Bone Disorders Flashcards
What is osteoporosis?
Significant reduction in bone density
What is the pathophysiology of osteoporosis?
Osteoclasts break down bone and osteoblasts remodel bone
In osteoporosis, the balance between remodelling and resorption is disrupted due to higher osteoclast activity
What are some risk factors that can lead to osteoporosis?
-Age
-Low BMI, reduced mobility/activity
-Post menopause (oestrogen is a protective factor)
-Alcohol and smoking
-Low calcium or vitamin D
-Family history of fractures
-Long term steroids
-Chronic disease
-Certain meds like SSRIs, PPIs, anti-epileptics
How is osteoporosis assessed?
T score of femoral neck via DEXA scan
(Measured in standard deviations away from avg healthy adult)
More than -1 = healthy
-1 to -2.5 = osteopenia
Less than -2.5 = osteoporosis
Less than -2.5 plus fracture = severe osteoporosis
Who is recommended to get assessed for osteoporosis?
Long term corticosteroid users
All women 65+ and men 75+, or over 50s with risk factors
What does the QFracture tool measure?
10 year risk of major fracture in osteoporosis
Offer DEXA scan if over 10%
Management plan for osteoporosis
1- address risk factors (eg smoking, activity levels)
2- address calcium and vitamin D intake
3- medical management:
bisphosphonates (eg alendronate/risedronate weekly or zoledronic acid yearly)
Can also give monoclonal antibodies (-umab), hormone replacement therapy
What is Paget’s disease?
Uncoordinated excessive bone turnover, leads to mixed density
What causes Paget’s disease?
Unknown, but likely to be multifactoral
(genetics x environment)
How does Paget’s disease present?
Commonly in old men
Can be asymptomatic
Bone pain and deformity
Fractures
Hearing loss
Compression neuropathy
How is Paget’s disease investigated?
xray:
Bone enlargement and deformity
Cotton wool skull (poor patchy definition)
V shaped osteolytic defects in long bones
Osteoporosis circumscripta- (well defined osteolytic lesions)
blood test:
Raised ALP
How is Paget’s disease managed?
bisphosphonates
Calcitonin as an alternative
Analgesia
Calcium and vitamin D
What are some complications of Paget’s disease?
Hearing loss if ear bones affected
Hypervascularity -> heart failure
Osteosarcoma
Spinal stenosis and compression
What is osteomyelitis?
Infection causing inflammation of bone and bone marrow
What causes osteomyelitis?
Staph aureus is most common causative organism
Can be haematogenous or direct (ie open fracture or operation)
What are the risk factors for osteomyelitis?
Open fractures
Surgery
Diabetes
PVD
IVDU
Immunosupression
Joint replacements can also become infected
How does osteomyelitis present?
Random and systemic symptoms
Fever, pain and tenderness, erythema, swelling
How is osteomyelitis investigated?
gold standard is MRI
Blood test shows raised inf. markers
Blood and bone cultures show causative organism
How is osteomyelitis managed?
Surgical debridement
Antibiotics -> 6 wk flucloxacillin with 2 wk rifampicin
(Clindamycin for allergies and vancomycin for MRSA)
What is the main possible complication of osteomyelitis?
Chronic osteomyelitis- requires 3 more months of antibiotics
What is osteomalacia?
Abnormal softening of the bone
What causes osteomalacia?
Vitamin D deficiency
Hypophosphataemia
Re feeding syndrome
Alcohol (affects phosphate absorption)
Malabsorption
Long term anticonvulsants
CKD
How does vitamin D affect osteomalacia pathology?
Vit D needed for calcium absorption and osteoblastic activity
If deficient it leads to hypocalcemia and high PTH
This leads to higher osteoclastic activity and more absorption, impairing mineralisation of newly formed osteoid
Leads to weak bone
How does osteomalacia present?
waddling gait
-Bone pain in pelvis, spine, and femora
-Hypocalcaemia symptoms (cramps, irritability, fatigue, seizures, brittle nails)
-easy fracture
Deformity
Proximal myopathy
Dental defects
How is osteomalacia investigated?
X-ray- pseudofractures (loosers zones) in pubic rami, proximal femora, ulna, ribs
Bloods show low calcium and phosphate, and high ALP
How is osteomalacia treated?
Vitamin D therapy with calcium and phosphate supplementation-
D3 tablets, calcitrol, alfacalcidol
Monitor CKD patients as they may be unable to convert vitamin D to calcitrol
What is osteogenesis imperfecta?
Brittle bone disease
What causes osteogenesis imperfecta?
Many genetic mutations that affect collagen formation
How does osteogenesis imperfecta present?
recurrent fractures with bone pain
blue/grey sclera- hallmark feature
Hypermobility
Early deafness
Deformities:
Dental formation issues
Triangle face
Short stature
Bowed legs
Scoliosis
How is osteogenesis imperfecta diagnosed?
Clinical diagnosis based on signs
How is osteogenesis imperfecta managed?
Bisphosphonates and vitamin D supplements
MDT -> physio, occ health, social workers
