DESENSITIZATION, ALLERGY
DEVELOPMENTAL DELAY
D
in which the patient is gradually expo-
sed to the cause of the fear.
desensitization, allergy
See
hyposen-
sitization
.
desferrioxamine
A drug used to rid
the body tissues of excess
iron
that
accumulates as a result of repeated
blood transfusions in anaemias, such
as aplastic
anaemia
and
thalassaemia.
It
is also used to treat iron poisoning and
may also be used to treat excess
alu-
minium
in people on
dialysis
.
The drug
is administered by intravenous injec-
tion or subcutaneous infusion and may
be given with
vitamin C
to boost excre-
tion of the iron.
Side effects may
include gastrointestinal disturbances,
dizziness, and skin reactions.
designer drugs
A group of illegally
produced chemicals that mimic the
effects of specific drugs of abuse. They
can cause
drug dependence
and
drug
poisoning
.
Made in illicit laboratories,
they are cheap to produce and undercut
the street prices of drugs.
There are 3 major groups: drugs derived
from opioid
analgesic drugs
such as fen-
tanyl; drugs similar to amfetamines,
such as
ecstasy
;
and variants of phency-
clidine (PCP), a hallucinogenic drug.
These highly potent drugs are not tested
for adverse effects or for the strength of
the tablets or capsules, making their use
hazardous. For example, some deriva-
tives of fentanyl are
20
-
2,000
times more
powerful than
morphine
.
Amfetamine
derivatives can cause brain damage at
doses only slightly higher than those
required for a stimulant effect. Many
designer drugs contain impurities that
can cause permanent damage.
desmoid tumour
A growth, usually in
the abdominal wall. The tumour is hard,
with a well-defined edge. The tumours
occur most frequently in women who
have had children. They may also arise
at the sites of old surgical incisions.
Surgical removal is the usual treatment.
desmopressin
A synthetic form of
ADH
(antidiuretic hormone) that is used to
treat
diabetes insipidus
and bed-wetting
(see
enuresis
).
desogestrel
A
progestogen drug
used
with
ethinylestradiol
as an ingredient of
some
combined
oral
contraceptives
.
Desogestrel is reported to have a slightly
higher risk of venous
thromboembolism
than older drugs. Side effects of deso-
gestrel include weight changes and
fluid retention. There may also be nau-
sea, vomiting, headache, depression,
and breast tenderness.
detergent poisoning
The toxic effects
that occur as a result of swallowing the
cleaning agents in shampoos, laundry
powders, and cleaning liquids.
development
The process of growth and
change by which an individual matures
physically, mentally, emotionally, and
socially. Development takes place in
major phases: during the first
2
months
of pregnancy (see
embryo
); to a lesser
extent, during the rest of pregnancy
(see
fetus
);
during the first 5 years of life
(see
child development
); and during
puberty
and
adolescence
.
developmental delay
A term used if a
baby or young child has not achieved
new abilities within the normal time
range. Normally, new abilities and new
patterns of behaviour appear at given
ages, and existing patterns of behaviour
change and sometimes disappear (see
child development
).
Delays vary in severity and may affect
the development of hand-eye coord-
ination, walking, listening, language,
speech, or social interaction. Delay may
first be noticed by parents or detected
during a routine developmental check.
There are many causes of develop-
mental delay. A child who is late in
most aspects of development usually
has a generalized problem. This may be
due to severe visual or hearing impair-
ment, limited intellectual abilities (see
learning difficulties
), or damage to the
brain before, during, or after birth.
Specific areas of delay may occur in
movement and walking. Often there is
no serious cause. However, specific
causes may include
muscular dystrophy
and
spina bifida
. Delay in developing
manipulative skills is often due to lack
of adequate stimulation.
A lack of response to sound may be
due to
deafness
.
Autism
is a rare cause
of unresponsiveness to the human
voice although hearing is normal. A
hearing problem may cause delayed
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