Bma Illustrated Medical Dictionary

cornea is several hundred times more

sensitive to painful stimuli than the

soles of the feet. (See also sensation.)

Tourette’s syndromeSee Gilles de la

Tourette’s syndrome.

tourniquetA device placed around a

limb to compress blood vessels. A tour-

niquet may be used to help locate a

vein for an intravenous injection or for

the withdrawal of blood. An inflatable

tourniquet, called an Esmarch’s bandage,

is used to control blood flow in some

limb operations. The use of a tourniquet

as a first-aid measure to stop severe

bleeding can cause gangrene.

toxaemiaPresence in the bloodstream

of toxinsproduced by bacteria. (See also

preeclampsia; toxic shock syndrome.)

toxaemia of pregnancySee pre-

eclampsia.

toxicityThe property of being toxic (pois-

onous). Toxicity also refers to the severity

of adverse effects or illness produced by

a toxin, a poison, or a drug overdose.

toxicologyThe study of poisons. (See

also poisoning.)

toxic shock syndromeAn uncommon,

severe illness caused by a toxinpro-

duced by the bacterium STAPHYLOCOCCUS

AUREUS. Many cases occur in women

using vaginal tampons. Other cases have

been linked to use of a contraceptive

cap, diaphragm, or sponge (see contra-

ception), or to skin wounds or infections

by the bacterium elsewhere in the body.

A high fever, vomiting, diarrhoea, head-

ache, muscle aches and pains, dizziness,

and disorientation develop suddenly. A

widespread skin rash that resembles sun-

burn and also affects the palms and

soles, develops. Blood pressure may fall

dangerously low, and shockmay develop.

Other complications include kidney fail-

ureand liver failure. Treatment in an

intensive care unit may be needed.

toxinA poisonous protein produced by

pathogenic (disease-causing) bacteria,

various animals, or some plants. Bacte-

rial toxins are sometimes subdivided into

3 categories: endotoxins, which are

released from dead bacteria; exotoxins,

which are released from live bacteria; and

enterotoxins, which inflame the intestine.

(See also poison; poisoning; toxaemia.)

toxocariasisAn infestation of humans,

usually children, with the larvae of TOXO-

CARA CANIS: a small, threadlike worm

that lives in the intestines of dogs.

Children who play with an infested dog

or soil contaminated with dog faeces,

and who then put their fingers in their

mouths, may swallow some of the worm

eggs. The eggs hatch in the intestines,

and the released larvae migrate to organs

such as the liver, lungs, brain, and eyes.

Usually, infestation causes mild fever

and malaise, which soon clears up; but

heavy infestation may lead to pneumonia

and seizures. Loss of vision may occur if

larvae enter the eye and die there.

A diagnosis is made from sputum

analysis, and by a liver biopsy. Severe

cases require treatment in hospital with

tiabendazoleand an anticonvulsant drug.

toxoidAn inactivated bacterial toxin. Cer-

tain toxoids are used to immunize against

specific diseases, such as tetanus.

toxoplasmosisAn infection caused by

the protozoanTOXOPLASMA GONDIIthat is

often caused by eating undercooked

meat from infected animals, or by hand-

ling faeces from infected cats. In most

cases there are no symptoms, but some-

timesthere may be a feverish illness

that resembles infectious mononucleosis.

Retinitis (inflammation of the retina)

and choroiditismay also develop. In peo-

ple with an immunodeficiency disorder

toxoplasmosis may cause lung and heart

damage and severe encephalitis.

TOURETTE’S SYNDROME TOXOPLASMOSIS

T

TOUCH

Meissner’s

corpuscle

TOUCH RECEPTORS IN SKIN

Pacinian

corpuscle

Merkel’s

disc

Free nerve

ending