MSK

Question 1

Brittle bones, blue sclera, hearing problems, and mishapen teeth

Answer 1

Osteogenesis Imperfecta
AD mutation in a1 or a2 strands of triple helix of type 1 collagen, results in too little bone formation and thus brittle bones
Sclera: decreased sclera collagen content and ability to see choroid underneath
Hearing loss: problems with bones of middle and inner ear
Teeth: dentin deficiency

Question 2

MCC dwarfism

Answer 2

achondroplasia
AD or spontanteous activating mutation in FGFR 3 which usually inhibits growth plate chondrocytes (enchondrial occification- cartilage, woven, laminar bone) but normal membranous ossification so head is large relative to body

Question 3

Easy fracture, hepatosplenomegaly, recurrent infection, cranial nerve palsy

Answer 3

osteopetrosis: congenital problem with osteoclasts so can’t reabsorb bone (no remodeling)

Question 4

Vitamin deficiencies causing bone disease

Answer 4

vit C (scurvy, issue with crosslinking of collagen fibrils)
vit D (rickets and osteomalacia)

Question 5

older persons with acute back pain, loss of height, kyphosis

Answer 5

compression fractures and collapse of vertebral bodies
loss of trabecular bone in osteoporosis associated with post-menopausal women (loss of estrogen which inhibits apoptosis of osteoblasts and triggers apoptosis of osteoclasts)

Question 6

older persons with fractures in weight bearing bones like femoral neck

Answer 6

loss of cortical bone in senile osteoporosis

Question 7

Secondary causes of osteoporosis

Answer 7

1. Excess glucocorticoids
2. Smoking
3. Excess alcohol
4. Anticonvulsants
5. Anticoagulants
6. Thyroid replacement therapy

Question 8

Mosaic pattern of lamellar bone

Answer 8

Paget’s disease

• Process of increased bone deposition but the bone is weak and disorganized (chalkstick fractures)
• May present with nerve impingement symptoms like visual or auditory disturbances or increased hat size; normal Ca, PTH, Ph but high ALP (thought to be inflammatory/viral)
• Rarely can process to osteosarcoma (v poor prognosis) or high output cardiac failure from increased vascularization due to increased demand from bone

Question 9

ALP

Answer 9

Alkaline phosphatase (30-120) 
Present in cells of billiary duct, bone, and placenta

Question 10

subperiosteal bone reabsorption along the radial aspects of the middle phalanges

Answer 10

characteristic radiographic finding of hyperPTH

Question 11

acute osteomyelitis in neonates

Answer 11

Ecoli, group B strep

Question 12

destructive lytic focus surrounded by edema and a sclerotic ring

Answer 12

radiographical findings in osteomyelitis

Question 13

20 y/o man complaining of localized pain that is most severe at night and relieved with aspirin, presents with

Answer 13

osteiod osteoma (benign bone tumor made of a mix of woven and lamellar bone and usually found under the periosteum or in the cortex)

Question 14

20 y/o man with diffuse vertebral pain that is not responsive to aspirin and shows a > 2 cm nodule on xray

Answer 14

osteoblastoma

Question 15

codman triangle

Answer 15

radiographic sign created by bone growth pushing up the periosteum and suggestive of an osteosarcoma

• dual peak below 20 and in the elderly
• RB gene mutation often found
• pulmonary mets

Question 16

Caucasian male

Answer 16

Ewing sarcoma
neuroectoderm derivative (homer wright rosettes) from 11, 22 translocation (EWS- FLI-1)
Onion skin lesion in diaphysis
Aggressive, treat with chemo and surgery

Question 17

Pain in weight bearing joints that is worse with use (at the end of the day) and improves with rest

Answer 17

osteoarthritis

Question 18

symmetric joint involvement with morning stiffness lasting longer than 30 minutes and other systemic symptoms

Answer 18

rheumatoid arthritis

HLA DR4

Question 19

sacroilliacitis

Answer 19

seronegative spodyloarthropathies
Autoimmune mediated arthropathy negative for RF
Pathological changes that begin in ligaments that are attached to bone
HLA-B27 associated
Ex: anklylosing spondylitis, Reiter disease. psoriatic arthritis

Question 20

tophi

Answer 20

gout

deposits of urate crystals surrounded by inflammatory reactive lymphocytes, macrophages, and foreign body giant cells

Question 21

HGPRT defiency

Answer 21

Lesch-Nyan syndrome
loss of enzyme in purine salvage pathway
X linked, recessive

Question 22

sudden onset, excruciating joint pain with erythema and warmth in the first metatarosphalangeal joint

Answer 22

acute arthritis of gout

Question 23

juxtaarticular bone erosion and loss of joint space

Answer 23

radiographic sign of chronic tophaceaus gout

caused by crystal deposits

Question 24

migratory arthritis with remissions and relapses

Answer 24

Lyme arthritis

Histological presentation can look like RA

Question 25

Drugs that cause a lupus like syndrome

Answer 25

SHIPP-E

Sulfa drugs, hydralazine, isoniazid, phenytoin, procainamide, etanercept

Question 26

Weakened muscles that respond to prolonged stimulation

Answer 26

Disease: Lampert Eaton
Path: Autoimmune disorder that targets the pre-synaptic Ca channels ; allows some vesicles to be dumped into the neuromuscular junction, but less than normal
Stx: proximal muscle weakness and autonomic issues (dry mouth, impotence)
Misc: associated with small cell lung cancer

Question 27

Epiphyseal tumor with soap bubble lesions

Answer 27

Giant cell tumor
Multinucleated giants cells
Locally aggressive but benign affecting people 20-40 y/o

Question 28

Gardner syndrome

Answer 28

Familial colerectal polyposis
AD mutation in APC (negative regulator of beta catenin)
Associated with colonic polyps, osteomas (benign tumors of the facial bone), and dental abnormalities