Utility of Thyroid Ultrasound in Predicting Anti-TPO Positivity

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 432-458-Thyroid Autoimmunity
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-453
Sheryl Najito Tugna* and Maria Jocelyn Capuli Isidro
Makati Medical Center, Makati City, Philippines

Principal Investigator:   Sheryl N. Tugna, MD

Supervising Consultant Investigator:   Maria Jocelyn Capuli-Isidro, MD, FPCP, FPSEM

Makati Medical Center Section of Endocrinology, Diabetes and Metabolism

Background: Hashimoto’s thyroiditis stands out as the most frequent cause of hypothyroidism. It is associated with complications such as mood disorders, poor obstetrical outcome among females and thyroid malignancies . Anti-TPO assay has been the test commonly used to confirm the presence of thyroid autoantibodies but it is not specific. Ultrasound is widely used in the evaluation of the thyroid gland since it is non-invasive and can provide detailed image of the thyroid gland. If positive correlation between specific ultrasound findings and positive anti –TPO can be established, then ultrasound can be used as a diagnostic modality that identify patients at risk for autoimmune thyroid disease. Clinicians who do not have anti-TPO assay in their places of practice can use these ultrasound findings in identifying patients who are risk for overt hypothyroidism in the future.

Objective: To establish possible association between thyroid ultrasound findings and anti-TPO positivity among patients with diffuse thyroid enlargement.

Methods: This is a cross-sectional study wherein data were analyzed retrospectively. The study population was 94 adult, patients with goiter seen at out-patient clinics of Makati Medical Center (MMC) in Manila, Philippines that had an anti-TPO test done in MMC Nuclear Medicine Department over a 1 year period. Anti-TPO level above 100 pmol/L confers positivity. Excluded in this study are those with thyroid pain, within 12 months postpartum, diagnosis of hyperthyroidism, with thyroid carcinoma and radioactive iodine treatment. Thyroid ultrasound reports were evaluated as to the size, echogenicity, echotexture and vascularity.

Results: Based on ultrasound results, patients with positive anti-TPO have larger thyroid size (p-value 0.0053) and frequent sonographic findings were: hypoechogenicity (79% vs 21%,p-value <0.001); heterogenous echotexture (71% vs 29%, p-value <0.001) and increased vascularity (93% vs 7%, p-value <0.001). All (100%) patients who showed combination of hypoechoic, heterogenous parenchyma and increased vascularity were anti-TPO positive.

Conclusion: Thyroid ultrasound findings found frequently among anti-TPO positive are increased thyroid size, hypoechoiec and heterogenous parenchyma and increased vascularity. Combined sonographic characteristics of hypoechoic, heterogenous pattern and increased vascularity are highly suggestive of presence of anti-TPO. In patients wherein thyroid ultrasound was the test done initially, or in places where anti-TPO assay is not available, the presence of above ultrasound findings warrant examination and follow-up.

(1)Mariotti S., Caturegli, P. Antithyroid Peroxidase Autoantibodies in Thyroid Diseases J Clin.Endocrinol Metab  1990 Vo.71 N0.3 661-669. (2)Marcocci C, Vitti P, Cetani F, Catalano F, Concetti R &Pinchera A. Thyroid ultrasonography helps to identify patients with diffuse lymphocytic thyroiditis who are prone to develop Hypothyroidism Journal Clinical Endocrinology and Metabolism 1991 72 ;209–213. (3)Vanderpump , M.P. et.al. The Incidence of Thyroid Disorders in the Community: A Seventy- year follow up of WhickhamSurvey .ClinEndocrinol (Oxf) 1995; 43:55:68 13-7.

Nothing to Disclose: SNT, MJCI

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