Musculoskeletal and Soft Tissue disorders

Question 1

osteogenesis imperfecta (brittle bone)

Answer 1

AD

defect in type I collagen synthesis

blue sclera, deafness

treat with bisphosphonate

Question 2

osteopetrosis (marble bone disease)

Answer 2

AR (severe), AD (less severe)

deficiency in osteoclasts, osteoblasts work fine–> too much bone

pancytopenia, anemia, pathologic fx and compression of CN

Question 3

osteomyelitis in sickle cell

Answer 3

due to salmonella paratyphi

Question 4

pseudomonoas aeroginosa

Answer 4

can cause osteomyelitis from puncture of foot through rubber footwear

Question 5

sequestra

Answer 5

devitalized bone

Question 6

involucrum

Answer 6

reactive bone formation in periosteum

Question 7

draining sinus tracts to the skin surface from osteomyelitis often occur

Answer 7

danger of SCC developing at orifice of sinus tract

Question 8

treat osteomyelitis with

Answer 8

S. aureus= vanco+ceftazidime

S. paratyphi(sickle cell)= ciprofloxacin

Question 9

primary osteoporosis

Answer 9

ideopathis type in children and young adults

postmenopausal women

senile type in men and women

Question 10

secondary osteoporosis

Answer 10

increased cortisol

heparin

hypogonadism (hypopituitarism)

malnutrition

space travel

Question 11

role of estrogen in osteoporosis

Answer 11

it inhibits osteoclasts and increases activity of osteoblasts

Question 12

clinical manifestations of osteoporosis

Answer 12

compression fractures of vertebral bodies (most common)

Colle’s fx of distal radius

Dowager’s hump

Question 13

Dx and Rx of osteoporosis

Answer 13

dual photon absorptiometry

first line agent is bisphosphonate which inhibits bone resorption, then calcitonin

Question 14

senile osteoporosis

Answer 14

decreased ability of osteoblasts to divide and produce osteoid

Question 15

aseptic necrosis

Answer 15

femoral head is most common site (subcapital fx)

corticosteroids most common cause

scaphoid most common wrist bone fx

MRI most sensitive test for early detection of aseptic necrosis

Question 16

Osteochondrosis

Answer 16

aseptic necrosis of ossification centers in children

Legg-Calve-Perthes disease= aseptic necrosis of femoral head ossification center in children 3-10

osteochondritis dissecans is a variant of osteochondrosis limited to articular epiphysis with the distal femur being the most common site

Question 17

osgood-schlatter disease

Answer 17

painful swelling of tibial tuberosity in active boys

presents as permanent knobby-appearing knees

Question 18

fibrous dysplasia

Answer 18

defect is osteoblasts maturation and differentiation

medullary bone is replaced by fibrous tissue with cyst formation

ribs most common site

Albright’s syndrome= polyostotic bone involvement, cafe au lait spots, precocious puberty

Question 19

bone tumors

Answer 19

mets is most common (specifically from breast CA)

multiple myeloma–> osteogenic sarcoma–> chondrosarcoma–> Ewing’s sarcoma

most common benign tumor is osteochondroma

Question 20

MSU crystals and CPP

Answer 20

MSU crystals have negative birefringence–> yellow when parallel to slow ray

CPP have positive birefringence–> blue when parallel to slow ray

Question 21

mucin clot test of synovial fluid

Answer 21

to evaluate joint viscosity

acid added to synovial fluid clots hyalouronic acid

poor clot formation reflects decreased quantaity of HUA-> sign of inflammation

Question 22

morning stiffness of joints, think…

Answer 22

RA, SLE, polymyalgia rheumatica

Question 23

alkaptonuria

Answer 23

AR

deficiency in homogentisic acid oxidase–> accumulation of HGA in intervertebral discs–> OA and other systemic findings

urine turns black when oxidized

Question 24

Heberden’s nodes

Answer 24

DIP joint enlargement with pain

Question 25

Bouchard's nodes

Answer 25

PIP joint enlargement with pain

Question 26

RA pathogenesis

Answer 26

HLA-DR4, trigger is EBV, parvovirus, HHV6,mycoplasma synovial cells express antigen that triggers B cell--\> RF which is IgM Ab aganst Fc receptor of IgG--\> formation immunocomplexes--\> activation of complement--\> pannus formation--\> release of cytokines that destroy articular cartilage--\> ankylosing of joints

Question 27

systemic manifestation of RA

Answer 27

**Lung**= interstitial fibrosis, effusions **blood**= anemia of chronic disease, autoimmune hemolytic anemia, Felty's syndrome=autoimmune neutropenia, splenomegaly) **cervical spine**=subluxation of atlantoaxial joint--\> cord compression along with vertebral artery occlusion **Caplan syndrome**= rheumatoid nodules in lung+ pneumoconiosis **CV**= pericarditis, aortitis, vasculitis **Baker's cys**t= outpouching of posterior joint space in knee Labs= +serum RF, ANA

Question 28

sjorgen syndrome

Answer 28

destruction of minor salivary and lacrimal glands xerophalmia (sand in my eyes), xerostomia (can't chew a cracker) and dental carries, arthritis Labs: +serum ANA, serum RF, anti-SS-A Ab (Ro), anti-SS-B Ab (La) confirm with lip biopsy and must show lymphoid destruction of minor salivary glands Rx=artificial tears, pilocarpine eye drops

Question 29

gout associations

Answer 29

urate nephropathy, renal stones, HTN, artery disease and Pb poisoning

Question 30

Acute gout

Answer 30

must confirm with joint aspiration. Hyperuricemia does not define gout

Question 31

tophus

Answer 31

MSU deposits in soft tissue around joint it destroys subadjacent joints causing erosive arthritis

Question 32

Rx for gout

Answer 32

prevent with low purine diet and low EToH intake treat acute with NSAID or colchicine treat chronic with uricosuric agents for underexcretors like probenecid Allopurinol for over-producers

Question 33

CPP dihydrate induced gout

Answer 33

increased with hemochromatosis, hemosiderosis (due to increased pyrophosphate inhibitor in these 2 disorders) and primary HPTH (due to increased Ca) CPPD OA variant presents with knee involvement--\> chondrocalcinosis which presents as linear deposits of CPP in articular cartilage

Question 34

RF seronegative spondyloarthropathies

Answer 34

-RF, +HLA-B27, male, sacroiliitis, spondylitis

Question 35

Ankylosing spondylitis

Answer 35

bamboo spine over time, aortitis, uveitis with potential for blindness

Question 36

Reiter's syndrome

Answer 36

C. trachomatis, urethritis, conjunctivitis, arthritis Achillis tendon periostitis is diagnostic

Question 37

psoriatic arthritis

Answer 37

sausage-shaped DIP joint in finger or toe pencil-in-cup deformity and extensive nail pitting

Question 38

Late lyme disease

Answer 38

disabling arthritis, bilateral Bell's palsy, myocarditis and pericarditis

Question 39

babesiosis

Answer 39

tick-transmitted hemolytic anemia due to babesia microti treat with atovaquone and azithromycin

Question 40

septic arthritis due to cat or dog bite

Answer 40

by pasteurella multocida most common infection secondary to animal bite see cellulitis, septic arthritis/tendinitis, osteomyelitis, endocarditis, meningitis treat with amoxicillin-calvulanate

Question 41

type I and II muscle fibers

Answer 41

type I= slow-twitching, red, rich in mitochondria, myoglobin and oxidative enzymes, weak ATPase enzymes (long muscles in back) type II= fast-twitching, white, poor in mitochondria, myoglobin and oxidative enzymes, rich in ATPase enzymes (extra-ocular muscles and fine muscles of hands)

Question 42

myotonic dystrophy

Answer 42

AD, most common adult muscular dystrophy CTG trinucleotide repeat inability to relax muscles see sagging face, frontal balding, cataracts, testicular atrophy, cardiac involvement