Thyroid dysfunction is relatively common in older patients, but its cl
inical presentation varies. It may be obvious from the classic present
ing symptoms, or it may be asymptomatic and discovered incidentally du
ring routine testing. The clinical diagnosis of hypothyroidism and hyp
erthyroidism can be difficult in older patients, because many of the u
sual symptoms may be mistaken for the effects of aging or other medica
l conditions. Even so, these diseases in their overt forms are always
significant and require treatment. On the other hand, subclinical hypo
- and hyperthyroidism are often incidental biochemical abnormalities t
hat may or may not require intervention.