context week 3 Flashcards
what is osteogenesis imperfecta
brittle bone disease, defect in maturation and organisation of Type 1 collagen.
what are the two types of osteogenesis imperfecta
autosomal dominant- mutliple fractures in childhood, short stature with deformity, blue sclera, loss of hearing
autosomal recessive - rarer, fatal prenatal or associated spinal deformity
(many genetic changes de novo)
what is osteogenesis imperfecta sometimes mistaken for
child abuse
what is shown on X-rays of osteogenesis imperfecta
mild cases have relatively normal X-rays with Hx of low energy fractures. [sometimes “psuedofractures”]
healing ability of osteogenesis imperfecta
fractures tend to heal with abundance but poor quality callus formation
treatment for osteogenesis imperfecta
splintage, traction or surgical stabilisation.
some cases can develop progressive deformity which may require multiple osteotomies and intramedullary stabilisation for correction.
what is skeletal dysplasia?
medical term for short stature (Dwarfism not used anymore).
why does skeletal dysplasia occur?
genetic error, abnormal connective tissue/ bone occurs.
what are proportionate and disproportionate statures in skeletal dysplasia?
proportionate - limb same size/proportional to spine
disproportionate - limbs and spine not proportional.
what is the commonest skeletal dysplasia? give some features of it.
achondroplasia.
autosomal dominant (80% spontaneous disease). lax ligaments and normal mental development. disproportionately short limbs to spine. wide nose, prominent forehead.
know that there are many other types of skeletal dysplasia each with their own features. (mild/severe signs/consequences/symptoms)
-
treatment for skeletal dysplasia
genetic testing of child and family.
correct deformities and lengthen limbs.
GH therapy may be appropriate
where is type 1 and 2 collagen found
1-bone, tendon, ligaments, skin
2-cartilage
what are CTDs due to?
genetic disorders of collagen synthesis
what is generalised (familial) joint laxity
CTD. double-jointed people, 5% population, more prone to ankle sprains (soft tissue injury) and painful dislocations (rucurrent shoulder/patellar)
medical name for double jointedness
generalised (familial) joint laxity
what is marfan’s?
CTD. tall, long limbs, ligamentous laxity.
what genetic abnormality occurs in Marfan’s
autosomal dominant/sporadic mutation of fibrillin gene
what are some common signs/consquences of Marfan’s
lens dislocation, retinal detachment, glaucoma,
high arched palate,
spontaneous pnuemothroax, apical blebs,
pectus excavatum/carinatum.
aortic dissction/aneurysm/regurgitation. mitral valve prolapse/regurgitation.
long arms/legs, scoliosis, arachnodactyly.
what does EDS stand for and what causes it?
Ehlers-Danlos syndrome, heterogenous condition autosomal dominantly inherited with abnormal elastin/collagen formation.
features of EDS
profound joint hyper mobility, vascular fragility, easy bruising, scoliosis, joint instability
treatment of EDS
bone surgery (wound dehiscence common as abnormal connective tissues)
Down’s syndrome is caused by what genetic problem?
trisomy 21.
features of Downs relating to CTD
short stature, joint laxity, possible recurrent dislocation (may require stabilisation), atlanto-axial instability may occur in C-spine