Endocrine Abstracts

Background: Graves’ Orbitopathy (GO) is the most common extra thyroidal feature of autoimmune thyroid disease presentation. It is characterized by development of orbital inflammation that involves both, adipose tissue and extra-ocular muscles. The condition is associated with increased psychological burden and in severe cases may lead to optic nerve damage, causing blindness. While most patients with GO present with bilateral disease, asymmetric or unilateral GO may affect a significant proportion of patients diagnosed with the condition. It has been shown that older age, male sex, active and severe disease are the most significant factors for development of unilateral form of the disease. The pathophysiological mechanisms of unilateral presentation of GO still remains uncertain.

Case presentation: We present a case of 39 years old male patient that presented in ambulatory setting with unilateral proptosis of the right eye that developed during a period of two months before consultation. The patient complained of rare episodes of diplopia during fatigue, occasional lacrimation and itching. He was in good general condition, and did not report any other symptoms usually seen in state of hyper function of the thyroid. Patient was active smoker, obese, with BMI of 38 kg/m2 and was diagnosed with hypertension during his frequent visits in our clinic and was treated accordingly. He had no other prior comorbidities and no prior chronic therapy. Biochemical analysis were in reference range. The thyroid function tests were in addition of thyrotoxicosis with supressed TSH of 0,001(0,27-4,5) uIU/ml, and slightly elevated fT4 of 29,96(9,5-25) pmol/l, with positive antibodies to TSH receptor -10,8 IU/l(0-1,76) and negative A-TPO. Ultrasound of thyroid was without any significant appearance, except of discreetly restructured parenchyma of the gland. The measurement of the anterior projection of the eye with Hertel exophthalmometar showed proptosis of the right eye of 28mm vs normal finding on the left eye of 17mm. Calculated CAS score of the patient was 4. Appointed orbital MRI showed pronounced thickening along the entire length of m.rectus medialis of the right orbit with compression of the optic nerve, as a result of massive inflammatory process of the rear compartment of the orbit Patient was advised cessation of smoking and started with thyroid suppression therapy of 20 mg Methimazole and titrated every three weeks to a low maintenance dose of 2,5 mg. After three months of therapy, an euthyroid state was accomplished with TFT of TSH 0,122mIU/ml, fT4 of 17,27 pmol/l and A-TSHR of 2,68IU/l. Since the severe involvment of the right optic nerve, it was indicated by ophtalmologist, to start with pulsatile corticosteroid therapy. He received cumulative dose of 4, 5 g methylprednisolone, six weekly courses of 500 mg and six weekly courses of 250 mg. After six months of initial start of the therapy, control MRI of the orbit showed complete resolution of the inflammatory process of the right eye. Control exophthalmometry measurement of the right eye proptosis was also improved by 7mm (Hertel 21mm). Patient was continued with low maintenance dose of thyroid suppression therapy and was advised cessation of smoking.

Conclusions: Medical treatment of GO has proven to be most effective during active phase of the disease. Approximately 35% of the patients with GO do not respond to immunosuppressive therapy, so it is a priority to recognise and focus the resources during this period. It has been observed that patient treated with pulsatile corticosteroid therapy for GO have reduced risk of hyperthyroidism relapse, which shows that immunosuppression is important for resolution of the process, especially in younger patients that relapse more often. Clinical activity score has a high predictive value for the outcome of immunosuppressive therapy. Some of the studies indicate that asymmetrical or unilateral GO can be an indicator of greater disease activity and severity and should prompt referral to a tertiary institution of this type of patients. Thyroid-related orbitopathy should be considered as a differential diagnose in all cases involving unilateral or asymmetric exophthalmos.