ENDOCRINOLOGY QUIZ-CASE 3 CONTINUING MEDICAL EDUCATION ΣΥΝΕΧΙΖΟΜΕΝΗ ΙΑΤΡΙΚΗ ΕΚΠΑΙΔΕΥΣΗ Endocrinology Quiz-Case 3
A 54-year old woman presented to outpatient endocrine clinic on January 1999 for assessment of her thyroid function, due to a history of Grave's disease diagnosed in 1988. At diagnosis the patient was treated with methimazole for one year and consecutively received thyroxine for one year more, until she became euthyroid and discontinued any medication. Annual thyroid testing revealed normal thyroid function without pathological ultrasonographic findings. On 2005, on a routine check,
... check, thyroid-stimulating hormone (TSH) value was found above normal range (5.42 μίU/mL with normal values 0.3 to 4), compatible with subclinical hypothyroidism and follow-up in 3 months time was advised. Although, during a two year follow-up period, TSH remained at that range and no treatment was prescribed, at the end (2007) thyroid testing revealed hyperthyroidism (suppressed TSH=0.03 μίU/mL and increased FT3: 7.07 pg/mL and FT4=3.04 ng/dL levels) (normal values for FT3: 2.30-6.19 and for FT4: 0.7-1.9, respectively) with positive thyroid autoantibodies [anti-TPO= 498 ίU/mL (0-150) and anti-TG= 209.5 ίU/mL (0-100)], but TSI antibodies were negative. On physical examination no signs and symptoms compatible with hyperthyroid-ism were documented. Thyroid gland was slightly enlarged, without pain during palpation and no thyroid murmur was detected. Thyroid scan with 50 μCi radioactive I-131 revealed a decreased uptake of radioactive drug (fig. 1). Additionally, uptake at 4 hours and 24 hours was 1.8% and 1.6% (NR >20%). These findings were compatible with absence of thyroid function. Two months later (3/07) and without any medication patient was hypothyroid with TSH 45.7 μίU/mL and decreased FT4, FT3 (2.2 pg/mL and 4.4 μg/dL). Patient started thyroxine treatment with a gradually increasing dose (fig. 2, Thyroid status of the patient during time). Comment A patient with a history of Graves' hyperthyroidism, free of the disease the last seven years, developed subclinical hypothyroidism for two years and subsequently developed suclinical hyperthyroidism with decreased uptake of radioactine iodine. Two months post Figure 2. Thyroid status of the patient through time. Figure 1. Thyroid scan of the patient.