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