HETEROSEXUALITY
HIP
H
infection involves the face and eye and
is called herpes zoster ophthalmicus.
Herpes zoster is caused by the
vari-
cella-zoster
virus, which also causes
chickenpox
.
After an attack of chicken-
pox, some of the viruses survive and lie
dormant for many years. In some peo-
ple, a decline in the efficiency of the
immune system
,
especially in old age or
because of disease, allows the viruses
to re-emerge and cause herpes zoster.
Herpes zoster is also common in people
whose immune system is weakened by
stress or by certain drugs, such as
corti-
costeroid drugs
or
anticancer drugs
.
The first indication of herpes zoster is
excessive sensitivity in the skin, fol-
lowed by pain. After about 5 days, the
rash appears as small, raised, red spots
that soon turn into blisters. These dry
and develop crusts that drop off, some-
times leaving small pitted scars.
The most serious feature of herpes
zoster is pain after the attack (posther-
petic pain), caused by nerve damage,
which may last for months or years.
Herpes zoster ophthalmicus may cause
a
corneal ulcer
or
uveitis
.
If treatment is begun soon after the
rash appears,
antiviral drugs,
such as
aciclovir
, will reduce the severity of the
symptoms and minimize nerve damage.
Analgesic drugs
may also be helpful.
heterosexuality
Sexual
attraction
to
members of the opposite sex. (See also
bisexuality
;
homosexuality.)
heterozygote
A term used to describe
a person whose cells contain
2
different
alleles
controlling a specified inherited
trait. A
homozygote
has identical alleles
controlling that trait. (See also
inheri-
tance
;
genetic disorders
.)
hexachlorophane
An
antibacterial drug
used in dusting powder form to prevent
staphylococcal infections in newborns,
and to prevent and treat pressure sores.
hiatus hernia
A condition in which part
of the
stomach
protrudes upwards into
the chest through the opening in the
dia-
phragm
that is normally occupied by the
oesophagus
. The cause is unknown but
it is more common in obese people and
those with a long-term cough, such as
smokers. In some cases, it is present at
birth. Many people have no symptoms.
In some people, there is
acid reflux
.
This
may lead to
oesophagitis
or
heartburn
.
Antacid drugs
or H
2
blockers may be
given to reduce stomach acidity. In
severe cases, surgery may be required.
Hib vaccine
A vaccine administered rou-
tinely at 2, 3, and 4 months of age to
provide immunity to the bacterium
Haem-
ophilus influenza
type b (Hib). Before
the vaccine was generally available, Hib
infection was a common cause of bacter-
ial
meningitis
and
epiglottitis
in children.
hiccup
A sudden, involuntary contraction
of the
diaphragm
followed by rapid clo-
sure of the
vocal cords
.
Most attacks of
hiccups last only a few minutes, and are
not medically significant. Rarely, they may
be due to a condition, such as
pneumonia
or
pancreatitis
, that causes irritation of the
diaphragm or
phrenic nerves
.
Chlorpro-
mazine
,
haloperidol
,
or
diazepam
may be
prescribed for frequent, prolonged attacks.
Hickman catheter
A flexible plastic
tube, also known as a skin-tunnelled
catheter, that is passed through the chest
and inserted into the subclavian vein,
which leads to the heart. It is often used
in people who have
leukaemia
or other
cancers and need regular
chemotherapy
and blood tests. The catheter allows
drugs to be injected directly into the
bloodstream and blood samples to be
obtained easily. The catheter is inserted,
under local
anaesthesia
. It can remain in
position for months; the external end is
plugged when not in use.
hidradenitis suppurativa
Inflammation
of the
sweat glands
in the armpits and
groin due to a bacterial infection. Ab-
scesses develop beneath the skin, which
becomes reddened and painful and may
ooze pus. The condition tends to be re-
current and can eventually cause scarring
in the affected areas. A
ntibiotic drugs
may
help to reduce the severity of an outbreak.
high density lipoprotein
One of a
group of proteins that transport
lipids
in
the blood. High levels of high density
lipoprotein can help protect against
atherosclerosis.
(See also
fats and oils;
low density lipoprotein
.)
hip
The
joint
between the
pelvis
and the
upper end of the
femur
. The hip is a
ball-and-socket joint; the smooth, roun-
ded head of the femur fits securely into
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