thyroiditis Thyroiditis is a heterogeneous group of diseases affecting the thyroid gland, characterized by the destruction of thyroid follicular structure due to various factors such as autoimmunity, viral infection, bacterial or fungal infection, radiation damage, medications, etc. This condition can lead to thyroid enlargement and inflammation, resulting in either an excess or a deficiency of thyroid hormones in the bloodstream, leading to symptoms resembling hypothyroidism or hyperthyroidism.

The thyroid is a butterfly-shaped gland located below the Adam's apple on either side of the trachea, forming an "H" shape. It regulates various bodily functions, including growth, metabolism, and protein synthesis, by secreting thyroid hormones.

Thyroiditis is a heterogeneous group of diseases affecting the thyroid gland, characterized by destruction of thyroid follicular structures due to factors such as autoimmunity, viral infection, bacterial or fungal infection, radiation damage, and medication. This condition can lead to thyroid enlargement and inflammation, resulting in either an excess or a deficiency of thyroid hormones in the bloodstream, leading to symptoms resembling hypothyroidism or hyperthyroidism.

Autoimmunity

In most cases, the patient's immune system, particularly lymphocyte T cells, attacks the thyroid, causing damage and apoptosis of thyroid cells, leading to destruction of thyroid follicles and inadequate production of thyroid hormones, thus triggering thyroiditis. Autoimmune-induced thyroiditis includes Hashimoto's thyroiditis, atrophic thyroiditis, painless thyroiditis, postpartum thyroiditis, and others.

Infection

Most commonly caused by bacterial or viral infections, which can be secondary to upper respiratory infections, influenza, where pathogens spread directly from the oral cavity or other soft tissues in the neck to the thyroid, causing tissue damage and inflammation. This includes acute suppurative thyroiditis, subacute thyroiditis, and others.

Radiation

High-dose radioactive iodine therapy and external radiation to the head and neck can cause radiation damage, leading to thyroid tissue edema and congestion, ultimately resulting in glandular atrophy and decreased thyroid function.

Local Symptoms

Generally, thyroiditis manifests as varying degrees of thyroid enlargement, with a firm texture and possible accompanying pain.

For patients with subacute thyroiditis, significant thyroid area pain is a characteristic feature.

For individuals with normal thyroid function affected by Hashimoto's thyroiditis, they may experience mild discomfort in the throat, mild swallowing difficulty, or a sense of neck compression.

Systemic Symptoms

Thyroiditis, characterized by thyroid swelling or inflammation, can result in excess or insufficient thyroid hormone secretion. Thyroiditis presents in three stages:

Thyrotoxic Phase

This phase occurs when thyroid inflammation leads to destruction or necrosis of follicles, causing leakage of thyroid hormones stored in the follicular lumen into the bloodstream. Due to hyperactive thyroid function, patients may exhibit irritability, weight loss, heat intolerance, insomnia, tachycardia, and fatigue.

Hypothyroid Phase

Several weeks or months after the excessive release of thyroid hormones, the thyroid fails to release sufficient hormones, resulting in a lack of thyroid hormones or decreased thyroid function. Patients may experience fatigue, edema, weight gain, cold intolerance, and constipation.

Recovery Phase

During this phase, the thyroid recovers from inflammation and can maintain normal hormone levels. Most patients regain normal function, while a few may experience permanent hypothyroidism.

For patients with hypothyroidism due to Hashimoto's thyroiditis, the predominant manifestation is thyroid function decline, with most patients seeking medical attention for thyroid enlargement or hypothyroid symptoms. Patients with subacute thyroiditis or painless thyroiditis may exhibit symptoms across these three stages.

Aside from medication, lifestyle changes related to diet can positively impact disease management.

Avoid consuming any food within one to two hours of taking thyroid medication, as it may affect the medication's absorption in the body.

Promote an iodine-appropriate diet, maintaining existing dietary habits (i.e., avoiding excessive or inadequate consumption of iodine-rich foods such as seaweed and kelp).

Maintain a balanced diet, including consumption of pork, beef, eggs, legumes, vegetables, and fruits. Consider taking supplements to ensure adequate supply of minerals and nutrients such as selenium and zinc, thereby maintaining normal thyroid function.

Minimize intake of gluten-containing foods, such as barley, wheat, and rye.

Most cases of thyroiditis cannot be prevented.

If the patient needs to undergo diagnostic and therapeutic radioactive iodine use, it is advisable to consult a doctor to understand the risk of developing thyroiditis and whether alternative treatments are available.

If the patient is using prescription medications that may lead to thyroiditis, such as interferon, it is important to consult their doctor about the risks of medication and whether discontinuation is advisable.

While thyroiditis cannot be prevented, understanding and recognizing its symptoms is crucial. Seeking medical attention promptly upon noticing symptoms can help limit the progression of the disease.