Other causes of osteoporosis include
removal of the ovaries; a diet that is
deficient in calcium; certain hormonal
disorders; prolonged treatment with
corticosteroid drugs; and prolonged
immobility. Osteoporosis is most com-
mon in heavy smokers and drinkers,
and in excessively thin people.
The first sign of osteoporosis is often a
fracture, typically just above the wrist or
at the top of the femur. One or several
vertebraemay fracture spontaneously
and cause the bones to crumble, lead-
ing to progressive height loss or pain
due to compression of a spinal nerve.
Osteoporosis is confirmed using bone
X-raysand densitometry. Bone loss can
be minimized by adequate dietary cal-
cium, and regular, sustained exercise to
build bones and maintain their strength.
Long-term hormone replacement therapy
after the menopause can prevent osteo-
porosis in women. Bisphosphonate drugs
may be given to prevent bone loss.
osteosarcomaA cancerous tumour of
the bone that spreads rapidly to the
lungs and, less commonly, to other areas.
An osteosarcoma may occur in adoles-
cents for noknown reason (usually in a
long bone of the arm or leg or around the
knee, hip, or shoulder). In elderly peo-
ple, osteosarcomas may develop in
several bones as a late, rare complica-
tion of Paget’s disease. The tumour
causes pain and swelling of the affected
bone if it occurs near the surface.
The condition may be treated by
radiotherapy, but the affected bone is
usually surgically removed. Sometimes
it is replaced by a bone graft or artificial
bone, but most often, an amputation
and a prosthesis (see limb, artificial) are
required. Anticancer drugs improve the
outlook; about half of those in whom
the disease is discovered early are cured.
osteosclerosisIncreased bone density,
visible on X-raysas an area of extreme
whiteness. Localized osteosclerosis may
be caused by a severe injury that com-
presses the bone, osteoarthritis, chronic
osteomyelitis, or an osteoma. Osteoscle-
rosis occurs throughout the body in the
inherited bone disorder osteopetrosis.
osteotomySurgery to change the align-
ment of, or shorten or lengthen, a bone,by cutting it. Osteotomy is used to cor-
rect a hallux valgusthat has caused a
bunion; coxa vara(a hip deformity); or
deformity due to congenital hip disloca-
tion (see hip, congenital dislocation of).
The procedure is also used to straighten
a long bone that has healed crookedly
after a fracture, or to shorten the unin-
jured leg if a fractured leg has shortened
during healing (see leg, shortening of).
ostomyThe term used to describe a
surgical opening or a junction of 2 hol-
low organs (for example, colostomy).
otalgiaThe medical term for earache.
OTC drugSee over-the-counter drug.
otitis externaAn earinfection affecting
the outer-ear canal. Otitis externa usu-
ally causes inflammation and swelling,
discharge, and, in some people, eczema
around the opening of the canal.The ear
may be itchy and painful and blocked
with pus, causing deafness.
Generalized infection of the canal, and
sometimes of the pinna (external ear),
may be due to a fungal or bacterial
infection. The ear may also sometimes
become inflamed as part of a generalized
skin disorder such as atopic eczema or
seborrhoeic dermatitis.
Often, the only treatment required for
otitis externa is to keep the ear thor-
oughly clean and dry until the infection
has cleared. Locally acting preparations
containing antibiotic drugs, antifungal
drugs, or corticosteroid drugsmay be
used. Oral antibiotics may be given to
treat severe bacterial infections.
otitis mediaInflammation of the mid-
dle ear. This condition is due to a viral
or bacterial infection extending up the
eustachian tube, which runs from the
back of the nose to the middle ear. The
tube may become blocked by inflamma-
tion or enlarged adenoids, causing fluid
and pus to accumulate in the middle
ear rather than draining away through
the tube. Children, particularly those
under 7 years, are especially suscepti-
ble to otitis media, and some children
have recurrent attacks.
Acute otitis media can cause sudden
severe earache, a feeling of fullness in
the ear, deafness, tinnitus, and fever. The
eardrum may burst, in which case healing
usually occurs within a few weeks. TheOSTEOSARCOMA OTITIS MEDIAO