ADD
cartilage, which is part of the
larynx
(voice-box). The Adam’s apple enlarges
in males at puberty.
ADD
The abbreviation for attention deficit
disorder, more commonly known as
attention deficit hyperactivity disorder.
addiction
Dependence on, and craving for, a par-
ticular drug, such as alcohol, diazepam
(a tranquillizer), or heroin. Reducing or
stopping intake of the drug may lead to
characteristic physiological and/or psy-
chological symptoms
(see
withdrawal
syndrome),
such as tremor or anxiety.
The term addiction may also be used in
relation to compulsive behaviour, such
as gambling.
(See also
alcohol depen-
dence
;
drug dependence.)
Addison’s disease
A rare chronic disorder in which there
is deficiency of the corticosteroid hor-
mones
hydrocortisone
and
aldosterone
,
which are normally produced by the
adrenal cortex (the outer parts of the
adrenal glands,
which are situated on the
top of the kidneys). In addition, exces-
sive amounts of the hormone
ACTH
are
secreted by the pituitary gland (at the
base of the brain) in an attempt to
increase output of the corticosteroid
hormones. The secretion and activity of
another hormone, melanocyte stimulat-
ing
hormone
(MSH),
also increase,
which leads to increased synthesis of
melanin
pigment in the skin.
CAUSES
Addison’s disease can be caused by any
disease that destroys the adrenal cor-
tices. The most common cause is an
autoimmune
disorder
in
which
the
immune system
produces antibodies
that attack the adrenal glands.
SYMPTOMS
Symptoms of the disease generally dev-
elop gradually over months or years and
include tiredness, weakness, abdominal
pain, and weight loss. Excess MSH may
cause darkening of the skin in the crea-
ses of the palms, pressure areas of the
body, and the mouth.
Acute
episodes,
called Addisonian
crises, brought on by infection, injury
or other stresses, can also occur. The
symptoms of these are mainly due to
aldosterone
deficiency
and
include
extreme muscle weakness, dehydration,
hypotension
(low blood pressure), confu-
sion, and coma.
Hypoglycaemia
(low
blood glucose) also occurs due to a
deficiency of hydrocortisone.
DIAGNOSIS AND TREATMENT
Diagnosis of Addison’s disease is gener-
ally made if the patient fails to respond
to an injection of ACTH, which norm-
ally stimulates hydrocortisone secretion.
Lifelong
corticosteroid drug
treatment
is needed to replace the deficient hor-
mones. Treatment of Addisonian crises
involves rapid infusion of saline and
glucose and supplementary doses of
corticosteroid hormones.
additives
See
food additives.
adduction
Movement 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 adduc-
tors. (See also
abduction.)
adductor
Any one of the muscles that carry out
the movement of
adduction.
adenitis
Inflammation of
lymph nodes.
Cervical
adenitis (swelling and tenderness of the
lymph nodes in the neck) occurs in cer-
tain
bacterial
infections,
especially
tonsillitis,
and the viral infection gland-
ular fever (see
mononucleosis, infectious).
Mesenteric lymphadenitis
is inflammation
of the lymph nodes inside the abdomen
and is usually caused by a viral infection.
In many cases of adenitis, treatment
is not necessary When it occurs as the
result of a bacterial infection, treatment
of the infection with
antibiotic drugs
will
generally also result in an improvement
in the condition of the lymph nodes.
adenocarcinoma
The technical name for a
cancer
of a
gland or glandular tissue, or for a can-
cer in which the cells form glandlike
structures. An adenocarcinoma arises
from epithelium (the layer of cells that
lines organs).
Cancers of the colon (the main part
of the large intestine), breast, pancreas,
and kidney are usually adenocarcino-
mas, as are some cancers of the cervix,
oesophagus, salivary glands, and various
other organs. (See also
intestine, cancer
of;
kidney cancer; pancreas, cancer of. )
adenoidectomy
Surgical removal of the
adenoids.
An
adenoidectomy is usually performed on
a child with abnormally large adenoids
that are causing recurrent infections of
the middle ear or air sinuses. The oper-
ation may be performed together with
tonsillectomy
.
There are few after-effects, and the
patient can generally begin to eat nor-
mally the following day.
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