DACRYOCYSTITIS
DEAFNESS
D
dacryocystitis
Inflammation of the tear
sac, usually resulting from blockage of
the tear duct. The condition may occur
in infants if the tear duct has not devel-
oped normally. In adults, it may follow
inflammation in the nose or an injury.
The cause is often unknown.
Symptoms include pain, redness, and
swelling between the inner corner of
the eyelids and the nose. Infection may
occur and cause a discharge. The obs-
truction may be cleared by flushing the
tear duct with saline.
Antibiotic
eye-drops
or ointment are given for infection. In
infants, massaging the tear sac may
clear a blockage. Surgery to drain the
tear sac (called dacryocystorhinostomy)
is occasionally necessary.
dactylitis
Inflammation of the fingers or
toes, which sometimes occurs in people
with
sickle cell anaemia.
More rarely,
dactylitis can be caused by
tuberculosis
and
syphilis
.
danazol
A drug used for treating
endo-
metriosis
, noncancerous breast disease,
and
menorrhagia
. Danazol suppresses
the release of
gonadotrophin hormones
,
which in turn reduces the production of
the hormone oestrogen. This action
usually prevents ovulation and causes
irregularity or absence of menstrual
periods. Possible side effects include
nausea, rash, and weight gain. Pregnancy
should be avoided while taking danazol.
D and C
An abbreviation for dilatation
and curettage, a gynaecological proce-
dure in which the
cervix
is dilated and
the
endometrium
is scraped away and a
sample removed for analysis. D and C
was once used to diagnose and treat
disorders of the
uterus
.
It has largely
been
replaced
by hysteroscopy,
an
endoscopic technique for removing the
endometrium (see
endometrial ablation
).
dander
Minute scales that are shed
from an animal's skin, hair, or feathers.
Some people are allergic to dander and
develop the symptoms of allergic
rhini-
tis
or
asthma
if they inhale the scales.
dandruff
A harmless condition in which
dead skin is shed from the scalp, often
producing white flakes. The usual cause
is the rash seborrhoeic
dermatitis
. Fre-
quent use of an antidandruff shampoo
usually controls the dandruff.
dantrolene
A
musde-relaxant drug
used
to relieve muscle spasm caused by
spinal injury
,
stroke
, or neurological dis-
orders such as
cerebral palsy
. The drug
does not cure the underlying disorder,
but often improves mobility.
dantron
A
laxative drug
used to treat
constipation in the terminally ill who
are often constipated as a side effect of
opioid
analgesic drugs
.
Dantron may
colour the urine red.
dapsone
An
antibacterial drug
used to
treat
Hansen's disease
(leprosy) and
dermatitis herpetformis
.
Combined with
pyrimethamine
, dapsone is also used
to prevent
malaria
. Dapsone may cause
nausea, vomiting, and, rarely, damage
to the liver, red blood cells, and nerves.
daydreaming
Conjuring up pleasant or
exciting images or situations in one's
mind during waking hours.
day surgery
Surgical treatment carried
out in a hospital or clinic without an
overnight stay. The proportion of all
operations performed on a day-surgery
basis has risen substantially in recent
years. Modern anaesthetics and surgical
methods, such as
minimally invasive sur-
gery
, allow a swifter recovery than in the
past, and patients can usually return
home within a few hours.
DDT
The abbreviation for the insecti-
cide dichlorodiphenyltrichloroethane. DDT
was once widely used in the fight against
diseases that are transmitted by insects,
particularly in hot climates. However,
some insects have developed resistance,
which can be passed on to offspring.
(See also
pesticides
.)
deafness
Complete or partial loss of
hearing in 1
or both ears. There are 2
types of deafness: conductive deafness,
which results from faulty propagation of
sound from the outer to the inner ear;
and sensorineural deafness, in which
there is a failure in transmission of
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