Journal List > J Korean Thyroid Assoc > v.8(1) > 1056588

Mo, Ryu, Kim, and Kim: The High Proportion of Painless Thyroiditis as a Cause of Thyrotoxicosis in Korea

Abstract

Background and Objectives

The most common cause of thyrotoxicosis is Graves' disease (GD), while painless thyroiditis (PT) comes in second. In Korea, the treatment of choice for GD is antithyroid drugs (ATDs). Since most cases of PT spontaneously improve, an accurate diagnosis is very important for the proper management of patients presenting with thyrotoxicosis.

Materials and Methods

Ninety-nine thyrotoxic patients were routinely checked with 99m Technetium (99mTc) thyroid scan except in pregnant or lactating women. We assessed the patients' clinical characteristics, serum levels of free T4 (FT4), thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb), thyrotropin-binding inhibitory immunoglobulin (TBII), and findings of 99mTc thyroid scan.

Results

Among the 99 thyrotoxic patients, 69 were diagnosed with GD and 30 had PT. All of the patients with GD, diagnosed by scan, improved clinically and the thyroid hormone returned to normal with ATDs. All patients with PT improved spontaneously without ATDs. TPOAb and TGAb were positive in 13 (43.3%) and 20 (66.7%) patients with PT, respectively. TPOAb and TGAb were positive in 45 (65.2%) and 44 (63.8%) patients with GD, respectively. TBII was positive in only 73.5% of GD, and was entirely negative in the PT group. Mean FT4 level in GD was higher than in PT, but some patients with PT showed the highest level of FT4.

Conclusion

PT accounted for a very high proportion of thyrotoxicosis in this study. All parameters investigated such as age, sex, goiter size or nature, level of FT4, TPOAb or TGAb, and TBII were unable to differentiate GD from PT. Considering the increased proportion of PT in the current study, we recommend routine thyroid scan in all thyrotoxic patients except in pregnant or lactating women.

References

1. Ponto KA, Kahaly GJ. Autoimmune thyrotoxicosis: diagnostic challenges. Am J Med. 2012; 125(9):S1.
crossref
2. Nikolai TF, Coombs GJ, McKenzie AK. Lymphocytic thyroiditis with spontaneously resolving hyperthyroidism and subacute thyroiditis. Long-term follow-up. Arch Intern Med. 1981; 141(11):1455–8.
crossref
3. Pearce EN, Farwell AP, Braverman LE. Thyroiditis. N Engl J Med. 2003; 348(26):2646–55.
crossref
4. Schorr AB, Miller JL, Shtasel P, Rose LI. Low incidence of painless thyroiditis in the Philadelphia area. Clin Nucl Med. 1986; 11(6):379–80.
crossref
5. Williams I, Ankrett VO, Lazarus JH, Volpe R. Aetiology of hyperthyroidism in Canada and Wales. J Epidemiol Community Health. 1983; 37(3):245–8.
crossref
6. Schwartz F, Bergmann N, Zerahn B, Faber J. Incidence rate of symptomatic painless thyroiditis presenting with thyrotoxicosis in Denmark as evaluated by consecutive thyroid scintigraphies. Scand J Clin Lab Invest. 2013; 73(3):240–4.
crossref
7. Hurley PJ, Maisey MN, Natarajan TK, Wagner HN Jr. A computerized system for rapid evaluation of thyroid function. J Clin Endocrinol Metab. 1972; 34(2):354–60.
crossref
8. Paunkovic J, Paunkovic N. Does autoantibody-negative Graves' disease exist? A second evaluation of the clinical diagnosis. Horm Metab Res. 2006; 38(1):53–6.
crossref
9. Pedersen IB, Knudsen N, Perrild H, Ovesen L, Laurberg P. TSH-receptor antibody measurement for differentiation of hyperthyroidism into Graves' disease and multinodular toxic goitre: a comparison of two competitive binding assays. Clin Endocrinol (Oxf). 2001; 55(3):381–90.
crossref
10. Schott M, Feldkamp J, Bathan C, Fritzen R, Scherbaum WA, Seissler J. Detecting TSH-receptor antibodies with the recombinant TBII assay: technical and clinical evaluation. Horm Metab Res. 2000; 32(10):429–35.
crossref
11. Laurberg P, Bulow Pedersen I, Knudsen N, Ovesen L, Andersen S. Environmental iodine intake affects the type of nonmalignant thyroid disease. Thyroid. 2001; 11(5):457–69.
crossref
12. Costagliola S, Morgenthaler NG, Hoermann R, Badenhoop K, Struck J, Freitag D. et al. Second generation assay for thyrotropin receptor antibodies has superior diagnostic sensitivity for Graves' disease. J Clin Endocrinol Metab. 1999; 84(1):90–7.
13. Morita T, Tamai H, Oshima A, Mukuta T, Fukata S, Kuma K. et al. The occurrence of thyrotropin binding-inhibiting immunoglobulins and thyroid-stimulating antibodies in patients with silent thyroiditis. J Clin Endocrinol Metab. 1990; 71(4):1051–5.
14. Kamijo K. TSH-receptor antibody measurement in patients with various thyrotoxicosis and Hashimoto's thyroiditis: a comparison of two two-step assays, coated plate ELISA using porcine TSH-receptor and coated tube radioassay using human recombinant TSH-receptor. Endocr J. 2003; 50(1):113–6.
crossref
15. Iitaka M, Morgenthaler NG, Momotani N, Nagata A, Ishikawa N, Ito K. et al. Stimulation of thyroid-stimulating hormone (TSH) receptor antibody production following painless thyroiditis. Clin Endocrinol (Oxf). 2004; 60(1):49–53.
16. Lee SM, Kim SK, Hahm JR, Jung JH, Kim HS, Kim S. et al. Differential diagnostic value of total T3/free T4 ratio in Graves' disease and painless thyroiditis presenting thyrotoxicosis. Endocrinol Metab. 2012; 27(2):121–5.
17. Amino N, Yabu Y, Miki T, Morimoto S, Kumahara Y, Mori H. et al. Serum ratio of triiodothyronine to thyroxine, and thyroxine-binding globulin and calcitonin concentrations in Graves' disease and destruction-induced thyrotoxicosis. J Clin Endocrinol Metab. 1981; 53(1):113–6.
18. Shigemasa C, Abe K, Taniguchi S, Mitani Y, Ueda Y, Adachi T. et al. Lower serum free thyroxine (T4) levels in painless thyroiditis compared with Graves' disease despite similar serum total T4 levels. J Clin Endocrinol Metab. 1987; 65(2):359–63.
19. Atkins HL, Klopper JF. Measurement of thyroidal technetium uptake with the gamma camera and computer system. Am J Roentgenol Radium Ther Nucl Med. 1973; 118(4):831–5.
crossref
20. Hays MT, Wesselossky B. Simultaneous measurement of thyroidal trapping (99mTcO4-) and binding (131I-): clinical and experimental studies in man. J Nucl Med. 1973; 14(11):785–92.
21. Schneider PB. Simple, rapid thyroid function testing with 99mTc-pertechnetate thyroid uptake ratio and neck/thigh ratio. AJR Am J Roentgenol. 1979; 132(2):249–53.
crossref
22. Higgins HP, Ball D, Eastham S. 20-Min 99mTc thyroid uptake: a simplified method using the gamma camera. J Nucl Med. 1973; 14(12):907–11.
23. Sucupira MS, Camargo EE, Nickoloff EL, Alderson PO, Wagner HN Jr. The role of 99mTc pertechnetate uptake in the evaluation of thyroid function. Int J Nucl Med Biol. 1983; 10(1):29–33.
crossref
24. Cho BY. Clinical thyroidology. 3rd ed. Seoul, Korea: Medical Book Publishing Company;2010; p.305–75.
25. Hollowell JG, Staehling NW, Flanders WD, Hannon WH, Gunter EW, Spencer CA. et al. Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab. 2002; 87(2):489–99.

Fig. 1.
Typical findings of thyroid scan of Graves' disease (left) and painless thyroiditis (right).
jkta-8-61f1.tif
Fig. 2.
The mean FT4 level of Graves' disease was higher than painless thyroiditis. The normal range of FT4 was 0.93-1.7 ng/dL. Three of 30 patients showed very high level of FT4 in PT and 5 of 59 patients showed highest level of FT4 in Graves' disease.
jkta-8-61f2.tif
Fig. 3.
Individual serum total T3/free T4 ratios in Graves' disease and painless thyroiditis. Total T3/free T4 ratio in patients with Graves' disease was significantly (p=0.044) higher than that in patients with painless thyroiditis.
jkta-8-61f3.tif
Table 1.
Baseline characteristics of thyrotoxic patients
Painless thyroiditis (n=30) Graves' disease (n=69) p value
Age (years) 44.03±12.40 44.03±12.44 0.999
Sex     0.166
Male (%) 12 (40.0) 18 (26.1)  
Female (%) 18 (60.0) 51 (73.9)  
Symptoms     0.001
Negative (%) 20 (66.7) 21 (30.4)  
Positive (%) 10 (33.3) 48 (69.6)  
Goiter     0.030
Negative (%) 17 (56.7) 23 (33.3)  
Positive (%) 13 (43.3) 46 (66.7)  
Consistency of goiter     0.918
Soft (%) 10 (56.7) 36 (78.3)  
Hard (%) 3 (23.1) 10 (21.7)  
Thyroid function test      
Total T3 (ng/dL) 213±94 369±150 <0.001
Free T4 (ng/dL) 2.87±1.68 4.44±1.84 <0.001
Total T3/Free T4 78.83±20.29 85.31±18.74 0.044
TPOAb     0.042
Negative (%) 17 (56.7) 24 (34.8)  
Positive (%) 13 (43.3) 44 (63.8)  
TGAb     0.782
Negative (%) 10 (33.3) 25 (36.2)  
Positive (%) 20 (66.7) 44 (63.8)  
TBII     <0.001
Negative (%) 30 (100) 18 (26.1)  
Positive (%) 0 (0) 50 (72.5)  

Continuous variables were analyzed by Mann-Whitney test. Categorical variables were analyzed by Pearson's Chi-square test. TBII: thyrotropin-binding inhibitory immunoglobulin, TGAb: thyroglobulin antibody, TPOAb: thyroid peroxidase antibody

Table 2.
The sensitivity and specificity of differential cut-off point of Graves' disease from painless thyroiditis
AUC (%) Cut-off point Sensitivity (%) Specificity (%)
Total T3 (ng/dL) 85.0 233.5 83.6 80.0
Free T4 (ng/dL) 80.9 3.21 67.2 86.7
Total T3/Free T4 63.1 75.21 77.0 60.0

AUC: area under the curve

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