QUEEN VICTORIA
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What are the symptoms of hyperthyroidism?
Hyperthyroidism is suggested by several signs and symptoms; however, patients with mild disease usually experience no symptoms. In patients older than 70 years, the typical signs and symptoms also may be absent. In general, the symptoms become more obvious as the degree of hyperthyroidism increases. The symptoms usually are related to an increase in the metabolic rate of the body. Common symptoms include:
Excessive sweating
Heat intolerance
Increased bowel movements
Tremor (usually fine shaking)
Nervousness; agitation
Rapid heart rate
Weight loss
Fatigue
Decreased concentration
Irregular and scant menstrual flow
In older patients, irregular heart rhythms and heart failure can occur. In its most severe form, untreated hyperthyroidism may result in "thyroid storm," a condition involving high blood pressure, fever, and heart failure. Mental changes, such as confusion and delirium, also may occur.
How is hyperthyroidism diagnosed?
Hyperthyroidism can be suspected in patients with tremors, excessive sweating, smooth, velvety skin, fine hair, a rapid heart rate and an enlarged thyroid gland. There may be puffiness around the eyes and a characteristic stare due to the elevation of the upper eyelids. Advanced symptoms are easily detected, but early symptoms, especially in the elderly, may be quite inconspicuous. In all cases, a blood test is needed to confirm the diagnosis.
The blood levels of thyroid hormones can be measured directly and usually are elevated with hyperthyroidism. However, the main tool for detection of hyperthyroidism is measurement of the blood TSH level. As mentioned earlier, TSH is secreted by the pituitary gland. If an excess amount of thyroid hormone is present, TSH is "down-regulated" and the level of TSH falls in an attempt to reduce production of thyroid hormone. Thus, the measurement of TSH should result in low or undetectable levels in cases of hyperthyroidism. However, there is one exception. If the excessive amount of thyroid hormone is due to a TSH-secreting pituitary tumor, then the levels of TSH will be abnormally high. This uncommon disease is known as "secondary hyperthyroidism."
Although the blood tests mentioned previously can confirm the presence of excessive thyroid hormone, they do not point to a specific cause. If there is obvious involvement of the eyes, a diagnosis of Graves' disease is almost certain. A combination of antibody screening (for Graves' disease) and a thyroid scan using radioactively-labelled iodine (which concentrates in the thyroid gland) can help diagnose the underlying thyroid disease. These investigations are chosen on a case-by-case basis.
QUEEN VICTORIA
Age: 124
7814 days old here
Total Posts: 26285
Points: 0
Location:
Lahore, Pakistan
Thyroid hormone regulation--the chain of command
The thyroid itself is regulated by another gland located in the brain, called the pituitary. In turn, the pituitary is regulated in part by thyroid hormone that is circulating in the blood (a "feedback" effect of thyroid hormone on the pituitary gland) and in part by another gland called the hypothalamus, also a part of the brain.
The hypothalamus releases a hormone called thyrotropin releasing hormone (TRH), which sends a signal to the pituitary to release thyroid stimulating hormone (TSH). In turn, TSH sends a signal to the thyroid to release thyroid hormones. If overactivity of any of these three glands occurs, an excessive amount of thyroid hormones can be produced, thereby resulting in hyperthyroidism.
Hypothalamus - TRH
Pituitary- TSH
Thyroid- T4 and T3
The rate of thyroid hormone production is controlled by the pituitary gland. If there is an insufficient amount of thyroid hormone circulating in the body to allow for normal functioning, the release of TSH is increased by the pituitary in an attempt to stimulate the thyroid to produce more thyroid hormone. In contrast, when there is an excessive amount of circulating thyroid hormone, the release of TSH is reduced as the pituitary attempts to decrease the production of thyroid hormone.
What causes hyperthyroidism?
Some common causes of hyperthyroidism include:
Graves' Disease
Functioning adenoma ("hot nodule") & Toxic Multinodular Goiter (TMNG)
Excessive intake of thyroid hormones
Abnormal secretion of TSH
Thyroiditis (inflammation of the thyroid gland)
Excessive iodine intake Graves' Disease