Osteoporosis Flashcards
What is osteoporosis?
A metabolic bone disease characterised by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk
How can osteoporosis be defined using DEXA bone scanning?
A result on DEXA bone scanning
How does bone mass change throughout life?
> Teens = Increase in bone size
> Around 30 = Peak bone mass
> Menopause (50yrs) = Accelerated loss begins
> Later life = Gradual loss
What are the associations with increased risk of fracture?
> Age > Bone metabolic disease > Falls > Bone turnover > Low BMI > Female > Rheumatoid arthritis > Long term steroid use > Diabetes mellitus > Endocrine issues > Other medications (SSRIs, PPIs, ant epileptics etc)
What online tool is used to assess fracture risk?
FRAX = Who fracture risk assessment tool
Q fracture
Who is likely to suffer from osteoporosis?
> I in 2 women over 50 will have an osteoporotic fracture before they die (Post menopausal)
> I in 5 men over 50 will suffer and osteoporotic fracture
> Endocrine causes
> Rheumatic causes
> Gastroenterological causes
> Medications
What is the lifetime risk of a 50 year old woman of having a hip fracture?
17%
If you have suffered a vertebral fracture what are you more likely to suffer from in the future?
> 5 times more likely to have another vertebral fracture
> 2 times more likely to have a hip fracture
What endocrine causes are there for osteoporosis?
> Thyrotoxicosis > Hyper and hypoparathyroidim > Cushings > Hyperprolactinaemia > Hypopituitarism > Early menopause
What Rheumatic causes are there for osteoporosis?
> Rheumatoid arthritis
Ankylosing spondylitis
Polymyalgia rheumatica
What gastroenterological causes are there for osteoporosis?
> Inflammatory diseases: UC and crohns
> Liver diseases: PBC, CAH, Alcoholic cirrhosis, Viral cirrhosis( hep C)
> Malabsorption: chronic pancreatitis, coeliac disease, whipples disease, short gut syndromes and ischaemic bowel
What medications are associated with increased risk of osteoporosis?
> Steroids
> PPI
> Enzyme inducting antiepileptic medications
> Aromatase inhibitors
> GnRH inhibitors
> Warfarin
What are the cornerstones in managing osteoporosis?
Minimise risk factors
Ensure good calcium and Vitamin D status
Falls prevention strategies
Medications
How is it determined whether someone requires treatment for osteoporosis or not?
Measure BMD using DEXA of hip and spine:
> Normal:
- T score above -1
- Reassure lifestyle advice
> Osteopenia:
- T score -1 to -2.5
- Lifestyle advice, treat if previous fracture
> Osteoporosis:
- T score below -2.5
- Lifestyle advice and offer treatment
- Less than -2.5 + a fracture = severe osteoporosis
SIGNs guidelines for osteoporosis and referral for DEXA scanning?
Referral for DEXA scanning based on FRAX or QFracture score of >10% fracture risk at any site over next 10 years
SIGNs guidelines for treatment of osteoporosis?
Treatment decisions after DXA scanning and individual report-fracture risk around 20% 10 year risk would be treatment threshold
If an individual is over the age of 65 and exposed to oral glucocorticoids for >3 months what should be done?
> Investigations
> General measures, advise treatment
If an individual has been on glucocorticoids for >3months and has a fragility fracture what should be done?
> Investigations
> General measures, advise treatment
If an individual <65 yrs old has been on glucocorticoids for >3 months and has a DXA scan hi and spine with a T-score -1.5 or lower what should be done?
> General measures, advise treatment
If an individual <65 yrs old has been on glucocorticoids for >3 months and has a DXA scan hi and spine with a T-score between 0 and -1.5 what should be done?
Repeat bone mineral density measurement (DXA scan) In 1-3 years if glucocorticoids continued
what is a fragility fracture?
A fracture occurring on minimal trauma after the age of 40 (Includes forearm, spine, hip, ribs and pelvis)
What are general measures taken in steroid induced osteoporosis?
> Reduce dose
Consider glucocorticoid sparing therapy e.g. azathioprine
Consider alternative route of admission
Recommend good nutrition, especially adequate calcium and Vitamin D
Recommend regular wight bearing exercise
Maintain body weight
Avoid tobacco use and alcohol abuse
Access falls risk
In a patient with previous fragility fracture which test are indicated?
> FBC, ESR
Bone and liver function test (Ca , P all, Phos, Albumin, ALT/GT)
Serum creatinine
Serum TSH
If indicated:
> Lateral thoracic and lumbar spine radiograph
> Serum paraproteins and Bence Jones protein
> Isotope bone scan
> Serum FSH if hormonal status unclear (Woman)
> Serum testosterone, LH, and SHBG (Man)
> Serum 25OHD and PTH
> BMD monitoring if required
Medications used in osteoporosis?
> Biphosphonates (First line)
HRT
Selective Oestrogen Receptor modulators (SERMS)
Denosumab (Monoclonal Abx against RANKL)
Teriparatide
What are the side effect of HRT (used in osteoporosis)?
> Increased risks of blood clots
> Increased risk of breast cancer with extended use into late 50s/early 60s
> Increased risk of Heart disease and stroke if used after large gap from menopause
What are the negative side effect of Selective Oestrogen Receptor modulators (SERMS) - (used in osteoporosis)?
Hot flushes if taken close to menopause
Increased clotting risks
Lack of protection at hip site
What is required before taking Biphosphonates (Used in osteoporosis)?
> Adequate renal function
Adequate calcium and Vitamin D status
Good dental health (Notify dentist that on Biphosphonates)
What is the action of nitrogen containing Biphosphonates?
Inhibit Osteoclasts
Examples of Biphosphonates?
> Aledronate *
Risedronate
Raloxifene
What are the negative side effects of Biphosphonates?
> Oesophagitis
Iritis/uveitis
ONJ ?
Atypical femoral shaft fractures ?
What usually need to occur after 10 years of Biphosphonate treatment?
A “drug holiday” coming off for 1-2 years
What is Denosumab?
A monoclonal antibody against RANKL
What is Denosumab used for and how does it work?
Is a monoclonal antibody against RANKL. Reduces osteoclastic bone respiration
Used in osteoporosis
If someone has significant renal impairment which drug should not be used in osteoporosis therapy? Which drug should be consider as an alternative?
Biphosphonates should not be used in individuals with significant renal impairment.
Consider denosumab as a alternative (A monoclonal antibody against RANKL)
How is Denosumab administered?
As a subcutaneous injection every 6 months
What are the negative side effect of denosumab?
Allergy/rash
Symptomatic hypocalcaemia if given when vitamin D deplete
?ONJ
? Atypical femoral shaft fractures
How does Teriparatide work?
> Teriparatide is a recombinant form of PTH that is used in patients with osteoporosis
> The usual drugs used in osteoporosis are anti resorptive agents
> Usual PTH demineralises bone however intermittent pulses of exogenous PTH stimulates osteoblastic activity (Given once daily)
What are the side effects of teriparatide ?
Injection site irritation
Rarely hypercalcaemia
Allergy
COST
In osteoporosis therapy most drugs are anti-resopative, which drug is not and what does it do instead?
Teriparate a recombinant form of PTH which when given intermittently acts to add bone instead
