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).
isometricA 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.)
isoniazidAn antibacterial drugused to
treat tuberculosis. Isoniazid is given in
combination with other antituberculous
drugs, usually for at least 6 months.
isoprenalineA drug that is used as a
bronchodilator, to dilate the air passages
in the lungs in conditions such as asth-
ma, and as a vasodilatorto stimulate the
heart in conditions such as heart block.
Side effects include dry mouth, dizziness,
headache, palpitations, and chest pain.
isosorbideA 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.
isotonicA 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.
isotretinoinA drug derived from vita-
min Aused 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.
ispaghulaA 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 diarrhoeaand in patients
who have had a colostomyor an ileosto-
myto control the consistency of faeces.
Adverse effects include flatulence,
abdominal distension, and discomfort.
itchingAn 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
thyroiddisorders.
Pruritus ani (itching around the anal
region) occurs with haemorrhoidsand
anal fissure. Threadworm infestationis
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-
biesinfestations cause intense itching.ISOMETRIC ITCHINGI