Patients with subacute thyroiditis may present with fever, excruciating pain over thyroid area, making difficult to differentiate from acute suppurative thyroiditis or thyroid abscess. Blood test for antibodies can be of help but unfortunately we do not have the facilities in our country to test the most important one, i.e., TSH receptor antibody (TSH Rab), specific for Graves’ disease. Thyroglobulin antibody (TGA) (antigen- thyroglobulin) and thyroid microsomal antibody (TMA) (antigen- thyroid peroxidase enzyme) are likely to be positive in a very high percentage of cases of AITD but they are also positive in significant numbers in the general population and relatives of patients with AITD. Radioisotope scan using I123 or Tc99m is helpful in diagnosing toxic nodule or toxic multinodular goitre. In the former, only the hot area will pick up the radiotracer agent while the rest of the areas will be inactive (suppressed) (Fig.11).

Fig. 11 - Solitary Toxic Nodule and Isotope scan showing hot nodule.

In toxic multinodular goitre only the overactive areas will pick up the tracer and the areas in between will be silent showing a patchy uptake. In Graves’ disease the uptake will be uniformly increased. Radioisotope scan can also pick up a cold nodule where the affected nodule will not pick up the isotope but the rest of the gland will (Fig.12).

Fig. 12 - Clinical photograph of a Thyroid nodule and an isotope scan showing the nodule to be cold.

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