Transcript degenerative diseases

Reader: Kostiv S.Ya.
Osteoporosis is the most common metabolic bone disease and
represents an increasingly serious problem, particularly as the
population ages. It has been most commonly recognized in
elderly white women, although it does occur in both sexes, all
races, and all age groups.
Osteoporosis is defined by the World Health Organization as a
T-score of -2.5. T-score is the value compared to control subjects
who are at their peak bone mineral density, while Z-score
reflects a value compared to patients matched for age and sex
Osteoporosis is a condition in which bone mass is low and
microarchitectural deterioration of bone tissue occurs, leading
to bone fragility and an increased risk of fracture. Homeostasis
of bone, a living tissue, is maintained by the osteoclast, which is
responsible for bone resorption, and the osteoblast, which is
responsible for bone formation. Increased bone resorption or
decreased bone formation may result in osteoporosis.
Osteoporosis can be caused both by a failure to build bone and
reach peak bone mass as a young adult and by bone loss later in
life.
Currently, 10 million Americans have osteoporosis. Another 34
million have low bone mass, which leaves them at increased risk
for osteoporosis. Each year in the United States, 1.5 million
osteoporotic fractures occur. Of these, 700,000 occur in the
spine, 300,000 occur in the hip, and 200,000 occur in the wrist.
The remainder of fractures occur at other sites in the body.
Patients who have sustained one osteoporotic fracture are at
increased risk for developing additional osteoporotic fractures.5
For example, the presence of at least one vertebral fracture
results in a 5-fold increased risk of developing another vertebral
fracture. Patients with previous hip fracture have a 2- to 10-fold
increased risk of sustaining a second hip fracture. In addition,
patients with ankle, knee, olecranon, and lumbar spine
fractures have a 1.5-, 3.5-, 4.1-, and 4.8-fold increased risk of
subsequent hip fracture, respectively
Non-Hispanic white women and Asian women are at increased risk for
osteoporosis. An estimated one half of all hip fractures will occur in
Asia in the next century. Twenty percent of non-Hispanic white and
Asian women aged 50 years or older are estimated to have
osteoporosis, and 52% have low bone mass. Ten percent of Hispanic
women aged 50 years or older are estimated to have osteoporosis, and
49% have low bone mass. Five percent of non-Hispanic black women
older than 50 years are estimated to have osteoporosis, and 35% have
low bone mass. Seven percent of non-Hispanic white and Asian men
aged 50 years or older have osteoporosis, and 35% have low bone mass.
Four percent of non-Hispanic black men aged 50 years or older have
osteoporosis, and 19% have low bone mass. Three percent of Hispanic
men aged 50 years or older have osteoporosis, and 23% have low bone
mass
Physical examination of the patient with osteoporosis may elicit
pain, or the patient may be pain free. Thoracic kyphosis may be
present secondary to vertebral compression fractures, a dowager
hump, and a history of loss of height. Patients may have an
associated scoliosis. Patients with acute vertebral fractures may
have percussion and/or palpation tenderness over the involved
vertebrae
Osteoporosis may be categorized as having both primary and
secondary causes . Primary causes may be further divided into
modifiable and nonmodifiable risk factors, while secondary
causes are attributed to various disease states and medications
Thyroid-stimulating hormone (TSH): Thyroid dysfunction has been associated with osteoporosis
and should, therefore, be ruled out.
Intact parathyroid hormone (PTH): An intact PTH level is essential in ruling out
hyperparathyroidism. An elevated PTH level may be present in benign familial hypocalciuric
hypercalcemia (FHH).
Calcium: Calcium levels can reflect underlying disease states. Severe hypercalcemia may reflect
underlying malignancy or hyperparathyroidism. In addition, hypocalcemia can contribute to
osteoporosis.
Twenty-four–hour urinary calcium levels: Urinary calcium levels help to rule out benign FHH, in
which urinary calcium levels are low.
Celiac sprue panels: Celiac sprue has been associated with approximately 5% of osteoporosis cases.
Bone alkaline phosphatase: Bone alkaline phosphatase can be mildly elevated in patients with
fractures. In addition, patients with hyperparathyroidism, Paget disease, or osteomalacia can have
elevations of bone alkaline phosphatase.
Serum and urine immunoelectrophoresis: Serum and urine immunoelectrophoresis are used to
exclude the presence of multiple myeloma.
Urinary N-telopeptide (NTX): NTX, a marker of bone resorption, should be measured. Elevation of
this value (>40 nmol bone collagen equivalent per mmol urinary creatine) indicates a high turnover
state. NTX levels may also be used to monitor responses to antiosteoporotic treatments.
25-Hydroxyvitamin D and 1,25-hydroxyvitamin D levels: Abnormalities in 25-hydroxyvitamin D and
1,25-hydroxyvitamin D can reflect liver disease and renal disease such as renal osteodystrophy.
Inadequate vitamin D levels can predispose persons to osteoporosis.
Radiographic findings can suggest the presence of osteopenia, or bone loss,
although they cannot be used to diagnose osteoporosis. Using the second metacarpal or
the metaphysis of a long bone, the sum of the cortical width should be at least equal to
the medullary width. Osteopenia is suggested by a sum that is less than the medullary
width. In addition, 30-40% bone loss must occur before osteopenia is detected on plain
radiography.
CT scanning may be useful in identifying fractures. CT scanning can be used
to identify not only the fracture line but also areas of callus formation and sclerosis,
consistent with healing fracture.
MRI may be useful in identifying fractures. Using fat suppression sequences,
marrow edema consistent with fracture may be noted as areas of hypointensity on T1weighted images in association with corresponding areas of hyperintensity on T2weighted images. MRI is a very sensitive modality and is believed by some to be the first
diagnostic imaging method of choice in the detection of acute fractures, such as sacral
fractures.
Bone scanning may be used to identify the presence of multiple osteoporotic
fractures. Areas of increased radioactive tracer uptake represent areas of fracture.
Bone biopsy: In situations in which an unexplained recurrent
fracture exists in the setting of appropriate antiosteoporotic
medical treatment, bone biopsy may be performed. Bone biopsy
can help to exclude underlying pathologic conditions such as
multiple myeloma, which may be responsible for presumed
osteoporotic fracture. Typically, iliac crest biopsy is performed
either in the minor procedure suite or in the operating room.
One may also perform a vertebral body bone biopsy when
performing a therapeutic procedure such as kyphoplasty
Osteoporosis. Lateral radiograph of the
patient seen in Image 1 following
kyphoplasty performed at 3 additional levels
Osteoporosis. Lateral radiograph
demonstrates multiple osteoporotic
vertebral compression fractures.
Kyphoplasty has been performed at one level
Therapeutic procedures include vertebroplasty and kyphoplasty.
Vertebroplasty and kyphoplasty are 2 new minimally invasive
spine procedures used for the management of painful
osteoporotic vertebral compression fractures
A diet that includes adequate vitamin D and calcium is
essential. Recommendations for patients with osteoporosis
include daily dosages of 400-800 IU of vitamin D and 1200-1500
mg of calcium. Good sources of calcium include dairy products,
sardines, nuts, sunflower seeds, tofu, vegetables such as turnip
greens, and fortified food such as orange juice. Good sources of
vitamin D include eggs, liver, butter, fatty fish, and fortified
food such as milk and orange juice. Patients who ingest
inadequate amounts of vitamin D and calcium should receive
oral supplementation
Physical activity is important in order to improve balance and
maintain and build bone mass, muscle strength, and flexibility.
Several different exercises have been shown to be beneficial in
patients with osteoporosis
Complications resulting from osteoporotic fracture can include
chronic pain from vertebral compression fractures and
increased morbidity and mortality secondary to vertebral
compression fractures and hip fractures. In addition, overall
quality of life can be impaired by the presence of these fractures
and their consequences, such as immobility
Patients with osteoporosis can increase bone mineral density
and decrease fracture risk with the appropriate antiosteoporotic
medication. In addition, patients can decrease their risk of falls
by participating in a multifaceted approach that includes
rehabilitation (see Activity) and environmental modifications,
among others.
Patient education is paramount in the treatment of
osteoporosis. Many patients are unaware of the serious
consequences of osteoporosis and only become concerned when
osteoporosis manifests in the form of fracture. Early prevention
and treatment are essential in the appropriate management of
osteoporosis.
For excellent patient education resources, visit eMedicine's Bone
Health Center. Also, see eMedicine's patient education articles
Osteoporosis and Understanding Osteoporosis Medications.