Osteoporosis
Content
•
Definition of osteoporosis
•
Pathogenesis
•
Diagnosis
•
Therapy
•
Future development
Objective
At the end of the lecture student will be able
to
• Explain osteoporosis
• Define pathogenesis of osteoporosis
• Describe the Factors affecting
osteoporosis
• Briefly explain the treatment of
osteoporosis
Osteoporosis
Definition
•
Clinical
–
Loss of bone mass sufficient to significantly
increase the risk of fracture
•
Diagnostic
–
T score – number of standard deviations above
or below the mean for a similar healthy
30 year old
·
Normal BMD = T: 0 to -1
·
Osteopenia BMD = T: -1 to -2.5
·
Osteoporosis BMD = T: less than -2.5
–
Z score – number of standard deviations above
or below the mean for the patients age,
sex and ethnicity
Epidemiology of Osteoporosis
•
United
States
–
10 million individuals with osteoporosis
–
34 million individuals with osteopenia
•
Fracture
Risks over age 50
–
50% of women will have an osteoporosis
related fracture
–
25 % of men will have an osteoporosis related
fracture
•
Estimated
costs
–
Direct health care $14 billion each year
Pathogenesis of Osteoporosis
•
Peak bone mass
•
Etiology Bone loss
•
Age
•
Secondary causes
Peak Bone Mass
•
Genetically determined
–
70-75%
–
Driven by sex hormones during puberty
–
Depends on site measured – spine, femur, radius
•
Ethnicity
–
Chinese American later than Caucasians
•
Women
–
Peak accrual ages 11-15
–
95 per cent achieved by late teens
•
Men
–
Peak accrual later teens
–
Maximum spine age 20
–
Radius and femur by mid twenties
Factors Affecting Peak Bone Mass
•
Delay or Failure of puberty
–
Primary Hypogonadism
•
Turners syndrome
•
Klinefelter syndrome
•
Absent cervix, uterus, cervix and/or vagina
•
Cryptorchidism
•
Chemotherapy, Radiotherapy
•
Chronic systemic diseases
–
Secondary Hypogonadism
•
Kallmann syndrome
•
CNS tumors, infiltrative disorders
•
Malnutrition
•
Chronic systemic illness
Etiology of Bone loss in Osteoporosis
Estrogen Deficiency
•
Women
–
Occurs earlier
–
At menopause bone loss rates to increase by 2 to
6 fold
–
For subsequent 6-8 years
–
Impairs calcium absorption from gut
•
Men
–
Testosterone declines age
–
Estrogen declines age
–
Both androgens and estrogen contribute
Fracture Risk with Aging
Secondary Causes of Accelerated
Bone-loss/Osteoporosis
•
Inherited
disorders
–
Osteogenesis imperfecta tarda
–
Thallasemia
•
Amenorrhea
–
Eating disorders
–
Low weight
–
Excess Exercise
–
Female athlete triad
•
Energy deficiency
•
Low bone mineral density
•
Amenorrhea
–
Premature ovarian failure
•
Respiratory
–
Cystic fibrosis
•
Gastrointestinal
–
Celiac sprue
–
Post Gastric by pass
–
Inflammatory bowel disease
•
Renal
–
Idiopathic hypercalciuria
–
Chronic renal failure
•
Post
organ transplant
–
Immunosuppressive therapy
•
Endocrine
–
Hyperthyroidism
–
Hyperparathyroidism
–
Cushing’s syndrome
–
Hypogonadism
–
Vitamin D deficiency
•
Rheumatology
–
Rheumatoid arthritis
–
Seronegative athropathies
•
Lifestyle
–
Smoking
–
Alcohol
•
Drugs
–
Glucocorticoids
–
Cyclosporine
–
Anti seizure medications
•
Phenobarbital
•
Phenytoin
–
Heparin
–
Chemotherapy
•
Aromatase inhibitors
–
Thyroxine
•
Over replacement
Diagnosis of Osteoporosis
•
Approach to patient
•
Investigations
–
Bloods
–
Urine
–
Imaging
–
FRAX use
•
Calcium and Vitamin D
Osteoporosis Investigations
•
Bloods
-Basic
–
CBC
–
Electrolytes and eGFR
–
Serum calcium and phosphate
–
TSH
–
Testosterone (Men)
–
Serum protein electrophoresis
–
Bone markers (consider)
•
Urine
–
24 hour urine
–
Volume
–
Creatinine and calcium
Bone Mineral Density Testing
•
Bone mineral density testing
–
Important means of assessing fracture risk
–
Not stand alone test
•
Other risk factors have impact on fracture risk
–
occasionally more significant impact than bone
density results alone
–
Glucorticoids
•
All known risk factors should be considered when
deciding to treat patients
–
Mostly treating patients based on risk
–
No overt disease
•
We need better tools for assessing fracture risk
Summary
•
Osteoporosis is an important public health
problem
•
Accurate diagnosis and treatment requires the
use of bone densitometry.
•
Radiologists play a central role in the
diagnosis and management
–
of this disease:
–
measuring bone density
–
diagnosing fractures
–
pointing out secondary causes of bone loss
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