LAUSR

A 64-year old woman was addressed to the endocrinology clinics, following the observation of subclinical hypothyroidism and positive anti-TPO auto-antibodies (TSH levels 6.28 uUI/ml). Ultrasound examination (Fig. 1a) showed a diffusely enlarged heterogeneous hypoechoic right lobe, with two micronodules (3 and 7 mm) and the absence of the left thyroid lobe. The patient started levothyroxine (L-T4) replacement therapy (50 μg/day), remaining euthyroid for almost 4 years. In August 2014, she presented tiredness, tremors, and palpitations with markedly increased free thyroid hormone and suppressed TSH levels. L-T4 therapy was discontinued, with no clinical improvement. On September 2014, the laboratory findings confirmed the persistence of thyrotoxicosis. The 99Tc scintiscan (Fig. 1b) showed increased uptake in the right thyroid lobe, suggesting the diagnosis of Graves’ disease which was corroborated by the demonstration of highly positive (46.2UI/L) TSH receptor antibodies (TRAb), measured using a 2nd generation TRAK human lumitest (Thermofisher, AG, Henningsdorf/ Berlin, Germany; normal value <1.8 U/L). Consequently, the patient started methymazole (MMI) treatment (30 mg/day). On November 2014, Graves’ Orbitopathy (GO) with symptomatic vertical diplopia appeared, requiring 8^ prisms for correction of constant diplopia. The Nuclear Magnetic Imaging (Fig. 1c) of the orbits showed thickening of extra-ocular muscles (medial and inferior right rectus and bilaterally superior recti). Further follow-up showed rapid progression of the GO, with deterioration of vertical diplopia. The ophthalmological assessment, according to the EUGOGO guidelines [1] demonstrated bilateral active GO with spontaneous orbital pain, chemosis, lid edema and hyperemia resulting in a clinical activity score (CAS) of 5/10. The patient presented also constant diplopia (Fig. 1d), a proptosis of 23.5/22 mm and significant worsening of eye motility. The severity NOSPECS score was 2B3A4B5060. The persistence of hyperthyroidism (TSH 0.01 mU/L, FT4 22.3 pmol/l and FT3 10.1 pmol/l) and elevated TRAb levels (41.4 U/L) required an increase of MMI to 40 mg/day. High doses of intravenous methylprednisolone (IVMP) were also administered once a week for 12 weeks (six pulses of 830 mg followed by six more pulses of 415 mg with a cumulative dose 7.5 g) from January to March 2015. Six weeks after completing corticosteroid treatment, the patient was re-examined, GO resulted inactive (CAS 2/10). Monthly follow-up showed progressive improvement of both inflammatory manifestations and eye motility. Euthyroidim was maintained, under escalating MMI dose which was discontinued on September 2015.GO persisted inactive, with only inconstant diplopia, a CAS of 1/10 and a severity NOSPECS score 2A3A405060GO. The patient could eventually resume her daily activities, including bicycle riding (February 2016). The patient remained euthyroid during the remaining follow-up (TSH 2.86 uUI/ml and undetectable TRAb on January 2018). Thyroid hemiagenesis is rare, with a prevalence estimated to 0.2% at systematic ultrasound screening [2]. Its association with Graves’ disease is exceptional and only 21 patients have been previously reported in the literature [3]. Interestingly, spontaneous conversion from hyperthyroidism to hypothyroidism or long-term remission has been previously reported in two cases. A third case, unresponsive to oral steroids underwent orbital decompression. Notably, the present report illustrates the second documented case of GO successfully treated with IVMP administration in thyroid hemiagenesis. * Giuseppe Costante [email protected]