The thyroid gland is located on the front part of the neck below the thyroid cartilage (Adam's apple). The gland produces thyroid hormones, which regulate metabolic rate (how fast calories are consumed to produce energy). Thyroid hormones are important in regulating body energy, body temperature, the body's use of other hormones and vitamins, and the growth and maturation of body tissues.
Diseases of the thyroid gland can result in either production of too much (overactive thyroid disease or hyperthyroidism), too little (underactive thyroid disease or hypothyroidism) thyroid hormone, thyroid nodules, and/or goiter. Thyroid problems are much more common in women than in men.
All types of hyperthyroidism are due to overproduction of thyroid hormones, but the condition can be caused in several ways:
Graves' disease. This is an auto-immune condition and is the commonest cause of an overactive thyroid gland.
Toxic adenomas. Nodules develop in the thyroid gland and begin to secrete thyroid hormones, upsetting the body's chemical balance. Some goitres may contain several of these nodules.
Subacute thyroiditis. This is where inflammation of the thyroid causes the gland to ‘leak’ excess hormones, resulting in temporary hyperthyroidism. The condition generally lasts a few weeks, but it may persist for months.
Pituitary gland malfunctions or cancerous growths in the thyroid gland. In rare cases, hyperthyroidism can also be due to these causes.
Anxiety
Insomnia
Hand tremors
Nervousness
Feeling excessively hot in normal or cold temperatures
Frequent bowel movements
Losing weight despite normal or increased appetite
Excessive sweating
Menstrual period becomes scant, or ceases altogether
Joint pains
Difficulty concentrating
Eyes seem to be enlarging
Hypothyroidism, by contrast, stems from an underproduction of thyroid hormones. Since your body's energy systems require certain amounts of thyroid hormones, a drop in hormone production leads to lower energy levels. Causes of hypothyroidism include:
Hashimoto's disease. In this autoimmune disorde r, the body’s own immune system attacks thyroid tissue, leading to reduced thyroid hormone.
Removal of the thyroid gland. The thyroid may be surgically removed or chemically destroyed as a treatment for hyperthyroidism.
Exposure to excessive amounts of iodide. Cold and sinus medicines, the heart medicine amiodarone or certain contrast dyes given before X-rays may expose you to too much iodine.
You may then be at greater risk of developing hypothyroidism, especially if you have had thyroid problem s in the past.
Lithium. This drug has also been linked to hypothyroidism.
Constipation
Poor feeding
Poor growth
Jaundice (yellow discoloration of the skin and eyes)
Excessive sleeping
Excessive fatigue
Delayed tooth development
Delayed sexual maturation
Easy fatigue, exhaustion
Poor tolerance to cold temperatures
Poor appetite
Weight gain
Dry skin
Hair loss
Intellectual ability worsens
Deeper, hoarse voice
Puffiness around the eyes
Depression
Irregular menstrual periods or lack of menstrual periods
