Osteoporosis - A Complete Account
Osteoporosis is a disease which involves an imbalance between bone deposition and absorption which is apparent with aging and affects large number of people around the world. Approximately 75 million are affected with the disease in UK, USA and Japan and now it has reached an epidemic proportion. It is a systemic skeletal disease characterized by low bone mass and micro architectural deterioration with a consequent increase in bone fragility and susceptibility to fracture. On medical grounds osteoporosis is defined as a bone mineral density (BMD) below 2.5 standard deviations (SD) from the mean peak value in young adults.
There are several risk factors for osteoporosis which include:
· Female sex
· Increasing age
· Early menopause
· Caucasians & Asian race
· Lack of exercise
· Family history
· Excessive alcohol consumption
· Nutritional causes like low calcium intake
· Non or delayed child bearing
Based on the aetiology osteoporosis is divided in to two categories they are,
a. Type I: Post menopausal (Oestrogen deficiency, mainly trabacular bone loss. Fractures of vertebral body and distal hand)
b. Type II: Senile (slower, age related, both sexes, both cortical and trabacular, hip fractures)
c. Idiopathic (at age <50yrs)
b. Malabsorption: Coeliac disease, partial gastrectomy, liver disease
c. Rheumatological : Rheumatoid arthritis, ankylosing spondylitis
d. Malignancy: Multiple myeloma , metastatic carcinoma
The most striking feature in this disease is that it remains unrecognized and untreated yet it is preventable and treatable. So it is important to keep high degree of clinical suspicion in managing patients with risk factors and clinical features like back pain which may present with fracture undiagnosed wedge fracture, deformities like kyphosis, abdominal protrution or loss of height. Importance of recognizing patients with osteoporosis is as for preventive measures since they have a higher risk of falling and getting fractures which are considered as low trauma fractures, and as these patients are old therefore if they get a fracture outcome is poorer than a young getting a fracture.
The investigations needed in such patients are;
· To establish presence of low-trauma fracture- Spine radiograph
· Evaluate degree of osteopenia- Bone densitometry
· Exclude 2ry osteoporosis
· Evaluate bone turnover – Biochemical markers, bone histomorphometry
· Quantitative CT
· Quantitative ultrasound measurements
· Bone biopsy
· Biochemical bone markers
Spinal x-rays are important in identifying wedge fractures of the spine which is one of the commonest fractures in patients with osteoporosis, X-ray will show
· Wedge deformity(Loss of anterior height)
· End plate deformity(Loss of middle height)
· Compression deformity(Loss of ant, post and middle height)
Here the Bone density measurements (BMD) are important in diagnosing the disease. But till the Dual Energy X-ray absortiometry(DEXA) remains an essential step in the diagnosis of Osteoporosis. BMD is useful in prevention, screening and in optimization of treatment.
Regarding management of patients with osteoporosis, there are several therapeutic goals to be achieved such as;
· Optimizing peak bone mass- Here encourage the patient to exercise, it must be regular and weight bearing (eg: walking, aerobics); excessive exercise may lead to bone loss. Uplifting of maximum mineral bone density in young should also be considered.
· Reducing rate of bone loss-Anti resorptive agents, Hormone replacement therapy, regular exercise, maintain Ca intake, stop smoking
Biphosphonates are important group of anti resorptive agent examples are Alendronate, Editronate. They should be taken 30 min before breakfast with a full glass of water. Patient should not lie down for 30min after ingestion of the drug. It is found that HRT increases BMD over 2 yrs of treatment. It is the most useful treatment, even in elderly females. But there are several risks involve in using HRT so the compliance is very poor, 50% drop out rate one year. It can be improved by using Tibolone which is used as continuous combined HRT. Raloxifene is a Selective Estrogen Receptor Modulator (SERM).With daily treatment it is found that it increases BMD and it’s a suitable alternative to HRT in those who do not want to use or cannot use. The advantage of Raloxifene is there is no risk of endometrial cancer which is there with HRT and can be taken without regard to meals but there are several adverse effects like hot flushes, deep vein thrombosis (DVT). Calcitonin is a hormone which involved in bone deposition it has an analgesic effect in acute vertebral fracture but it is not as effective as HRT and Bophosphonates. Calcitriol is the active form of vitamin D which stimulates ca absorption and stimulates osteoblasts directly.
Other aspects of treatment are proper pain relief, stabilization of fracture, treat secondary causes. Also it is important to take measures to prevent falls during old age like; treating postural hypotension preventing drugs causing drowsiness, physiotherapy to improve balance, provide appropriate walking aids.