Characteristics of thyroid diseases

There are two features of thyroid diseases, changes in “function” and “shape” of the thyroid. Some diseases cause both changes, while others cause only one type of change.

Changes in thyroid “function”

Some diseases may cause a condition called “thyroid dysfunction,” in which abnormalities occur in the production of thyroid hormones. The level of thyroid hormone production may be excessive or insufficient.

【 Thyrotoxicosis 】

his is a condition in which thyroid hormones are produced in excess. Increased levels of thyroid hormones in the blood accelerates metabolism. These disorders are generally divided into two categories: hyperthyroidism and destructive thyroiditis.

【 Hypothyroidism 】

This is a condition in which the production of thyroid hormones is reduced, leading to a low metabolism.

Changes in thyroid “shape”

Some diseases can cause swelling or lumps in the thyroid gland, resulting in changes in shape. Swelling is called “goiter.

【 Diffuse goiter 】

A condition in which the entire thyroid gland enlarges

	Simple diffuse goiter This condition occurs when the entire thyroid gland slightly swells without thyroid dysfunction. Simple diffuse goiter may develop into Basedow’s disease or Hashimoto’s disease in the future.
	Basedow’s disease Basedow’s disease occurs when a substance in the body causes the thyroid gland to be overactive. It can cause palpitations, swelling of the thyroid gland, and eye symptoms.
	Hashimoto’s disease This disease, also called chronic thyroiditis, is characterized by chronic inflammation of the thyroid gland. Many patients exhibit no thyroid dysfunction, but some have reduced production of thyroid hormones. In certain cases, thyroid function temporarily fluctuates, a condition known as painless thyroiditis.
	Subacute thyroiditis This is a condition in which the thyroid swells and is painful. Fever often occurs as well. Since the thyroid temporarily releases excessive levels of hormones, subacute thyroiditis has symptoms similar to Basedow’s disease. However, symptoms gradually subside. Recurrence is rare.

【 Nodular goiter 】

A condition in which lumps develop in part of the thyroid

Thyroid tumors Most tumors do not cause abnormalities in thyroid function, but there are cases in which functional nodules result in overproduction of thyroid hormones. Some patients have fluid accumulation in sac-like nodules (cysts). These nodules are classified as benign or malignant tumors.

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