HASHIMOTO'S THYROIDITIS: Causes, Symptoms and Treatment of Chronic Autoimmune Thyroiditis

There Chronic Hashimoto's thyroiditis, also called chronic autoimmune thyroiditis or lymphocytic thyroiditis, is a chronic inflammation of the thyroid gland, and is a very common disease. In fact, it represents the more frequent cause of hypothyroidism of the adult, and is secondary to an autoimmune process affecting the thyroid tissue. THE symptoms of Hashimoto's thyroiditis are the classics symptoms of hypothyroidism (weight gain, constipation, depression). The therapy is based on the use of levothyroxine for the correction of hypothyroidism, the prognosis is very good.

What is Hashimoto's Thyroiditis

There Hashimoto's thyroiditis it is the most frequent chronic thyroid disease of all, as well as the main cause of hypothyroidism. It is also called chronic autoimmune thyroiditis or lymphocytic thyroiditis, since it is characterized by the presence of circulating antibodies to thyroperoxidase (anti-TPO) and to thyroglobulin (anti-Tg) with high titer, by a lymphocytic infiltration of thegland thyroid (this datum is verifiable only with a histological analysis of the thyroid tissue), and it is frequently associated with other autoimmune diseases, such as autoimmune diabetes, celiac disease and vitiligo.In fact, the presence of autoantibodies directed against thyroid antigens, in particular against thyroglobulin (Tg) and thyroid peroxidase (TPO), is common in this pathology.

It also appears that cellular type immunity, ie that mediated directly by lymphocytes CD4 + which stimulate the macrophage production of cytokines and by CD8 + lymphocytes which could carry out a direct damage action against thyroid cells, have a decisive role in the onset of chronic damage that leads to hypothyroidism. The confirmation that the Hashimoto's lymphocytic thyroiditis is a thyroiditis of autoimmune etiology  is found by observing the high number of people who developed thyroiditis and hypothyroidism during therapy with interferon, a drug used in the hematology field and, although now abandoned, in the hepatology field for the treatment of viral hepatitis.

Interferon is a substance, also produced by our organism, capable of inducing and modulating the expression of particular proteins on cell surfaces (HLA class I and II antigens) and of activating or reducing the immune response, depending on the case. Another factor confirming the autoimmune genesis of this thyroiditis is the familial predisposition: people with autoimmune diseases (type 1 diabetes, celiac disease, alopecia and vitiligo, myasthenia, autoimmune hepatitis and many others) also often suffer from Hashimoto's thyroiditis, and have or will have relatives who in turn are or will be affected by autoimmune diseases.It is good to know that Hashimoto's thyroiditis is not the only autoimmune disease that can affect the thyroid: there are also other autoimmune thyroid diseases, among which we remember Graves' disease (or Basedow's disease), thyroid ophthalmopathy and atrophic thyroiditis.

Curiosity: patients often shorten the name of the pathology by defining it Hashimoto's thyroid gland, a term that actually has no meaning. In other cases we speak of Hashimoto syndrome you hate Hashimoto's disease, not quite exact definitions that cannot replace the correct one of Hashimoto's chronic thyroiditis.

Hashimoto's Thyroiditis

Hashimoto's thyroiditis is an autoimmune disease that affects the thyroid gland and often results in hypothyroidism.

What Happens to the Thyroid During Hashimoto's Autoimmune Thyroiditis?

The thyroid usually appears enlarged, retains its symmetry and bilobed shape. More rarely, thyroiditis presents with a single lump of increased consistency. The perithyroid and laterocervical lymph nodes are often enlarged. Analyzing the thyroid at a histological level (such as can be done after obtaining a sample of thyroid tissue with a thyroid fine needle aspiration with a fine needle FNAB), the thyroid tissue affected by an intense interstitial inflammatory infiltrate will be observed. Residual thyroid follicular cells will be markedly infiltrated by lymphocytes and plasma cells. In the more advanced stages the Hashimoto's thyroiditis it will evolve from a called phase mobile phone, not infrequently associated with hyperthyroidism, with a phase called fibrous, characterized by thyroid gland atrophy and hypothyroidism.

Symptoms of Hashimoto's Thyroiditis

What are the main signs and symptoms of Hashimoto's thyroiditis? It depends on what moment of the disease is being examined! In the Early stages of Hashimoto's thyroiditis, the main symptoms they will be:

  • goiter of modest size, not painful
  • low-grade fever
  • swollen lymph nodes in the neck
  • tremors
  • slimming
  • irritability
  • increased heart rate
  • diarrhea
  • bulging eyes (thyroid ophthalmopathy, is rare, only in the case of Graves' disease developing within the defined "Hashitoxicosis")
  • pretibial myxedema (thyroid inflammatory dermopathy, also rare)

These symptoms are present only in the first moments of lymphocytic thyroiditis and are obviously associated with the possible thyrotoxicosis that develops in some cases in the first days of the disease. As the weeks go by, the thyroid gland will progressively lose its synthesis function of the thyroid hormones thyroxine and triiodothyronine, evolving towards a hypothyroidism, initially subclinical (High TSH with normal fT3 and fT4) and then proclaimed (High TSH with low fT3 and fT4).THE main symptoms of chronic Hashimoto's thyroiditis during the period of evolution towards hypothyroidism will therefore be:

  • tiredness and easy fatigue
  • tendency to gain weight
  • reduced heart rate
  • constipation (constipation)
  • tendency to depression
  • skin pallor
  • fragility of nails, hair and body hair

Clinical course of Hashimoto's thyroiditis

Chronic thyroiditis is often diagnosed in the stage of subclinical hypothyroidism due to the presence of goiter, or, more frequently, due to the chance finding of an increase in thyrotropin in blood tests. Although it is not always possible to predict what the evolution of autoimmune thyroiditis will be, in general the probability of developing a state of clinical hypothyroidism is linked with the extent of the elevation of TSH and anti-thyroid peroxidase antibodies (ab TPO); in the presence of TSH greater than 10 mU / ml and antiperoxidase antibodies with a high titre, the risk of developing clinical hypothyroidism within a few years is very high.

Are there any complications that can appear even after the onset of thyroiditis? The rare association between Hashimoto's thyroiditis and thyroid lymphoma and systemic neoplasms of the lymphatic tissue is described in the literature since it is thought that the chronic antigenic stimulation of lymphocytes that occurs in autoimmune diseases can induce a greater ease of neoplastic transformation in some lymphocyte populations.

Diagnosis of Hashimoto's Thyroiditis

How do you know if you have Hashimoto's autoimmune thyroiditis? The diagnosis of chronic autoimmune thyroiditis is relatively simple, and is facilitated thanks to specific laboratory tests. In fact, in the suspicion of thyroiditis are blood tests to be carried out on the front line:

  1. TSH (thyrotropin)
  2. T4 and fT4 (total and free thyroxine)
  3. T3 and fT3 (total and free triiodothyronine)
  4. antibodies to thyroglobulin
  5. antibodies to thyroid peroxidase

During the initial stages of thyroiditis, antithyroglobulin antibodies are increased, while in the more advanced stages the antibodies to thyroglobulin are slowly reduced, with a simultaneous increase in antibodies to thyroperoxidase, which remain at a high titer in circulation for many years. The normality of circulating levels of FT3 and FT4 (free fraction of thyroxine and triiodothyronine) does not allow to exclude the diagnosis of Hashimoto's chronic autoimmune thyroiditis, since, as we have already seen, the circulating levels of thyroid hormones vary depending on which phase of the disease is being observed. 

L'thyrotropic or thyroid stimulating hormone (TSH) is the main marker which, checked periodically, allows to monitor the progress of the disease and the possible progression towards hypothyroidism, if this is associated with a reduction in thyroid hormonesAt the ultrasound level, thyroid nodules or inflammatory foci causing a focal swelling of the thyroid parenchyma simulating a nodule may be evident in a small number of cases. The fine needle aspiration and subsequent cytological examination is usually notessential for diagnosis, but must be performed for the differential diagnosis of suspicious thyroid nodulations.

Second level tests for the diagnosis of Hashimoto's thyroiditis they are the execution of antibodies to TSH receptor, the anti r-TSH, which are more frequent in Graves' disease and serve to differentiate this latter pathology from Hashimoto's thyroiditis in the initial phase. Other second-level tests are labeled radioiodine uptake tests or thyroid scintigraphy.Another factor that can give, if necessary, further confirmation of the presence of a chronic thyroid disease, is the simultaneous presence of signs or symptoms of associated autoimmune diseases, which your endocrinologist will certainly look for at the time of the medical history and physical examination.

Hashimoto's Thyroiditis Therapy

How is chronic autoimmune thyroiditis treated? The main treatment is obviously the replacement treatment with L-thyroxine (levothyroxine, more known trade names Eutirox or TIrosint), which restores the normal values of thyroid hormones, in addition to inhibiting the exaggerated production of TSH and obtaining a regression of the goiter. There levothyroxine therapy it is recommended in all patients with Hashimoto's thyroiditis, even in those with subclinical hypothyroidism, as the disease has a progressive course that ends with actual hypothyroidism.

It is also good to know that, during replacement therapy, the antibody titer of antiTPO and antiTGB is not relevant to the success of the treatment: in other words, having fluctuations in the antibody values does not mean that the therapy has more or less effect. .In the initial stages of Hashimoto's thyroiditis there may be the possible presence of Hashitoxicosis, i.e. thyrotoxicosis with hyperthyroidism due to increased release of T3 and T4 from damaged thyrocytes. In these cases, a suppressive therapy based on is evaluated with the endocrinologist specialist methimazole (trade name Tapazole, starting dose of 20 mg per day) or propylthiouracil (trade name Pertiroid, starting dose 200 mg per day), which reduces the effect of thyroid hormones on the body.

If suppressive therapy is not enough, for symptoms such as tachycardia, anxiety, weight loss, the temporary introduction of a beta-blocker drug will also be evaluated.In these phases the thyroid hormones should be checked first weekly, then every 15 days, until the thyrotoxic phase is resolved.The therapy of chronic lymphocytic thyroiditis is then usually monitored by performing first monthly and then at shorter intervals (3, 6, 12 months) of blood tests including TSH, the free fraction of the thyroid hormones fT4 and fT3, and, based on the type of attendance, the anti-thyroid antibodies listed above.

Hashimoto's Thyroiditis Prognosis

If recognized and treated adequately, this type of pathology allows an absolutely normal daily life and without a reduction in life expectancy.

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