Osteoporosis - B. Pharma 2nd Semester Pathophysiology notes pdf

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