The thyroid is a small, butterfly-shaped gland—measuring about 2 inches across—found just below the Adam’s apple.
“The thyroid gland secretes thyroid hormones, which control the speed at which the body’s chemical functions proceed [metabolic rate],” notes The Merck Manual of Medical Information. “Thyroid hormones influence the metabolic rate in two ways: by stimulating almost every tissue in the body to produce proteins and by increasing the amount of oxygen the cells use.
“Thyroid hormones affect many vital body functions: the heart rate, the respiratory rate, the rate at which calories are burned, skin maintenance, growth, heat production, fertility and digestion,” the manual adds.
When the body fails to make enough thyroid hormone to maintain the body’s metabolism, it starts slowing down. Sufferers gain weight, feel tired, and suffer memory lapses —the symptoms are myriad and confusing.
Medical science calls it hypothyroidism. “[It] is underactivity of the thyroid gland that leads to inadequate production of thyroid hormone and a slowing of vital body functions,” the Merck manual points out.
Women are five times more likely to develop hypothyroidism than men. “The disease tends to manifest itself as the person ages,” says Professor Mafauzy Mohamed, consultant endocrinologist and campus director of Universiti Sains Malaysia.
By age 60 as many as 17 percent of women have hypothyroidism. Among newborns and infants, hypothyroidism poses a special danger as a lack of thyroid hormones in the system can lead to mental retardation and stunted growth.
Although hypothyroidism strikes mostly women, men are not spared. In 2010 TV Patrol‘s resident weatherman Kim Atienza said he was diagnosed with hypothyroidism in an interview with Showbiz News Ngayon.
“Nalaman ng doktor ko na all these years pala ako ay hypothyroid. Bagamat ako ay very active sa TV at very hyper akong nakikita ng tao, hypothyroid pala ako. Ibig sabihin napakabagal ng metabolismo ko,” he was quoted as saying.
Causes
In an article published in the web site, endocrineweb.com, Dr. James Norman says there are two common causes of hypothyroidism. “The first is a result of previous [or currently ongoing] inflammation of the thyroid gland, which leaves a large percentage of the cells of the thyroid damaged [or dead] and incapable of producing sufficient hormone,” he writes. “The most common cause of thyroid gland failure is called autoimmune thyroiditis [also called Hashimoto’s thyroiditis], a form of thyroid inflammation caused by the patient’s own immune system.”
The second major cause is classified in the broad category of “medical treatments.” Norman explains: “The treatment of many thyroid conditions warrants surgical removal of a portion or all of the thyroid gland. If the total mass of thyroid producing cells left within the body are not enough to meet the needs of the body, the patient will develop hypothyroidism.”
That is often the goal of the surgery for thyroid cancer. But, in some instances, the surgery only removes the worrisome nodule, leaving half of the thyroid in the neck undisturbed. “Sometimes, this remaining thyroid lobe and isthmus will produce enough thyroid hormone to meet the demands of the body,” Norman says. “For other patients, however, it may become apparent years later that the remaining thyroid just can’t quite keep up with demand.”
The Mayo Clinic says hypothyroidism may also result, although less often, from one of the following:
- Congenital disease: Some babies are born with a defective thyroid gland or no thyroid gland. In most cases, the thyroid gland didn’t develop normally for unknown reasons, but some children have an inherited form of the disorder. Often, infants with congenital hypothyroidism appear normal at birth. That’s one reason why most states now require newborn thyroid screening.
- Pituitary disorder: A relatively rare cause of hypothyroidism is the failure of the pituitary gland to produce enough thyroid-stimulating hormone (TSH)—usually because of a benign tumor of the pituitary gland.
- Pregnancy: Some women develop hypothyroidism during or after pregnancy (postpartum hypothyroidism), often because they produce antibodies to their own thyroid gland. Left untreated, hypothyroidism increases the risk of miscarriage, premature delivery and preeclampsia—a condition that causes a significant rise in a woman’s blood pressure during the last three months of pregnancy. It can also seriously affect the developing fetus.
- Iodine deficiency: The trace mineral iodine—found primarily in seafood, seaweed, plants grown in iodine-rich soil and iodized salt—is essential for the production of thyroid hormones. The solution to this problem is adding iodine to table salt; but it should not be taken more than what is recommended as it may also result to hypothyroidism.
Symptoms
According to the Mayo Clinic, a person with hypothyroidism may barely notice the symptoms, such as fatigue and weight gain. She may simply attribute them to getting older. But as her metabolism continues to slow, she may develop more obvious signs and symptoms: fatigue, increased sensitivity to cold, constipation, dry skin, unexplained weight gain, puffy face, hoarseness, muscle weakness, elevated blood cholesterol level; muscle aches, tenderness and stiffness; pain, stiffness or swelling in the joints; heavier than normal or irregular menstrual periods, thinning hair, slowed heart rate, depression and impaired memory.
“When hypothyroidism isn’t treated, signs and symptoms can gradually become more severe,” the Mayo Clinic says. “Constant stimulation of your thyroid gland to release more hormones may lead to an enlarged thyroid (goiter). In addition, you may become more forgetful, your thought processes may slow, or you may feel depressed.”
Diagnosis and treatment
Usually, hypothyroidism can be diagnosed with one simple blood test: the measurement of thyroid-stimulating hormone. “Many experts suggest that the test be performed at least every other year in people older than 55, because hypothyroidism is so common among older yet so difficult, in its mild stages, for doctors to distinguish from other disorders that affect people in this age group,” the Merck manual notes.
Dr. David T. Derrer in an article published in the web site WebMD.com, says treatment involves replacing thyroid hormone using oral preparation. “If you have hypothyroidism, your doctor will prescribe a synthetic [man-made] thyroid hormone T4,” he writes. “You take this pill every day. Certain other medications can interfere with how your body absorbs synthetic thyroid hormone. Make sure you doctor knows about all the medicines, herbs and supplements you take, including over-the-counter products.”
In addition, the patient needs to undergo regular blood tests to check the thyroid hormone levels. “Your doctor may need to adjust your medication dose from time to time,” says Derrer, adding that untreated hypothyroidism may cause heart problems, infertility, joint pain and obesity.