-IBIS-1.5.0-
tx
musculoskeletal system
osteoporosis
diagnoses
definition and etiology
definition:
An overall decrease in bone mass: the remaining bone has a normal mineral ratio. There is a greater loss of trabecular bone than compact bone, causing the main complication of the disease: crush fractures of the vertebrae, the femur and distal radius.
etiology:
primary osteoporosis: This is idiopathic, with no clear single or multiple reason(s) for the onset. It is caused by an increase in bone resorption: whether bone formation remains normal or not is not clearly known. Primary osteoporosis is most common in post-menopausal white women. White women have histologically less dense bones at maturity than blacks, which may account for the specificity of the disease to Caucasians. Post-menopausal women produce less estrogens which stimulate osteoblasts to form new bone. Other factors involved in the development of the disease include malabsorption of intestinal calcium; vitamin D deficiency; little muscle mass; history of smoking cigarettes; high protein (acid) diets; use of heparin; failure to maximize bone mass during young adult life; and a sedentary lifestyle (lack of impact exercising that creates more bone mass).
secondary osteoporosis: This may be a response to several medical problems (see "differential diagnosis") and may also appear during nursing and pregnancy.
signs and symptoms
signs and symptoms:
Osteoporosis generally affects the entire skeletal system, but is seen especially in the weight-bearing bones: spine, hips, feet, and legs.
Patients in the early stages or with mild disease may remain asymptomatic for years.
As the disease progresses, aching pain in the bones may appear, most notably in the back.
Crush vertebrae fractures are usually not related to trauma, and are most often seen in the weight-bearing vertebrae (T8 and below). The pain with the fracture is acute, non-radiating, worse weight-bearing, and gradually subsides to tenderness over the local area in days or weeks. Patients often do not seek medical help unless the pain is severe.
Cervical lordosis and thoracic kyphosis, as well as constant aching in the lower thoracics and lumbar vertebrae follow multiple crushed vertebrae.
Other patients may not have their osteoporosis uncovered until they suffer from a hip or Colles' fracture.
lab findings: generally undiagnostic; patients have:
normal ESR, serum calcium, alkaline phosphatase, and phosphorus.
If the lab values are abnormal, secondary osteoporosis should be suspected and the cause sought.
X-ray changes include a loss of radiodensity, increased visibility of both the cortical endplates and the existing vertical trabeculae of vertebrae. X-rays of fractures will show anterior wedging in the thoracic area and swelling of the vertebral interspaces in the lumbar region. Secondary osteoporosis from corticosteroid excess shows radiolucency of the rib fractures, skull and excessive callus formation.
may see increased urine calcium
course and prognosis
The disease is usually gradually progressive and deforms the correct alignment of the spinal vertebrae because of crush fractures. Hip fractures in elderly women account for a significant amount of mortality from immobilization-induced repercussions: e.g. malnutrition and pneumonia.
The key element is prevention by maintaining a vigorous exercise program throughout life.
differential diagnosis
Osteomalacia: Has similar x-ray signs, and is differentiated by lab findings.
Osteogenesis imperfecta.
Malignancies: multiple myeloma, lymphoma, leukemia, carcinomatosis.
Paget's Disease.
Thyrotoxicosis.
Hyperparathyroidism.
Acromegaly.
Hyperadrenocorticism.
Hypogonadism.
footnotes