Thyroid Hormone Resistance Syndrome: Report of two cases

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 449-497-Thyroid Neoplasia & Case Reports
Clinical
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-491
Mariana R N Couto*, Gil L P Afonso, Kelly M Ferro, Daniel D R Paulo, Ricardo A Guerra, Evandro S Portes, Livia M Santos and Alisson M C Vale
Hospital do Servidor Publico Estadual de Sao Paulo
Introduction:Thyroid Hormone Resistance Syndrome (RHT) is a rare disorder with autosomal dominant inheritance, characterized by variable tissue hyporesponsiveness to thyroid hormone (TH) due to genetic alteration in its specific receptor. There are two genes that express different forms of the receptor HT (TR): gene alpha (α) that can express the TRα 1 or 2, and beta (β) that can express the β 1 or 2. Except in a very recent report, all mutations are described in TRβ gene. The main differential diagnosis is pituitary adenoma producing TSH which presents with increased serum α-subunit of pituitary glycoprotein hormones which does not occurin the RTH.

Cases Report:The first case is a 28-year-old male patient who began medical monitoring due to palpitations, oscillating between insomnia and sleepiness as hyperthyroidism and was treated with anti-thyroid drug (ATD) that stopped after eight years without medical advice. At 38 came our hospital with palpitations and was evidenced TSH 8.4 µUI /ml (0.27 - 4.2), FT4 3.34 ng/dl (1.0 - 1.7), FT3 3,0 ng/dl (0,25-0,45), USG (ultrasonography) with multinodular goiter, scintigraphy uptake suggestive of diffuse goiter, subunit α without change, anti-thyroid antibodies were not reactive (NR), Magnetic Resonance Imaging (MRI) of the sela changes without being chosen to β-blocker to control sinus tachycardia. The other case, a 35-year-old female, was diagnosed with hyperthyroidism and made use of ATD for 3 months it stopped without medical advice. At 37 she was referred to hospital due paroxysmal tachycardia and research evidenced TSH 2.65 µUI/ml, FT4 3.03 ng/dl, T3 246 ng/dl (40-180), USG of normal thyroid, thyroid scintigraphy with uptake, Anti-thyroid NR, Sub-unit α and MRI of sela without changes being chosen to maintain without medication because the patient was asymptomatic.

Conclusion:These reports emphasize the clinical importance and suspicion of the RHT diagnosis. The differential diagnosis is essential for therapeutic decision since the TSH-producing adenoma should be surgically treated and asymptomatic RTH patients are not candidates for treatment. When symptomatic, whose main symptom is tachycardia, β-blocker can be used, but if there is a predominance of symptoms of hypothyroidism treatment with high doses of 5,3-Triiodothyroacetic Acid is more effective, and there is no ATD indication in RHT or TSH-producing adenoma.

Nothing to Disclose: MRNC, GLPA, KMF, DDRP, RAG, ESP, LMS, AMCV

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