Musculoskeletal disorders Flashcards
What kind of disorder is dysostosis, and what are 4 of its overall/general features?
Congenital disorder. Developmental anomaly of bone
Abnormal mesenchymal migration
Defective ossification of fetal cartilage
Sporadic (isolated) or part of a syndrome
Homeobox gene alterations
What are 3 specific features of dysostosis?
Aplasia (absent or incomplete development, abnormal function)
Supernumerary digits
Abnormal fusion of bones
What is dysplasia?
Mutations interfere with growth or homeostasis (dwarfism)
What are the 2 general kinds of dysplasia?
Bone: osteodysplasia
Cartilage: condrodysplasia
What are 3 notable pathologies of dysostosis?
Klippel-fiel syndrome
Polydactyly
Syndactyly
What osteological features are noted with Klippel-fiel syndrome?
Idiopathic congenital fusion of any 2 cervical vertebrae
Sprengel’s deformity
What kind of mutations are found with osteogenesis imperfecta (AKA brittle bone disease), and what does it cause?
Mutations of type I collagen (alpha 1 or alpha 2 chains).
Abnormal collagen -> premature breakdown.
What anatomy is affected by ostegenesis imperfecta?
ECM of eyes, joints, inner ear bones, skin, teeth/
What is the range of severity with osteogenesis imperfecta?
Type I: normal lifespan
Type II: Lethal in utero
What 2 lethal conditions does type II osteogenesis imperfecta cause?
Cerebral hemorrhage, respiratory failure.
Abnormal collagen of sclera is attributed to what condition?
Type I O.I.
What secondary conditions are associated with Type I O.I?
Fractures, extremity bowing, scoliosis, ligamentous laxity (dislocations), hearing loss, fragility.
What kind of adjusting is specifically contraindicated by O.I.?
Extremity adjusting
What radiologic sign is associated with O.I?
Zebra stripe sign
What are children with O.I. normally treated with?
Bisphosphonates (cyclical).
What is the most common form of dwarfism?
Achondroplasia
With achondroplasia there is decreased cartilage synthesis, which leads to what?
Decreased growth plate expansion
What mutation is implicated in achondroplasia?
Fibroblast growth factor receptor (FGFR3) gene mutation
What specific issue does mutation of the FGFR3 gene cause?
Inhibits epiphyseal (growth plate) chondrocytes
What percent of achondroplasia cases are spontaneous?
75%
What percent of achondroplasia cases are autosomal dominant?
25%
What deformations are noticed with achondroplasia?
Short proximal extremities, lower extremity bowing, frontal bossing, midface hypoplasia (low nasal bridge).
What are some spinal features noted in achondroplasia?
Hyper lordosis and kyphosis at birth, bullet vertebrae, scoliosis, spinal stenosis (of foramen magnum and or spinal canal).
How can death occur in achondroplasia patients due to it’s effect on the spine?
Death: brain stem compression, cardiovascular abnormalities.