Chronic lymphocytic thyroiditis includes two types: the goiter type, Hashimoto’s thyroiditis (HT), and the atrophic thyroid type, atrophic thyroiditis (AT), both of which are autoimmune thyroiditis. The disease is recognized as an organ-specific autoimmune disease with a genetic predisposition, and is associated with HLA-B8 in HT and HLA-DR3 in AT. Patients with HT and AT have high titers of TPOAb and TGAb. Clinical manifestations The disease is one of the most common autoimmune thyroid disorders, occurring three times more frequently in women than in men, with a high incidence at 30-50 years of age; the thyroid gland is moderately enlarged and firm. The first symptom of HT is moderate enlargement and hardness of the thyroid gland. 50% of HT cases present with hypothyroidism; the first symptom of AT is hypothyroidism; a few cases may present with HT-like goiter with hyperthyroidism, called Hashimoto’s thyrotoxicosis, and a few cases may also present with infiltrative proptosis. Laboratory tests: TPOAb and TGAb titers are significantly higher in normal thyroid function, which is the most meaningful diagnostic indicator. 50% of HT limbs develop hypothyroidism, with reduced serum FT3 and FT4 and significantly higher TSH. In some cases, only subclinical hypothyroidism occurs, i.e. normal serum FT3 and FT4 and significantly increased TSH; late 131 iodine uptake is reduced; uneven distribution of thyroid scans and “cold nodules” are seen; fine needle aspiration biopsy of the thyroid gland is helpful for diagnosis. Diagnosis and differential diagnosis HT should be suspected in middle-aged women with a hard goiter, especially with isthmus vertebral lobe enlargement, without functional changes in the thyroid gland; the diagnosis is established if the serum TPOAb and TGAb are elevated; in cases where the increase in antibodies is not significant, a thyroid needle aspiration should be performed. In cases of thyroid atrophy with hypothyroidism, the diagnosis of AT is established when the serum TPOAb and TGAb are significantly elevated. A firm goiter should be differentiated from thyroid cancer. Treatment Those with goiter only usually do not require treatment. Treatment with levothyroxine or thyroxine may be given when clinical hypothyroidism or subclinical hypothyroidism occurs. If the thyroid gland is enlarged with local pain or pressure symptoms, glucocorticoid therapy is given (prednisone 30mg/d in three oral doses and reduced when symptoms are relieved). If the symptoms of compression are obvious and not relieved by drug treatment, surgery may be considered. In patients with Hashimoto’s thyrotoxicosis, antithyroid medication is generally given, and surgery and radioiodine therapy are not taken to avoid accelerating the onset of hypothyroidism.