Encyclopedia of Health and Medicine

344 The Musculoskeletal System
blood count (CBC) are likely to show elevated
white blood cell (WBC) count and other changes
in the blood when there is an infection present.
Treatment Options and Outlook
Surgical debridement (an OPERATION to clean pus
and damaged tissue from the infected area) and
ANTIBIOTIC MEDICATIONS administered intravenously
are the first course of treatment for osteomyelitis.
Once the infection is under control, the doctor
may switch to oral antibiotics. The course of
antibiotic treatment may extend six weeks or
more, depending on how well the infection
responds.
Infections in the bone are particularly hard to
treat because the bone’s blood circulation does not
deliver antibiotic medications to the bone very
effectively. The infection may cause an ABSCESS
(pocket of pus) that in turn causes the death of
bone tissue. When such a scenario unfolds, the
osteomyelitis becomes chronic and may destroy
considerable bone tissue. It may be necessary for
the orthopedic surgeon to create a surgical wound
over the site of the infection to clean it and irrigate
the area.
Acute osteomyelitis that responds to antibiotic
medication may heal without complications.
Chronic osteomyelitis, particularly with abscess,
may have a less favorable outcome with extended
antibiotic therapy necessary for several months.
Several surgical operations may be necessary to
clean the infection site and prevent abscesses from
forming. The surgeon may leave the wound open
or insert a drain to facilitate HEALING. Long-term
chronic osteomyelitis can cause permanent damage
to the structure of the bone. When chronic
osteomyelitis accompanies joint replacement, it
may be necessary to remove the prosthesis until
the infection heals. The treatment of last resort is
AMPUTATION.
Risk Factors and Preventive Measures
People at particular risk for osteomyelitis are those
who have DIABETES or who are on hemodialysis for
END-STAGE RENAL DISEASE (ESRD). Trauma to the
bone, such as open fracture or surgery, also
increases the risk for infection. Prevention is not
always possible, though using measures to appropriately
care for wounds and respond to early
symptoms such as pain can keep the infection
contained enough for antibiotic therapy to be
effective.
See also BACTERIA; FUNGUS.
osteopenia A preclinical circumstance of
reduced BONE DENSITY. Doctors generally consider
osteopenia to precede OSTEOPOROSIS. Osteopenia
has no symptoms and is a diagnosis the doctor
arrives at as a consequence of the person’s BONE
density score with radiologic (X-RAY based) bone
density measurement. About 34 million Americans,
mostly women at or beyond MENOPAUSE and
men older than age 60, have osteopenia.
Osteopenia may result from various metabolic
circumstances. The World Health Organization
(WHO) defines osteopenia as bone density that is
no greater than 2.5 standard deviations below
normal bone density (reported as a T-score
between –0.1 and –2.5). Conventional diagnostic
methods establish a scale of bone density relative
to that of a young person of the same gender at an
age when bone density is at its peak.
Many people can restore bone density through
RESISTANCE EXERCISE and increased calcium consumption.
Doctors generally do not treat osteopenia
beyond these measures but instead closely
monitor bone density. Osteopenia is a warning
sign for women approaching or beyond
menopause, as bone density loss accelerates when
estrogen levels in the body decrease. Lifestyle factors
that contribute to osteopenia include physical
inactivity, cigarette smoking, and excessive ALCO-
HOL consumption, all of which interfere with calcium
transfer and other metabolic processes
related to bone remodeling.
See also CALCIUM AND BONE HEALTH; ESTROGENS;
EXERCISE AND HEALTH; LIFESTYLE AND HEALTH; OSTEOPET-
ROSIS.
osteopetrosis A rare genetic disorder in which
BONE remodeling is defective. Though the body
builds new bone (osteoblastic activity), it does not
adequately clear away old bone (osteoclastic activity).
Consequently the bones become very dense
though are also very brittle and vulnerable to
FRACTURE. When symptoms are present early in
childhood (infantile osteopetrosis), the outcome is
very poor because the excessive bone structure