| Erickson et al., Rochester, MN, USA, studied the expression of leptin and the TSH receptor (TSH-R) in undifferentiated preadipocytes and preadipocyes differentiated into fibroblasts, in retroocular tissue of 5 patients with severe TED. In undifferentiated cells there was only faint immunofluorescent staining for leptin and no for TSH-R. In contrast, in differentiated orbital preadipocyte fibroblasts clear staining was present for both leptin and TSH-R. The authors conclude that in patients with TED an unknown in vivo stimulus to adipocyte differentiation might act to both expand the volume of the orbital adipose tissues and to increase the expression of the likely autoantigen (TSH-R) of TED. (Comment: any role of leptin in development of TED?) Eckstein et al., Essen, Germany, studied the impact of smoking on severity of eyesigns and response to therapy (steroids and subsequent irradiation) in a group of 50 patients with TED, of whom 35 were smokers and 15 non-smokers. Frequency of smoking was measured as reflected by levels of hydroxyethylvaline and cyanoethylvaline that are hemoglobin adducts due to smoking. Improvement of eye symptoms was more marked in patients with low hemoglobin adducts than with high levels. A negative correlation was present between the concentrations of these compounds and improvement of lid edema and ocular motility. However, no relation was found before the start of therapy between the concentrations of these substances and the severity of TED. (Comment: These latter results are discrepant with those of others who do find a correlation between smoking and severity of TED at first presentation.) Kahaly et al., Mainz, Germany, reported about an operative technique of combined transpalpebral and endonasal decompression for TED. It consists of removal of palpebral adipose tissue from upper and lower lids and removal of the medial orbital wall. In total 55 patients (median age 50 years, 43 females) were operated. Median Hertel values decreased by 3.5 mm, 3 months after operation and decreased further to a median value of 4.5 mm after 1 year. After 3 months, median lid aperture decreased by 2 mm, and intraocular pressure in norm- and in upgaze decreased by 2.5 mmHg and 5 mmHg respectively. Chemosis was present in 65% of patients before operation, but in 7% after 1 year. Bulbar motion improved as well after this type of surgery. Strabismus surgery was done once in 16 and twice in 3% of cases. From these and other results the authors conclude that this technique gives favourable results and less side effects (newly developed diplopia and sinusitis) as with other techniques. Salvi et al., Parma, Italy, developed a so-called neural network model based on 13 eye parameters to predict disease progression in patients with TED. In total 244 eyes were tested and two ophthalmologists were involved in the assessment of these eye parameters. This study was a retrospective evaluation. From the results it appeared that at first examination of TED, the outcome (without treatment) could be predicted in 70% of patients. The authors expect that when a second examination is included in this model, correct prediction can be optimized. Gorman et al., Rochester, MN, and Sacramento, CA, USA, prospectively treated 42 euthyroid patients with mild to moderate TED with 20 Gy to 1 randomly selected orbit while the other orbit was treated 6 months later. Measurements of thyroid function, antibody status, proptosis, volume of extraocular muscle and fat, range of extraocular muscle motion, eyelid fissures, and extent of diplopia were done. The results of this study were that no significant differences between the treated and the untreated orbit in any parameter at 3 or 6 months were noted. No trend towards selective improvement of the first treated orbit between 6 and 12 months was found. The authors conclude that if radiotherapy is beneficial for TED, it's ameliorative effects did not reach the detection level of the techniques used in this study. (Comment: As a medical student I learned that there was (and apparently still is) an ophthalmic syndrome called: sympathetic ophthalmitis. It was defined as "a condition in which serious inflammation attacks the sound eye after injury of the other". Using Medline with keywords sympathetic and ophthalmitis, I found in total 62 references, the most recent one dating 1996. The results of this provocative study indicate either that orbital irradiation in TED is not of significant benefit or that a "reversed" ophthalmic effect may occur as well, in that irradiation of one eye may also have a beneficial effect on the other eye. For the moment I advise to continue with orbital irradiation in indicated cases.) Aniszewski et al., Rochester, MN, USA, retrospectively reviewed the medical records of 45 patients diagnosed with myasthenia gravis (MG) associated with Graves' disease. Hyperthyroid Graves' disease was present in 39/45 patients, of whom 20/39 had TED, 6/45 patients were euthyroid, and all had TED. The authors conclude that in patients with MG associated with Graves' disease TED is a common feature. The association between MG and TED may indicate common pathways in pathogenesis. (Comment: The association between MG and Graves' disease is known for long. Furthermore, when patients with Graves' disease are carefully examined for eye signs, using sophisticated methods, it appears that most of them have TED as well. So far thus no difference in TED prevalence in patients with Graves' disease with or without MG.) |
