An underactive thyroid is also known as hypothyroidism and this means there is a reduced amount of thyroid hormone circulating in the body. Thyroid hormones regulate body metabolism. Lower than normal amounts of thyroid hormone in the body means metabolism will become sluggish.

An underactive thyroid is most common in women and the risk increases with age. Simple treatments are usually quite effective but they can be lifelong.

Primary hypothyroidism is caused by an inadequate production of thyroid hormones. This can be caused by an inflammation of the thyroid. Hashimoto’s Thyroiditis is a common type of inflammation that tends to run in families and sometimes occurs postpartum or after a bacterial or viral illness.

Another cause of primary hypothyroidism is due to a birth defect which results in a child being born without a thyroid gland or with a non functioning gland. This condition can cause severe physical and mental disabilities if it is not diagnosed and treated early.

Acquired hypothyroidism can occur after surgery due to thyroid cancer or to correct hyperthyroidism. Some drugs can also affect the thyroid and cause hypothyroidism. These include amiodarone which is used for palpitations, lithium which is used to treat bipolar disease, and radioactive iodine which is used to treat hyperthyroidism.

Iodine deficiency can also contribute to acquired hypothyroidism because iodine is required to produce thyroid hormones. Iodine deficiency is rare in Western countries since iodine is commonly added to table salt.

Secondary hypothyroidism occurs when the pituitary gland does not create enough Thyroid Stimulating Hormone (TSH) to trigger the manufacture of thyroid hormone in the thyroid.

Symptoms in the early stages of hypothyroidism may be nonexistent or attributed to another cause. As the underactive thyroid gland becomes more severe, the symptoms become more severe as it becomes obvious the body’s metabolism has slowed. Symptoms include weakness, fatigue, constipation, slow reflexes, unable to tolerate cold, slow heart rate, poor memory, poor appetite, weight gain, dry or thickened skin, hoarse voice and muscle spasms.

An underactive thyroid is easily diagnosed with a blood test. A patient is found to have hypothyroidism if the amount of thyroid hormone in the blood is lower than normal. Treatment for the condition is both simple and effective. The thyroid hormone levels are brought back to normal by taking thyroid hormone replacement pills on a daily basis.

Therapy begis with a small dose which is gradually raised until the hormone levels are within a normal range. Once the optimum dosage is determined, the patient will probably remain on the same dose for life unless yearly blood tests determine the dosage needs to be adjusted.

Thyroid hormone replacement medication, or Thyroxine, should be taken first thing in the morning at least a half an hour before eating breakfast. Foods high in fiber and bran as well as iron supplements and antacids can interfere with the absorption of Thyroxine and should not be taken close together.

Side effects of Thyroxine are rare and are usually the result of not taking the proper amount of medication. Too much will cause side effects consistent with symptoms of hyperthyroidism and not enough will cause side effects consistent with hypothyroidism. Most people with an underactive thyroid gland lead normal healthy lives as long as they receive effective treatment.