Metabolic Bone Disease Flashcards
What are the stages of Osteoclast cell formation?
Myeloid pregenitor cell - preosteoclast cell - Osteoclast.
What are the stages of Osteoblast cell formation?
Mesenchymal progenitor cell - preosteoblast - osteoblast.
What are some factors that stimulate osteoblast expression of RANK ligand?
Glucocorticoids Vitamin D PTH IL-11 IL-1 TNF-alpha PTHrP PGE2
What is Paget’s disease?
Localised disorder of bone turnover.
Increased bone reabsorption followed by increased bone formation.
Leads to disorganised bone - bigger, less compact, more vascular bone that is susceptible to deformity and fracture.
How are genetics involved in Paget’s disease?
Strong genetic component.
15-30% are familial
Loci of SQSTMI gene
Restricted geographic distribution - only those of anglo-saxon origins.
What are the symptoms of Paget’s disease?
Bone pain
Bone deformity
Excessive heat over pagetic bone
Neurological complications e.g nerve deafness.
Isolated elevation of serum alkaline phosphatase.
Osteosarcoma
What are some treatment options of Paget’s disease?
Intravenous bisphosphonate therapy (one off)
NSAIDs
Supportive therapies eg physiotherapy.
Calcium and vitamin D supplements
Surgery for severe complications e.g fractures, deformities, joint damage.
What is Rickets and Osteomalacia ?
Severe nutritional vitamin D or calcium deficiency causing insufficient mineralisation, leading to poor bone growth and soft, weak bone formation.
Rickets is the children, osteomalacia is in adults.
What is Osteogenesis Imperfects?
Genetic disorder of connective tissue characterised by fragile bones from mild trauma and even acts of daily life.
Involves defects in type 1 collagen, there are 28 but first 4 types are most common.
What are the most common types of collagen defect in OI?
Type 1- milder form, when child starts to walk and can present in adults.
Type II - lethal by age 1
Type III - progressive deforming with severe bone dysplasia and poor growth.
Type IV - more severe form of type I.
What are some signs and symptoms of osteogenesis imperfecta?
Growth deficiency Defective tooth formation (dentigenesis imperfecta) Hearing loss Blue sclera Scoliosis Barrel chest Ligamentous Laxity Easy bruising
What scoring system id used in OI?
Beighton Score
One point for each thumb that can touch wrist.
One point for each finger that can bend back > 90 degrees.
One point of reach elbow extending >10 degrees.
One point for each knee extending >10 degrees.
One point if can touch the palmar surface on floor with straight legs.
How is Osteogenesis Imperfecta managed?
Surgery to treat fractures
Medical to prevent fracture e.g IV bisphosphonates.
Social and educational adaptations.
Genetic counselling for parents and next generation.
What is Osteoporosis?
Metabolic bone disease characterised by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and increase in fracture risk or thin bones with increased risk of low trauma fracture.
