Hypothyroidism
Hypothyroidism, or underactive thyroid, occurs when your thyroid gland fails to produce sufficient hormones to meet your body's needs, causing many bodily functions to slow down.
What is hypothyroidism?
Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the way the body uses energy. These hormones affect nearly every organ in your body and control many of your body's most important functions, such as breathing, heart rate, weight, digestion, and moods. Without enough thyroid hormones, many of your body's functions slow down, though treatments are available to help.
What causes hypothyroidism?
Hypothyroidism has several causes, including:
- Hashimoto's disease, an autoimmune disorder where your immune system attacks your thyroid (the most common cause).
- Thyroiditis, inflammation of the thyroid.
- Congenital hypothyroidism, which is present at birth.
- Surgical removal of part or all of the thyroid.
- Radiation treatment of the thyroid.
- Certain medicines.
- In rare cases, a pituitary disease or an imbalance of iodine in your diet.
Who is at risk for hypothyroidism?
You are at higher risk for hypothyroidism if you:
- Are a woman.
- Are older than age 60.
- Have had a thyroid problem before, such as a goiter.
- Have had surgery to correct a thyroid problem.
- Have received radiation treatment to the thyroid, neck, or chest.
- Have a family history of thyroid disease.
- Were pregnant or had a baby in the past 6 months.
- Have Turner syndrome, a genetic disorder that affects females.
- Have pernicious anemia, in which the body cannot make enough healthy red blood cells due to a lack of vitamin B12.
- Have Sjogren's syndrome, a disease that causes dry eyes and mouth.
- Have type 1 diabetes.
- Have rheumatoid arthritis, an autoimmune disease that affects the joints.
- Have lupus, a chronic autoimmune disease.
What are the symptoms of hypothyroidism?
Symptoms can vary from person to person and may include:
- Fatigue
- Weight gain
- A puffy face
- Trouble tolerating cold
- Joint and muscle pain
- Constipation
- Dry skin
- Dry, thinning hair
- Decreased sweating
- Heavy or irregular menstrual periods
- Fertility problems in women
- Depression
- Slowed heart rate
- Goiter, an enlarged thyroid that may cause your neck to look swollen and potentially cause trouble with breathing or swallowing.
Because hypothyroidism develops slowly, many people do not notice symptoms for months or even years.
What other problems can hypothyroidism cause?
Hypothyroidism can contribute to high cholesterol. In rare cases, untreated hypothyroidism can cause myxedema coma, a life-threatening condition where the body's functions slow down significantly.
During pregnancy, hypothyroidism can cause complications such as premature birth, high blood pressure, and miscarriage. It can also slow the baby's growth and development.
How is hypothyroidism diagnosed?
Your health care provider may use several tools to make a diagnosis:
- A medical history, including questions about your symptoms.
- A physical exam.
- Thyroid tests, such as:
- TSH, T3, T4, and thyroid antibody blood tests.
- Imaging tests, such as a thyroid scan, ultrasound, or radioactive iodine uptake test, which measures how much radioactive iodine your thyroid takes up from your blood.
What are the treatments for hypothyroidism?
The treatment for hypothyroidism is medicine to replace the hormone that your thyroid can no longer make. About 6 to 8 weeks after starting the medicine, you will have a blood test to check your hormone levels, and your provider will adjust your dose if needed. Once the right dose is found, you will typically have follow-up blood tests every 6 months, and eventually once a year.
If you take your medicine according to instructions, you should be able to control the condition. Never stop taking your medicine without talking to your health care provider first.
If you have Hashimoto's disease or other autoimmune thyroid disorders, you may be sensitive to side effects from iodine. Consult your provider regarding which foods, supplements, and medicines to avoid. Women need more iodine during pregnancy; talk to your provider about your specific iodine requirements.