D
dacryocystitisInflammation 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. Antibioticeye-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.
dactylitisInflammation of the fingers or
toes, which sometimes occurs in people
with sickle cell anaemia. More rarely,
dactylitis can be caused by tuberculosis
and syphilis.
danazolA 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 CAn abbreviation for dilatation
and curettage, a gynaecological proce-
dure in which the cervixis dilated and
the endometriumis 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been replaced by hysteroscopy, an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).
danderMinute 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-
tisor asthmaif they inhale the scales.
dandruffA 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.
dantroleneA muscle-relaxant drugused
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.
dantronA laxative drugused 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.
dapsoneAn antibacterial drugused to
treat Hansen’s disease (leprosy) and
dermatitis herpetiformis. 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.
daydreamingConjuring up pleasant or
exciting images or situations in one’s
mind during waking hours.
day surgerySurgical 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.
DDTThe 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.)
deafnessComplete 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 ofDACRYOCYSTITIS DEAFNESSD