ISOMETRIC
ITCHING
being infected. The patient is usually
isolated in a single room.
Complete isolation is used if a patient
has a contagious disease, such as
Lassa
fever
, that can be transmitted to others
by direct contact and airborne germs. In
this case, all bedding, equipment and
clothing are either sterilized or inciner-
ated after use.
Partial
isolation
is
carried out if the disease is transmitted
in a more limited way (by droplet spread,
as in
tuberculosis,
for example).
Reverse isolation, also called reverse
barrier nursing, is used to protect a
patient whose resistance to infection is
severely lowered by a disease or treat-
ment such as
chemotherapy
. The air
supply to the room is filtered. All staff
and visitors wear caps, gowns, masks,
and gloves. Occasionally, long-term re-
verse isolation is needed for patients
with severe combined immunodeficiency
(see
immunodeficiency disorders).
isometric
A system of
exercise
without
body movement in which muscles build
up strength by working against resis-
tance, provided by either a fixed object
or an opposing set of muscles. (See
also
isotonic
.)
isoniazid
An
antibacterial drug
used to
treat
tuberculosis.
Isoniazid is given in
combination with other antituberculous
drugs, usually for at least 6 months.
isoprenaline
A drug that is used as a
bronchodilator
, to dilate the air passages
in the lungs in conditions such as
asth-
ma
, and as a
vasodilator
to stimulate the
heart in conditions such as
heart block
.
Side effects include dry mouth, dizziness,
headache, palpitations, and chest pain.
isosorbide
A long-acting
nitrate drug
that acts as a vasodilator drug. Isosor-
bide is used to reduce the severity and
frequency of
angina pectoris
. This drug
is also given to treat severe
heart failure.
Adverse effects include headache, hot
flushes, and dizziness.
isotonic
A system of
exercise
, such as
weight lifting, in which muscle tension is
kept constant as the body works against
its own, or an external, weight. The term
also describes fluids, such as intravenous
fluids or drinks, with the same osmotic
pressure (see
osmosis
) as the blood.
(See also
isometric.)
isotope scanning
See
radionuclide scan-
ning.
isotretinoin
A drug derived from
vita-
min A
used in the treatment of severe
acne
.
It works by reducing the formation
of sebum (natural skin oils) and keratin
(a tough protein that is the major com-
ponent of the outer layer of skin).
Side effects include itching, dryness
and flaking of the skin, and cracking of
the lips. Isotretinoin may damage a
developing fetus; pregnancy must be
avoided during treatment and for at
least 3 months after taking the drug.
Regular blood tests are recommended
to check for complications.
ispaghula
A bulk-forming
laxative drug
used to treat
constipation
,
diverticular
disease
, and
irritable bowel syndrome
.
As ispaghula travels through the intes-
tine, it absorbs water from surrounding
blood vessels, thereby softening and
increasing the volume of the faeces.
Ispaghula is also used in people with
chronic, watery
diarrhoea
and in patients
who have had a
colostomy
or an
ileosto-
m y
to control the consistency of faeces.
Adverse
effects
include
flatulence,
abdominal distension, and discomfort.
itching
An intense irritation or tickling
sensation in the skin. Generalized itch-
ing may result from excessive bathing,
which removes the skin's natural oils
and may leave the skin excessively dry.
Some people experience general itching
after taking certain drugs. Many elderly
people suffer from dry, itchy skin, espe-
cially on their backs. Itching commonly
occurs during pregnancy.
Many skin conditions, including
chick-
enpox
,
urticaria
(nettle rash), and
eczema
,
produce an itchy rash. Generalized skin
itchiness can be a result of
diabetes
mellitus
,
kidney failure
,
jaundice
, and
thyroid
disorders.
Pruritus ani (itching around the anal
region) occurs with
haemorrhoids
and
anal fissure
.
Threadworm infestation
is
the most likely cause of anal itching in
children. Pruritus vulvae (itching of the
external genitalia in women) may be due
to
candidiasis
, hormonal changes, or to
use of spermicides or vaginal ointments
and deodorants.
Insect bites, lice,
and
sca-
bies
infestations cause intense itching.
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