Thyroid-associated eye disease: clinical management

Evaluation of macular blood flow after intermittent intravenous infusion of high-dose corticosteroids (pulse therapy) in patients with thyroid-associated orbitopathy (TAO) using angio-OCT

PURPOSE

The aim of this study is to evaluate the changes in macular blood flow index (BFI) in patients with moderate to severe thyroid-associated orbitopathy (TAO) before and after pulse therapy and their relationship with clinical features and disease activity using angio-OCT technology.

METHODS

We analyzed twenty-four eyes. Every patient underwent a complete eye examination and angio-OCT analysis (OCT Topcon ImageNet 6; DRI OCT Triton, Topcon Corporation) before (T0) and two months (T2) after pulse therapy. We analyzed macular vascular blood flow in four angiographic levels: superficial plexus (SP), deep plexus (DP), external retina (ER), and choriocapillaris (CC). We used the clinical activity score (CAS) score to define TAO as moderate or severe.

RESULTS

Macular BFI significantly increased at T2 in the DP, ER, and CC (p < 0.01). CAS score (5.8 ± 0.8 vs. 3.9 ± 0.9, p < 0.01) and Hertel exophthalmometry values (22.6 ± 2.3 mm vs. 21.2 ± 2,5 mm, p < 0.01) improved for all patients at T2 compared T0. Mean IOP increased from 13.3 ± 2.8 mmHg to 14.3 ± 2.1 mmHg (p < 0.01). No correlation was found between CAS score and macular BFI in all the analyzed levels.

CONCLUSIONS

Pulse therapy treatment can change macular BFI. In particular, two months alter pulse therapy, all the patients show an increase in macular vascular blood flow in each angiographic level. According to our results, angio-OCT analysis of the macular BFI may be a useful tool in the follow-up of TAO patients after pulse therapy.

Change in proptosis following extraocular muscle surgery: effects of muscle recession in thyroid-associated orbitopathy

PURPOSE

To evaluate the effect of strabismus surgery on proptosis in patients with thyroid-associated orbitopathy.

METHODS

The medical records of 22 consecutive patients with thyroid-associated orbitopathy undergoing strabismus surgery were reviewed. Data pertaining to the number of muscles operated on, amount of muscle recession, prior orbital decompression, and exophthalmometry were evaluated.

RESULTS

Thirty-eight eyes in 22 patients with thyroid-associated orbitopathy were studied before and after strabismus surgery. The mean change in exophthalmometry following strabismus surgery in all eyes was +0.6 mm (p < 0.01). Eyes with prior decompression averaged a 0.9 mm increase following strabismus surgery (p < 0.01); those without decompression averaged a 0.2 mm decrease (p = 0.658). In eyes that underwent two rectus muscle recessions the increase in Hertel measurements averaged 1.2 mm; when only one muscle was recessed, the average increase was 0.2 mm. In the eyes with muscle recession < or =5 mm, the mean exophthalmometric increase was 0.7 mm. When a muscle recession of more than 5 mm was performed, the exophthalmometry showed a mean increase of 0.5 mm.

CONCLUSIONS

Strabismus surgery on patients with thyroid-associated orbitopathy can worsen proptosis, especially in those with prior decompression. When planning for orbital decompression, the surgeon should consider this effect. Moreover, patients should be made aware of the possible changes to their appearance.

Muscle surgery in patients with Graves' disease using topical anesthesia

PURPOSE

To report our experience in extraocular muscle surgery for Graves' disease using topical anesthesia.

DESIGN

Retrospective, noncomparative, observational case series.

PARTICIPANTS

In 135 patients with Graves' disease, a total of 200 ocular muscles were operated during the past 20 years at the Department of Ophthalmology, Ludwig-Maximilian-University, Munich, Germany.

METHODS

Surgery was performed under topical anesthesia with tetracaine hydrochloride 1% eyedrops. Because of the restrictive nature of the motility impairment, recession of the muscles was used in all patients. The exact amount of recession was determined during the operation with active cooperation from the patient.

MAIN OUTCOME MEASURES

Binocular single vision and the angle of deviation were evaluated preoperatively and postoperatively.

RESULTS

Postoperative binocular single vision in the primary position was achieved by 78.7% of the patients on the first postoperative day. Subsequent evaluation demonstrated binocular single vision in 91.9% of all patients and in 96.4% of the group with only 1 muscle (inferior rectus) operated.

CONCLUSIONS

The authors have demonstrated that topical anesthesia is a feasible and reliable method for performing extraocular muscle surgery in patients with Graves' disease. Intraoperative patient discomfort seemed insignificant, and the active cooperation of the patient in finding the appropriate extent of surgery was advantageous. The overall results showed that deviation surgery with the use of topical anesthesia is highly successful in restoring binocular single vision in patients with endocrine orbitopathy.

Retrobulbar irradiation for thyroid-associated orbitopathy: double-blind comparison between 2.4 and 16 Gy

PURPOSE

Retrobulbar irradiation is used as a standard therapy for thyroid-associated orbitopathy. The evidence of its effectiveness is, however, scarce. Doses from 2.5 to 20 Gy have been recommended.

METHODS

Forty-three patients with active thyroid-associated orbitopathy were irradiated with 2.4 Gy and 43 with 16 Gy. Five measures of outcome were used: (1) appearance of the eye region, documented with photographs; (2) Hertel exophthalmometry; (3) range of vertical eye movements; (4) eye muscle thickness (sum of three MRI sections across the eight rectus eye muscles); and (5) complaints, indicated on a visual analog scale.

RESULTS

At 3 and 6 months after irradiation, no difference between 2.4 and 16 Gy was found in any of the five outcome measures (p between 0.099 and 0.993; Kruskal-Wallis test, Holm correction). Most outcome measures were slightly, but not significantly, improved in both the 2.4 and the 16 Gy groups. Patient complaints had improved significantly in both groups and the eye muscle thickness was significantly reduced in the 2.4 Gy group after 6 months.

CONCLUSION

The lack of a difference between 2.4 and 16 Gy is compatible with four different interpretations: (1) the irradiation could be ineffective; (2) the maximal effect could be already reached at 2.4 Gy; (3) the maximal effect could lie between 2.4 and 16 Gy; and (4) the effect could increase beyond a threshold of >or=16 Gy. From general experience with inflammatory disease, the last two possibilities are unlikely; only the first two interpretations carry some probability. Although the design of the study did not allow a distinction between these two possibilities, we conclude that retrobulbar irradiation for thyroid-associated orbitopathy should not exceed 2.4 Gy.

Surgical treatment of endocrine exophthalmos by removal of orbital fat: clinical experience

PURPOSE

To report a series of 73 patients with endocrine exophthalmos treated by removal of orbital fat using the transpalpebral approach during the period 1989 to 1999.

METHODS

The operation was performed according to the technique described by Olivari. Aesthetic analysis was done preoperatively and postoperatively (more than 6 months after surgery). The number of complications was also observed.

RESULTS

The average volume of resected fat was approximately 7.6 mL per orbit. No major complication was observed. In 9 patients with epiphora, all improved. One patient developed postoperative diplopia and 5 complained of temporary diplopia. Appearance improved in 62 patients (85%).

CONCLUSION

Surgical removal of orbital fat associated with endocrine exophthalmos provides consistent improvement in appearance with a low rate of complications. Additional procedures may be indicated to improve the cosmetic outcome.

Controversies in the clinical evaluation of active thyroid-associated orbitopathy: use of a detailed protocol with comparative photographs for objective assessment

Despite many learned publications over recent decades, the assessment of active thyroid-associated orbitopathy (TAO) remains difficult and controversial. There are no biochemical, immunological or imaging investigations which can identify active disease reliably, and clinical assessment is still of paramount importance. We therefore review the strengths and weaknesses of all methods of clinical assessment. A new atlas for clinical assessment of soft tissue signs has been developed, and its reproducibility assessed. It details a suggested protocol that could help standardize descriptions of TAO and allow more objective assessment of its activity and severity. This is relevant to general endocrinologists, who have a crucial role in the identification of patients who require ophthalmological assessment. Certain aspects are more relevant to ophthalmologists and endocrinologists who have a special clinical and research interest in TAO. Unless a reproducible system of assessment is devised and widely adopted, it will remain difficult to interpret research meaningfully, particularly if results appear to contradict.

Thyroid-associated orbitopathy developed during hormone replacement therapy

Thyroid-associated orbitopathy (TAO) developed in relation to estrogen combined with progesterone therapy has not been reported previously. We report a case of a 56-year-old postmenopausal woman who during estrogen/progesterone treatment developed signs and symptoms of orbitopathy. The patient had no previous history of autoimmune- or thyroid disorders. The initial eye symptoms disappeared after withdrawal of hormone replacement therapy. Five years later estrogen/progesterone treatment was re-instituted. The patient had relapse of orbitopathy. The hormones were discontinued and the eye symptoms disappeared again. This suggests that estrogen and/or progesterone could be of some pathogenetic importance in the induction of orbitopathy

T cells and fibroblasts in affected extraocular muscles in early and late thyroid associated ophthalmopathy

AIM

To determine whether there are differences in the lymphocytic cell infiltrate present in affected extraocular muscles (EOM) during early and late stages of thyroid associated ophthalmopathy (TAO).

METHODS

17 biopsies of affected EOMs were collected from two groups of TAO patients (n=14): the first of five patients with early, active TAO, and the second of nine patients with late, inactive TAO. The control group was of EOM biopsies taken from 14 non-TAO patients undergoing squint surgery. Immunohistochemical analysis was undertaken using the relevant monoclonal antibodies and an avidin-biotin system and the three groups compared.

RESULTS

Both CD4+ and CD8+ T cells were found in the cellular infiltrate in early, active TAO specimens which were much less evident either in late, inactive stage disease or in control tissue. There was also a significant increase in both CD45RO+ and CD45RB+ cells and macrophages in early TAO compared with the others. Increased expression of HLA-DR antigen by interstitial cells including fibroblasts was detected in both early and late disease but the EOM fibres remained morphologically intact and did not express MHC class II antigens at any time.

CONCLUSION

These results demonstrate that T cells are only significantly present in early disease but increased HLA-DR antigen expression on fibroblasts is observed at all stages. This suggests that T cells are much more involved in the early than the later stages of the disease process and that early activation of fibroblasts occurs. Early intervention with immunosuppressive therapy to downregulate cytokine production by T cells may significantly influence the sequelae caused by EOM fibrosis.

Antioxidant agents in the treatment of Graves' ophthalmopathy

PURPOSE

To report the effect of antioxidant agents in the treatment of mild and moderately severe Graves' ophthalmopathy.

METHODS

Prospective, nonrandomized, comparative study performed at a referral center. A series of 11 patients with mild or moderately severe, active, newly diagnosed Graves' ophthalmopathy were included in the study. Allopurinol (300 mg daily) orally and nicotinamide (300 mg daily) orally were used for 3 months. A complete ophthalmologic examination was performed before and 1 and 3 months after initiation of treatment. The response to treatment was estimated separately for each component of the disease and overall by its effect on a total eye score. Eleven patients with mild or moderately severe, active, newly diagnosed Graves' ophthalmopathy who received placebo were also examined at the same time points. Patients in each group were recruited consecutively. Although nonsmoking was not an exclusion criterion, all patients were cigarette smokers.

RESULTS

Nine (82%) of 11 patients treated with oral antioxidants showed improvement of mild to moderately severe Graves' ophthalmopathy versus three (27%) of 11 patients in the control group (P <.05). Soft tissue inflammation was the component of the disease that responded more to treatment. No side effects of antioxidant treatment were recorded. Patients' satisfaction was high.

CONCLUSIONS

This pilot study presents encouraging results in the treatment of mild and moderately severe Graves' ophthalmopathy with antioxidant agents. To evaluate these preliminary results, randomized prospec-tive studies are needed.

An ultrastructural and systemic analysis of glycosaminoglycans in thyroid-associated ophthalmopathy

PURPOSE

To determine the ultrastructural localisation of glycosaminoglycans (GAGs) in the extraocular muscles (EOMs) of patients with thyroid-associated ophthalmopathy (TAO) and to see whether the quantity and type of GAGs present in blood and urine are markers of the disease.

METHODS

Biopsies of affected EOMs were taken and studied by transmission electron microscopy (TEM). These were either fixed conventional for TEM, or in 0.5% tannic acid and others for immunogold staining. Serum hyaluronan (HA) was measured using a radioimmunoassay in patients with TAO as well as control subjects, and urinary GAG levels assessed by photometric quantitation of hexuronic acid after reaction with carbazole. The excretion pattern of the urinary GAGs was determined by discontinuous electrophoresis.

RESULTS

TEM showed that there is a marked expansion of the endomysial space in TAO EOM biopsies as compared with non-TAO strabismus specimens. This is caused by an increased number of collagen fibres, interspersed with a granular amorphous material surrounding striated collagen fibres shown to be hyaluronan by immunogold staining. In contrast, serum hyaluronan concentrations were similar in TAO and control patients, although there was a statistically significant difference in the urinary GAG excretion between the two groups of patients examined. By discontinuous electrophoresis, chondroitin sulphate and heparan sulphate were present in both patients and controls.

CONCLUSION

GAGs and in particularly HA are present at the EOM level in patients with recently inactive TAO. However, serum levels of HA and urinary GAGs are not sensitive indicators for their presence within the EOMs.

Thyroid-associated ophthalmopathy: pathogenesis and clinical management

The pathogenesis of thyroid-associated ophthalmopathy is autoimmune. The questions to which answers are eagerly awaited are the identification of the autoantigen(s) and the definition of the autoimmune processes (cellular or humoral) responsible. Cellular and humoral immune responses and modulation by cytokines, against orbital tissues have been described. A link between the thyroid and the orbit seems inevitable, possibly in the form of a cross-reactive antigen, and top of the list of candidate antigens is the TSH receptor. Optimal treatment of TAO necessitates careful assessment. Thoughtful planning and timing and choice of intervention with conventional therapies, can lead to satisfactory results in the majority of cases. In addition to treating the severe complications, such as optic neuropathy, corneal exposure and muscle misalignment, corrective surgery to reconstruct the appearance of the patient's eyes should be made available.

Natural history of thyroid associated ophthalmopathy

BACKGROUND

The natural history of thyroid associated ophthalmopathy is poorly documented, although it is widely thought that many cases improve spontaneously with time. This has important implications in the management of patients and is also a critical factor when assessing the effects of different treatments.

OBJECTIVE

To document the natural history of thyroid associated ophthalmopathy, 59 patients were studied longitudinally and the severity of eye disease documented at regular intervals.

METHODS

Fifty-nine patients with thyroid associated ophthalmopathy who had not received immunosuppressive or surgical treatment for their eye disease, were recruited from a combined thyroid-eye clinic. They were assessed at presentation and at 3-6-monthly intervals for a median of 12 months. The eyes were assessed by separate and objective measurements relating to the status of the eyelids, cornea, extraocular muscles, proptosis and optic nerve function. In addition, a scoring system based on the above measurements was used to grade the overall severity of eye disease.

RESULTS

Thirteen patients (22%) improved substantially, 25 patients (42.4%) showed minor improvement, 13 patients (22%) did not change, and 8 patients (13.5%) deteriorated progressively, to the extent that immunosuppressive treatment was considered to be necessary.

CONCLUSIONS

A significant proportion of patients with thyroid associated ophthalmopathy (64.4% in the present series) improve spontaneously so serial assessment plays an important part in deciding which patients require immunosuppressive treatment. These findings also support the view that clinical trials designed to test the efficacy of new treatments in thyroid associated ophthalmopathy should be scrupulously controlled to allow for the natural tendency towards remission.

Extraocular muscle problems in thyroid eye disease

In this paper methods of visualisation of the extraocular muscle changes in thyroid eye disease are discussed. The histopathology of extraocular muscle biopsies has been studied by both light and electron microscopy to show the type of cellular infiltration and the amorphous material in the extracellular matrix. A series of questions to which answers have not yet been found concerning thyroid eye disease are posed which may help to direct new research projects. Finally, in the last part of the paper, the surgical results in a series of 41 patients having ocular muscle surgery for diplopia and/or compensatory head postures due to thyroid eye disease are described. The conclusions drawn from these results are that one should maintain the patient euthyroid, establish by orthoptic measurements that the ocular movements have been stable for at least 6 months, treat by recessing tight muscles using adjustable sutures, and aim to undercorrect the vertical deviation at the time of adjustment.

Retrobulbar T cells from patients with Graves' ophthalmopathy are CD8+ and specifically recognize autologous fibroblasts

Graves' ophthalmopathy is an autoimmune condition characterized by T cell infiltration of the retrobulbar tissue. Phenotypic and functional analysis of these infiltrating cells may provide insight into the pathogenesis of the disease. IL-2-responsive cells were therefore grown out of the retrobulbar tissue from two patients with severe Graves' ophthalmopathy undergoing orbital decompression surgery, and six T cell lines were established and characterized. They consisted predominantly of CD8 + CD45RO+ cells and secreted IL-4, IFN-gamma, and IL-10 upon activation. When screened for their antigen reactivity, all lines proliferated in response to stimulation with autologous retrobulbar fibroblasts in an HLA class I-restricted manner, but did not recognize autologous peripheral blood mononuclear cells, crude eye muscle extract, allogeneic cells, or purified protein derivate of Mycobacterium tuberculosis. In contrast, PBMC from the same patients responded readily to purified protein derivate of Mycobacterium tuberculosis and allogeneic PBMC, but did not recognize autologous fibroblasts. Interestingly, only one of the six retrobulbar T cell lines displayed cytotoxicity towards its specific target cell population. These results suggest that the retrobulbar fibroblasts are a major T cell target in Graves' ophthalmopathy. Pronounced cytokine production in the absence of target cell cytotoxicity may explain fibroblast proliferation, glycosaminoglycan secretion, and secondary eye muscle enlargement in this condition.

Contrast sensitivity function in Graves' ophthalmopathy and dysthyroid optic neuropathy

Contrast sensitivity function was measured by a computer automated method on 38 eyes with dysthyroid optic neuropathy and 34 eyes with Graves' ophthalmopathy only. The results were compared with 74 healthy control eyes. Disturbances of contrast sensitivity functions were found in both groups when compared with controls. The eyes affected with dysthyroid optic neuropathy showed pronounced loss of contrast sensitivity in the low frequency range, which facilitates differentiation between the two groups.

A new ultrasonographic method to detect disease activity and predict response to immunosuppressive treatment in Graves ophthalmopathy

PURPOSE

To determine whether the internal reflectivity of the eye muscles on A-mode ultrasonography serves as indicator for disease activity in Graves ophthalmopathy, thereby predicting response to immunosuppressive treatment.

METHODS

Eye muscle reflectivity, expressed as percentage of the initial scleral spike, was measured in the superior, medial, and lateral recti, and normal values were determined in 23 healthy controls. These were compared with values in 16 consecutive patients with untreated, moderately severe Graves ophthalmopathy. The accuracy of the measurement was assessed by calculating the intra- and interobserver coefficient of repeatability. Baseline eye muscle reflectivity in the 16 patients was correlated to the therapeutic outcome 24 weeks after start of immunosuppressive therapy. The response to treatment served as indicator for pretreatment disease activity.

RESULTS

Eye muscle reflectivity could be measured reliably, with an intraobserver coefficient of repeatability of 8.2% in controls and 10.2% in patients. Patients had lower reflectivity than controls (54.6 +/- 17.4% versus 70.7 +/- 6.6%; P < 0.001). Reflectivity in eye muscles with the lowest echogenicity was lower in responders than in nonresponders (25.8 +/- 8.4% versus 40.6 +/- 13.6%; P = 0.02). From the individual data, a cut-off value of 40% was derived, which appeared as an accurate predictor of outcome (positive predictive value 73%; 95% confidence interval 39%-94%).

CONCLUSIONS

Measuring eye muscle reflectivity in Graves ophthalmopathy appears to be a reliable new method to determine disease activity, with a promising accuracy in predicting therapeutic outcome of immunosuppressive treatment.

Radiotherapy and ophthalmology: time for a friendly re-acquaintance

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Immunosuppressive treatment of Graves' ophthalmopathy

Glucocorticoids and retrobulbar irradiation are the most employed immunosuppressive treatment modalities in Graves' ophthalmopathy. The response rate is approximately 60%. Efficacy is good for improvement of appearance and visual acuity, moderate for correction of extraocular muscle dysfunction, and poor for reduction of proptosis. Immunosuppression seldom cures the eye disease. Its main advantage is to stabilize the eye disease by inactivating the inflammation of orbital tissues, thereby permitting corrective eye surgery to be performed at an earlier time. Future developments in immunosuppression aim at reduction of side effects and enhancement of efficacy. Alternative treatment schedules (e.g., methylprednisolone pulses, intravenous immunoglobulin) may have equal efficacy but less side effects than classic high-dose oral steroids. Efficacy can be improved by restriction of immunosuppression to patients with active eye disease who are more likely to respond. Disease activity might well be the main determinant of therapeutic outcome of immunosuppression in Graves' ophthalmopathy.