Osteoporosis Flashcards
What is osteoporosis?
A condition characterised by decreased bone mass and micro architectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture
BMD changes to classify as osteoporosis?
BMD >2.5 SDs below the peak bone mass for you adults
What is osteopenia as per BMD?
BMD with T score between -1.0 and -2.5 SD below mean
What is primary osteoporosis?
Type 1: most common in post-menopausal women due to decline in oestrogen, worsens with age
Type 2: occurs after age 75, seen in females and males at 2:1 ratio; possibly due to Zn deficiency
Causes of secondary osteoporosis?
- GIT: malabsorption, CLD, gastrectomy
- Bone marrow disorders: MM, lymphoma, leukemia
- Endocrine: Cushing’s syndrome, hyperparathyroidism, hyperthyroidism, premature menopause, diabetes
- Malignancy: secondary to chemo, myeloma
- Drugs
- Other: RA, SLE, AnkSpond, renal disease, poor nutrition, immobilisation
What are the drugs precipitating osteoporosis?
- Corticosteroid therapy
- Phenytoin
- Chronic heparin therapy
- Androgen deprivation therapy
- Aromatase inhibitors
CFx of osteoporosis?
Often asymptomatic:
- Height loss due to vert #
- Fractures: most common in hip, vertebrae, humerus and wrist
- Pain (esp backache) ass/w #
Xray features of osteoporotic vertebral fractures?
- Vertebral compression and crush #
- Wedge fractures
- Codfishing sign = weakening of subchondral plates and expansion of intervertebral discs
What are the indications for BMD testing in adults 50+?
-All age 65+ Those with clinical RFx for #: -fragility # after age 40 -prolonged steroid use -other high risk medications -parental hip fracture -vert# or osteopenia identified on XR -current smoking -high alcohol intake -low body weight -RA -Other disorders with strong association
What is the treatment for osteoporosis?
LIFESTYLE: diet ++ calcium and Vit D; exercise (esp weight bearing); stop smoking, reduce caffeine DRUG: -Bisphosphonates (1st line) -RANKL inhibitors -Parathyroid hormone (teriparatide) -DABA (strontium) -Calcitonin (2nd line)
What is the function of bisphosphonates?
Inhibit osteoclast formation/binding
What are the bisphosphonates?
Alendronate, risendronate, zoledronic acid
What are the RANKL inhibitors? Function?
Denosumab; binds RANKL inhibiting osteoclast formation, activity and survival.
Osteoporosis treatment to consider selective to post menopausal women?
- SERM
- HRT (oestrogen + progesterone)
What are the SERMS? (name and function)
e.g. raloxifene.
Agonist effect on bone, antagonist on breast, uterus.
DXA Z score?
The number of SDs above or below the mean for the patients age, sex and ethnicity
DXA T score?
The number of SDs above or below the mean for a healthy 30y adult of the same sex and ethnicity as the patient
Vit D target?
> 50 nmol/L
What is P1NP?
Bone formation marker; cleared by liver endothelial cells
What is CTX?
Bone resorption marker; cleaved during bone resorption. Cleared by kidneys.
What are the goals of osteoporosis therapy?
- Fracture risk reduction
- Reduction in mortality by avoiding hip fractures
- Improved quality of life; preserved mobility and independence
Function of teriparatide?
Intermittent PTH stimulates osteoblasts
What is strontium? How does it work?
Dual action bone agent; both activates osteoblasts and inhibits osteoclasts. Chemically similar to calcium and can be incorporated into bone.
CIx to strontium?
-Increased risk of MI therefore Cix = -IHD / PVD / CVD -HT Other relative contraindications include other significant RFx for CV events
