Metabolic bone disease and osteoporosis (inc pagets) Flashcards
aetiology of pagets
15-30% familial, loci of SQSTMI, anglosaxon origins, chronic viral infections within osteoclasts may induce it.
symptoms of pagets
bone pain, deformity, heat, neruological complications (nerve deafness)
TIBIAL BOWING
presentation of pagets
LEG BOWING
elevated serum ALKphosphatase, hearing loss, rare development of osteosarcoma in the effected bone.
Ix of pagets
xray, serum Calcium and ALKPhosphate, urinary hydroxyproline.
complications of pagets?
osteosarcoma,
deafness,
high output cardiac failure
bone pain,
tx of pagets
iv bisphosponate therapy. Iv zoledronic acid, bed rest and analgesia, calcitonin too.
What is Rickets and Osteomalacia?
Severe nutritional vitamin D or Calcium deficiency causes insufficient mineralisation and thus rickets in a growing child and Osteomalacia in the adult when the epiphyseal lines are closed. Vitamin D stimulates the absorption of calcium and phosphate from the gut and calcium and phosphate then become available for bone mineralisation. Muscle function is also impaired in low vitamin D states
signs of rickets
large forehead, stunted growth, odd curve to the spine, odd shaped ribs and breast bones, large abdomen, wide bones, odd shhaped legs, wide ankles, wide joints at thhe elbow and wrist.
What is Osteogenesis Imperfecta?
Genetic disorder of connective tissue characterised by fragile bones from mild trauma and even acts of daily life Broad clinical range from those which are prenatally fatal to those only presenting in 40s with early ‘osteoporosis’
name thhe types of OI
Defects in type 1 collagen twenty-eight different types exist/ first 4 most common: Type 1: milder form-when child starts to walk and can present in adults Type 11: lethal by age 1 Type 111: progressive deforming with severe bone dysplasia and poor growth Type 1V : similar to type 1 but more severe
signs and symptoms of OI
growth deficiency, defective tooth formation, hearing loss, blue sclera, scoliosis, barrel chest, ligamentous laxity, easy bruising. (use the Beighton score)
Mx of OI
surgical, iv bisphosphonates, genetic counselling, social and educational adaptations.
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 A result on DXA bone scanning
how is fracture risk assessed?
age, BMD, falls, bone turnover, FRAX tool by WHO
who is at risk of osteoporosis/ osteoporotic fracture?
1 in 2 women over 50, 1 in 5 men over 50. If you suffer 1 vertebral fracture you are 5 times more likely to have another and twice as likely to have hip fracture than if you had no vertebral fractures. Poor dietary calcium, premature menopause, lack of weight bearing exersice, prolongued amenhorrea, anorexia nervosa.
what are the edocrine causes of osteoporosis?
thyrotoxicosis, hyper/hypothyroidism, cushings,hyperprolactinaemia, hypopituitarism, early menopause,
rheumatic causes of osetoporosis?
RA, ankylosing spondylitis, polymyalgia rheumatica.
GI causes?
inflammatory disease (UC or crohns), liver diseases, malabsorption: chronic pancreatitis, coeliac disease, whipples, short gut, ischaemic bowel
medications which cause osteoporosis
steroids, PPI, enzyme inducting antiepileptic medications, aromatase inhibitors, GnRH inhhibitors, Warfarin.
what does a BMD of -1 to -2.5 indicate?
osteopenia
what does a BMD of below -2.5 indicate?
osteoporosis
what is the sign guideline for osteoporosis?
refer for a dexa scan based of FRAX or qfracture score above 10% fracture risk at any site over the next 10 yrs. Tx decisions after dexa scanning and individual report-fracture risk around 20% 10yr risk would be tx threshold.
Tx of osteoporosis
Bisphosphonates (alendronate, risedronate, raloxifene),
Hormone replacement therapy,
selective estrogen receptor modulator (SERM’s),
Denosumab (monoclonal antibody against RANKL)
Teriparatide (intermittent parathyroid hormone, increases bone density)
Calcitonin.
Analgesia.
advice to patients and family
exersice regularly for weight bearing, calcium in diet, avoid smoking and alcohol excess.
what are the se’s of hrt?
increased risk of blood clots, breast cancer, heart disease and stroke.
what are the negative effects of SERM’s?
hot flushes, clotting risks, lack of protection at the hip site.
se’s of bisphosphonates
oesophagitis, uveitis, ONJ, atypical shaft fractures. Need to take a drug holiday for 1-2 yrs typically after 10yrs of oral bisphosphonates.
what is denosumab and how is it good?
monoclonal antibody against RANKL, it binds the RANK ligand and inhibits osteoclast formation, function and survival. Reduces osteoclastic bone resorption, subcutaneous injection every 6 months, safer in patients with a significant renal impairment than bisphosphonates.
se’s of denosumab
allery/ rash, symptomatic hypocalcaemia if given when vit D depletes.
what is Teriparatide?
reduces fracture risk, it is an intermittent parathyroid hormone, increases bone density
se’s of Teriparatide
injection site irritation, rarely hypercalcaemia, allergy, costly.
what do osteoblasts, clasts do?
blasts - bone production, clasts - bone destruction.
go over hormonal regulation of calcium (vit d)
what is Pagets disease?
disorder of bone turnover, increased bone resorption followed by increased bone formation.DECREASED MINERALISATION. Leads to disorganised bone (bigger, less compact, more vascular and more suceptible to deformity and fractures).
