MUSCULOSKELETAL PATHOLOGY-2 Flashcards
Covers the Congenital and Metabolic bone disorders
What is the most likely basis for defective osteoclastic activity in this patient?
Anemia, Optic atrophy, Facial paralysis
Xray- diffuse symmetric skeletal sclerosis
Renal tubular acidosis
Cerebral calcification
Carbonic anhydrase II enzyme deficiency
2 consequences of Scurvy in the bones and joints
Subperiosteal hemorrhages
Joint hematomas
2 key factors in the pathogenesis of senile osteoporosis
decreased activity of 1 alpha hydroxylase
decreased osteoblastic activity
1. Identify the condition described.
2 year old child
fractures
anemia
optic atrophy, deafness, and facial paralysis
diffuse symmetric skeletal sclerosis on Xray
2. What is the pathogenesis?
- Osteopetrosis
- impaired formation or function of osteoclasts
Why do patients with osteopetrosis experience optic atrophy, deafness / facial paralysis?
Because the neural foramina are small and compress exiting nerves
List the 3 sequential phases of osteitis deformans
(1) an initial osteolytic stage
(2) a mixed osteoclastic-osteoblastic stage, which ends with a predominance of osteoblastic activity and evolves ultimately into
(3) a final burned-out quiescent osteosclerotic stage
Why is there exacerbation of underlying cardiovascular disease in Osteitis Deformans?
Increased blood flow from Increased arteriovenous shunts may cause high-output heart failure
3 cardinal features of Carbonic anhydrase enzyme II deficiency
Osteopetrosis
Renal tubular acidosis
Cerebral calcification
List the 3 bone resorptive cytokines
IL-1, IL-6 and TNF
Why do patients with osteopetrosis have pancytopenia/anemia?
Due to due to persistence of the primary spongiosa, which fills the medullary cavity and displaces the hematopoietic marrow
Predict the following hormone levels in secondary hyperparathyroidism due to CKD
Serum Calcium
Serum Phosphorus
Serum PTH
Serum ALP
WHO definition of osteoporosis
T-score of −2.5 or lower
Identify the condition from the radiologic findings attached
Osteitis Deformans
Morphologic findings in osteomalacia
exaggeration of osteoid seams
3 morphologic consequences of hyperparathyroidism
Osteoporosis
Brown tumors
Osteitis fibrosa cystica
Predict the following hormone levels in hypervitaminosis D
Serum Calcium
Serum Phosphorus
Serum PTH
Serum ALP
List 5 clinical features of Osteitis deformans
Pain localized to the affected bone
increased hat size
hearing loss
anterior bowing of the femurs and tibiae
Chalk stick fracture
What is the fundamental defect in Rickets/Osteomalacia?
impairment of mineralization and a resultant accumulation of unmineralized matrix.
What is the basis of the condition described?
Child presenting with
Anemia
Optic atrophy
Facial paralysis
See attached image
impaired formation or function of osteoclasts
(Osteopetrosis/Marble-bone disease)
Identify the metabolic bone disorders from the morphologic findings shown
Osteoporosis
(reduction in the number and size of trabeculae)
How do the bone resorptive cytokines favor osteoclastic activity in post menopausal osteoporosis?
Expression of RANK and RANKL
Inhibition of OPG expression
List the 6 non modifiable risk factors for osteoporosis
- Caucasian ethnicity
- Rheumatoid arthritis
- Advancing age
- Postmenopausal status
- Previous fragility fracture
- Genetics
List 4 modifiable risk factors for osteoporosis
- Low body weight
- Excessive alcohol consumption
- History of heavy/protracted glucocorticoid use
- Current cigarette smoking
List 2 morphologic findings of rickets
Deposition of osteoid matrix on inadequately mineralized cartilaginous remnants
Growth plate is conspicuously thickened, irregular and lobulated
Idenify the condition associated with the gross image attached.
The image shows Brown tumor
The condition associated is Hyperparathyroidism
What is the underlying basis of the condition described?
Blue sclerae
multiple skeletal fractures
hearing loss
small, misshapen and blue-yellow teeth
Defective synthesis of Type I collagen
(Osteogenesis imperfecta)
Classic radiologic finding of Osteomalacia
pseudofractures of Milkman-Looser syndrome
(radiolucent transverse defects)
Which bone cell type is most active in the stage of Osteitis deformans described below:
initial osteolytic stage
Osteoclasts
Normal sized head and vertebral column
Shortened arms and legs
Short stature, rhizomelic shortening of limbs, frontal bossing, midface deficiency
What’s the etiopathogenesis of this disorder?
FGFR3 mutation
Predict the following hormone levels in Rickets/Osteomalacia
Serum Calcium
Serum Phosphorus
Serum PTH
Serum ALP
See the attached image .
What’s the most likely diagnosis?
Osteogenesis imperfecta
How does chronic kidney disease lead to secondary hyperparathyroidism?
Decreased phosphate excretion –> hyperphosphatemia –> hypocalcemia —>secondary hyperparathyroidism
What are the 3 key ways in which renal osteodystrophy occurs?
See the flow chart in the attached image
- Identify the finding shown in the attached image.
- Which condition is it associated with?
- Loss of palisades of cartilage
- Rickets
Normal sized head and vertebral column
Shortened arms and legs
Short stature, rhizomelic shortening of limbs, frontal bossing, midface deficiency
Mode of inheritance?
Autosomal dominant
What is the typical radiologic finding associated with the condition described below?
2 year old child
fractures
anemia
optic atrophy, deafness, and facial paralysis
Diffuse symmetric sclerosis (bone-in-bone)
Shown here is a photomicrograph of a bone biopsy stained with von Kossa stain
Identify the finding shown
Osteomalcaia
The surfaces of the bony trabeculae (black) are covered by a thicker than normal layer of osteoid (red)
List 1 tumor condition that may arise from Pagetic bone
osteosarcoma
Which bone cell type is most active in the stage of Osteitis deformans described below:
mosaic pattern (jigsaw puzzle) of lamellar bone visible due to prominent cement lines, which join haphazardly oriented units of lamellar bone
Osteoblasts
Normal sized head and vertebral column
Shortened arms and legs
Short stature, rhizomelic shortening of limbs, frontal bossing, midface deficiency
What cell type is involved in the pathogenesis of this disorder?
This disorders is assoc with impaired proliferation of cartilage at the growth plate. Therefore, the main cell type involved is the chondrocyte.
1 consequence of accumulation of vertebral body fractures in senile osteoporosis
progressive kyphosis of the thoracic spine (Dowager’s hump)
Best investigation to estimate bone loss in osteoporosis
Dual-energy x-ray absorptiometry
Why is the growth plate thickened in Rickets?
in children, the growth plates (physes) are open.
Osteoclastic activity functions only if the matrix is mineralized.
In rickets, the growth plate does not calcify normally–>no osteoclastic resorption—>thick growth plate
Predict the following hormone levels in Paget’s disease (Osteitis deformans)
Serum Calcium
Serum Phosphorus
Serum PTH
Serum ALP
Why is the sclera blue in osteogenesis imperfecta?
decreased collagen content —–>makes the sclera translucent—–>partial visualization of the underlying choroid
WHO definition of Osteopenia
T-scores between −1 and −2.5
Identify the condition from the radiologic image attached.
List 3 key findings
Fraying – edge of metaphysis loses its sharp border
Splaying – widening of the metaphyseal end of bone
Cupping – edge of the metaphysis changes from a flat/ convex surface to a concave surface.
Increased distance between ends of bone shafts and the epiphyseal center
Modality of investigation used to estimate bone mineral density
Dual-energy x-ray absorptiometry (DXA) also known as DEXA scan
Predict the following hormone levels in primary hyperparathyroidism
Serum Calcium
Serum Phosphorus
Serum PTH
Serum ALP
What is the technique used to measure deposition of osteoid is osteomalacia?
double tetracycline labeling
Why are African American women less prone to osteoporosis?
Due to higher peak bone mass
What’s the diagnosis?
55 year old male
Pain in the affected bone
Hearing loss
elevated serum alkaline phosphatase levels
normal serum calcium and phosphorus
Xray findings attached
Osteitis Deformans
(The Xray shows extensive bony sclerosis in the region of the hip joint on the left)
Why does carbonic anhydrase II enzyme deficiency cause osteopetrosis?
interference with the process of acidification of the osteoclast resorption pit
Predict the following hormone levels in Osteoporosis
Serum Calcium
Serum Phosphorus
Serum PTH
Serum ALP
micromelic shortening of the limbs
frontal bossing
relative macrocephaly
small chest cavity
bell-shaped abdomen
Thanatophoric dysplasia
Osteitis fibrosa cystica is a combination of which 3 key events/findings in hyperparathyroidism
increased bone cell activity + peritrabecular fibrosis + cystic brown tumors
