FULMINANT
F
in some cases, adopts a new identity.
Afterwards, the person has no recollec-
tion of what has occurred.
Fugues may last for hours or days.
During a short fugue, the sufferer may
be confused and agitated. During a
fugue lasting for days, behaviour may
appear
norm al
but
there
may
be
accompanying symptoms, such as hal-
lucinations, feelings of unreality, and
unstable mood.
Fugues are rare. Possible causes in -
clude
dissociative disorders
,
temporal lobe
epilepsy
,
depression
,
head injury
,
and
dementia
.
(See also
amnesia
. )
fulminant
A term used to describe a disorder that
develops and progresses suddenly and
w ith great severity. A virulent infec-
tion, a severe form of arthritis, or a
cancer that has spread rapidly is often
described as being fulminant.
fumes
See
pollution
.
functional disorders
Illnesses in w hich there is no evidence
of organic disturbance even though
physical performance is impaired.
functional endoscopic sinus
surgery (FESS)
Surgery that is carried out in order to
improve
the
drainage
of the
facial
sinuses or to clear a blockage in them.
The procedure, w hich involves the use
of an endoscope, enlarges the drainage
holes leading to the nose.
fundus
The bottom or base of an organ, or the
part that is farthest away from the
organ’s opening. The optic fundus is
the
back
of the
retina
as
viewed
through an ophthalmoscope.
fungal infections
A wide
range
of diseases
that
are
caused
by
the
m ultiplication
and
spread of
fungi
.
Fungal infections, also
known as mycoses, range from m ild
and barely noticed to severe and some-
times
even
fatal.
(In
addition
to
infections, fungi are also responsible
for some allergic disorders, such as
allergic
alveolitis
and
asthma.
)
CAUSES
Some fungi are harmlessly present all
of the time in areas of the body such as
the mouth, skin, intestines, and vagina.
Usually, however, they are prevented
from m ultiplying by competition from
bacteria. Other fungi are kept from
m ultiplying to a harmful degree by the
body’s
immune system
.
Fungal infections are therefore more
common in people w ho are taking
antibiotic drugs
(w hich destroy the bac-
terial competition) and in those whose
immune
systems
are
suppressed by
immunosuppressant drugs
,
corticosteroid
drugs
,
by a disorder such as
AIDS,
or by
chemotherapy.
Such
serious
fungal
infections are described as
opportunistic
infections
because they take advantage
of the body’s lowered defences. Some
fungal infections are more common in
people w ith
diabetes mellitus
.
Fungi
that
cause
skin
infections
thrive in warm, moist conditions, such
as those that occur between the toes
and in the genital area.
TYPES
Fungal infections can be broadly classi-
fied into three categories: superficial
(affecting the skin, hair, nails, inside of
the mouth, and genital organs); subcu-
taneous (beneath the skin); and deep
(affecting internal organs).
The main superficial infections are
tinea
(including ringworm
and ath-
lete’s foot)
and
candidiasis
(thrush),
both of w hich
are
common. Tinea
affects external areas of the body. Can-
didiasis is caused by the yeast C
a n d i d a
a l b i c a n s
and usually affects the genitals
or inside of the mouth.
Subcutaneous
infections
are
rare.
The most common is
sporotrichosis
,
w hich may follow contamination of a
scratch. Most other conditions of this
type, the most important of w hich is
mycetoma
,
occur
m ainly
in
tropical
countries.
Deep fungal infections are uncom-
mon, but they can present a serious
threat to people who have an immune
deficiency
disorder
or
those
who
are taking immunosuppressant drugs.
Fungal infections of this sort include
aspergillosis
,
histoplasmosis
,
cryptococco-
sis
,
and
blastomycosis
,
all of w hich are
caused by different species of fungi.
The
fungal
spores
enter
the
body
through inhalation into the lungs. Can-
didiasis can also spread from its usual
sites of infection to affect the oesoph-
agus,
the
urinary
tract,
and
other
internal tissues.
TREATMENT
Treatment of fungal infections is with
antifungal drugs,
either used topically
on the infected area or given by mouth
for generalized infections. (For further
information, see
Fungal diseases
box,
opposite.)
fungi
Simple parasitic life-form s that include
yeasts, moulds, mushrooms, and toad-
stools. The fungi that are responsible
for causing disease can be divided into
two
groups:
filamentous
fungi
and
yeasts. Filamentous fungi are made up
of
branching
threads
known
as
hyphae, w hich form a network called
a mycelium.
Mushrooms
and toad-
stools are the reproductive structures
(known as fruiting bodies) of a fila-
mentous fungus that has spread in
dead matter or soil. Yeasts are single-
celled organisms.
FUNGI AND DISEASE
The majority of fungi are either com-
pletely harmless or actually beneficial
to human health. However, there are a
number of fungi that can cause illness
and disease.
The fruiting bodies of some fungi
contain toxins that may cause poison-
ing if they are eaten (see
mushroom
poisoning
) .
Certain other fungi infect
food crops and also produce toxins
that may cause food poisoning. The
best known of these fungi is a species
that infects cereals and produces
ergot
,
a toxin that constricts blood vessels.
Another fungus that sometimes grows
on peanuts and produces
aflatoxin
,
a
poison and
carcinogen
.
The inhaled spores of some fungi
can cause allergic
alveolitis
,
a persistent
allergic reaction in the lungs. Farmer’s
lung, w hich is caused by spores from
mouldy hay, is an example of such a
reaction. Fungal spores are sometimes
responsible for various other allergic
disorders, such as allergic
rhinitis
(hay-
fever) and
asthma
.
Some fungi are capable of invading
the body and forming colonies in var-
ious parts of the body such as the
lungs, the skin, or sometimes in a var-
iety of tissues throughout the body,
leading to conditions that range from
m ild irritation to severe, even fatal,
widespread infection (see
fungal infec-
tions
)
and
illness.
For
further
information, see
Fungal diseases
box,
opposite. (See also
candidiasis
. )
fungicidal
A term used to describe the ability to
kill fungi (see
antifungal drugs
) .
326
previous page 325 BMA A Z Family Medical Encyclopedia   2004 read online next page 327 BMA A Z Family Medical Encyclopedia   2004 read online Home Toggle text on/off