The thyroid is a small gland in the neck, which releases hormones that control how fast the cells in the body work. Diseases of the thyroid result, therefore, in a slowing down or speeding up of cell function, with corresponding associated symptoms. Thyroid diseases are not different in older than in young people, to any great degree. However, other diseases that occur in the elderly, and the fact that older patients take more medications, can make the diagnosis of thyroid diseases in the elderly quite difficult.

Conditions such as bad nutrition, poorly-controlled diabetes, liver disease, heart failure or cancer can all produce changes in lab tests of thyroid function without there actually being anything wrong with the thyroid. Drugs commonly taken by elderly patients that can have the same upsetting effect on thyroid tests include drugs for epilepsy, aspirin, arthritis drugs, Parkinson's disease drugs, and heparin. In addition, drugs can cause changes in the function of the thyroid by acting directly on the gland, although this is less common. And, unfortunately, the signs of thyroid disease in the elderly can be confused quite readily with some of the normal signs of aging and other common diseases seen in older people. All this makes the diagnosis of thyroid diseases more difficult in older than in younger people.

Thyroid diseases are generally grouped into those that are due to reduced activity of the gland (hypothyroidism) and those due to overactivity (hyperthyroidism). The former are more common in older people.

The usual signs of reduced thyroid activity in young people - feeling cold, loss of eyebrows, coarse hair, dry scaling skin, lethargy - are all signs that can occur in older people for quite different reasons. However, old people with reduced thyroid activity may have neurological symptoms (shakiness, disturbed sensation) and mental effects (depression, disturbed mental ability). Thyroid lab tests should make the diagnosis clear, provided the possibility of interference from other diseases or medications is taken into consideration.

Treatment is usually with a synthetic hormone (thyroxine, or levothyroxine) that should bring things back to normal within 6 to 8 weeks. This drug needs to be continued for life, with occasional lab tests done to check that the dose is correct.

Overactivity of the thyroid in the elderly is due to a goiter (swelling of all or part of the gland) or a generalized overactivity of the gland tissue, sometimes accompanied by eye changes. Some geographical areas are still considered to have too low levels of iodine in the drinking water (parts of Germany, East Europe) so that goiter is more common there.

The classic signs of overactive thyroid - physical over-activity, increased appetite, weight loss, staring eyes, sweating - are not always seen in older patients. More likely, some signs of heart failure will be present. Weight loss occurs, but with loss of appetite rather than increased hunger. Depression, lethargy and confusion can occur. Again, the diagnosis is usually made from the lab test results, bearing in mind the possible effects of other diseases and medications.

People with overactive thyroids should best be seen by a specialist. Initial treatment will be with drugs to restore the activity of the gland to normal, and to treat the heart condition, if necessary. Quite often drugs fail to work after a time, so that definitive treatment is necessary. This involves destroying the activity of the gland by consuming radioactive iodine (just once), or surgical removal. There are pros and cons to both forms of treatment, which can be explained by the specialist. Taking radioactive iodine is relatively risk-free, but occasionally there is some pain, tenderness and swelling of the gland, and the procedure may have to be repeated in a small proportion of patients. Surgery carries a slight operative risk, and is usually reserved for older patients who have a large goiter or eye problems.

Nodules in the thyroid are common as people age, especially in women. However, there is not an increased frequency of thyroid cancer with age (unlike prostate cancer, for example). If cancer is diagnosed, surgery, external radiation and chemotherapy are all used in treatment, according to the individual circumstances.