Osteoporosis: Its Clinical Significance, Causes, Pathogenesis, Presentations, Diagnosis And Treatment
A General Overview
Osteroporosis is defined as a reduction of bone mass per unit volume without gross alteration in its chemical composition. The bone matrix itself is deficient but osteoid that is present is normally mineralized. Bone formation and resorption are in quilibrium in adults up to the age of 50 years and therefore, up to this age, the bone mass is fairly constant. The bone mass declines steadily but slightly after the age of 50. Osteoporosis results from excessive resorption compared to formation. The precise mechanism leading to osteoporosis is not clear. In the majority, an etiological factor is demonstrable while in a few, this is not so.
Idiopathic osteoporosis: Two types of idiopathic oesteoporosis are seen: the adult type and the juvenile type (8-12 years).
Secondary osteoporosis: The secondary osteoporosis comprises the following abnormalities:
- Senile osteoporosis
- Prolonged bed rest, especially in the elderly subjects.
- Endocrine abnormalities: Postmenopausal osteoporosis, diabetes mellitus, Cushing’s syndrome, hypogonadism, hypopituitarism, thyrotoxicosis and hyperparathyroidism.
Nutritional Causes: Such as protein malnutrition, malabsorption syndrome, scurvy and alcoholism.
Hereditary connective tissue diseases: Such as Ehler’s Danlos syndrome, Marfan’s syndrome, homocystinuria and osteogenesis imperfecta.
- Localized immobilization following fractures,
- Inflammatory arthropathy, e.g. rheumatoid arthritis,
- Reflex bone dystrophy, e.g shoulder-hand syndrome and
- Secondary to irradiation therapy.
The resorption rate is high in osteoporosis, eventhough bone formation proceeds normally, Particular areas of the skeleton such as the metacarpals, femoral neck and vertebral bodies show higher rates of resorption. Maximum impact is on the axial skeleton. The peripheral bones are affected to a lesser extent.
Clinical Features And Management
Osteoporosis remains asymptomatic for considerable periods till bone loss has become advanced. The vertebral bodies become soft and compressed. The intervertebral discs herniated into the vertebral bodies and this results in shortening of the vertebral column. The terms “dowager’s hump” or “widow’s hump” are used to denote the dorsal- kyphosis with exaggerated cervical lordosis brought about by vertebral compression. When symptoms occur, they include vague muscular aches and pains, loss of height of the spine, and kyphoscoliosis. Vertebral collapse, fracture neck of the femur and Colle’s fractures (fracture distal end of the radius) develop as a result of trivial trauma or even spontaneously. In general, the fractures heal within 4- 6 weeks with simple treatment.
Skiagram reveals reduction in density of the vertebral bodies in the early stages, and the vertical trabeculations appear more prominent. The vertebrae become biconcave and this is referred to as codfish vertebra. The intervertebral discs herniate into the vertebral bodies. Vertebral collapse is the late stages results in anterior wedging of the vertebral bodies. The medullary cavities of long bones are expanded with thinning of the cortex. Sometimes differentiation from osteomalacia can be extremely difficult but pseudofractures are not seen in osteoporosis.
The serum calcium, phosphorus and alkaline phosphatase are normal and this distinguishes oesteoporosis from osteomalacia in which calcium and phosphorus are low and alkaline phosphatase is elevated. As a result of excessive resoroption of bone, urinary hydroxyproline is elevated above normal range (6.42 mg/g of creatinine up to 55 years of age), during the active phase of the disease.
General measures include adequate nutrition, especially with supplements of calcium, vitamin D and proteins. Vertebral collapse usually heals satisfactorily with bed rest and analgesics. Early ambulation and exercise help in improving muscle tone. Provision of weight-bearing appliances or corsets help in relieving pain and prevent further damage.
In postmenopausal osteoporosis, administration of 0.625 to 1.25 mg of conjugated estrogen, daily for 3 weeks every month helps in arresting the progrestrogen daily for 3 weeks every month helps in arresting the progesterone of bone loss. Calcium lactate 300 mg thrice daily with vitamin D 25,000 units twice weekly helps to relieve symptoms and hasten recovery. Also, administration of sodium fluoride 25 mg/day in addition to calcium and vitamin D results in accelerated new bone formation, and prevent osteoporosis on a long term basis. Side effects of fluoride are gastrointestinal upsets and rheumatic pains which subside on stopping therapy.
Alteration to the primary cause is necessary in relieving secondary osteoporosis. Anabolic steroids were used widely for osteoporosis. Their place in routine treatment is conversial. Incidence of generalized osteoporosis can be reduced by ensuring regular exercises and proper intake of protein, vitamins and calcium in persons above the age of 65 years.
© 2014 Funom Theophilus Makama