of actinomycosis affects the pelvis in
women, causing lower abdominal pain
and bleeding between periods. This
form was associated with a type of IUD,
no longer in use, that did not contain
copper. Rarely, forms of the disorder
affect the appendix or lung. Actinomy-
cosis is treated with antibiotics.
acuity, visualSee visual acuity.
acupressureA derivative of acupunc-
ture in which pressure is applied
instead of needles.
acupunctureA branch of Chinese med-
icinein which needles are inserted into
a patient’s skin as therapy for various
disorders or to induce anaesthesia.
Traditional Chinese medicine main-
tains that the chi (life-force) flows
through the body along channels called
meridians. A blockage in one or more of
these meridians is thought to cause ill
health. Acupuncturists aim to restore
health by inserting needles at appropri-
ate sites along the affected meridians.
The needles are stimulated by rotation
or by an electric current. Acupuncture
has been used successfully as an anaes-
thetic for surgical procedures and to
provide pain relief after operations and
for chronic conditions.
acuteA term often used to describe a
disorder or symptom that develops sud-
denly. Acute conditions may or may not
be severe, and they are usually of short
duration. (See also chronic.)
Adam’s appleA projection at the front
of the neck, just beneath the skin, that
is formed by a prominence on the thy-
roid cartilage, which is part of the larynx
(voice box). The Adam’s apple enlarges
in males at puberty.
ADDThe abbreviation for attention defi-
cit disorder, more commonly known as
attention deficit hyperactivity disorder.
addictionDependence on, and craving
for, a particular drug, for example alco-
hol, diazepam (a tranquillizer), or heroin.
Reducing or stopping intake of the drug
may lead to characteristic physiological
or psychological symptoms (see with-
drawal syndrome), such as tremor or
anxiety. (See also alcohol dependence;
drug dependence.)
Addison’s diseaseA rare chronic dis-
order in which there is a deficiency of
the corticosteroid hormones hydrocorti-
soneand aldosterone, normally produced
by the adrenal cortex (the outer part of
the adrenal glands). Excessive amounts
ofACTHare secreted by the pituitary
gland in an attempt to increase output
of the corticosteroid hormones. Secre-
tion and activity of another hormone,
melanocyte stimulating hormone (MSH),
is also increased.
Addison’s disease can be caused by
any disease that destroys the adrenal
cortices. The most common cause is an
autoimmune disorder in which the
immune system produces antibodies
that attack the adrenal glands.
Symptoms generally develop gradu-
ally over months or years, and include
tiredness, weakness, abdominal pain,
and weight loss. Excess MSH may cause
darkening of the skin in the creases of
the palms, pressure areas of the body,
and the mouth. Acute episodes, called
Addisonian crises, brought on by infec-
tion, injury, or other stresses, can also
occur. The symptoms of these include
extreme muscle weakness, dehydration,
hypotension(lowblood pressure), con-
fusion, and coma. Hypoglycaemia(low
blood glucose) also occurs.
Life-long corticosteroid drug treatment
is needed. Treatment of Addisonian
crises involves rapid infusion of saline
and glucose, and supplementary doses
of corticosteroid hormones.
adductionMovement of a limb towards
the central line of the body, or of a digit
towards the axis of a limb. Muscles that
carry out this movement are often called
adductors. (See also abduction.)
adenitisInflammation of lymph nodes.
Cervical adenitis (swelling and tender-
ness of the lymph nodes in the neck)
occurs in certain bacterial infections,
especially tonsillitis, and glandular fever
(see infectious mononucleosis). Mesen-
teric lymphadenitisis inflammation of
the lymph nodes inside the abdomen
and is usually caused by viral infection.
Treatment of adenitis may include anal-
gesic drugs,and antibiotic drugsif there
is a bacterial infection.
adenocarcinomaThe technical name
for a cancer of a gland or glandular tis-
sue, or for a cancer in which the cellsACUITY, VISUAL ADENOCARCINOMA
A