Technetium-99m thyroid scan; does it have a diagnostic aid in sub-clinical auto-immune thyroid disease in systemic lupus erythematosus patients?

PURPOSE: Technetium-99m (Tc-99m) thyroid scintigraphy is a well known diagnostic tool that shows the entire gland in a single image. We aimed to evaluate its additive diagnostic value in subclinical autoimmune thyroid disease (S-AITD) in systemic lupus erythematosus (SLE) patients.

METHODS: We investigated 100 systemic lupus erythematosus (SLE) patients without overt thyroid involvement (eight men and 92 women; mean age 40±6.5 years) and 50 age and sex matched controls. All were subjected to thyroid evaluation using anti-thyroglobulin (anti-TG) and anti-thyroid peroxidase (anti-TPO) antibodies; hormones (FT3; FT4 and TSH) and Tc-99m thyroid scintigraphy.

RESULTS: 14/100 (14%) and none (0%) were positive for S-AITD in SLE and control groups, respectively (P = 0.0001). They were classified by thyroid scintigraphy and hormonal profile into 2/14 Hashimoto; 10/14 atrophic thyroiditis and 2/14 Graves' disease. Anti-TPO was elevated in 12 SLE cases, while anti-TG was elevated in only 2/14 (P = 0.0001). Thyroid scintigraphy showed statistically significant associations with FT4, TSH and anti-TPO.

CONCLUSION: Tc-99m thyroid scintigraphy may have an additional diagnostic role in S-AITD among SLE patients, with an impact on patient management. This potential needs to be further evaluated in a larger series on a multicenter basis.