THYROID HORMONES
TIETZE'S SYNDROME
thyroid horm ones The 3 hormones
produced by the
th}/roid gland
are thy-
roxine (T4) and triiodothyronine (T3),
which regulate metabolism, and
calci-
tonin,
which helps to regulate calcium
levels in the body.
thyroiditis Inflammation of the
thy/roid
gland.
Thyroiditis occurs in several dif-
ferent forms. The most common is
Hashimoto's th}/roiditis,
an
autoimmune
disorder
that results in
h}/poth}/roidism.
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 scanning Techniques, such as
radionuclide scanning
and
ultrasound
scanning,
that are used to provide infor-
mation about the location, anatomy,
and function of the
th}/roid gland.
thyrotoxicosis Overactivity of the thy-
roid gland, also called
h}/perth}/roidism.
thyroxine The most important
thy/roid
hormone.
Thyroxine is represented by
the symbol T4.
TTA The abbreviation for
transient isch-
aemic attack.
tiabendazole A rarely used
anthelmintic
drug
used to treat
worm infestations,
including
strong}/-
loidiasis.
It
has
been replaced by
newer
anthelmin-
tics that have few
side effects,
tibia Also
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
talus
to form part
of the
ankle
joint.
On the inside of
the ankle, the tibia
is widened and protrudes to form a
bony prominence that is known as
the medial malleolus.
tibolone A 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.
tic A repeated, uncontrolled, purpose-
less contraction of a
muscle
or 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
Giles de
la Tourette's syndrome.)
tic douloureux An alternative name for
trigeminal neuralgia.
ticks and disease Small,
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 syndrome Chest 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.
T
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