Injury and Healing Flashcards
3 mechanisms of bone fracture + definitions?
Trauma - Low energy transfer and high energy transfer
Pathological - normal stresses on abnormal bone.
Stress - abnormal stresses on normal bone.
What are ADLs?
Activities of daily living.
When does a bone experience stress?
Bone experiences a stress whenever a force is loaded upon it. Low levels of these forces cause bone to deform → Strain.
2 types of trauma?
High energy
Low energy
Briefly explain a stress fracture?
Repetitive applications of forces on a particular bone results in stress exertion on localised region → Excess remodelling capacity → Bone weakening persists → Stress fractures (potentiates risk of complete fracture).
List pathological causes of fracture.
Osteoporosis - Soft bone, reduced BMD Malignancy - Primary, bone metastases VD deficiency - Insufficient exposure to sunlight, reduced vitamin-D source → Osteomalacia + Ricket's Osteomyelitis - Infection of the bone OI - Collagen deficiency Paget's disease
What are the weight bearing bones?
Femur, tibia, metatarsals, navicular
What is the female triad?
Amenorrhoea - Absence of periods; low oestrogen levels.
Osteoporosis - Reduction in bone mineral density, thus increasing porous structure; susceptible to fracture.
Disordered eating - Ca2+ deficiency.
What type of trauma is more common in people with osteoporosis?
Low energy trauma
Outline the basic pathophysiology behind osteopenia and osteoporosis.
Bone resorption (Osteoclast activity) > Bone formation (Osteoblast activity) → Disrupted microarchitecture.
(RANK ligand and RANK → mediators of osteoclast activity. Production of RANKL by osteoblastic cells bind to cognate RANK receptor; activates intracellular pathways (NF kappa beta), results in induction of osteoclastogenic genes.)
In what age range can women experience post-menopausal osteoporosis?
50-70
What is secondary osteoporosis associated with?
Hypogonadism
Alcoholism
Glucorticoid excess
What type of fracture and where are associated with osteoporosis?
Fragility fracture
Hip, spine, wrist associated with low energy trauma.
Senile osteoporosis age?
> 70
Outline the diagnosis system for osteoporosis and osteopenia.
Based on measurement of bone mineral density (BMD), using dual energy X-ray absorptiometry.
The parameters of the DEXA baseline comparisons are sex-attached and age matched in comparison to health population presenting a Z-score. Alternatively the BMD results are reported as a comparison to a sex-matched young healthy adult (T-score). These scores are expressed in standard deviations.
Osteoporosis: T score of -2.5 or less.
Osteopenia: T score between -1 and -2.5.
What does Vitamin D facilitate?
Calcium, magnesium and phosphate absorption.
What is the clinical significance of Vitamin D deficiency in adults and children?
Pre-epiphyseal closure → Rickets
Post-epiphyseal closure → Osteomalacia
What does Vitamin D deficiency do to the body as a whole?
Vitamin-D deficiency (Calcitriol) attributed to dysfunctional renal 1-alpha-hydroxylase and hepatic 25-hydroxylase results in reduced calcitriol activity. → Hypocalcaemia conditions (Reduced Ca2+ absorption, renal absorption and hyperparathyroidism.
What is often seen in people who had or have rickets?
Bowing of bones
Inheritance pattern of OI?
Can be autosomal dominant or recessive
Outline the pathogenesis of OI.
Reduction in type I collagen secretion. Collagen is an ECM protein secreted by fibroblasts and osteoblasts and organised into insoluble fibres, comprising the ECM surrounding cells → Provides mechanical strength and rigidity to tissues and organs, especially to skeletal tissues: Bone cartilage, tendons and ligaments.
Insufficient osteoid production.
What things does OI effect?
Bones
Hearing
Heart
Sight (Blue sclerae, lens dislocation)
Aetiology of Paget’s disease?
Genetic and acquired factors.
Explain the pathogenesis of Paget’s.
Excessive bone degradation and disorganised bone remodelling → Deformity, pain, fracture or arthritis. May transform into malignant disease.
