Osteoporosis Flashcards
Discuss the variation of bone mass throughout an individuals lifetime?
- There is a net gain of bone mass which reaches maturity about 25-30 years of age
- The increase of bone mass, plateaus here for around 10 years
- From 40 years old there will be a net loss in bone mass- this loss is faster in post-menopausal women
What factors impact rate of bone loss?
Genetic factors (75%):
- More likely to develop Osteoporosis if there is a family history of the condition
- Possible involvement of genes- Vitamin D receptor gene, Oestrogen receptor gene, Interleukin-6 gene
Environmental factors:
- Low calcium intake or absorption
- Low vitamin D intake or lack of exposure to sunlight- common in those in residential/nursing homes
- Physical inactivity
- Increased alcohol consumption- the toxicity can decrease bone mineral density- Alcohol can decrease the absorption of calcium via the intestine, or it can have effects on the pancreas and vitamin D metabolism
- Smoking- can cause abnormal metabolism of oestrogen and can decrease the absorption of calcium leading to low bone density
What is osteoporosis?
Osteoporosis is a health condition that weakens bones, making them fragile and more likely to break. It develops slowly over several years and is often only diagnosed when a fall or sudden impact causes a bone to break
- cause by a reduction in bone mass leading to increase bone fragility and susceptibility to fracture
What is the assigning of a T-score in osteoporosis?
Created by WHO that looks at the number of standard deviations by which the individual’s bone mass density (g/cm2) differs from the mean peak bone mass density of younger adults of the same sex.
The fracture risk doubles for every standard deviation below the standard:
Score:
Normal= above -1
Osteopenia= between -1 and -2.5
osteoporosis= -2.5 or less
established osteoporosis= -2.5 or less and presence of a fracture
What are the most commonly bones fractures/broken in osteoporosis?
Hips
Vertebrae
Wrist
pelvis
arm
What is osteopenia?
The stage before osteoporosis where scans show a lower bone mass density than normal, but is not low enough to be diagnosed as Osteoporosis.
What percentage of males and females over the age of 50 have osteoporosis?
Males = 6.7%
Females = 21.9%
This increases further with age to be 50% at 80 years
How is osteoporosis diagnosed?
To diagnose a DEXA scan is used (dual energy x-ray absorptiometry)
This involves laying on your back and a scanning arm is passed over the body
The machine measures the amount of x-rays passed through the body to give a T-score:
Normal= above -1
Osteopenia= between -1 and -2.5
osteoporosis= -2.5 or less
established osteoporosis= -2.5 or less and presence of a fracture
A ‘Z’ score is used instead in those who are children or under 30 but still growing- if score is below -2 it is lower than it should be.
Why can’t traditional X-rays be used to diagnose osteoporosis
- X-rays can’t detect bone loss until 30% of bone mass is lost. By this stage, there is already significant disease
so x-rays cant be used to diagnose osteoporosis or osteopenia
What is primary osteoporosis?
The most common of osteoporosis in which the patient has no other disorders known to cause osteoporosis:
e.g. Post-menopausal osteoporosis
Age or ‘denial’ related osteoporosis
What is secondary osteoporosis?
This is osteoporosis related to a known medical condition e.g:
- Anorexia
- IBD- chrons, collitis
- Endocrine conditions- type 1 DM, Cushing’s syndrome, hyperthyroidism
- Rheumatoid arthirtis
or can be ‘Drug-induced’:
- Most commonly steroid-induced (13% of cases in males and 10% in females) as steroids:
Decrease osteoblast activity- the cells responsible for bone forming
Decrease Ca2+ absorption from the intestine and increase renal Ca2+ renal loss- this causes abnormal parathyroid hormone and vitamin D activity
Suppresses sex hormone production- Oestrogen is important in maintaining bone structure
- also can be impacted by other drugs such as phenytoin, heparin, furosemide, ciclosporin, lansoprazole
What is the fracture threshold?
Is the bone mineral density at which a patient can sustain a fracture with little or no trauma
What is a fragility fracture?
A fracture that occurs as a result of forces that would not ordinary cause a fracture
WHO quantifies this e.g. as a fall from standing height or less- would not usually cause a fracture
What is kyphosis?
A forward curvature of the spine. Can occur as a result of osteoporosis
What is the prognosis of Osteoporosis (mostly after a hip fracture)?
- 50% of patients with a hip fracture, loose ability to live independently
- Excess mortality after hip fracture increases by 20%
- There is an increased risk of further fractures e.g. after an initial vertebral fracture, there is a 7-fold increase in further fracture and a 13% increase in 5 year risk of hip fracture
- Can lead to substantial disability
Who are at risk of developing osteoporosis?
- Post-menopausal women- due to loss of protective effects of oestrogen
- Low BMI- especially 19 or lower
- Untreated premature menopause- e.g. had a hysterectomy
- Family history of maternal hip fracture before 75 years
- Having conditions such as rheumatoid arthritis, coeliac disease, bid, hyperthyroididsm
- Prolonged immobility or sedentary lifestyle
- Increased alcohol intake and smoking
- Steroid users (gluticorticoid)- greatest loss of BMD occurs in first few months of steroid usage
When is Osteoporosis prophylaxis required for those on steroids?
- If hava a prior fragility fracture
- Women older than 70 years old
- Women and men over the age of 50 who are on high doses of steroids (e.g. prednisolone) - e.g. 7.5 mg + a day over 3 months
- Men and women over 50 with a high FRAX score
What is FRAX?
Fracture risk assessment tool
This is an online programme used to predict a persons 10 year risk of developing a major osteoporotic fracture.
It looks at risk factors including age, sex, smoking, alcohol, arthritis etc
What are the treatment recommendations for the risk scores from the FRAX tool?
Low risk= Give lifestyle advice and calcium/vitamin D supplementd
Intermediate risk= Assess bone mass density using a DEXA scan
High risk= consider starting treatment without need for BMD assessment with a DEXA scan
What lifestyle changes are recommended for an individual at risk of osteoporosis?
- Regular exercise: this should include low-impact weight bearing excercise e.g. walking AND high intensity strength training to target muscles around the hip, spine and wrists- risk areas
- Avoid smoking
- Reduce alcohol
- Diet changes:
Need 3-4 portions of calcium per day- minimum of 700mg a day. Calcium-containing foods include 200ml milk, 4 slices of white bread, 30g cheese, 125g yoghurt, 60g sardines
Vitamin D- Dietary intake should include 400 units/day
can be obtained from oily fish, cereals, eggs
Also by exposure to sunlight
Give vitamin D/calcium supplements
What dose should be given in calcium and vitamin D supplements?
Minimum 1000mg of calcium and 800 units of vitamin D per day depending on dietary intake
What are some examples of vitamin D + calcium supplements?
Calcichew D3 forte
Adcal D3
What factors should be assessed in those deemed at risk of falls?
Drug history: All can cause falls
- Anti-hypertensives- can lower blood pressure too much which can cause dizziness
- Sedatives and hypnotics- can cause drowziness
- Diuretics- Lower blood pressure and also increased urge to urinate can cause falls
Also check:
- Balance
- Poor vision
- Cardiovascular status- bp, pulse
- environmental factors e.g. loose carpets, poorly fitting slippers etc
What is the first line treatment for osteoporosis ?
Bisphosphonates e.g.
Alendronate
Risedronate
Ibandronate
Zolendronate
