMV), orbital fat volume (OFV), and bony orbit volume (BOV) of the patients were measured using three-dimensional reconstruction. MCIV was measured using artificially defined boundaries. The associations between these volumes and clinical indicators were studied, and the diagnostic efficacy of these volumes for DON was described using receiver operating characteristic (ROC) curves.

RESULTS

The ROC curve showed that the area under the curve of MCIV/BOV (%) combined with EOMV/BOV (%) reached 0.862 (p < 0.001), with a sensitivity of 85.7% and a specificity of 76.1%.

CONCLUSION

The combination of MCIV/BOV (%) and EOMV/BOV (%) is a good indicator for the diagnosis of DON, which aids in the early detection and intervention of DON.

Extraocular muscle volume index at the orbital apex with optic neuritis: a combined parameter for diagnosis of dysthyroid optic neuropathy

OBJECTIVES

To evaluate the diagnostic performance of the extraocular muscle volume index at the orbital apex (AMI) and the signal intensity ratio (SIR) of the optic nerve in dysthyroid optic neuropathy (DON).

METHODS

Clinical data and magnetic resonance imaging were collected retrospectively from 63 Graves' ophthalmopathy patients, including 24 patients with DON and 39 without DON. The volume of these structures was obtained by reconstructing their orbital fat and extraocular muscles. The SIR of the optic nerve and axial length of eyeball were also measured. The posterior 3/5 of the retrobulbar space volume was used as the orbital apex to compare parameters in patients with or without DON. Area under the receiver operating characteristic curve (AUC) analysis was used to select the morphological and inflammatory parameters with the highest diagnostic value. A logistic regression was performed to identify the risk factors of DON.

RESULTS

One hundred twenty-six orbits (35 with DON and 91 without DON) were analyzed. Most of the parameters in DON patients were significantly higher than in non-DON patients. However, the SIR 3 mm behind the eyeball of the optic nerve and AMI had the highest diagnostic value in these parameters and are independent risk factors of DON by stepwise multivariate logistic regression analysis. Combining AMI and SIR had a higher diagnostic value than a single index.

CONCLUSIONS

Combining AMI with SIR 3 mm behind the eyeball's orbital nerve can be a potential parameter for diagnosing DON.

CLINICAL RELEVANCE STATEMENT

The present study provided a quantitative index based on morphological and signal changes to assess the DON, allowing clinicians and radiologists to monitor DON patients timely.

KEY POINTS

The extraocular muscle volume index at the orbital apex (AMI) has excellent diagnostic performance for dysthyroid optic neuropathy. A signal intensity ratio (SIR) of 3 mm behind the eyeball has a higher AUC compared to other slices. Combining AMI and SIR has a higher diagnostic value than a single index.

Aberrant spontaneous brain activity in patients with thyroid-associated ophthalmopathy with and without optic neuropathy: a resting-state functional MRI study

OBJECTIVES

To investigate the brain functional alterations in dysthyroid optic neuropathy (DON) by evaluating spontaneous neural activity, using functional magnetic resonance imaging (fMRI) with regional homogeneity (ReHo), and its relationship with ophthalmologic performance.

METHODS

Forty-seven patients with thyroid-associated ophthalmopathy (TAO; 20 with DON, 27 with non-DON) and 33 age-, sex-, and education-matched healthy controls (HCs) underwent fMRI. ReHo values were compared using one-way analysis of variance (ANOVA) with post hoc pairwise comparisons (voxel-level p < 0.01, Gaussian random field correction, cluster-level p < 0.05). Correlations between ReHo values and ophthalmological metrics were assessed for DONs, with Bonferroni correction for multiple comparisons (p < 0.004). ROC curves were applied to evaluate the diagnostic performance of ReHo metrics.

RESULTS

ReHo values were significantly lower in the left insula and right superior temporal gyrus, and higher in the left posterior cingulate cortex (LPCC), of DON than of non-DON patients. ReHo values were also significantly lower in the right middle temporal, left insula, and left precentral gyrus in DON than in HCs. Meanwhile, ReHo values were higher in LPCC in non-DON than in HCs. ReHo values correlated with ophthalmic examinations to varying degrees in DON. For distinguishing DON, the ReHo values in LPCC showed optimal individually (AUC = 0.843), the combination of the ReHo in both the left insula and LPCC performed better (AUC = 0.915).

CONCLUSION

Spontaneous brain activity differed between TAO with and without DON, which may reflect the underlying pathological mechanism of DON. The ReHo index can be considered a diagnostic biomarker.

CLINICAL RELEVANCE STATEMENT

Spontaneous brain activity in DON differed from that in TAO without DON, which may reflect the underlying pathological mechanism of DON. The ReHo index can be considered a diagnostic biomarker for early detection of DON.

KEY POINTS

• Dysthyroid optic neuropathy (DON) affects brain activity, which contributes in the understanding of its visual dysfunction. • Regional homogeneity values differ between thyroid-associated ophthalmopathy with and without DON in various brain regions. • Regional homogeneity values can be used as a biomarker in the differential diagnosis of DON.

A diagnostic model based on color vision examination for dysthyroid optic neuropathy using Hardy-Rand-Rittler color plates

PURPOSE

To investigate color vision deficiency and the value of Hardy-Rand-Rittler (HRR) color plates in monitoring dysthyroid optic neuropathy (DON) to improve the diagnosis of DON.

METHODS

The participants were divided into DON and non-DON (mild and moderate-to-severe) groups. All the subjects underwent HRR color examination and comprehensive ophthalmic examinations. The random forest and decision tree models based on the HRR score were constructed by R software. The ROC curve and accuracy of different models in diagnosing DON were calculated and compared.

RESULTS

Thirty DON patients (57 eyes) and sixty non-DON patients (120 eyes) were enrolled. The HRR score was lower in DON patients than in non-DON patients (12.1 ± 6.2 versus 18.7 ± 1.8, p < 0.001). The major color deficiency was red-green deficiency in DON using HRR test. The HRR score, CAS, RNFL, and AP100 were found to be important factors in predicting DON from random forest and selected by decision tree to construct the multifactor model. The sensitivity, specificity, and the area under the curve (AUC) of the HRR score were 86%, 72%, and 0.87, respectively. The HRR score decision tree had a sensitivity, specificity, and AUC of 93%, 57%, and 0.75, respectively, with an accuracy of 82%. The data of the multifactor decision tree were 90%, 89%, and 0.93 for sensitivity, specificity, and AUC, respectively, with an accuracy of 91%.

CONCLUSION

The HRR test was valid as screening method for DON. The multifactor decision tree based on the HRR test improved the diagnostic efficacy for DON. An HRR score of less than 12 and red-green deficiency may be characteristic of DON.

Combined endonasal and orbital approach for annulus of Zinn area decompression in dysthyroid optic neuropathy

BACKGROUND

Dysthyroid optic neuropathy (DON) is a serious complication of thyroid-associated ophthalmopathy (TAO) that can cause permanent vision loss from orbital apex syndrome. Urgent management of high-dose corticosteroid pulse therapy is recommended, and salvage orbital apex decompression surgery may require in refractory patients ineffective with corticosteroid pulse therapy.

PURPOSE

To evaluate the short-term efficacy and safety of combined endoscopic endonasal and orbital approach decompression in the annulus of the Zinn (AZ) area in refractory dysthyroid optic neuropathy (DON).

METHODS

In this retrospective study, patients who underwent combined endoscopic endonasal and orbital approach decompression around the AZ area for the treatment of refractory DON from May 2021 to March 2022 were enrolled. A total of 15 orbital apex were decompressed across 9 patients. The demographic, imaging, and surgical data, as well as preoperative and postoperative best corrected visual acuity (BCVA), proptosis degree and Modified-Chinese-TAO-QOL scores, were collected and assessed. The t-test was used to identify differences between preoperative and postoperative parameters: visual acuity, proptosis and QOL scores.

RESULTS

The mean best corrected visual acuity (BCVA) improved from 0.79 ± 0.77 LogMAR preoperatively to 0.21 ± 0.27 LogMAR (P < 0.001) postoperatively. Additionally, proptosis decreased from 22.25 ± 2.01 mm to 18.42 ± 1.85 mm (P < 0.01), with an average decrease of 3.7 mm. The preoperative scores of the visual, psychological, and comprehensive components of QoL were 14.60 ± 9.08, 37.49 ± 6.26 and 26.75 ± 3.70, respectively, which significantly improved postoperatively to 54.18 ± 7.23, 68.78 ± 12.53 and 61.88 ± 9.37, respectively. The postoperative follow-up time ranged from 2 to 11 months, and the median follow-up time was 7 months. There was 1 case of transient postoperative sinusitis and 1 new case of transient diplopia, which was relieved after 3 months.

CONCLUSION

Combined endoscopic endonasal and orbital approach adequate decompression for AZ area significantly improves visual acuity and QOL in patients with DON.

Residual Apical Lamina Papyracea as a Cause for Persistent Dysthyroid Optic Neuropathy After Orbital Decompression

Two patients had persistent compressive dysthyroid optic neuropathy after decompression of the medial orbital wall and floor. In both cases, there was ~3 mm of unresected lamina papyracea anterior to the Annulus of Zinn, and removal of this residual bone led to resolution of the neuropathy. These illustrative cases suggest that, in some patients, even small amounts of residual crowding at the orbital apex can critically embarrass optic nerve perfusion, with resulting continued ischemic optic neuropathy.

A 46-Year-Old Woman with a 4-Year History of Graves Disease, with Severe Corticosteroid-Unresponsive Thyroid Eye Disease, Successfully Treated with Tocilizumab

BACKGROUND Tocilizumab is a therapeutic biologic antagonist of the interleukin-6 (IL-6) receptor that has been approved to treat some autoimmune and chronic inflammatory diseases. This report is of a patient with a history of Graves disease and severe corticosteroid-unresponsive thyroid eye disease that included edema of the optic nerve and choroid, which was successfully treated with tocilizumab. CASE REPORT A 46-year-old woman with a 4-year history of Graves disease presented with acutely progressive bilateral severe optic nerve compression, severe bilateral optic nerve edema, bilateral restriction of eye movement, and bilateral choroidal folds. The patient was managed with an initial high dose of systemic steroid without any success. She then underwent bilateral orbital wall decompression without any noticeable amelioration. She subsequently received 4 doses of a tocilizumab (8 mg/kg) infusion. This resulted in a considerable decrease in inflammatory signs and improvement in optic nerve function, thereby improving her quality of life. The patient did not have any adverse reactions to the tocilizumab. CONCLUSIONS The findings from this case support recent case reports and clinical trials indicating that tocilizumab may be effective in corticosteroid-resistant thyroid eye disease associated with autoimmune hyperthyroidism.

The relationship between atherosclerotic disease and relapse during ATD treatment

Background

Clinical relapse is a potential risk for traditional antithyroid drug (ATD) treatment in hyperthyroid patients. Evidence suggests that atherosclerotic disease is closely associated with hyperthyroidism, while the relationship between atherosclerosis and relapse remains unclear.

Methods

Two hundred and twenty-five patients with GD who underwent ATD as their first treatment were studied; 88 and 137 patients were categorized as drug reduction relapse and drug reduction remission, respectively. Logistic regression was used to analyze risk factors of drug reduction relapse in patients with GD.

Results

During a median of 48 months followed up 88 patients who relapsed. According to multivariate analyses, atherosclerosis related diseases, FT4, goiter, and anxiety rating scores are independent risk factors for drug reduction. According to K-M survival analysis, patients with atherosclerosis related diseases, FT4 &gt; 18.82 pmol/L, anxiety rating scores &gt; 23, and gradation of goiter ≥ Grade II had a higher risk of relapse than those with lower levels. ROC analysis shown atherosclerosis related diseases significantly improved the predictive accuracy of relapse.

Conclusions

Atherosclerotic disease is closely related to the relapse of hyperthyroidism, ATD treatment in hyperthyroid patients with atherosclerosis should be given more attention.