Paget Disease Flashcards
What is another name for Paget disease?
Osteitis deformans
What is the most common metabolic disease worldwide?
osteoporosis
What is the 2nd most common metabolic disease worldwide?
Paget disease
What is Paget disease?
Bone remodeling disorder characterized by accelerated and abnormal remodeling:
- ^resorption of bone
- ^deposition of disorganized bone
What age group is generally effected by Paget disease?
> 50 years
What geographic areas have higher rates of Paget disease?
Northern European populations and areas with high immigration from Britain (eg. Australia, New Zealand, Canada, US)
What geographic areas have lower rates of Paget disease?
- Asia
- Middle East
- Africa
- South America
Paget disease is most likely to be found in which country?
A) Brazil
B) Turkey
C) Japan
D) Scotland
Scotland (northern europe)
What term implies that a bone disorder affects only one bone in the body?
monostotic
What term implies that a bone disorder affects multiple bones, but not all bones in the body?
polyostotic
What is the etiology of Paget disease?
- mutations in genes encoding for proteins in RANK signaling pathway
- infection with paramyxovirus (measles) activates genes
The RANK system induces ____ and ____
osteoclast activity
osteoclastogenensis
What changes to osteoclasts occur in Paget disease?
- multinucleated (>100)
- may contain inclusion bodies
What are inclusion bodies?
Virus-like particles that especially resemble paramyxoviruses (measles)
Most cases of Paget disease are (monostotic/polyostotic)
monostotic
Where is Paget disease commonly found in the body?
axial skeleton
- spine
- skull
- pelvis
- femur
- tibia
- humerus
Name the radiographic characteristics of Paget disease
- bony expansion
- cortical thickening
- extensive trabecular patterns
How is Paget disease differentiated from metabolic diseases?
Paget disease is usually monostotic, unlike metabolic diseases which have generalized skeletal involvement
What diagnostic method would determine whether a case of Paget disease is monostotic or polyostotic?
bone scan (can look at all bones at once)
Name the stages of Paget disease?
- Lytic
- Mixed
- Blastic
- Malignant transformation (debated)
If Pagetic bone undergoes malignant transformation, it will become a(n) ____
osteosarcoma
Which stage of Paget disease is described as “hot” and why?
stage 1 - osteoclastic resorptive stage (lytic stage)
^vascularization of Pagetic bone
What occurs during stage 1 of Paget disease?
- widespread osteolysis
- marrow fibrosis (fibrous replacement of marrow)
- dilation of marrow sinusoids
Marrow fibrosis in polyostotic Paget disease would increase the risk of ____
anemia (decreased blood cells)
How would stage 1 of Paget disease appear radiographically?
“blade of grass” or “candle flame”
(tapered appearance where there is less bone)
Bone scans show ____ activity, which occurs in reaction to ____ activity in Paget disease
blastic
lytic
How does stage 2 of Paget disease appear radiographically?
- bones appear larger (bony expansion)
- thickened cortex, accentuation of cancellous bone
- “picture frame” appearance of vertebral bodies
- protrusio acetabuli
What is protrusio acetabuli?
Acetabulum protrudes into pelvis, seen radiographically where the femoral head crosses the ilio-ischial line (Kohlers’s line)
In what stage of Paget disease is osteoclastic activity slowing down, while osteoblastic activity is catching up?
Stage 2: mixed osteoclastic & osteoblastic stage
What stage of Paget disease becomes a contraindication for adjusting and why?
Stage 2
bone softening –> deformities & ^Fx risk
How can Paget disease be differentiated from metastasis?
metastasis doesn’t change size of bone, while Paget disease shows bony expansion
In what stage(s) is Paget disease most commonly found?
Stages 2 & 3
What stage of Paget disease is described as “cold” and why?
Stage 3: burnt-out (blastic) stage
Histologically, minimal osteoclastic activity
What stage of Paget disease shows a mosaic pattern in bone with prominent and irregular basophilic-staining cement lines histologically?
Stage 3: burn-out (blastic) stage
How does stage 3 of Paget disease appear radiographically?
thickened & disordered bone
What stage of Paget disease is typically seen in severe polyostotic cases?
Stage 4: neoplastic transformation
The lytic phase of Paget disease in the skull is called ____
osteoporosis circumscripta
What is osteoporosis circumscripta? Where does it usually occur?
localized lysis in the skull (stage 1 pagets), usually frontal & parietal bones (calvarium)
The mixed/blastic phases of Paget disease in the skull creates the appearance called ____
cotton wool skull
Describe the appearance of the mixed/blastic stages of Paget disease in the skull.
- thickening of inner & outer tables of calvarium
- platybasia
- basilar impression/invagination
- misshapen jaw
- tooth loss
- Leontiasis Ossei
What are some of the consequences of Paget disease in the skull?
- increased cranial pressure –> headaches
- basilar invagination/impression
- platybasia –> can compress medulla/spinal cord
- compress CN VIII –> hearing changes (tinitus)
- cerebellar gait disturbances
- “hat doesn’t fit”
What is basilar invagination/impression?
Skull becomes too heavy and collapses on C1, so that the cervical spine is protruding into foramen magnum –> causing brain/spinal cord compression
What is Leontiasis Ossei?
“lion-like face”
increase in facial bone size due to Paget disease in the skull
What is platybasia?
flattening of the base of the skull
How does Paget disease appear radiographically in the spine?
- ivory vertebra
- “picture frame” vertebrae (mixed/blastic stages)
What is an ivory vertebra?
densely blastic vertebral body
In Paget disease in the spine, bone gets bigger in what dimension?
laterally (A-P + M-L)
(bone softening, will compress bones, not allowing vertically)
How would you form your differential diagnosis if you see “ivory vertebrae” on a radiograph?
IHOP:
- idiopathic (Dx of exclusion, must rule out the following)
- hodgkins lymphoma
- osteoblastic metastasis (no thickening/^size)
- Paget disease (picture frame vertebra)
What is a possible consequence of Paget disease in the spine? How would this manifest clinically?
- vertebral canal stenosis/narrowing (bone expands inward)
- provoked in extension, feels better in flexion
How does Paget disease appear in the tibia?
- sabre shin (may affect gait)
- pseudofractures
- transverse fractures
What term describes the course trabecular expansion creating the appearance of a curved anterior tibia?
sabre shin
What term describes a “seam” of unmineralized osteoid?
pseudofracture
Where do pseudofractures occur in Pagetic long bones?
convex side
In what conditions might you see pseudofractures?
PROF:
- Paget disease
- Rickets
- Osteomalacia
- Fibrous dysplasia
In a patient with pseudofractures, how is Rickets differentiated from Paget disease?
Rickets occurs in young population
In a patient with pseudofractures, how is Osteomalacia differentiated from Paget disease?
osteopenic change in osteomalacia
In a patient with pseudofractures, how is Fibrous dysplasia differentiated from Paget disease?
occurs on concave side in Fibrous dysplasia
Transverse fractures are also called ____
banana fracture
What are the general clinical manifestations of Paget disease?
- frequently asymptomatic
- bone pain in affected area
- ^osteoarthritis when adjacent to joint
- patho Fx
- headaches
- hearing loss
- hat size changes
What are the clinical manifestations of polyostotic Paget disease?
- Pagetic steal
- cardiomegaly
- high output cardiac failure
Why does Pagetic steal occur in Paget disease?
bone steals blood from rest of body –> can cause dizziness & gait disturbances
Why does cardiomegaly occur in Paget disease?
bone increases demand for blood
Why does high output cardiac failure occur in Paget disease?
heart can’t keep up with Pagetic bone demand
What are the findings of diagnostic labs for Paget disease?
- normal Ca and PO
- ^alkaline phosphatase
- ^serum & urinary hydroxyproline > hydroxylysine
Hydroxyproline and hydroxylysine are large components of ____
collagen
What levels of hydroxyproline and hydroxylysine would be found in diagnostic labs for Paget disease and why?
- increased hydroxyproline > hydroxylysine
- both are components of collagen
- ^turnover of osteoid + destruction in Paget disease
What is the treatment for Paget disease?
- none, if asymptomatic
- manage symptoms (Fx & osteoarthritis)
- refer to rheumatology: osteoclast inhibitors (calcitonin & bisphosphonates)
Pagetic steal is caused by the over proliferation of vasculature in dense, disorganized bone tissue causing patients to experience ____
A) orthostatic hypertension
B) hypercalcemia
C) orthostatic hypotension
D) spinal cord compression
orthostatic hypotension
(can cause dizziness & gait disturbances)
Stage 1 of Paget disease is characterized by increased ____
A) osteoclastic activity
B) osteoclastic & osteoblastic activity
C) burn-out
D) necrosis
osteoclastic activity
TRUE or FALSE:
Paget disease patients have an increased risk of developing a malignant bone tumor
true
In what stage of Paget disease is “picture frame” vertebrae found?
mixed/blastic stages
What % change is necessary to show on a Bone Scan?
3-5%
What is an example of a bisphosphonate given for treatment of Paget disease?
Fosamax
