Signs and symptoms of hyperthyroidism

Enlarged thyroid gland. Sometimes, but not always, the thyroid gland becomes enlarged and may protrude from your neck to form a goiter. If the goiter is large enough, it may feel lumpy.

Heat intolerance. A sped-up metabolism leads to an increase in body temperature. You may be the only one in the room who wants to open a window, or you may find yourself in short sleeves while others are wearing sweaters.

Exhaustion. A body that's perpetually in overdrive tires out more quickly. You may find yourself out of breath after crossing the street or exhausted after carrying in the groceries.

Emotional changes. Your body's exhausted state coupled with an overstimulated central nervous system can lead to a variety of emotional changes. A hyperthyroid person may experience anxiety that may be intermixed with depression, as well as insomnia or irritability.

Perspiration and thirst. As your body temperature rises, your sweat glands tend to overproduce, and you feel the need to continually replenish fluids.

Constant hunger. As your body uses up energy, it tends to cry out for more. Some people have an insatiable appetite.

Unexplained weight loss. Even though you may eat constantly, you could lose weight, usually between 5 and 10 pounds. Someone with severe thyrotoxicosis can experience extreme weight loss.

Racing heart. Hyperthyroidism causes abnormal heart rhythms. You may, out of nowhere, suddenly feel your heart race. This can occur when you are exerting yourself or when you are relaxing.

Fast pulse. If you take your pulse, you may notice that it's more rapid than usual. If your normal heart rate in the past was in the range of 60 to 70 beats per minute, you may find that your heart is beating 80 to 100 times a minute.

Hand tremors. You may notice your hands shaking. It might be subtle, or it could be to the point where you can't steadily carry a drink without spilling it. This is the result of overstimulated nerves.

Muscle weakness. Excess thyroid hormone tends to break down muscle. You are likely to experience a feeling of weakness, particularly in the arms and legs. If you are a physically active person, you may notice marked changes in your performance.

Diarrhea. An overactive thyroid causes your digestive system to speed up, and this leads to frequent, loose bowel movements.

Eye problems. In some people, most often those with Graves' disease, eye problems can occur and can be quite severe. The most common eye symptom is a retraction of the eyelids that makes the eyes appear to bulge or stare dramatically. Your eyes may also be puffy and watery, and you may experience double vision.

Menstrual changes and infertility. Your periods may be lighter, or you may skip periods. This can lead to changes in your ovulation cycle and infertility.

Infertility in men. Hyperthyroidism also interferes with a man's sperm cycle, causing temporary infertility.

Hives. You might notice an itchy rash that can be relieved with antihistamines.

Signs and symptoms of hyperthyroidism in an older person

The diagnosis of hyperthyroidism is often delayed in older people because they tend not to experience the number of symptoms that younger people do. One study, conducted in France and published in 1996, compared signs and symptoms in elderly hyperthyroid patients with those of patients under age 50. The older patients were less likely to show symptoms of increased sweating, heat intolerance, hand tremors, nervousness, excessive thirst, increased appetite, and hyperactive reflexes.

While some older people do experience classic symptoms of hyperthyroidism, it is more typical for this age group to show a few or only one of the following symptoms:

Depression. An older person with hyperthyroidism is more likely than a younger person with the disease to develop depression.

Congestive heart failure. The most prominent sign of hyperthyroidism in an older person is often congestive heart failure, the symptoms of which include breathlessness, swelling in the ankles, weakness, and fatigue. In the case of an overactive thyroid, the heavy burden hyperthyroidism places on the heart leads to ineffective pumping and a backup in blood flow.

Atrial fibrillation. A study comparing older and younger people with hyperthyroidism found that 35% of older patients experienced the disorganized heart rhythms of atrial fibrillation while only 2% of younger patients did.

Fast pulse. Some older people experience an abnormally fast pulse (tachycardia), over 100 beats per minute, but may not know it if their pulse hasn't been checked.

Nervousness and exhaustion. The typical nervousness and anxiety experienced by younger patients occur in about 20% of older people with an overactive thyroid. Some older people with the disease are lethargic.

Excessive weight loss. A younger person with hyperthyroidism may experience some weight loss, but older people tend to lose even more weight, to the point where they could appear malnourished.

Muscle weakness. Older people who have lost a lot of weight are also likely to have profound muscle weakness because of an accelerated breakdown of muscles.