APPETITE STIMULANTS
A
head injury
that has damaged the
hypo-
thalamus
or cerebral cortex (the parts
of the
brain that control appetite).
Other physical causes include intestinal
disorders, such as
gastritis
(inflamma-
tion of the stomach lining, which is
common in problem drinkers),
stomach
cancer,
a
gastric ulcer,
and liver disorders
such as
hepatitis.
Many infectious dis-
eases, such as
influenza,
can also lead to
loss of appetite.
Between the ages of about two and
four, some children go through a per-
iod of refusing food. If there are no
other symptoms, this phase should be
regarded as a normal part of a child’s
development.
For an otherwise healthy person, a
period of two or three days without food
is not harmful, provided that plenty of
nonalcoholic fluids are drunk. A doctor
should always be consulted, however, if
there are other health problems (par-
ticularly
diabetes mellitus
) or if regular
medication is being taken.
All cases of appetite loss that last for
more than a few days should be investi-
gated by a doctor. Appetite generally
returns to normal once any underlying
illness
has
been
treated.
(See
also
appetite stimulants.)
appetite stimulants
Various tonics and remedies that have
been traditionally prescribed to stim-
ulate the appetite. None are proven to
be effective.
Some
drugs, such as
corticosteroid
drugs,
may stimulate the appetite when
used to treat unrelated disorders.
appetite suppressants
A group of drugs that reduce the desire
to eat. Sibutramine is the only appetite
suppressant now commonly prescribed.
Appetite suppressants may be used in
the treatment of severe
obesity,
along
with dieting and exercise, when serious
attempts at dieting and exercise have
previously failed to bring about suffi-
cient weight loss.
HOW THEY WORK
Sibutramine works by inhibiting the
reuptake of
noradrenaline
(norepineph-
rine) and
serotonin.
SIDE EFFECTS
Common side effects of sibutramine
include constipation, a dry mouth (see
mouth, dry),
insomnia, nausea, palpita-
tions,
hypertension
(high blood pressure),
headache, anxiety, sweating, and distur-
bance of the sense of taste.
The
use
of
sibutramine
is
strictly
controlled and is limited to a maximum
of one year.
appliance
See
orthodontic appliances.
apraxia
The inability to carry out purposeful
movements
despite
normal
muscle
power
and
coordination. Apraxia
is
caused by damage to nerve tracts in the
cerebrum
(the main mass of the brain)
that translate the idea for a movement
into an actual movement. People with
apraxia usually know what they want to
do but are unable to recall from memo-
ry the sequence of actions necessary to
achieve the movement. Damage to the
cerebrum may be caused by a
head
injury,
an infection, a
stroke
(damage to
part of the brain caused by interruption
to its blood supply), or a
brain tumour.
TYPES
Apraxia takes various forms, and each is
related to damage in different parts of
the brain. Ideomotor apraxia is the inab-
ility to carry out a spoken command to
make a certain movement, but to make
the same movement unconsciously at
other times. In sensory apraxia, a person
may not be able to use an object due to
loss of ability to recognize its purpose.
Agraphia
(difficulty in writing) and
aphasia
(severe difficulty in expressing
language) are special forms of apraxia.
OUTLOOK
Recovery from apraxia is highly variable
and is dependent on the cause. Lost
skills may need to be relearned.
APUD cell tumour
A growth composed of cells that pro-
duce various hormones. APUD (amine
precursor uptake and decarboxylation)
cells occur in different parts of the body.
Some tumours of the thyroid gland,
pancreas,
and
lungs
are APUD
cell
tumours,
as
are
carcinoid
tumours
(tumours of the intestine or lung, see
carcinoid syndrome
) and
phaeochromo-
cytoma
(a type of adrenal tumour).
aqueous cream
An
emollient
preparation that is com-
monly used to treat dry, scaly, or itchy
skin in conditions such as
eczema
.
aqueous humour
A watery fluid that fills the front cham-
ber of the eye, behind the
cornea
(the
transparent front part of the eyeball).
arachidonic acid
One of the fatty acids in the body that
are essential for growth.
arachis oil
Peanut or ground-nut oil. Arachis oil is
used in
enemas
to lubricate and soften
impacted faeces and to make bowel
movements easier. It can also be applied
to the scalp, followed by shampooing,
in the treatment of
cradle cap
.
arachnodactyly
A term for long, thin, spiderlike fingers
and
toes. Arachnodactyly
sometimes
occurs spontaneously but is also charac-
teristic of
Marfan syndrome,
an inherited
connective tissue disease.
arachnoiditis
A rare condition that is characterized by
chronic inflammation and thickening of
the arachnoid mater, which is the mid-
dle of the three
meninges
(membranes)
that cover the brain and spinal cord.
The cause of arachnoiditis is often
unknown. However, the condition may
develop following an episode of
menin-
gitis
(inflammation of the meninges) or
a
subarachnoid haemorrhage
(a type of
brain haemorrhage). It may also be a
feature of
syphilis
or
ankylosing spondy-
litis
(a disorder affecting the spine).
Arachnoiditis
may
also
result
from
injury or certain medical procedures.
Symptoms
may include
headache,
epileptic seizures, blindness, or diffi-
culty with movements due to increased
muscle tension. There is no effective
treatment for arachnoiditis.
arachnoid mater
The middle of the three layers of mem-
brane (see
meninges)
that cover the
brain
and spinal cord.
arbovirus
Any of the many viruses transmitted by
a member of the arthropod group of
animals, including insects, mites, and
ticks. (See also
insects and disease; mites
and disease; ticks and disease).
ARC
An abbreviation for
AIDS-related complex
.
(See also
AIDS
.)
arcus senilis
A grey-white ring near the edge of the
cornea
(the transparent front part of
the
eyeball)
overlying
the
iris
(the
coloured part of the eye).
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