achondroplasia is and path
congenital disorder resulting in rhizomelic dwarfism
FGFR3 mutation on chromosome 4p16.3 which causes abnormal cartilage formation
gain of function mutation with activation of inhib signal. all bones formed by endochondral ossification affected. membranous (like skull) normal.
Achondroplasia imaging
Antenatal
- short femur
- trident hand
- frontal bossing
- depressed nasal bridge
Cranial
- large vault, small base
- frontal bossing
- depressed nasal
- narrow FM
- comm hydrocephalus
Spinal
- posterior vert scalloping
- pregressive decreased interpedicular distance
- gibbus; kyphosis with bullet vert
- short pedicle canal stenosis
- widening IVD
Chest
- anteiror flaring
- AP narrowing of ribs
Pelvis
- horizontal acetabular roof
- tombstone iliac wings
- trident acetabulum
- champagne pelvic inlet
Limbs
- metaphyseal flaring
- rhizomelic shortening
Nail patella syndrome is
a rare AD condition results from symmetrical mesodermal and ectodermal abnormalities.
underlying genetic defect caused by loss of function mutation on LMX1B chromosome 9
XR
- hypoplastic/absent patella
- hypoplasia radial head/capitellum
- bilateral posterior iliac horns
- flared iliac crests with protuberant anterior iliac spines
Cleidocranial dysostosis is and imaging
rare polyostotic skeletal dysplasia caused by a CBFA1 gene mutation in AD inherited or sporadic mutation pattern
incomplete ossification of midline structures, including the clavicle and pubic bones
Skull
- wormians
- widened sutures/fontanelles
- basilar invag
- supernumery teeth
- abnormal ear structures
Chest
- absent/hypoplastic clavicles
- supernumery ribs
- hemivert with spondylosis
Pelvis
- iliac hypoplasia
- absent/delayed ossification pubic bone
Limbs
- short/absent fibular/raidus
- coxa vara
Melorheostosis is and pathology
aka leri disease. uncommon mesenchymal dysplasia manifesting as regions of sclerosing bone with dripping wax appearance
can be mono or polyostotic. tends to be monomelic. predilection for long bones. tendency for sclerotome distribution
Melorheostosis imaging
Classic
- periosteal cortical thickening
- endosteal thickening
- thick undulating ridges of bone (candle wax)
- confined to sclerotome
Osteoma like
Myositis ossificans like
Osteopathia striata like
Mixed
Mixed sclerosing bone dysplasia has features of
Melorheostosis
Osteopathia striata
Osteopoikilosis
Duchenne muscular dystrophy is
the most common muscular dystrophy
characterised by progressive muscle weakness and fatty replacement
x linked recessive pattern. DMD gene, encodes for dystrophin, becomes non fucntioning (more severe than Beckers)
Duchenne muscular dystophy imaging
fatty muscle replacement
scoliosis
hypoinflated lungs
cardiomegaly
gracile bones
MR
early invovlemnt of gastroc
eventual glutes, add magnus, then psoas, iliacus, quads, rectus, biceps, peroneus, soleus
sparing of; sartorius, gracilis, semitend, semimemb, tib posterior
Upper limb;
trics, bics, teres major, RC
spares; deltoid
Olliers disease is
a non hered skeletal disorder characterised by multiple enchondromas
should stop growingwhen the patient does, otherwise concern for malignant trasnformation
typically short tubular bones of hands and feet
Maffuci syndrome is
a congenital non hered mesodermal dysplasia characterised by multiple enchondromas with soft tissue venous malformations and/or spindle cell haemangiomas
somatic mutations in IDH1 or IDH2
Metachondromatosis is
the rare combination of multiple enchondromoatosis and osteochondromatosis (olliers and diaphyseal ecclasia)
Osteogenesis imperfecta is and path
a hetergenous group of congenital non sex linked genetic disorders of collagen type 1 production
disturbance in the synthesis of type 1 collagen, predominant protein of the extracellular matrix in most tissues
COL1A1 and COL1A2. can be AD, AR or sporadic.
can be mild, perinatal lethal or progressive deforming
hjallmark feature is osteoporosis and fragile bones that fracture easily. also blue sclera, dental frag and hearing loss
Osteogenesis imperfecta imaging
Head/spine
- basilar invag
- wormian bones
- scoliosis
- compression fractures
- codfish vert
- platyspondyly
Chest
- pectas ex or carinatum
- accordion ribs
Pelvis
- protusion acetabuli
- coxa vara
General
- severe op
- gracile bones
- cortical thinning
- popcorn calrc at meta/epiphysis
- zebra stipe sign (cyclic bisphosphonate therarpy)
- pseudoarthroses
Gracile bones ddx
NF1
Immobilisation
Muscular dystrophy
JRA
OI
Marfans
Homocystinuria
Haemophilia
NIMROD
- NF1
- Immob
- MD
- RA
- OI
- Dysplasia (marfans, homocystinuria)
- also haemophilia i guess
Wormian bones ddx
PORKCHOPS
Pyknodyostosis
OI
Rickets
Kinky hair
Cleidocranial dysostosis
Hypothyroid/hypophosphate
Otopalatodigital syndrome
Primary acroosteolysis (Hajdu Cheney)/ progeria
Syndrome of a Downs
Osteopetrosis is and path
AKA albers schonberg disease or marble bone disease
uncommon hered disorder. results from defective osteoclasts and overgrowth of bones. bones become thick and sclerotic, but more brittle
can crowd the marrow, resulting in myelophthisic anaemia and EMH/splenomaegaly
Features depend on subtype
- infantile AR osteopetrosis
- Benign adult AD osteopetrosis
Osteopetrosis types and imaging
AUTOSOMAL DOMINANT
- less severe type
- benign/adult
imaging
- bone in a bone
- erlenmeyer flask
- sanwich vertebrae
- alternating radiolucent metaphyseal bands
AUTOSOMAL RECESSIVE
- more severe, presents earlier
Imaging
- bone in bone
- triangle mandible sign
- defective dentition
- paranasal sinuses poorly pnematosised
- hyperteolrism
- dense inner table, low attenuation diploic, dense inner table
- hair on end
Bone in bone ddx
Normal
Cortical splitting and new periostitis
- sickle cell
- thalassemia
- gaucher
- chronic OM
- scurvy
Caffey disease
Abnormal metab
- hypothyroid
- hypparathy
- pagets
- acromegaly
- osteopetrosis
Disordered growth
- heavy metal
- hyper vit d
Subcortical osteopenia
- leukaemia
- mets
- complex regional pain syndrome
Oxalosis
Iatrogenic
- grafts
- bisphosphonate
Bone healing
Mnemonic: GHOST DRAGON
Growth arrest
Heavy metal/hypoparathy/hypothy
Osteopetrosis
Sickle cell, scurvy, syphillis
Thalessemia, TB
Disease of caffey, hypervit D
Rickets, radiation
Acromegaly
Gauchers
Oxalosis
Normal
Erlenmeyer flask deformity causes
AP OF DR GHLN
- achondroplasia
- Pyle disease
- Osteopetrosis /osteochondromatosis
- Fibrous dysplasia
- Down syndrome
- RA/RIckets
- Gaucher
- Hypophosphataemia, haemoglobinopathies
- Leukamia, lead poisoning
- Niemann Pick disease
Hair on end sign causes
HI NEST
Hereditary spherocytosis
Iron def anemia
Neuroblastoma
Enzyome def
Sickle cell
Thalassemia major
Osteopoikilosis is and assoc
sclerosing bony dysplasia characterised by multiple benign enostoses
often found with osteopathia striata and melorheatosis
Arthrogryposis is and assoc
descriptor that denotes congenital non progressive joint contractures invovling two or more body regions
Syndromes
- pena shokeir
- multiple pterygium
- fowler
- freeman sheldon
Non syndrome
- CNS anomalies
- NM disorders
Achondrogenesis is
a rare and extreme group of skeletal dysplasias
affects both bone and cartilage development
Can be AR or AD depending on type. May involving mutations in SLC26A2 and COL2A1 depending on type, or may be unknown.