BONE MARROW BIOPSY
B
DISORDERS OF BONE
Bone is affected by the same types of
disorders as other body tissues, but its
hard, rigid structure makes for extra
complications. If a bone receives a direct
blow or suffers from repeated stress, it
may
fracture.
If it becomes infected (due
to
osteomyelitis
or a
bone abscess,
for
example), the resulting inflammation
may interfere with the blood supply,
leading to death of part of the bone.
Genetic disorders
Several inherited conditions may affect
bone growth; these include
achondro-
plasia
and
osteogenesis imperfecta.
Such
disorders often result in short stature.
Nutritional disorders
Lack of calcium and vitamin D in the
diet may result in
rickets
in children
and
osteomalacia
in adults; in both
conditions the bones become soft and
lose their shape.
Hormonaldisorders
If the pituitary gland produces excess
growth hormone before puberty, this
results in excessive growth of the bones
and other organs, leading to
gigantism.
Excess parathyroid hormone may lead
to
bone cysts. Osteoporosis
(loss of
bone density) is common in women
following the menopause, when
oestrogen levels fall.
Tumours
Several different types of cancerous and
noncancerous growth can arise from
bone (see
bone cancer
and
bone tumour).
In addition, the bones are a common
site for secondary tumours (metastases)
that have spread from cancerous
tumours elsewhere in the body.
Other disorders
Paget’s disease
involves thickening of
some areas of the bones, while other
areas become spongy.
INVESTIGATION
Bone disorders are investigated using
imaging techniques such as
X-rays, CT
scanning, radionuclide scanning,
and
densitometry;
by
biopsy;
and
blood tests.
tissue and fat. If the body needs to
increase its rate of blood formation,
some of the yellow marrow will be
replaced by red. Sometimes marrow
fails to produce sufficient numbers of
normal blood cells, as occurs in aplastic
anaemia (see
anaemia, aplastic)
or when
marrow has been displaced by tumour
cells. In other cases, marrow may over-
produce certain blood cells, as occurs in
polycythaemia
and
leukaemia.
bone marrow biopsy
A procedure to obtain a sample of cells
from the bone marrow (an aspiration
biopsy) or a small core of bone with
marrow inside (a trephine biopsy). The
sample is usually taken, under local
anaesthesia,
from the sternum (breast-
bone) or iliac crests (upper part of the
hip-bones).
Microscopic
examination
gives information on the development
of the blood components and on the
presence of cells foreign to the marrow.
It is useful in the diagnosis of many
blood disorders,
including
leukaemia
and
anaemia.
It can also show whether
bone marrow has been invaded by
lym-
phoma
or cells from other tumours.
bone marrow transplant
The technique of using normal red
bone
marrow
to replace cancerous, defective,
or diseased bone marrow in a patient.
In allogeneic bone marrow transplan-
tation (BMT), healthy marrow is taken
from a donor with a very similar tissue-
type to the recipient’s (often a brother or
sister). In autologous BMT, the patient’s
own healthy bone marrow is harvested
while his or her disease is in remission
and is reinfused at a later time. Generally,
BMT is used only in the treatment of
serious, potentially life-threatening blood
and immune system disorders, including
aplastic anaemia (see
anaemia, aplastic),
sickle cell anaemia,
and
leukaemia.
An alternative treatment is
stem-cell
transplantation, in which cells from the
umbilical cord of a newborn baby or
the bloodstream of an adult are trans-
planted instead of bone marrow.
HOW IT IS DONE
Before transplantation, all of the recipi-
ent’s bone marrow is destroyed with
cytotoxic drugs
or radiation in order to
prevent rejection of the donated cells
and to kill any cancer cells present. The
donor bone marrow is transfused into
the circulation from where cells find
their way to the bone marrow cavities
and start to grow.
In autologous BMT, the patient’s bone
marrow is stored by
cryopreservation
(freezing).
Before being
frozen,
the
marrow is usually treated to eliminate
any undetected cancerous cells. If the
patient’s disease recurs, the stored bone
marrow can then be reinfused.
COMPLICATIONS
The major risks with BMT are infection
during the recovery period and rejec-
tion (known as
graft-versus-host disease,
or GVHD).
Immunosuppressant drugs
are
used to prevent and treat rejection. The
risk of GVHD may be reduced by
removing the T-cells (see
T-lymphocyte)
from the marrow using monoclonal anti-
bodies (see
antibody, monoclonal)
before
it is reinfused. GVHD does not occur
with autologous BMT or with stem-cell
transplantation.
bone metastases
Cancerous
tumours
in bone, also known
as secondary bone cancers, that have
spread from a cancer in another part of
the body (see
bone cancer
).The bones of
the ribs, pelvis, skull, and spine are par-
ticularly affected.
bone pain
An unpleasant sensation (see
pain)
felt
in a part of the skeleton (see
musculo-
skeletal pain).
Bone pain is frequently
described as constant and gnawing, and
it may disturb sleep. There are many
possible causes of bone pain, including
trauma of the bone (see
fracture
), infec-
tion (see
osteomyelitis
), disorders of the
bone itself (such as
Paget’s disease),
and
bone tumours.
(See also
osteoid osteoma;
osteomalacia; sickle cell anaemia.)
bone resorption
Loss of
bone
tissue. Bone resorption and
the laying down of new bone tissue are
continuous processes. With increasing
age, resorption exceeds new bone for-
mation, and the bone tissue gradually
becomes thinner. However, in certain
disorders (for example,
osteoporosis),
resorption takes place more rapidly and
to a greater extent, causing weakening
of bone and increased risk of
fractures.
bone tumour
A bone swelling that may be cancerous
(see
bone cancer
) or noncancerous. The
most common type of noncancerous
bone
tumour
is
an
osteochondroma.
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