ABSTRACT
Inflammatory diseases of thyroid consist of numerous disorders of varying etiologies as all the diseases with intrathyroidal inflammation are included in it. The most common disease among the group is autoimmune thyroiditis (AIT) that itself can present incidentally with goiter, hypothyroidism or Grave's disease (GD). Related to this is thyroiditis associated with radioiodine ablation for hyperthyroidism that commonly leads to hypothyroidism in long term. The classical symptoms and signs of hypothyroidism are not seen in all cases particularly in southeast Asians and a high index of suspicion is required which makes the biochemical investigations necessary even in atypical cases. Rarely, AIT presents as destructive thyroiditis that is more commonly seen in postpartum period and often leads to confusion with GD. The other common causes of destructive thyroiditis are infections particularly post-viral (De Quervain's thyroiditis) which may be painful and have triphasic presentation. Rarely, sarcoidosis, Riedel's thyroiditis, irradiation and drugs can cause thyroiditis that may present with biochemical thyroid function abnormalities.
