FIFTH DISEASE
F
A fractured fibula may take up to six
weeks to heal, depending on its seve-
rity and the age o f the patient.
fifth disease
An infectious disease that often causes
a widespread rash. Fifth disease, w hich
is also known as slapped cheek disease
or
erythema
infectiosum,
principally
affects children and is caused by a strain
of
erythrovirus
.
Erythrovirus
is
trans-
mitted in airborne droplets from the
coughs and sneezes o f individuals who
are carrying the infection, but it may
occasionally be transmitted through a
blood transfusion.
Many children do not develop symp-
toms;
in
other
children,
the
rash
appears seven to 14 days after infection.
The rash o f fifth disease starts on the
cheeks
as
separate,
rose-red,
raised
spots, w hich subsequently converge to
give the characteristic appearance of the
condition. W ithin a few days, the rash
spreads in a lacy pattern over the limbs,
but only sparsely on the trunk. The rash
is frequently accompanied by m ild fever
and generally clears up after approx-
imately ten days.
Adults,
w ho
contract
the
disease
only rarely, tend to be more severely
affected than children. They may have
joint pain and swelling that lasts for up
to two years. Infection may bring a
temporary halt to the production o f
red blood cells in the bone marrow
(know n as an aplastic crisis); it can
therefore have serious implications for
people with
anaemia
.
The only treatment for the infection
is w ith drugs to reduce the fever. In
most cases, the condition clears up
w ithin two weeks. However, people at
risk
o f anaemia may need hospital
treatment. One attack o f erythrovirus
confers lifelong immunity.
fight-or-flight response
The arousal o f the sympathetic part
of the
autonomic nervous system
,
gener-
ally
in
response
to
fear.
Adrenaline
(epinephrine),
noradrenaline
(norepin-
ephrine),
and
other
hormones
are
released from the adrenal glands and
nervous system, leading to a raised
heart rate, pupil dilation, and increased
blood
flow
to
the
muscles.
These
responses make the body more effi-
cient in either fighting or fleeing the
apparent danger. Prolonged or exces-
sive fight-or-flight responses occur as
part of
anxiety disorders
.
figure-of-eight bandage
A
bandage
that is wrapped over itself
a number of times to resemble the fig-
ure eight. A figure-of-eight bandage is
often used in first aid to support the
elbows, wrists, knees, and ankles, par-
ticularly if the joint is to be kept in a
flexed position.
filariasis
A group o f tropical diseases, caused by
various parasitic worms or their larvae,
w hich are transmitted to humans by
insect bites. Adult female worms, w hich
may measure anything between
2
and
5 0 cm, produce many thousands of lar-
vae, w hich are
carried through
the
body in the bloodstream. Blood-suck-
ing insects (prim arily certain species of
mosquito) ingest the larvae while feed-
ing on blood from infected people and
transmit them by biting others .
Filariasis
is
prevalent
in
tropical
Africa, Indonesia,
the
South
Pacific,
coastal Asia, southern Arabia, Mexico,
and Guatemala.
TYPES AND SYMPTOMS
Some species of worm live in the lym -
phatic vessels (see
lymphatic system
).
Swollen
lymph nodes
and recurring fever
are early symptoms of the disease. In-
flammation o f lymph vessels results in
localized
oedema
(the accumulation of
fluid in the tissues, causing swelling).
After repeated infections, the affected
area, w hich is commonly a limb or the
scrotum,
becomes very
enlarged; in
addition,
the
skin
becomes
thick,
coarse, and fissured, resulting in a con-
dition known as
elephantiasis
.
The larvae o f another type o f worm
invade the eye, causing blindness (see
onchocerciasis
) .
A third type of larva,
w hich may sometimes be seen and felt
moving
beneath
the
skin,
causes
loiasis
,
characterized by irritating and
sometimes painful areas
o f oedema
called calabar swellings.
DIAGNOSIS AND TREATMENT
A diagnosis of filariasis is confirmed by
microscopic examination o f the blood
(see
blood tests
) .
The
anthelmintic drugs
diethylcarbamazine or ivermectin gen-
erally cure the infection, but they may
also cause certain side effects, however,
such as fever, sickness, muscle pains,
and increased itching.
PREVENTION
The drug diethylcarbamazine can be
given as a preventative measure; and
the use o f insecticides and protective
clothing are useful protection against
insect
bites.
(See
also
roundworms
;
insects and disease.
)
filling defect
An abnormal finding on
contrast X-rays
due to a lesion occupying space within
a hollow organ. Normally, in contrast
X-rays, a radio-opaque dye (a contrast
medium) is introduced into a hollow
body structure, such as the intestine,
310
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