Overview
Resistance to thyroid hormone syndrome (RTH) is characterized by impaired peripheral response to thyroid hormones despite normal thyroid function tests, often manifesting with symptoms like tachycardia 1.Diagnosis
Normal thyroid function tests: T4, free T4, T3, TBG, radioiodine uptake, TSH, and T3 suppressibility are typically normal 1.
Decreased TSH response to TRH: Indicative of altered hypothalamic-pituitary feedback 1.
Increased nuclear T3 receptor binding capacity: Elevated T3 receptor affinity and binding capacity in lymphocytes, suggesting hypersensitivity 1.
Clinical presentation: Recurrent tachycardia crises, often present since childhood, without goiter or exophthalmos 1.Management
Antithyroid medications: Carbimazole can alleviate symptoms like tachycardia crises, though patients remain euthyroid 1.
Symptom-specific treatment: Pindolol ineffective; focus on managing arrhythmias and symptoms directly 1.Special Populations
No specific data: The provided abstract does not cover management in pregnancy, pediatrics, elderly, or comorbidities 1.Key Recommendations
Evaluate for decreased TSH response to TRH and increased lymphocyte T3 receptor binding capacity in patients with unexplained tachycardia crises 1 (Evidence: Moderate).
Consider antithyroid therapy (e.g., carbimazole) for symptom management in RTH, despite euthyroid state 1 (Evidence: Weak).
Monitor and manage symptoms directly, as beta-blockers like pindolol may not be effective 1 (Evidence: Weak).References
1 Jaffiol C, Baldet L, Torresani J, Bismuth J, Papachristou C. A case of hypersensitivity to thyroid hormones with normally functioning thyroid gland and increased nuclear triiodothyronine receptors. Journal of endocrinological investigation 1990. link