Thyroiditis is an inflammation of the thyroid gland. I remind you that, in general, whenever we encounter the suffix -ite (for example bronchitis, pneumonia, gastritis, tendonitis, etc.) it means that we are in the presence of an inflammatory process.
The term thyroiditis is therefore used to indicate a group of disorders united by the presence of an inflammatory process affecting the thyroid. However, these disorders are also very different from each other in causes, symptoms, evolution and other aspects. To better understand some of these differences, the various forms of thyroiditis are distinguished, based on the course, into acute, subacute and chronic.
Among all thyroiditis, the most common forms are chronic lymphocytic thyroiditis, also called Hashimoto's thyroiditis, which progressively shuts down the thyroid and its function, and De Quervain's subacute thyroiditis, which instead involves transient changes in thyroid activity. known forms are acute suppurative thyroiditis, postpartum (or sporadic) silent thyroiditis and Riedel's thyroiditis.
Given the broad premise, it is obvious that thyroiditis recognizes various causes.
In the case of chronic Hashimoto's thyroiditis, the inflammation is caused by an abnormal activation of the immune system, which - no longer recognizing them as its own - attacks healthy thyroid cells with antibodies. For this reason, Hashimoto's thyroiditis is considered an autoimmune disease, since the immune system acts as if the thyroid were a foreign tissue, dangerous and therefore worthy of an attack.
Chronic thyroiditis can also appear in the post-pregnancy period or be triggered by the use of certain drugs or by local irradiation of the neck.
Acute thyroiditis, on the other hand, is often caused by a bacterial infection, while the subacute one generally recognizes a viral origin. Precisely for this etiology, thyroiditis is sometimes preceded by an affection of the upper respiratory tract, such as pharyngitis or laryngitis, that is the classic sore throat.
Now let's see, briefly, the characteristics of the most frequent thyroiditis, starting from Hashimoto's thyroiditis.
As we have seen, Hashimoto's thyroiditis is a chronic autoimmune disease, therefore present throughout life. The onset is slow and often completely asymptomatic, but can be associated with the onset of goiter. Paradoxically, in the initial phase of chronic Hashimoto's thyroiditis, some symptoms typical of the presence of an excess of thyroid hormones in the circulation can be found. Later, this autoimmune disease predisposes to thyroid dysfunction, more frequently in the sense of an increasingly marked and irreversible hypothyroidism. In fact, we recall that Hashimoto's thyroiditis is among the most frequent causes of primary hypothyroidism.
Interestingly, patients with this form of thyroiditis often have other associated autoimmune diseases and there is a family-related risk percentage.
De Quervain's thyroiditis, on the other hand, is a transient inflammation of the thyroid gland. It typically has an abrupt onset and frequently follows a viral infection. The course is sub-acute, that is, the recovery is neither fast nor slow, in short, somewhere in between.
As for the symptoms, De Quervain's thyroiditis is characterized by the onset of fever, general malaise, enlarged thyroid and neck pain. In the initial phase, there may be an excessive release of thyroid hormones from the damaged thyroid tissue due to inflammation, which however tends to regress over time. Once healed, this condition rarely evolves into mild hypothyroidism.
In the case of De Quervain's thyroiditis there is no specific treatment, but, fortunately, the resolution is spontaneous and occurs within a few weeks (this is why the course is called subacute); antiviral and anti-inflammatory therapy can facilitate the healing process.
The symptoms of thyroiditis are also different and, in many cases, the variety of manifestations reflects the different evolution of the inflammatory process.
I'll explain. If thyroiditis causes slow and chronic damage to thyroid cells, resulting in a decrease in the levels of thyroid hormones in the blood, the symptoms are typical of hypothyroidism, therefore: fatigue, weight gain, constipation, dry skin and depression. This is, for example, the case with Hashimoto's thyroiditis.
If, on the other hand, the inflammatory process is fast and abrupt, as in the case of De Quervain's subacute thyroiditis, due to cell damage the thyroid hormones accumulated inside the thyroid are released into the bloodstream causing their levels and symptoms to increase. similar to those of hyperthyroidism, such as anxiety, insomnia, palpitations, fatigue, irritability and weight loss. I open a small parenthesis: in such circumstances, it would be more correct to speak of thyrotoxicosis rather than hyperthyroidism. The difference is subtle; both conditions are in fact characterized by elevated levels of thyroid hormones in the blood, therefore by similar symptoms. However, while in the case of hyperthyroidism there is an increased production of thyroid hormones, in thyrotoxicosis this increase depends on the release of the preformed hormones contained in the colloid of the follicles which have been destroyed by the inflammatory process. Other causes of thyrotoxicosis are, for example, the intake of synthetic thyroid hormones or the ectopic synthesis of these hormones by other organs.
Returning to us, an "other difference from" hyperthyroidism is that acute and subacute thyroiditis tend to manifest itself with some typical symptoms, such as fever, swelling and pain in the neck, with the overlying skin hot and red.
The diagnosis of thyroiditis is based on: anamnesis (therefore on the collection of information reported by the patient), laboratory tests and instrumental tests.
First, the function of the gland is studied through a "blood test for the determination of thyroid hormones and thyroid stimulating hormone (TSH). Many patients with thyroiditis have normal thyroid function; others, however, develop hypothyroidism or episodes of increased thyroid function. Markers demonstrating the autoimmune nature of the disease are represented by the increase in the blood of anti-thyroid antibodies, that is, produced by the body itself against the thyroid, in particular anti-thyroid peroxidase antibodies (or AbTPO) and antithyroglobulin (or AbTg) In case of acute thyroiditis, ESR and other inflammation indices are elevated, while blood culture can be positive in the case of septicemia.
With regard to instrumental investigations, thyroid ultrasound can help in highlighting an inflammatory picture, especially with regard to inhomogeneity or a pseudo-nodular aspect of the thyroid. The histological examination of the thyroid tissue, taken by fine needle aspiration, can be especially useful in the evaluation of suspicious nodules and in the differential diagnosis with thyroid neoplasms. The fine needle aspiration is, in many cases, useful in "identifying the pathogen responsible for thyroiditis. Finally, scintigraphy can sometimes show a low uptake of radioactive iodine in the inflamed area.
Treatments depend on the type of thyroiditis diagnosed. Acute and subacute thyroiditis are usually transient and heal completely, leaving no permanent changes in thyroid function.
If the cause of thyroiditis is a bacterial infection, broad-spectrum or specific antibiotics are prescribed, based on the antibiogram of the pathogen isolated from the gland.
For Hashimoto's thyroiditis, treatment often involves hormone replacement therapy, to correct the hypothyroidism that the thyroid may experience. In these cases, the intake of thyroid hormones must continue throughout life. However, we have seen how Hashimoto's thyroiditis can initially present itself with thyrotoxicosis. In this case, the patient may need rest, non-steroidal anti-inflammatory drugs and beta-blockers to lower the heart rate and reduce tremors.
For non-infectious forms of thyroiditis, non-steroidal anti-inflammatory drugs (NSAIDs) or corticosteroids are used, depending on the severity of the case, which determine a resolution of painful symptoms related to local inflammation.
Finally, if the gland has increased excessively in volume, or in the presence of any aesthetic damage or suspicious nodules, some patients may undergo surgical treatment, especially to preserve the adjacent structures.
