Exophthalmic goitre, also known as Graves disease, is an autoimmune disease. It is a disease related to the thyroid gland and it is caused due to hyperthyroidism. Thyroid glands generally become enlarged and secrete high levels of thyroid hormones. A combination of genetic and environmental factors are responsible for the disease.
Exophthalmic goitre is characterised by over-secretion of thyroid hormones, protruded eyeballs, weight loss and an increase in Basal Metabolic Rate (BMR).
Thyroid Gland
The thyroid gland is an endocrine gland. It is a butterfly-shaped gland that is present on either side of the trachea. The isthmus connects the two lobes of the thyroid gland. The two main hormones synthesised by the follicular cells of the thyroid gland are tetraiodothyronine or thyroxine (T4) and triiodothyronine (T3). Iodine is essential for the synthesis of thyroid hormones.
The thyroid gland regulates many biological processes, such as Basal Metabolic Rate (BMR), carbohydrate, fat and protein metabolism, electrolyte balance, etc. The thyroid gland also stimulates Red Blood Cell (RBC) production.
Thyrocalcitonin (TCT) produced by the thyroid is responsible for maintaining blood calcium levels.
The optimal hormonal level is necessary for the normal functioning of the body. Too high or too low levels of thyroid hormones cause various disorders.
Hypothyroidism
Hypothyroidism is caused due to low levels of thyroid hormones. Iodine deficiency in the diet causes hypothyroidism. It leads to the enlargement of the thyroid gland, which is known as goitre. Cretinism is caused due to hypothyroidism during pregnancy. It is a congenital thyroid deficiency. Cretinism is characterised by stunted growth, mental retardation, learning difficulties, abnormal skin, etc.
Hypothyroidism is one of the reasons for the irregular menstrual cycle in women.
Hyperthyroidism
Hyperthyroidism is caused due to excessive secretion of the thyroid hormones. It occurs due to thyroid cancer or nodule formation. Exophthalmic goitre is an example of hyperthyroidism.
Exophthalmic Goitre – Causes
It is an autoimmune disease. It is also known as Grave’s disease. Exophthalmic goitre is caused due to genetic as well as environmental factors. Pregnancy, infection or even stress can lead to the disease. People with any other autoimmune diseases are at high risk to develop exophthalmic goitre.
In exophthalmic goitre, the immune system starts producing antibodies that stimulate the synthesis of thyroid hormones. The body starts producing thyroid-stimulating immunoglobulin (TSI). It acts like a Thyroid-stimulating Hormone (TSH) and stimulates the thyroid gland to produce more thyroid hormones. The TSI recognises and binds to TSH receptors and stimulates the synthesis of T4 and T3.
Exophthalmic Goitre Symptoms
The main symptoms of exophthalmic goitre are protruded eyeballs, inflammation, dry and swollen eyes, weight loss and an increase in Basal Metabolic Rate (BMR). A person with exophthalmic goitre shows most symptoms of hyperthyroidism, like weight loss, insomnia, excessive sweating, hair loss, muscle weakness, tremors, heat intolerance, etc.
Exophthalmic Goitre Treatment
The treatment of exophthalmic goitre includes
- Radioactive iodine administration, which shrinks the thyroid gland.
- Anti-thyroid medications, which reduce the synthesis of thyroid hormones.
- Thyroidectomy, i.e., removal of the thyroid gland.
- Beta-blockers can be used to inhibit the sympathetic nervous system. It reduces symptoms like rapid heart rate, palpitations, tremors, etc.
- Corticosteroids can be used to treat Graves ophthalmopathy.
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