The most common cause is autoimmune in nature, specifically Hashimoto’s thyroiditis. Other causes include: radioactive iodine treatment, thyroid operation, medications, and spontaneous onset.
In its earliest stage, hypothyroidism may cause few symptoms, since the body has the ability to partially compensate for a failing thyroid gland by increasing the stimulation to it, much like pressing down on the accelerator when climbing a hill, to keep the car going the same speed. However, as thyroid hormone production decreases, and the body’s metabolism slows, a variety of symptoms may result such as: fatigue, drowsiness, forgetfulness, constipation, weight gain, and irregular menstrual flow.
Hypothyroidism is diagnosed by your endocrinologist, who along with a physical exam looking for clinical evidence of hypothyroidism, will perform diagnostic lab tests such as: TSH, free T4, and thyroid antibodies.
Once detected, hypothyroidism is treated with a single daily dose of thyroid hormone given as a tablet. Thyroid hormone acts slowly in the body, so it can take several months after treatment is started, to notice improvement in symptoms. Since most cases of hypothyroidism are permanent, and often progressive, it is usually necessary to treat this condition throughout one’s lifetime. Periodic monitoring of TSH levels, and clinical status, are necessary to ensure that the proper dose is being given, since medication doses may have to be adjusted from time to time. It is extremely important that women planning to become pregnant are kept well adjusted, since hypothyroidism can affect the development of the baby.
Appropriate management of hypothyroidism requires continued care by a physician experienced in the treatment of this condition.