HASHIMOTO THYROIDITIS
(CHRONIC LYMPHOCYTIC THYROIDIT, AUTOIMMUNE THYROIDIT)
Hashimoto’s thyroiditis was defined as one of the chronic autoimmune thyroiditis in 1908. and was first named “struma lymphomatosis”.
It is very common in all societies. It begins with enlargement of the thyroid gland, resulting in hypothyroidism. It is usually asymptomatic.
The prevalence of Hashimoto’s thyroiditis has been shown to be associated with iodine intake. High prevalence has been found in countries with high iodine intake such as the USA and Japan. It has been determined that iodine prophylaxis in regions with iodine deficiency increases lymphocyte infiltration in the thyroid gland by 3 times and the prevalence of serum thyroid antibody positivity exceeds 40%. Again, iodine-induced hypothyroidism is common in amiodarone users. In patients using lithium, hypothyroidism develops in 1/3 of the cases, although it is often temporary. Thyroid antibodies and hypothyroidism may also develop in cases using interferon alpha therapy.
Hashimoto’s thyroiditis is the most common of all thyroid diseases and is found in 2% of the population. Although it can occur at any age, it is common between the ages of 30-50. It is 15-20 times more common in women than men. The most common presentation is an elderly woman with an asymptomatic goiter. 20% of cases present with signs of hypothyroidism.
Hashimoto’s thyroiditis; It is common with hypogonadism, Addison’s disease, diabetes mellitus, hypoparathyroidism, and pernicious anemia. This combination is called “Polyglandular insufficiency syndrome”. 2-4% of cases present with hyperthyroidism and this is called “Hashitoxicosis”. After the thyrotoxic phase, transient hypothyroidism occurs, then the euthyroidism phase, and finally permanent hypothyroidism.
In ultrasonographic examination, enlargement of the thyroid gland, low echogenicity and heterogeneous appearance are characteristic.
As laboratory findings; anti-thyroid peroxidase antibody positivity-anti TPO and anti-thyroglobulin antibody positivity are found. While 50-75% of thyroid antibodies positive cases were euthyroid, subclinical hypothyroidism was found in 25-50% of them.
Thyroid lymphoma is a rare but serious complication of Hashimoto’s thyroiditis. Thyroid lymphoma is more common in older women and is confined to the thyroid gland.
TREATMENT
1. Treatment of hashitoxicosis: Treatment is with beta-blocker drugs. (eg: propranolol 20-40mg 3×1/day). It is difficult to clinically distinguish hashitoxicosis from Graves’ hyperthyroidism. On palpation of the gland, Hashitoxicosis has a hard goiter, while Graves’ disease has a soft goiter. High antibody titers may also suggest Hashitoxicosis.
2. Treatment of hypothyroidism: All cases with overt hypothyroidism should be treated with levothyroxine. The dose of levothyroxine should be adjusted to bring the serum TSH level to the lower limit of normal, that is, 0.3-1.0 IU/L. Most women require a 25-50% increase in dose during pregnancy. If TSH is >4IU/L and anti-TPO (+), treatment should be started.
3. Treatment of goiter: In cases with Hashimoto’s thyroiditis with goiter, levothyroxine should be given to reduce goiter even if the patient is euthyroid. It has been shown that goiter shrinks in 50-90% of cases with 6 months of levothyroxine treatment. Good response is usually obtained, especially in young patients.
4.Surgical treatment: Surgical treatment can only be considered in the presence of significant compression symptoms and if there is strong suspicion of cancer. Non-iodized salt is recommended for patients with Hashimoto’s thyroiditis:
Conditions to suspect Hashimoto’s Disease
Hypothyroidism not attributable to other causes
Anti-TPO or anti-TG positivity without thyroid dysfunction/goiter
Thyroid cases with suspected lymphoma
Hypoechoic, heterogeneous appearance in ultrasonographic examination
PREPARED BY: UZM.DR.ELYESA KARACA
INTERNAL DISEASES SPECIALIST
