MSK pathoma

Question 1

Achondroplasia

whats it due to?

whats the mutation?

Answer 1

Short stature (midgets)

failure of longitudinal bone growth (endochondrial ossification)

-FGFR3: inhibits chondrocyte proliferation

Question 2

Osteogenesis imperfecta

whats the defect?

other symptoms?

Answer 2

Brittle bone disease

AD defect in Type 1 collagen synth.

-blue sclera/hearing loss

Question 3

why do you get blue sclera?

Answer 3

exposure of the chorodial veins

Question 4

Osteopetrosis

where is the mutation?

what other problems can this lead to?

Answer 4

defect in bone reabsorption

fuck up of the osteoclasts

• mutation in the Carbonic anhydrase 2 (can no longer make acidic environment to reasbsorb bone
• pancytopenia due to thickening of bone replacing medulla

Question 5

Osteomalacia/rickets

whats it due to?

Answer 5

defect in osteoid mineralization

due to a deficency of Vit. D

Question 6

ricketts

who gets it? why? presentation?

Answer 6

children, due to deficiency in Vit. D

bowed legs, richitic rosary, pigeon chest, soft skull

Question 7

Osteoporosis

Answer 7

Trabecular (spongy) bone loss

porous bone w/ incr. risk of fracture

Question 8

how do bisphosphonates work?

Answer 8

they inhibit osteoclast activity

Question 9

Pagets dz of bone

what does the bone look like?

how do you treat it?

what are some complications?

Answer 9

improper balance of osteoclast and osteoblast function

results in thick bone that fractures easily

calcitonin/bisphosphonates

- Incr. blood flow due to AV shunts. leads to High output cardiac failure

-osteosarcoma

Question 10

Osteochondroma

Answer 10

most common benign bone tumor

grows off the metapiphysis growth plate (laterally)

has a cartiligenous cap

Question 11

OsteoSarcoma

whats the age distribution?

predisposing factors?

xray finding?

Answer 11

malignant prolliferation of osteoblast (inside the long bones)

• bimodal: teenagers and elderly get it
• Familial retinoblastoma, Pagets Dz of bone, radiation
• Codman’s triangle (elevation of periosteum)

Question 12

Giant Cell Bone tumor

where does it arise? whats it look like on xray

Answer 12

Epiphysis!

-Soap bubble on xray

Question 13

Ewings sarcoma

where are they derived from

whats it look like on xray?

whats the translocation?

Answer 13

malignant tumor of diaphysis of long bones under 15.

• neuroectoderm.
• onion skinning of the periosteum
• small blue cells

t(11;22)

Question 14

Chondroma

where does it arise

Answer 14

proliferation of Cartiledge

usually in the medulla of small bones (hands/feet)

Question 15

Chondrosarcoma

Answer 15

malignant prolif of cartilage

arises in medulla of pelvis or central skeleton

Question 16

Metastatic Bone tumors

what do they look like

Answer 16

Punched out osteolytic lesions

Question 17

whats Articular cartilage made out of

Answer 17

Type 2 collagen (Cartwolage)

Question 18

Rheumatoid Arthritis

whats the daily pattern of pain?

which joints are hit?

Answer 18

HLA-DR4

Autoimmune dz: inflammation of the synovium that leads to formation of a pannus

Destruction of the cartilage and anklosying (fusion) of the joint

morning stiffness that improves throughout the day

PIP (sparing dip)

Question 19

whats rheumatoid factor?

Answer 19

IgM antibody AGAINST the Fc portion of IgG

(Anti-IgG antibody)

Question 20

Characteristics of Seronegative Spondyloarhtopathies

Answer 20

No Rheumatoid factor

Axial skeleton involvement

HLA-B27

Question 21

Ankylosing Spondylitis

Answer 21

Involvment ont eh spine and sacroiliac joints

(joint Fusion) Bamboo spine

uveitis, and aortic regurg

Question 22

Reactive Arthritis

Answer 22

Cant see, cant pee, cant climb a tree

Conjunctivitis, Urethritis, Arthritis

Question 23

Psoriatic Arthritis

Answer 23

DIP of hands and feet usually involved.

dactylitis aka sausage fingers

“pencil in cup” deformity

Question 24

Gout

Answer 24

increased uric acid in blood (from purine metabolism)

deposition of monosodium urate crystals

needle shaped/ negative (-)biregringent under light

Crystals deposited in Big toe (podagra)

Question 25

Psuedogout

Answer 25

Deposition of Calcium pyrophosphate

Rhomboid crystals

postive (+) biferingent under light

Question 26

Dermatomyositis

clinical features

whats the lab findings?

what type of inflamaiton?

Answer 26

Inflam disorder of the skin and muscle

-bilateral Proximal muscle weakness

(cant comb hair/ climb stairs)

• rash of upper eyelids and malar rash (not lupus)
• red papules on elbows and kuckles (Grotton)
• Incr. Creatine Kinase (damaged muscle), +ANA,

+anti-Jo-1

-Perimysial Inflamation

Question 27

Polymyositis

what kind of inflam?

Answer 27

Infalammatory Disorder of the muscle (skin is not involved)

-endomysial inflamn(CD 8 t cells)

Question 28

X-linked Muscular dystrophy

whats the deletion

whats clinical presentation

whats the common cause of death?

Answer 28

Degenerative disorder characterized by muscle wasting

-replacement of skeletal muscle with fat (psuedohypertophy of calf muscle)

Deletion of Dystrophin

Gower sign

-Dilated cardiomyopathy

Question 29

whats the role of dystrophin

Answer 29

it helps anchor muscle fibers. it connects the cytoskeleton (actin) to the transmembrane proteins. which are connected to the Extracellular matrix (ECM)

Question 30

Becker muscular dystrophy

Answer 30

Mutation of Dystrophin

milder form of Duchennes

Question 31

Myasthenia gravis

clinical signs?

whats a huge thing its associated with?

Answer 31

Autoantibodies to Post synaptic Ach receptors

Gets worse with muscle use

Ach E inhibitors work well

• Ptosis, diplopia, weakness
• thymic hyperplasia/ thymoma

Question 32

Lambert Eaton

daily pattern

Answer 32

Antibodies against Presynaptic Calcium channels

(prevents/decreases Ach Release into synapse)

muscles improve w/ use

Question 33

What are they symptoms of CREST

Answer 33

Calcinosis, Raynauds, Esophogeal dysmotility, Slceryldactyl, talengectias

esophageal dysmo is caused by Fibrous replacement of the esophagus which can lead to gerd