Raised TSH: a diagnostic conundrum!

Case 1 74 year old was referred with 5 years of TSH ranging between 4.9 7.9 miu/L (0.2 -4.0), fT4 18.527 pmol/L (9.0-19) and free T3 (fT3) 4.5 to 12 pmol/L (2.5-5.7). Thyroid peroxidase antibodies (TPOA) were negative. He reported tremor, weight loss and exertional shortness of breath. He had small goitre, no thyroid ophthalmopathy, normal visual fields, BMI (Kg/m2) 22 and atrial fibrillation.