Bma Illustrated Medical Dictionary

thyroid hormonesThe 3 hormones

produced by the thyroid glandare thy-

roxine (T 4 ) and triiodothyronine (T 3 ),

which regulate metabolism, and calci-

tonin, which helps to regulate calcium

levels in the body.

thyroiditisInflammation of the thyroid

gland. Thyroiditis occurs in several dif-

ferent forms. The most common is

Hashimoto’s thyroiditis, an autoimmune

disorderthat results in hypothyroidism.

Less commonly, the inflammation is

associated with a viral infection, or it

may occur temporarily soon after child-

birth; in both these cases, long-term

damage to the gland is uncommon.

thyroid scanningTechniques, such as

radionuclide scanning and ultrasound

scanning, that are used to provide infor-

mation about the location, anatomy,

and function of the thyroid gland.

thyrotoxicosisOveractivity of the thy-

roid gland, also called hyperthyroidism.

thyroxineThe most important thyroid

hormone. Thyroxine is represented by

the symbol T 4.

TIAThe abbreviation for transient isch-

aemic attack.

tiabendazoleA rarely used anthelmintic

drug used to treat worm infestations,

including strongy-

loidiasis. It has

been replaced by

newer anthelmin-

tics that have few

side effects.

tibiaAlso called

the shin, the inner

and thicker of the

2 long bones in

the lower leg. The

tibia runs parallel

to the fibula, the

narrower bone to

which it is attached

by ligaments. The

upper end articu-

lates with the femur

to form the knee

joint; the lower end

articulates with the

talusto form part

of the anklejoint.

On the inside of

the ankle, the tibia

is widened and protrudes to form a

bony prominence that is known as

the medial malleolus.

tiboloneA drug used in the treatment

of menopausal symptoms and to protect

against osteoporosis. The drug is given

continuously and combines the effects

of oestrogens and progestogens. Possi-

ble adverse effects include irregular

vaginal bleeding, changes in body

weight, ankle oedema, dizziness, skin

reactions, headache, migraine, growth

of facial hair, depression, and myalgia.

ticA repeated, uncontrolled, purpose-

less contraction of a muscleor group of

muscles, most commonly in the face,

shoulders, or arms. Typical tics include

blinking, mouth twitching, and shrug-

ging. Tics usually develop in childhood

and are often a sign of a minor psycho-

logical disturbance. They usually stop

within a year of onset but in some cases

persist into adult life. (See also Gilles de

la Tourette’s syndrome.)

tic douloureuxAn alternative name for

trigeminal neuralgia.

ticks and diseaseSmall, 8-legged anim-

als that feed on blood and sometimes

transmit diseases to humans via their

bites. Ticks are about 3 mm long before

feeding and become larger when bloated

with blood. Ticks may be picked up in

long grass, scrub, woodland, or caves.

In the UK, the only disease known to be

transmitted to humans by ticks is Lyme

disease. Others transmitted in various

parts of the world include relapsing fever,

Rocky Mountain spotted fever, Q fever,

tularaemia, and certain types of viral en-

cephalitis. The prolonged bite of certain

female ticks can cause tick paralysis, in

which a toxin in the tick saliva affects

the nerves that control movement. In

extreme cases, this can be fatal.

Tietze’s syndromeChest pain local-

ized to an area on the front of the chest

wall, usually made worse by movement

of the arms or trunk or by pressure on

the chest wall. The syndrome is caused

by inflammation of 1 or several rib carti-

lages and symptoms may persist for

months. Treatment is with analgesics,

nonsteroidal anti-inflammatory drugs, or

local injections of corticosteroid drugs

into the cartilage.

THYROID HORMONES TIETZE’S SYNDROME

T

TIBIA

Patella

Tibia

Fibula

Femur

Medial
malleolus

Talus