Osteoporosis is the most prevalent bone disease in the world. It is characterized reduced bone mass, deterioration of bone matrix, and diminished bone architectural strength. The rate of bone reabsorption is greater than the rate of bone formation. The bones become progressively porous, brittle and fragile which makes them more liable to be fractured easily. Multiple compression fractures of the vertebrae resulting in skeletal deformity (kyphosis). This kyphosis is associated with loss height (shortening of length).
Pathophysiology of Osteoporosis
Normal homeostatic bone turnover is altered; the rate of bone reabsorption that is maintained by osteoblasts, resulting in a reduced total bone mass. The bones become fragile and brittle; they fracture easily under any Stresses that would not break the normal bone. These susceptibility to fracture, which occur most commonly as compression fractures of the thoracic and lumbar spine, hip fractures and Colles’ fractures of the wrist. These fractures may be the first clinical manifestation of osteoporosis (NOF, 2008).
What are the risk factors for osteoporosis?
- Risk factors include postmenopausal women and small-framed, non-obese Caucasian women.
- Additionally, it includes inadequate nutrition, inadequate vitamin D and calcium and lifestyle choices (e.g. smoking, caffeine intake and alcohol consumption), genetics and lack of physical activity.
- Age-related bone loss begins soon after the peak bone mass is achieved in the fourth decade of life.
- Withdrawal of estrogens at menopause or oophorectomy causes decreased calcitonin and accelerated bone reabsorption, which continues during menopausal years.
- Immobility contributes to the development of osteoporosis. Secondary osteoporosis is the result of medications or other conditions and diseases that affect bone metabolism. Specific disease states (e.g. celiac disease, hypogonadism) and medications such as corticosteroids, antiseizure medications that place patients at risk need to be identified and therapies instituted to reverse the development of osteoporosis.
- The Prevalence rate of osteoporosis in women older than 80 years is 50%. The average 75 years old women have lost 25% of her cortical bone and 40% of her trabecular bone.
- Asymptomatic osteoporotic-related vertebral fractures are associated with loss of height, respiratory dysfunction, increased risk of mortality and increased risk of subsequent fractures.
- Elderly people fall frequently as a result of environmental hazards, neuromuscular disorders, diminished senses and Cardiovascular responses, and responses to medications.
- The patient and family need to be included in planning for care and preventive management regimens. For example, the home or streets environment should be assessed for safety and elimination of potential hazards (e.g. scatter rugs, cluttered rooms, and staircase, toys on the floor, pets underfoot).
- A safe environment can then be created (e.g. well-lighted staircase with secure handrails, grab bars in the bathroom, properly fitting footwear).
- Elderly people absorb dietary calcium less efficiently and excrete it more readily through their kidneys; therefore, postmenopausal women and the elderly need to consume approximately 1200 mg of daily calcium; quantities larger than this may place patients at heightened risk for renal stones or Cardiovascular disease.
- Osteoporosis is identified on routine x-ray films when there has been 25% to 40% demineralization.
- Dual-energy x-ray absorptiometry (DEXA; DXA) provides information about spine and hip bone mass and bone mineral density (BMD).
Laboratory studies (e.g. serum calcium, serum phosphate, serum alkaline phosphatase, urine calcium excretion, urinary hydroxyproline excretion, haematocrit, Erythrocyte sedimentation rate [ESR] and x-ray are used to exclude other diagnoses.
The first line drugs used to treat and prevent osteoporosis include calcium and vitamin D supplements and bisphosphonates. To ensure adequate calcium intake, a calcium supplement (Caltrate, citracal) with vitamin D may be prescribed and taken with meals or with a beverage high in vitamin C to promote absorption. Common adverse effects of calcium supplements are abdominal distension and constipation. Bisphosphonates that include daily or weekly oral preparations of alendronate (Fosamax) or risedronate (Actonel), monthly oral preparations of ibandronate (Boniva) or yearly intravenous IV infusions of zoledronic acid (Reclast) increase bone mass and decrease bone loss by inhibiting osteoclast function. These medications have demonstrated cost-effectiveness in preventing osteoporotic-related fractures in elderly women. Adequate calcium and vitamin D intake are needed for maximum effect but these supplements should not be taken at the same time of day as Bisphosphonates. Common adverse effects include nausea, dyspepsia, flatulence, diarrhea, and constipation. Some may also develop gastric ulcers and oesophagal ulcers.
Calcitonin (Miacalcin) directly inhibits osteoclasts, thereby reducing bone loss and increasing BMD. It is administered by nasal spray or by subcutaneous or intramuscular injection. Selective estrogen receptor modulators (SERMs) such as raloxifene (Evista), reduce the risk of osteoporosis by preserving BMD without estrogenic effects on the uterus. Teriparatide (Forteo) is a subcutaneously administered anabolic agent that is administered once daily. It stimulates osteoblasts to build the matrix and facilitates overall absorption of calcium.
Fractures of the hip that occur as a consequence of osteoporosis are managed surgically by joint replacement or by closed or open reduction with internal fixation such as hip pinning, total hip replacement. Patients need to be evaluated for osteoporosis and treated, as indicated in order to prevent additional fractures. Osteoporotic compression fractures of the vertebrae are managed conservatively for example skin or skeletal traction, splint and cast to immobilize the fracture. Most patients who experience these fractures are asymptomatic and do not require acute care management; for those who experience pain, acute care management is indicated as outlined in the nursing process and medical management. Percutaneous vertebroplasty or kyphoplasty is an injection of polymethylmethacrylate bone cement into the fractured vertebra followed by inflation of a pressurized balloon to restore the shape of the affected vertebra. It can provide rapid pain relief of acute pain and improve quality of life. It is contraindicated in the presence of infection, old fractures, and certain coagulopathies.
Preventive approach and preventing injury
- A diet rich in calcium and vitamin D throughout life, with an increased calcium intake during adolescence, young adulthood, and the middle years protects against skeletal demineralization. Such diet includes three glasses of skim or whole vitamin D-enriched milk or other foods high in calcium (e.g. cheese and other dairy products, steamed broccoli, canned salmon with bones) daily.
- Preferably outdoors in the sunshine to enhance the body’s ability to produce vitamin D, is encouraged.
- Sudden bending, jarring and strenuous lifting are avoided.
- Avoid smoking, alcohol, caffeine and carbonated beverages intake.
- Regular weight-bearing exercise promotes bone formation. From 20 to 30 minutes of aerobic exercise (walking, playing sports), 3 days or more a week is recommended.
- Weight training stimulates an increase in BMD. In addition, exercise improves balance, reducing the incidence of falls and fractures.
- Have a knowledge regarding good body mechanics.
- Participation in screening for osteoporosis.
- Follow up after the surgery.