ERS Case 1: Calcium Metabolism Flashcards
Describe osteoporosis
- Decreased in bone density
- Total bone mass reduced with an equal loss of mineral + matrix
- Higher risk of fracture
Bone mineral density >= 2.5 SD below young, normal individuals
Mechanism:
- failure to attain optimal bone mass before age 30
- rate of bone resorption exceeds rate of bone formation after peak bone mass attained
Primary osteoporosis
- Type 1: excess loss of trabecular bone
- Type 2: equal loss of cortical + trabecular bone
Secondary osteoporosis
- other causes e.g. Steroid therapy, Immobilisation, Hyperthyroidism
Describe the risk factors of osteoporosis and associated diseases
Causes:
- ↓ Vitamin D intake (from sunlight)
- ↓ Renal conversion —> ↓ Active Vit D
- ↓ Fat in diet —> ↓ Vit D absorption
- ↓ Ca from diet
- ↓ Calcitonin (age-related)
- ↓ Androgen
Other endocrine causes:
- Cushing syndrome
- Thyrotoxicosis
- Postmenopausal estrogen deficiency
Risk factors:
- Unmodifiable: Gender, Age, Race, Family history, Frame size
- Hormonal factors: Estrogen, Testosterone, Hyperthyroidism, Hyperparathyroidism, Overactive Adrenal glands, Long term steroid use
- Diet: Low Ca, Anorexia, GI surgery
- Lifestyle: Lack of exercise, Alcohol consumption, Caffeine intake, Smoking
Explain bone structure and Ca metabolism
See lecture
Discuss drug / non-drug treatment of osteoporosis
See lecture
Drug:
- Bisphosphonate (inhibit osteoclastic activity by binding to hydroxyapatite)
- PTH / human recombinant PTH therapy
- Calcitonin (short term)
Non-drug treatment:
- Daily Ca, Vit D
- Weight-bearing exercise
- Smoking cessation
- Reduce alcohol intake
Demonstrate understanding of diseases apart from osteoporosis that affect Ca metabolism
Hypercalcaemia:
- Hyperparathyroidism
- Hypercalcaemia of malignancy
- Vit D toxicity
- Sarcoidosis
Hypocalcaemia:
- Chronic renal failure
- Hypoparathyroidism
- Vit D deficiency
Describe clinical features and treatment of hypercalcaemia
- Painful bone
- Renal stone
- polyuria - Abdominal groans
- constipation
- abdominal pain
- N+V - Psychic moans
- confusion
- depression
- impaired concentration and memory - Muscle weakness
- CVS
- hypertension
- arrhythmia
Treatment:
1. IV hydration / Fluid intake / Saline infusion / Diuretics
—> ↑ urinary excretion
- Osteoclastic disease (e.g. malignancy)
—> SC **Calcitonin, IV **Bisphosphonate
—> ***Prednisolone to control Ca - Haemodialysis for renal failure
- Phosphate
- effective but risk of metastatic calcification
Interpret laboratory results
See notes
Albumin level:
- assess liver’s synthetic capacity
- use to calculate corrected Ca level if ionised Ca level not available
—> Corrected Ca = Total Ca + [0.02 x (40-albumin)]
Demonstrate understanding of investigations by X-rays and bone scan in osteoporosis
See lecture and notes
DEXA (Dual-energy X ray absorptiometry) scan: Gold standard
- Femoral neck
- Lumbar spine
- Radius
T-score: All postmenopausal and perimenopausal women, men over 50 - Normal >=1 - Osteopenia -1 to -2.5 - Osteoporosis <= -2.5 Z-score: All other patients
Identify causes and risk of falls in elderly and needs of elderly living alone
- Osteoporosis
- Muscle weakness
- Impaired vision
- Acute illness
- CVS diseases
- Medication / Alcohol
- Environmental hazards
- Parkinson, Foot disorder, Gaiting disturbances, Balance disorder —> Postural instability
Current trend in epidemiology and public health impact of osteoporosis worldwide and in HK
Growing burden due to:
- Population ageing
- Urbanisation
- Lifestyle changes
Hip fracture rising rapidly
Impact of osteoporosis:
- Mortality —> Hip fracture
- Morbidity —> Low back pain
- Disability
- Medical cost due to hospitalisation / treatment of hip fracture
Role of health care professionals and international and local not-for-profit, non-governmental societies in prevention and treatment of osteoporosis
Doctors
- Endocrinologist
- Rheumatologist
- Family doctors
- Orthopaedic surgeons
- Geriatricians
Local organisation
- The Osteoporosis Society of Hong Kong
- Family Planning Association of Hong Kong (collaborate with Osteoporosis Centre of QM hospital) —> Osteoporosis Shared Care Service
International organisation
- International Osteoporosis Foundation
Cost effectiveness for osteoporosis treatment and prevention and explain the principles of economic evaluations for osteoporosis treatment
See lecture
Bisphosphonate prevents more fractures than Calcium therapy
