I
CAUSES
The
causes of ADHD are not fully
understood, but the disorder often runs
in families, which suggests that genetic
factors may be involved. ADHD is not,
as popularly believed, a result of poor
parenting or abuse.
SYMPTOMS AND SIGNS
Symptoms of the condition develop in
early childhood, usually between the
ages
of three
and seven,
and may
include the inability to finish tasks;
inability to concentrate in class; a short
attention span; difficulty in following
instructions; a tendency to talk exces-
sively,
frequently
interrupting
other
people; difficulty in waiting or taking
turns; inability to play alone, quietly;
and physical impulsiveness.
Children with ADHD may have diffi-
culty in forming friendships. Self-esteem
is often low because an affected child is
frequently scolded and criticized.
TREATMENT AND OUTLOOK
Treatment of ADHD includes behaviour
modification techniques, both at home
and at school. In some children, avoid-
ance of certain foods or food additives
seems to reduce symptoms. In severe
cases,
stimulant drugs,
usually
methylphen-
idate,
may be prescribed. Paradoxically,
the use of stimulant drugs in the treat-
ment of ADHD reduces hyperactivity
and improves concentration.
In general, the condition improves by
adolescence but may be followed by
antisocial behaviour and
drug abuse
or
substance abuse.
attenuated
A term used to refer to microorganisms
that have been treated to reduce their
ability
to
cause
disease.
Attenuated
organisms are used in some
vaccines
.
atypical
A term used to describe something that
is not the usual type or that does not fit
into the usual pattern. The atypical
presentation of a disease or disorder is
one in which the early symptoms and
signs differ from those that normally
occur, which may make diagnosis of
the condition more difficult.
audiogram
A graph that is produced as a result of
audiometry
(measurement of the sense
of hearing). An audiogram shows the
hearing threshold (the minimum audi-
ble decibel level) for each of a range of
sound frequencies.
AUSCULTATION
audiology
The study of hearing, especially im-
paired hearing.
audiometry
Measurement of the sense of hearing.
The term audiometry often refers to
hearing tests
in which a machine is used
to produce sounds of a defined inten-
sity (loudness) and frequency (pitch),
and in which the hearing in each ear
is measured over the full range of
normally
audible
sounds.
(See
also
impedance audiometry.)
auditory nerve
The part of the
vestibulocochlear nerve
(the
eighth
cranial nerve
)
concerned
with hearing. The auditory nerve is also
known as the acoustic nerve.
aura
A peculiar “warning” sensation that
precedes or marks the onset of a
mig-
raine
attack or a seizure in
epilepsy.
A migraine attack may be preceded
by a feeling of elation, excessive energy,
or drowsiness; thirst or a craving for
sweet foods may develop. A migraine
may also be heralded by flashing lights
before
the
eyes,
blurred
or
tunnel
vision, or difficulty in speaking. There
may also be weakness, numbness, or
tingling in one half of the body. As these
symptoms subside, the migraine head-
ache begins.
An epileptic aura may occur as a
distorted perception, such as a hallu-
cinatory smell or sound or a sensation
of movement in a part of the body. One
type of attack (in people who have
tem-
poral lobe epilepsy)
is often preceded by
a vague feeling of discomfort in the
upper abdomen, sometimes followed
by borborygmi (rumbling or gurgling
bowel sounds, and by a sensation of
fullness in the head.
auranofin
A
gold
preparation used as an
anti-
rheumatic drug
in
the
treatment
of
rheumatoid arthritis.
Unlike other gold
preparations, which are given as intra-
muscular injections, auranofin can be
taken by mouth.
auricle
Another name for the pinna, the exter-
nal flap of the ear.The term is also used
to describe the earlike appendages of
the atria (the upper chambers of the
heart, see
atrium
).
auriscope
Also called an
otoscope,
an instrument
for examining the ear.
auscultation
A procedure that involves listening to
sounds within the body, using a
stetho-
scope,
to assess the functioning of an
organ or to detect disease.
AUSCULTATION OF THE HEART
To listen to the heart, the doctor places
the stethoscope on the chest at four
points which correspond to the location
of the heart valves. With the patient
either sitting up, lying in a semi-reclin-
ing position, or lying on his or her left
side, the doctor listens for any abnor-
mality in the rate and rhythm of the
heartbeat and for a heart
murmur
or
other abnormal
heart sound
that may
indicate a heart defect.
AUSCULTATION OF THE LUNGS
When listening to the lungs, the doctor
places the stethoscope on numerous
areas of the chest and back. The patient
breathes normally, and then takes deep
breaths, so that the doctor can compare
the sounds on the right and left sides.
Abnormal breath sounds may indicate
pneumonia, bronchitis,
and
pneumothorax
(in which air enters the space between
the
pleura,
the membranes lining the
outside of the lungs and the inside of
the chest cavity). Cracking or bubbling
sounds
(known
as
crepitations)
are
caused by fluid in the lungs; wheezing
sounds result from spasm of the air-
ways, usually as a result of
asthma
.
Pleurisy
(inflammation of the pleura)
causes a scratching sound as inflamed
areas of the lung rub together.
The doctor may also test for vocal
resonance
by
asking
the
patient to
whisper something. The sound is louder
if there is pus in the lung due to a con-
dition such as pneumonia.
AUSCULTATION OF THE BLOOD VESSELS
Blood vessels near the skin surface (usu-
ally the carotid artery in the neck, the
abdominal aorta, or the renal artery)
may be listened to for bruits (sounds
made by turbulent or abnormally fast
blood circulation). Bruits occur when
blood vessels are narrowed (for exam-
ple by fatty deposits in
atherosclerosis
)
or widened (by an
aneurysm,
for exam-
ple). They may also be present if heart
valves have been narrowed or damaged
(for example by
endocarditis
).
AUSCULTATION OF THE ABDOMEN
The abdomen is auscultated for borbo-
rygmi (loud rumbling, gurgling sounds
A
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