Bone Lesions

Question 1

Z score for osteoporosis age demographic?

Answer 1

age-matched women

Question 2

Osteoporosis, osteopenia

Answer 2

osteoporosis: T score < -2.5

Question 3

causes of osteoporosis

Answer 3

osteomalacia, alcoholism, hhypophosphatemia, scurvy (Wimberger sign); hyperparathyroidism, Cushing disease, OI, gaucher disease, anemia, immobility/disuse, reflex sympathetic dystrophy, transient regional osteoporosis of the hip

Question 4

how does scurvy cause osteopenia?

Answer 4

osteoblasts need vitamin C to form mature osteoid tissue

Question 5

Wimberger ring sign and Pelkin’s fracture

Answer 5

Wimberger ring: epiphyseal sclerosis

Pelkin’s fracture: metaphyseal corner fracture

Question 6

how does vitamin D deficiency cause osteomalacia?

Answer 6

faulty mineralization of bone matrix vs rickets in children

Question 7

what is a looser zone

Answer 7

pseudofracture ;cortical stress fracture filled with abnormal bone

Question 8

how does acromegaly affect the skeleton?

Answer 8

bones grow longitudinally, acral/distal growth and widening after physes close; thickening of cranial bones/jaw, enlargement of frtonal sinuses, beak like metacarpal osteophytes, spade like growths of distal phalanges, increase in heel pad thickness (24 mm)

Question 9

heel pad thickeness, normal

Answer 9

24 mm normally; increase 1 mm for ever 25 lbs over 150lb.

Question 10

primary vs secondary hyperparathyroidism

Answer 10

primary: parathyroid adenoma
secondary: hypocalcemia secondary to renal failure

Tertiary: prolonged secondary hyperparathyroidism

Question 11

Hallmarks of hyperparathyroidism

Answer 11

skull: salt and pepper
hands: subperiosteal resorption of radial 2nd/3rd middle phalanges
clavicle: subperiosteal resorption of distal clavicle
knee: resorption of medial proximal tibial metaphysis
teeth: loss of lamina dura surrounding tooth socket

brown tumors
diffuse osteopenia

Question 12

arthropathy type in primary hyperparathyroidism

Answer 12

CPPD

Question 13

radiographic findings of renal osteodystrophy

Answer 13

osteomyelities, avascular necrosis, chronic dialysis, rugger jersey spine, soft tissue/vascular calcifications

Question 14

radiographic findings of hypothyroidism

Answer 14

delay in skeletal/dental maturity; bullet shaped vertebral bodies and wormian bones in skull; SCFE

Question 15

hallmarks of hypoparathyroidism

Answer 15

metastatic deposition of calcium; basal ganglia nad subcutaneous tissue

Question 16

pseudohypoparathyroidism and pseudo pseudohypoparathyroidsm findings

Answer 16

short 4th/5th digits or thumb

also consider Turner syndrome

Question 17

how does hyperthyroidism affect bone growth?

Answer 17

accelerated bone maturity

thyroid acropachy: diaphyseal periosteal reaction of multiple bones

Question 18

cause of paget’s

Answer 18

unknown, possibly paramyxovirus

Question 19

phases of pagets

Answer 19

phase I: osteolytic
phase II: lytic/sclerotic mixed
phase III: sclerotic

Question 20

paget in different body parts: skull, vertebral bodies, pelvis

Answer 20

skull: osteoporosis circumscripta to cotton wool in phase 2

vertebral bodies: picture frame (phase 2), ivory,

pelvis: asymmetric coarsened trabecular thickening; acetabular protrusio

long bnes: blade of grass/flame shaped

Question 21

juvenile paget?

Answer 21

hereditary hyperphosphatasia; AR with epiphyseal sparing

Question 22

osteopetrosis

Answer 22

deficiency of osteoclastic carbonic anhydrase; osteoclasts cannot resorb bone

rugger jersey/sandiwchh appearance similar to renal osteodystrophy

Question 23

gaucher disease defect?

Answer 23

glucocerebrosidase deficiency; AR

gaucher cells cause bone infarcts, medullary expansion, hepatosplenomegaly

Question 24

Hallmarks of gaucher

Answer 24

erlenmeyer flask deformity of long bones, H shaped vertebral bodies (endplate avascular necrosis like sickle cell)

Question 25

Hallmarks of sickle cell

Answer 25

bone infarcts, increased risk of osteomyelitis, marrow expansion/hyperplasia

Sickle cell bone infarcts/avascular necrosis: H shaped/lincoln log vertebral bodies, femoral heads, metaphyses of long bones

sickle cell dactylitis/hand foot syndrome: persistent hematopoietic marrow

Salmonella osteomyelitis

sickle cell marrow expansion (more than thalassemia): low T1 signal, hair on end striations

Question 26

Cause of thalassemia

Answer 26

alpha/beta hemoglobin subunit defect

Question 27

cause of sickle cell

Answer 27

AR defect in beta chain of hemoglobin which can cause microvascular occlusion due to sickle shape of RBC

Question 28

Osseous hallmarks of thalassemia

Answer 28

bone infarcts, marrow hyperplasia, infection; marrow expansion more severe in SC

• marrow expansion causes widening/squaring of phalanges/metacarpals
• marrow expansion obliterate paranasal sinuses, rodent like facies
• marrow expansion in long bones; erlenmeyer flask deformity
• hair on end striations in skull

Question 29

myelofibrosis hallmarks

Answer 29

sclerotic bones; anemia, splenomegaly

progressive fibrosis of bone marrow

Question 30

mastocytosis hallmarks

Answer 30

diffuse osteoporosis/sclerosis from reaction of marrow to infiltrating mast cells (mast cell proliferation)