Bma Illustrated Medical Dictionary

the functioning of the vocal cords. In

adults, the most common laryngeal dis-

order is laryngitis. In children, croupis

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 nodescan also occur on the vocal

cords. The larynx may also be affected by

cancerous tumours (see larynx, cancer of).

laserA 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 treatmentUse of a laserbeam 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 ophthalmologyto treat eye dis-

orders, in gynaecology(for example, to

unblock fallopian tubes), and to remove

birthmarksand tattoos.

LASER TREATMENT

LASIK The abbreviation for laser-assisted

in-situ keratomileusis, a type of eye sur-

gery in which a laseris used to reshape

the corneato correct refractive errors

(see refraction) such as shortsightedness

(see myopia) and astigmatism.

Lassa feverA 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 ribavirinand serum

containing antibodiesto the virus.

lassitudeA term describing a feeling of

tiredness, weakness, or exhaustion.

lateralRelating to, or situated on, one

side. “Bilateral” means “on both sides”.

latissimus dorsiA large, flat, triangu-

lar musclein the back. Contraction of

the muscle moves the arm downwards

and backwards.

laudanumA solution of opium, former-

ly used as a sedative and painkiller and

in the treatment of diarrhoea.

laughing gasThe popular name for

nitrous oxide.

Laurence–Biedl–Moon syndromeA

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, gastricWashing out the stom-

ach with water, usually to remove toxins.

laxative drugsA 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 eyeAn ambiguous name for the

visual defect that commonly results

from squint (see amblyopia).

LDLSee low density lipoprotein.

LASER LDL

L

Safety goggles to

protect the eyes

Laser

probe

Laser
unit

Dermatologist

Reclining chair

LASER SKIN TREATMENT