LASER
LDL
the functioning of the
vocal cords.
In
adults, the most common laryngeal dis-
order is
laryngitis.
In children,
croup
is
common up to the age of 4. Much rarer
is
epiglottitis,
a life-threatening disorder
in young children. Rarely, a baby is born
with a soft, limp larynx, a condition called
laryngomalacia, which causes noisy brea-
thing during feeding; the larynx usually
attains normal firmness by the age of
2
.
Various kinds of tumour may develop
on the vocal cords. The most common is
a
polyp
(a noncancerous swelling caused
by smoking, an infection such as influ-
enza, or straining the voice). Warts and
small noncancerous growths called
sing-
er's nodes
can also occur on the vocal
cords. The larynx may also be affected by
cancerous tumours (see
larynx, cancer of
).
laser
A device that produces a concen-
trated beam of light radiation; “laser” is
an acronym for “light amplification by
stimulated emission of radiation”. (See
laser treatment.)
laser treatment
Use of a
laser
beam in
a variety of medical procedures. High-
intensity laser beams cut through tissue
and cause blood clotting. They can be
used in surgery and to destroy abnor-
mal blood vessels. Lasers are frequently
used in
ophthalmology
to treat eye dis-
orders, in
gynaecology
(for example, to
unblock
fallopian tubes
)
,
and to remove
birthmarks
and tattoos.
LASER SKIN TREATMENT
LASIK
The abbreviation for laser-assisted
in-situ keratomileusis, a type of eye sur-
gery in which a
laser
is used to reshape
the
cornea
to correct refractive errors
(see
refraction
) such as shortsightedness
(see
myopia
) and
astigmatism
.
Lassa fever
A dangerous infectious
disease caused by a virus carried by
rodents. Lassa fever is largely confined
to West Africa. The illness starts with
fever, headache, muscular aches, and a
sore throat. Later, severe diarrhoea and
vomiting develop. In extreme cases, the
disease can be fatal. Treatment is injec-
tions of the drug
ribavirin
and serum
containing
antibodies
to the virus.
lassitude
A term describing a feeling of
tiredness
, weakness, or exhaustion.
lateral
Relating to, or situated on, one
side. “Bilateral” means “on both sides”.
latissimus dorsi
A large, flat, triangu-
lar
muscle
in the back. Contraction of
the muscle moves the arm downwards
and backwards.
laudanum
A solution of
opium
, former-
ly used as a sedative and painkiller and
in the treatment of diarrhoea.
laughing gas
The popular name for
nitrous oxide
.
Laurence-Biedl-Moon syndrome
A
rare inherited disorder characterized by
increasing
obesity
,
retinitis pigmentosa
that may lead to blindness,
learning dif-
ficulties
,
polydactyly
,
and
hypogonadism
.
(See also
genetic disorders.
)
lavage, gastric
Washing out the stom-
ach with water, usually to remove toxins.
laxative drugs
A group of drugs used
to treat
constipation
.
There are various
types. Bulk-forming laxatives increase
the volume and softness of faeces and
make them easier to pass. Stimulant
laxatives stimulate the intestinal wall to
contract and speed up the elimination
of faeces. Lubricant laxatives soften and
facilitate the passage of faeces. Osmotic
laxatives increase the water content and
volume of the faeces. If used in excess,
laxative drugs may cause diarrhoea,
abdominal cramps, and flatulence, and
may impair normal bowel function.
lazy eye
An ambiguous name for the
visual defect that commonly results
from squint (see
amblyopia
).
LDL
See
low density lipoprotein.
335
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