TROPHOBLASTIC TUMOUR
TUBERCULOSIS
trophoblastic tumour A growth aris-
ing from the tissues that develop into
the
placenta.
The most common type of
trophoblastic tumour is a
hydatidform
mole.
(See also
choriocarcinoma.)
tropical diseases Diseases prevalent
in the tropics because of living condi-
tions and diet include
malnutrition,
measles, diphtheria, tuberculosis, typhoid
fever
,
shigellosis
,
cholera
,
amoebiasis
,
and
tapeworm
infestation
.
Diseases
spread through the tropics by insects
include
malaria
,
yellow fever
,
sleeping
sickness,
and
leishmaniasis.
Exposure to
strong sunlight in the tropics causes an
increased tendency to
skin cancer
, and
may lead to
pinguecula
and
pterygium.
tropical ulcer An area of persistent skin
and tissue loss caused by infection with
1 or more organisms. The condition is
most common in malnourished people
living in the tropics. Treatment is clean-
ing and dressing of the ulcer, a course of
antibiotic drugs
, and a high protein diet.
The ulcer usually heals but may scar.
tropicamide A drug used to dilate the
pupil.
Adverse effects of the drug include
blurred vision, increased sensitivity to
light, stinging, and, rarely, dry mouth,
flushing, and
glaucoma.
trunk The central part of the body, com-
prising the chest and abdomen. The
term also refers to any large blood ves-
sel or nerve, from which smaller vessels
or nerves branch off.
truss An elastic, canvas, or padded metal
appliance used to hold an abdominal
hernia
in place. Trusses are only used if
corrective surgery cannot be undertaken.
trypanosomiasis A tropical disease cau-
sed by
trypanosoma
parasites. (See also
sleeping sickness; Chagas' disease
.)
tsetse fly bites The bites of tsetse flies,
which are found in Africa, can be painful.
The flies, resembling brown houseflies,
spread
sleeping sickness.
T-tube cholangiography An
imaging
technique
performed to check that there
are no
gallstones
left in the bile duct
after a
cholecystectomy
. A T-shaped rub-
ber tube is inserted into the bile duct
during the surgery. A week or so later,
contrast medium
is inserted into the
tube and
X-rays
are taken.
tubal ligation See
sterilization, female
.
tubal pregnancy See
ectopic pregnancy
.
tubercle A grey, nodular mass found in
tissues affected by
tuberculosis
. The
term also refers to a small rounded pro-
trusion on the surface of a bone.
tuberculin tests Skin tests used to
determine whether or not a person has
been exposed to the bacterium that
causes
tuberculosis
. Tuberculin tests are
carried out for diagnosis of tuberculosis,
and before
BCG vaccination.
A small
amount of tuberculin (purified protein
from the bacteria) is injected into the
skin. A few days later, the skin reaction,
if any, is noted. A reaction indicates
previous exposure.
tuberculosis An infectious disease, com-
monly called TB, caused in humans by
the bacterium
mycobacterium tuber-
culosis.
TB is usually transmitted in
airborne droplets expelled when an infec-
ted person coughs
or sneezes. An
inhaled droplet enters the lungs and
the
bacteria
begin
multiplying.
The
immune system usually seals off the
infection at this point, but in about 5 per
cent of cases the infection spreads to the
lymph nodes.
It may also spread to
other organs through the bloodstream,
which may lead to miliary tuberculosis,
a potentially fatal form of the disease.
In about another 5 per cent of cases,
bacteria held in a dormant state by the
immune system
become reactivated
months, or even years, later. The infec-
tion may then progressively damage the
lungs, forming cavities.
The primary infection is usually with-
out symptoms. Progressive infection in
the lungs causes coughing (sometimes
bringing up blood), chest pain, short-
ness of breath, fever and sweating, poor
appetite, and weight loss.
Pleural effu-
sion
or
pneumothorax
may develop. The
lung damage may be fatal.
A diagnosis is made from the symp-
toms and signs, from a
chest X-ray
, and
from tests on the sputum. Alternatively,
a
bronchoscopy
may also be carried out
to obtain samples for culture.
Treatment is usually with a course of 3
or 4 drugs, taken daily for 2 months, fol-
lowed by daily doses of
isoniazid
and
rfampicin
for 4-6 months. However, TB
bacteria are increasingly resistant to the
T
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