Bma Illustrated Medical Dictionary

the ears) occurring after a noise has

ceased is an indication that some dam-

age has probably occurred.

nomaThe death of tissue in the lips and

cheeks due to bacterial infection. Also

called cancrum oris, it is largely confined

to young, severely malnourished children

in developing countries. Noma can also

occur in the last stages of leukaemia.

Without treatment, noma causes severe

ulceration, eventual destruction of the

bones around the mouth, and loss of

teeth. Healing occurs naturally, but

scarring may be severe.

Antibacterial drugsand improved nutri-

tion halt the progress of the disease.

nonaccidental injurySee child abuse.

nongonococcal urethritisFormerly

known as nonspecific urethritis, inflam-

mation of the urethra due to a cause

other than gonorrhoea. Worldwide, non-

gonococcal urethritis is a very common

type of sexually transmitted infection.

Almost 50 per cent of cases are known

to be caused by chlamydia trachomatis

(see chlamydial infections); others are

caused by the virus that causes herpes

simplex, trichomonas vaginalis infections

(see trichomoniasis), or other microor-

ganisms. In the remainder of cases, the

cause remains unknown.

In men, the infection usually causes a

clear or a purulent urethral discharge,

often accompanied by pain or discom-

fort on passing urine. The equivalent

condition in women, called nonspecific

genital infection, may not cause symp-

toms unless there are complications.

Treatment may be difficult if the cause

of symptoms cannot be determined.

Antibiotic drugs, such as doxycycline

and erythromycin, are given. Follow-up

visits may be advised after treatment.

In men, epididymitis, prostatitisand ure-

thralstricture(narrowing of the urethra)

can occur as complications of nongono-

coccal urethritis. Reiter’s syndrome(in

which there is arthritis and conjunctivi-

tis as well as urethritis) occurs as a

complication in some men who develop

nongonococcal urethritis.

In women, pelvic inflammatory disease

and cysts of the Bartholin’s glandsmay

occur. Ophthalmianeonatorum, a type

of conjunctivitis, sometimes develops

in babies born to women with chlamy-

dial cervicitis.

noninvasiveA term used to describe

any medical procedure that does not

involve penetration of the skin or entry

into the body through any of the natural

openings. Examples include CT scan-

ningand echocardiography. The term

noninvasive is sometimes also applied

to noncancerous tumours that do not

spread throughout body tissues.

nonoxinol 9A spermicideused in con-

traceptive preparations such as gels,

foams, and creams.

nonspecific urethritisSee nongono-

coccal urethritis.

nonsteroidal anti-inflammatory drugs

A group of drugs, also known as NSAIDs

that produce analgesia(pain relief) and

reduce inflammation in joints and soft

tissues such as muscles and ligaments.

Nonsteroidal anti-inflammatory drugs

are widely used to relieve symptoms

caused by types of arthritis, such as

rheumatoid arthritis, osteoarthritis, and

gout. They do not cure or halt the

progress of disease. NSAIDs are also

used in the treatment of back pain,

NOMA NONSTEROIDAL

N

NOISE-INDUCED HEARING LOSS

160

140

120

100

80

60

40

20

0

RISK OF NOISE-INDUCED HEARING LOSS

SOUND LEVEL (DECIBELS)

Immediate injury

Risk of

injury

SOURCE OF NOISE

Rock concertJet engine at30 m (100 ft) Shotgun blastat 5 m (15 ft)

Traffic at5 m (15 ft)

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