Metabolic Bone Disease Flashcards
What are metabolic bone diseases?
Any of several diseases that cause various abnormalities or deformities of bone
Name some metabolic bone diseases
- Osteoporosis
- Rickets
- Osteomalacia
- Osteogenesis Imperfecta
- Marble Bone Disease (osteopetrosis)
- Paget Disease
- Fibrous Dysplasia
Describe the pathology of osteomalacia
Incomplete mineralisation of bone matrix in adults following bone fusion
These bones are therefore softer, can bend, crack and become painful
Symptoms include bone pain, muscle weakness and partial fractures
What are causes of osteomalacia?
- Vit D Deficiency
- Calcium deficiency (rare cause)
- Phosphorus deficiency
- Untreated coeliac
- liver disease
- kidney failure
- epilepsy tablets
Describe vit d deficiency in osteomalacia
Body needs around 10ug/400 units of Vit D a day to protect from osteomalacia
Less than this puts at risk
Describe tests carried out to diagnose osteomalacia
Blood tests
- calcium
- phosphorus
- vit D
- alkaline phosphatase (produced by osteoblasts) may be raised
- PTH raised due to body’s reaction to condition
What treatment is used for osteomalacia?
If caused by deficiency Vit D - vit D supplements
Calcium supplements may help bone healing
Common presenting complaint in patients with osteoporosis
Broken wrist, hip or vertebrae
Not usually painful until a bone is broken
Some older patients will develop characteristic stooped posture
What is the stage of bone loss before osteoporosis?
Osteopenia
This is when a bone density scan shows you have lower bone density than average for your age but not low enough to be classed as osteoporosis
What are causes of osteoporosis?
Women > men
Risk factors include
- high dose steroids > 3 months
- other medical conditions i.e. inflammatory conditions
- FH of osteoporosis
- heavy smoking and drinking
How is osteoporosis diagnosed?
Bone density scan (DEXA)
- measured as a Standard deviation
- above -1 is normal
- between -1 and -2.5 shows bone loss and is defined as osteopenia
- below -2.5 shows bone loss defined as osteoporosis
How is osteoporosis treated?
Treat and prevent broken bones, take medication to strengthen bones
Bisphosphonates
SERMS
Parathyroid Hormone
Calcium and Vit D Supplements
How do bisphosphonates work in treatment of osteoporosis?
Maintain bone density by reducing rate at which bone is broken down
Includes
- alendronic acid
- ibandronic acid
- risedronic acid
- zoledronic acid
Tablets or injections
Main side effects include oesophageal irritation, swallowing problems, stomach pain
What are SERMS (osteoporosis treatment)?
Selective oestrogen receptor modulators
Similar effect as hormone oestrogen; help maintain bone density and reduce risk fracture
Raloxifene taken as daily tablet
Side effects include hot flushes, leg cramps, potential increase risk blood clots
Describe the use of parathyroid hormone treatments in Osteoporosis
i.e. teriparatide
Used to stim cells to create new bone
Given by injection
Can increase bone density but only used in small number of people whose bone density very low and other treatments not working
Common side effects; nausea and vomiting
Describe rickets
Condition affecting bone development in children
Causes bone pain, poor growth and soft, weak bones
can lead to bone deformities
What are causes of rickets?
Lack of Vit D or calcium most common
Rarely genetic form
Can also develop if another condition affects how minerals and vitamins are absorbed by the body
Describe hereditary hypophosphatemic rickets
Genetic congenital condition related to low phosphate levels in blood
Signs and symptoms generally begin early childhood
Describe treatment of rickets
ensuring children eat foods containing calcium and vit D or taking vitamin supplements
Describe osteogenesis imperfecta
AKA brittle bone disease, a genetic condition present from birth
Results in bones that break easily
DEscrieb the pathology of osteogenesis imperfecta
A defect where collagen (protein responsible for bone structure) missing, reduced or low quality
Makes bones weak and easy to fracture
Signs and symptoms of osteogenesis imperfecta
Range from mild to severe
- fractures w/ minimal force
- bones may have altered shape
- whites of eyes more blue/grey
- hypermobile/v flexible joints
- joint or bone pain
- problems with teeth formation
Describe the diagnosis of osteogenesis imperfecta
Mostly clinical diagnosis
X-rays to assess for fractures and bone changes
DEXA for children >10kg
Describe treatment of osteogenesis imperfecta
Physiotherapy
Management of symptoms
Main meds are pamidronate and zoledronic acid (bisphosphonates; prevent loss of bone mass)
Vit D supplements recommended
