causes hypothyroidism

Hypothyroidism can be central or principal. Central hypothyroidism can go to a malfunction of the system known as the hypothalamic-pituitary axis, resulting in decreased release of thyrotropin-stimulating hormone (TSH) and decreased the biological effects of TSH. Therefore, there is a decrease in the recovery of TSH thyroid gland and, secondly, a decrease in thyroid hormone production and release. Primary hypothyroidism refers directly to a deficiency in the thyroid gland resulting in lower production and release of thyroid hormones.

The mid range of disease is usually divided into a second hypothyroidism, if the lack of the pituitary gland, and tertiary hypothyroidism, where the fault lies in the hypothalamus. Since a useful approach, the result is the same: a decrease in physiologically active hormone secretion. Diversity of problems can arise in central hypothyroidism.

Although the lack of a solitary thyroid-stimulating hormone-releasing hormone (TRH) and TSH, it is likely that the more often a person who is central to the disease seems to be the absence of other pituitary hormones, and this is just a piece of a broader clinical picture of hypopituitarism.

Depending on the severity of the damage incurred by the hypothalamic-pituitary axis, the origin of central hypothyroidism be reversible or permanent.

Pituitary adenomas are most common in clinical practice. A small amount of the situation including pituitary apoplexy, and infiltrative disorders of the hypothalamic-pituitary axis, granulomatous diseases such as sarcoidosis, tuberculosis and others.

Some of the hypothalamus or pituitary gland injury due to central hypothyroidism

Aneurysms

Chronic Lymphocytic hypophysitis

Congenital anomalies

Defects of the thyrotropin-releasing hormone, TSH, or both bleeding

Infectious diseases

Infiltrative disorders

Metastasis

Necrosis

Other brain tumors

Pituitary tumors

Surgery

Trauma

Chronic autoimmune (Hashimoto's) thyroiditis is the most important source of primary hypothyroidism in areas with sufficient iodine. Pathophysiological damage cells and not mediated by humoral thyroid gland. Occasionally, a person may exhibit thyrotoxicosis due to the presence of thyroid stimulating antibodies (a program called Hashitoxicosis).

The frequency of hypothyroidism explicit range from less than 1% to 2% of the population. Euthyroid persons have detectable autoantibodies are at increased risk of developing hypothyroidism clear. Hypothyroidism caused by autoimmune thyroiditis may be part of a polyglandular dysfunction syndrome, which may include an auto-immune adrenal insufficiency, type 1 diabetes, hypogonadism, pernicious anemia and vitiligo.

Up to 15% of women have thyroid antibodies. The occurrence is more than a few times higher in women than in men. Most patients have measurable antibodies against several molecules of the thyroid gland, and thyroid peroxidase, thyroglobulin, TSH receptor, etc. Clinically, patients with Hashimoto's thyroiditis can show their disease, with or without goiter. Primary hypothyroidism is responsible for most of the reports of hypothyroidism.

Some of the lesions of the thyroid gland that causes primary hypothyroidism

Agenesis or dysgenesis of the thyroid

The chronic autoimmune thyroiditis

Drugs

I-131 treatment, external radiation

Iodine deficiency, excess iodine

Infiltrative disorders

Postpartum subacute thyroiditis, silent

Thyroid Surgery