Bone Disorders - part I Flashcards
inherited bone disorders
- osteogenesis imperfecta
- osteopetrosis
- cleidocranial dysplasia
- cherubism
acquired bone disorders
- osteitis deformans (Paget disease)
- fibro-osseous lesions of the jaw: fibrous dysplasia
- fibro-osseous lesions of the jaw: cemento-osseous dysplasia (COD)
- osteoporotic bone marrow defect
- idiopathic osteosclerosis
- simple bone cyst
osteogenesis imperfecta
“brittle bone disease”
several rare disorders of bone
what does defective collagen in osteogenesis imperfecta cause?
defective collagen –> abnormal bone mineralization –> low bone density (osteopenia)
etioloigy of osteogenesis imperfecta
mutation in collagen gene
T/F: osteogenesis imperfecta can be autosomal dominant or recessive
true
T/F: a majority of osteogenesis imperfecta cases are autosomal recessive
false, 90% are autosomal dominant
T/F: some of the osteogenesis imperfecta are sporadic
true
T/F: osteogenesis imperfecta is one of the most common heritable bone diseases
true
why does the severity of osteogenesis imperfecta widely varies?
it depends on mutation
clinical features of osteogenesis imperfecta
- bones fragile, fracture easily; varies widely with the type of mutation
- blue sclerae
- hearing loss
- Bowing deformity long bones
- craniofacial alterations (CL III occlusion, triangular facies)
dental alterations of OI that are identical to dentinogenesis imperfecta
- blue, yellow or brown translucence (more noticeable in primary teeth)
- opalescent teeth
- severe attrition leading to loss of VDO and potential tooth loss
T/F: OI and dentinogenesis imperfecta can have similar tooth alterations and blue sclerae, but they are distinct mutations, different diseases
true
dental defects associated with OI should be designated as what?
“opalescent teeth”
T/F: “dentinogenesis imperfecta” is reserved for alterations isolated to the teeth
true
T/F: OI can appear identical to dentinogenesis imperfecta radiographically
true
radiographic features of osteogenesis imperfecta
- “shell teeth”, or premature pulpal obliteration
2. narrow or “corn cob” shaped roots
treatment for osteogenesis imperfecta
- physiotherapy/rehabilitation
- orthopedic surgery
- minimize factors leading to fracture
- IV bisphosphonates for children with moderate-severe pain
why are IV visphosphonates indicated for children with moderate-severe pain?
reduce fracture rates
treatment for dentition of osteogenesis imperfecta
- crown/bridge
- partial or complete dentures
- ± implants
- orthognathic surgery
- orthodontics
prognosis of osteogenesis imperfecta depends on what?
- mutation
2. expression of the gene
what is the range of prognosis for osteogenesis imperfecta?
ranges from minimal bone deformity with essentially normal growth to severe forms leading to death from passage through the birth canal
T/F: osteopetrosis have several forms, both autosomal dominant and recessive
true
T/F: autosomal dominant form of osteopetrosis is more severe
false, recessive more severe
what happens when osteoclasts fail to fxn normally?
bone is not resorbed
what will happen if bone continued to form and ossify in osteopetrosis?
increased bone density
pancytopenia
loss of hematopoietic precursor cells
what happens when pancytopenia occurs in osteopetrosis?
increased susceptibility to infections and osteomyelitis
T/F: osteopetrosis is rare
true
clinical features of osteopetrosis
- blindness and deafness due to CN compression
- fractures
- osteomyelitis
what is the cause of frequent complication of tooth extraction in osteopetrosis pts?
osteomyelitis
radiographic findings of osteopetrosis
- diffuse density of skeleton
- marrow spaces filled in by dense bone
- tooth roots difficult to visualize due to surrounding dense bone
- failure of tooth eruption
tx of osteopetrosis
- supportive measures
- bone marrow transplant
- alternative therapies
supportive measures for osteopetrosis
transfusions and abx when necessary
alternative therapies for osteopetrosis
- interferon with calcitriol
- restriction of Ca2+ intake
- steroids
T/F: autosomal dominant form of osteopetrosis can have long-term survival
true
what is the prognosis for autosomal recessive form of osteopetrosis?
poor
T/F: patients with the autosomal recessive form of osteopetrosis usually die before 20 y.o.
true
T/F: cleidocranial dysplasia is autosomal recessive
false, autosomal dominant
T/F: spontaneous mutations have also been reported for cleidocranial dysplasia
true
T/F: investigators have proposed an autosomal recessive form of cleoidcranial dysplasia
true
T/F: cleidocranial dysplasia is common
false, uncommon
where does the cleidocranial dysplasia primarily affect?
- skull
- jaws
- clavicles
clinical features of cleidocranial dysplasia
- prominent forehead, hypoplastic midface
- long neck
- shoulders narrow and drooping (hypoplastic or missing clavicles)
- hypermobility of shoulders
dental findings of cleidocranial dysplasia
- primary dentition retained because permanent teeth don’t erupt
- numerous impacted and supernumerary teeth (i.e. plenty of teeth; not erupting in the correct space, or, not erupting at all)
tx for cleidocranial dysplasia
combined surgical and orthodontic care to
- correct skeletal relations
- remove supernumerary teeth
- correct alignment of permanent teeth
prognosis of cleidocranial dysplasia
good
T/F: life span of ppl with cleidocranial dysplasia is essentially normal
true
T/F: cherubism is autosomal recessive
false, autsomal dominant
T/F: cherubism has limited expressivity
false, variable
when is cherubism detected?
in childhood
clinical features of cherubism
- painless bilateral expansion of jaws, especially mandible
- chubby cheeks
- involvement of inferior and/or lateral orbital walls may tilt the eyeballs upward and retract lower eyelid “eyes upturned to heaven”
T/F: cherubism involves the maxilla more frequently
false, less frequently
radiographic features of cherubism
- bilateral multilocular radiolucencies posterior mandible, maxilla
- often significant displacement of teeth
T/F: cherubism is occasionally appears unilocular in radiographs
true
histopathologic features of cherubism
- cellular fibrous CT
- sparse benign-appearing multinucleated giant cells
- may see perivascular hyalinization
tx for cherubism
- optimal tx has not been determined
2. surgical intervention sometimes accelerates growth of lesions
T/F: many cherubism cases involute during puberty
true
T/F: pts with cherubism will have persistent facial deformity or continued disease progression
true
etiology of osteitis deformans (Paget disease)
unknown
osteitis deformans (Paget disease)
abnormal resorption and deposition, resulting distored, weaker bone
what happens to the affected bones in Paget disease?
becomes thickened
T/F: Paget disease is often discovered incidentally on routine blood test or dental radiographs
true
Paget disease is primarily of what ancestry?
Anglo-Saxon
T/F: Paget disease has a 2:1 female predilection
false, 2:1 MALE predilection
who is affected by Paget disease?
older pts, rare <40 y.o.
40% of Paget disease cases have what in common?
bone pain
clinical features of Paget disease
- “Simian” (monkey-like) stance if femurs involved
- elevated serum alkaline phosphatase
- skull involvement - progressive enlargement, “hate won’t fit”
what happens if femur is involved in Paget disease?
bowing of legs
T/F: most Paget disease cases are polyostotic
true
what happens to the jaw if involved in Paget disease?
thickened, enlarged alveolar bone “dentures don’t fit”
radiographic features of Paget disease
- “cotton wool” appearance of bone
2. may have extensive hypercementosis
histopathologic features of Paget disease
- “Mosaic” pattern of irregular trabeculae with resting and reversal lines
- marrow replaced by vascular fibrous CT
tx for Paget disease if asymptomatic
no tx
Paget disease if symptomatic
bisphosphonates
T/F: Paget disease is chronic and progressive, but usually not life-threatening
true
what should pts with Paget disease be monitored for?
development of a giant cell tumor or malignant tumors esp osteosarcoma
why would an extraction be difficult on pts with Paget disease?
difficulty extracting teeth w hypercementosis and/or ankylosis
what is a dental complication during the vascular/lytic phase for pts with Paget disease?
hemorrhage
poor wound healing in pts with Paget disease increases susceptibility to what during avascular/sclerotic phase?
osteomyelitits
T/F: new dentures may be required periodically for pts with Paget disease
true
T/F: implant placement is generally favorable for pts with Paget disease
false, unfavorable and more so with use of bisphosphonates
etiologies of fibro-osseous lesions
- developmental (hamartomatous)
- reactive
- dysplastic
- neoplastic
fibro-osseous lesions
- fibrous dysplasia
2. cemento-osseous dysplasia (COD)
T/F: fibrous dysplasia is a post-zygotic mutation
true
post-zygotic mutation of fibrous dysplasia
- pluripotent stem cell
- skeletal progenitor cell
- post-natal life
what determines the extent of fibrous dysplasia
time of occurrence of mutation
when does fibrous dysplasia presents?
~1st-2nd decade (younger than Paget disease)
T/F fibrous dysplasia has a female predilection
false, NO gender predilection
T/F: fibrous dysplasia can be polyostotic or monostotic, but a majority of the cases are polyostotic
false, 75-80% monostotic
clinical features of fibrous dysplasia
- painless, unilateral swelling
- slow growth
- craniofacial fibrous dysplasia
which bone is most commonly affected by fibrous dysplasia?
jaws
T/F: mandible is more often affected by fibrous dysplasia than maxilla
false, maxilla > mandible
craniofacial fibrous dysplasia lesions may involve what?
adjacent facial bones
what may craniofacial fibrous dysplasia result in?
marked facial deformity
how are the early stages of fibrous dysplasia seen radiographically?
radiolucent or mottled
radiographic features of fibrous dysplasia
- opacify as they grow
- obliteration of maxillary sinus
- classic “ground glass” pattern
- poorly defined, blending margins
what are the 2 types of polyostotic fibrous dysplasia?
- Jaffe type
2. McCune-Albright type
Jaffe type of polyostotic fibrous dysplasia
2 or more bones affected and cafe-au-lait spots with jagged borders (coast of Maine)
McCune-Albright type of polyostotic fibrous dysplasia
2 or more bones affected by fibrous dysplasia, cafe-au-lait spots and endocrine disturbances
what is the result of endocrine disturbances in McCune-Albright type of polyostotic fibrous dysplasia
precocious puberty
histopathologic features of fibrous dysplasia
- irregular-shaped trabeculae of immature (woven) bone in cellular fibrous stroma
- no capsule - abnormal bone fuses to adjacent normal bone
tx for fibrous dysplasia if lesion(s) are small
none
when should surgery be delayed for fibrous dysplasia?
until disease quiescent
tx for fibrous dysplasia
- surgical reduction if cosmetic or functional problem
2. en-bloc resection
what is contraindicated in txing fibrous dysplasia?
radiation
T/F: sometimes fibrous dysplasia stabilizes with skeletal maturation
true
T/F: surgically treated fibrous dysplasia lesions show regrowth esp in younger pts
true
T/F: malignant transformation of fibrous dysplasia is rare ans is usually in lesions which have received radiation
true
