What is Hypothyroidism?
The pituitary gland and hypothalamus both control the thyroid. When thyroid hormone levels drop, the hypothalamus secretes TSH Releasing Hormone (TRH), which alerts the pituitary to produce thyroid stimulating hormone (TSH).
The thyroid keeps your metabolism under control with thyroid hormone, which it makes by extracting iodine from the blood.
Every cell in your body depends on the thyroid to manage its metabolism.
Hypothyroidism occurs when the thyroid fails to make enough of these hormones.
When the thyroid gland is unable to produce sufficient amounts of thyroxine (T4) and tri-iodothyronine (T3) then problems start to occur in all of the body’s systems as the normal bodily functions start to slow down.
All the body hormones work together, so that changes in one effect others. When our body is young this generally works like a well oiled machine. When we pass middle age, the changes affect us more.
This is a possible reason why more women than men appear to be affected by hyperthyroidism especially after they turn 50.
There are three types of hypothyroidism.
The most common is primary hypothyroidism, in which the thyroid gland itself becomes diseased and fails to produce sufficient amounts of the thyroid hormone. The most common forms include Hashimoto’s thyroiditis (an autoimmune disease) and radioiodine therapy for hyperthyroidism.
Secondary hypothyroidism is caused by problems with the pituitary gland and accounts for less than 5-10% of hypothyroidism disorders. It occurs if the pituitary gland does not create enough thyroid-stimulating hormone (TSH) to stimulate the thyroid gland to produce the required amount of thyroxine and triiodothyronine. It is usually caused by damage to the pituitary gland, as by a tumor, radiation, or surgery.
Tertiary hypothyroidism results when the hypothalamus fails to produce sufficient thyrotropin releasing hormone (TRH). TRH prompts the pituitary gland to produce thyroid-stimulating hormone (TSH). Hence tertiary may also be termed hypothalamic-pituitary-axis hypothyroidism. It accounts for less than 5% of hypothyroidism cases.
Patients who have hypothyroidism should exercise caution with certain activities, especially if an activity has a risk of injury (eg, operating presses or heavy equipment, driving, heavy physical labour and contact sports. If their treatment is not yet stabilised and they are having difficulty maintaining concentration in low-stimulus activities, they may have slowed reaction times.
They may also be at risk for ligamental injury, particularly from excessive force across joints due to generalized hypotonia. Hypotonia is a state of low muscle tone (the amount of tension or resistance to movement in a muscle), often involving reduced muscle strength.
Hypothyroidism may be linked to other autoimmune diseases, such as Addisons disease, Chronic Fatigue Syndrome, Diabetes Mellitus, Euthyroid Sick Syndrome, Fibromyalgia, Lupus, Polyglandular Autoimmune Syndrome & Vitiligo.
- Pituitary hormone TSH found to directly influence bone growth (eurekalert.org)
- Giving Your Thyroid a Helping Hand (bigsexymedia.com)
- Energy Shortage: Is Your Thyroid to Blame? (abcnews.go.com)