Endocrine Abstracts

Background: Hashimoto’s thyroiditis (HT) is considered the most common autoimmune disease and the predominant cause of hypothyroidism in iodine sufficient countries. HT may appear clinically in approximately 0.1–2% of the population.

Aim: The study in hand aimed at assessing the role of thyroid ultrasonography in the diagnosis of HT patients discriminating them from other causes of hypothyroidism. A scoring system of sonographic findings was aimed to be used side by side with the auto antibodies routinely used for diagnosis.

Subjects: The current study included 160 subjects with manifestations of hypothyroidism,who attended Cairo University, Kasr Al-Ainy Outpatient Endocrinology Clinic,112 patients with HT and 48 hypothyroid non-Hashimoto’s controls.

Methods: All included patients were subjected to full history taking, clinical and local thyroid examination, BMI calculation, thyroid ultrasound examination (US) and a panel of assays (TSH, f.T3, f.T4, anti-TPO Ab, anti-TG Ab, calcium, alkaline phosphatase and phosphate). Regarding thyroid US scanning, the number of US findings (thyroid volume, heterogeneity, nodularity and vascularity) were counted for each studied patient. A score was given to each patient ranging from 0 (no finding) to 4 findings. Thyroid antibodies were assayed using ELISA.

Results: 112 subjects were considered as HT (with anti-TPO Ab levels >75 IU/ml and/or anti-TG Ab > 110 IU/ml). 48 subjects were included as control group (withnegativeanti-TPO Ab and anti-TG Ab; <20 IU/ml and <90 IU/ml respectively). A statistically significant increase in total thyroid volume was observed in HT patients (P = 0.002).A cutoff volume ≥4.8 ml was found discriminative with specificity (95% CL) of 60.4 (45.3–74.2)% and sensitivity of 65.2 (55.6–73.9)%. However, the remaining thyroid US features were statistically insignificant. A discriminatory cutoff for the scoring system was studied to differentiateHT patients from control group based on the number of their US findings. No significant difference was found between both groups, whether 0–1 vs 2–4 scores; (P = 0.422), or 0 vs 1–4 (P = 0.104).

Conclusion: All positive thyroid ultrasound findings cannot discriminate between HT and other hypothyroid non-Hashimoto’s patients except thyroid volume. No scoring system based on US findings can be adopted for diagnosis of HT. However, a thyroid volume at a cutoff of 4.8 ml can be an added value tothe laboratory findings to discriminate between HT and control group with specificity 60.4% and sensitivity 65.2%.