MSK pathology

Question 1

Connective tissue disease? e.g.?

Answer 1

Autoimmune - inflammatory diseases characterised by presence of auto-antibodies

e.g. rheumatoid arthritis, SLE, scleroderma, dermatomyositis

Question 2

Rheuamatoid arthritis? Marker? Histology?

Answer 2

Inflammation of joints

* Marker = rheumatoid factor, auto ab against Fc IgG

* Histo = lots of lymphocytes + plasma cells in synovial tissue

Question 3

Phases of rheumatoid arthritis?

Answer 3

* Acute phase = inflammatory granulaion tissue (pannus) + hyperplastic synovium

* Chronic phase = fibrosis, deformity

Question 4

SLE dx? Histo?

Answer 4

Dx: ANA+, anti double-stranded DNA, biopsy

Histo = chronic inflammation (lymphocytes + plasma cells)

Question 5

Examples of metabolic MSK diease? (3)

Answer 5

Pagets, osteomalacia, crystal arthropathies

Question 6

Crystal arthropathy? What process involves urate production?

Answer 6

gout, uric acid (end-product of purine synthesis)

* Urate formed in DNA replication as guanine and adenine are purine based

Question 7

Causes of hyperuricaemia? (2)

Answer 7

* Increased production e.g. idiopathic,enzyme defect (Lynch Nyhan syndrome), cancer, psoriasis

* Reduced excretion (most common cause of gout) - drug side effect e.g. thiazide diuretics

Question 8

Ax crystal arthropathy?

Answer 8

Crystals in joints causing inflammatory reaction

Question 9

Pathological findings crystal arthropathy?

Answer 9

* Cytology – joint fluid shows needle-shaped crystals

* Histology – amorphous eosinophilic debris (giant cells), will not see crystals, another form of crystal arthropathy that can look similar = pyrophosphate arthropathy

Question 10

What is another form of crystal arthropathy not involving urate crystals?

Answer 10

Calcium pyrophosphate = pseudogout or chondrocalcinosis

Question 11

Pseudogout s/s?

Answer 11

* Usually asymptomatic (ncidental finding on x-ray)

* Can experience some joint pain

Question 12

Cytology pseudogout?

Answer 12

Crystals are bigger, coarser and more rhomboid in shape (in contrast to urate crystals)

Question 13

Paget’s disease of bone?

Answer 13

* Abnormality of bone turnover

* Increased osteoclastic activity

* Paradoxically – more bone but not normally structured (so often weaker, patients prone to develop fractures with minor trauma)

Question 14

Ax Paget’s disease of bone?

Answer 14

Cause uncertain: possible genetics, viral infection (paramyxovirus, measles, RSV)

Question 15

Pathological finding paget’s disease?

Answer 15

* Osteolytic (less dense)

* Burnt out

Question 16

s/s Paget’s disease of bone? (4)

Secondary malignancy?

Answer 16

* Pain

* Enlargement + abnormal shape

* Increased metabolism (heat)

* AV shunt can lead to HF

Secondary malignancy = osteosarcoma

Question 17

phases of bone fracture?

Answer 17

Initial phase - haematoma, inflammatory cells, cytokine release

1 week - callus, organised haematoma, remodelling bone

2-3 weeks - woven bone deposited perpendicular to cortical bone, cartilage deposition at fracture site

Question 18

Effects of metastatic bone disease? (3)

Answer 18

* Most are osteolytic – loss of bone

* Prostate is osteosclerotic (more dense) – areas of opacity

* Remember myoloma/plasmacytoma - malignant proliferation of plasma cells, causes bony lesions

Question 19

Avascular necrosis? Ax?

Answer 19

bone infarction (often asymptomatic until very end stage)

* Ax: trauma, alcohol, dysbarism, steroid injection, sickle cell, infection

Question 20

Morphology avascular necrosis? Histology?

Answer 20

wedge-shape dinfarct (usually subcortical)

* Histo: creeping substitution (new bone growing over dead bone)

Question 21

Osteoarthritis?

Answer 21

Degenerative bone disease

Question 22

Features of osteoarthritis?

Answer 22

* Cartilage cracks (fibrillation) - reduced joint space

* Subchondral cysts

* Osteocytes - new bone formation at side

* Sclerosis

Question 23

Answer 23

Ganglion cyst - space with myxoid material. Secondary inflammatory changes

Question 24

Answer 24

Giant cell tumour

Question 25

Answer 25

Liposarcoma

Question 26

Answer 26

rhabdomyosarcoma

Question 27

Answer 27

Osteoma

Question 28

Answer 28

Osteoid osteoma

Question 29

Answer 29

Osteosarcoma

Question 30

Answer 30

Ewing's sarcoma - small round blue cell tumours

Question 31

Answer 31

Myositis ossificans

Question 32

Answer 32

...

Question 33

Answer 33

Osteoarthritis

Question 34

Answer 34

Synovial proliferation and inflammation in rheumatoid arthritis

Question 35

Answer 35

Athroscopic appearance of normal joint (top) vs rheumatoid joint

Question 36

Answer 36

...

Question 37

Answer 37

...

Question 38

Answer 38

Osteoarthritis Right hip = normal, left hip = loss of joint space, subchondral cysts Loss of joint space between tibia and calcanea

Question 39

Answer 39

CHRONIC TOPHACEOUS GOUT

Question 40

Answer 40

Calcium pyrophosphate deposition disease

Question 41

Answer 41

CPPD

Question 42

Answer 42

Milwaukee shoulder

Question 43

Answer 43

Synovitis (RA)

Question 44

Answer 44

extensor tenosynovitis

Question 45

Answer 45

Enthesitis as a result on spondylarthropathy

Question 46

Answer 46

Dactylitis (“sausage” digits)- spondylarthropathy

Question 47

Answer 47

...

Question 48

Answer 48

Ankylosing spondylitis

Question 49

Answer 49

Ankylosing sponylitis (SIJ fusion) - LATE SiGN (so like normal SIJ joints on x-ray is not a reassuring sign!)

Question 50

Answer 50

...

Question 51

Answer 51

MRI- bone marrow oedema, enthesitis - EARLY SIGNS of AS!! (White corner of SIJ is marrow oedema)

Question 52

Answer 52

"pencil in cup" - psoriatic arthritis

Question 53

Answer 53

Keratodema Blenorrhagica - reactive arthritis (reiter's syndrome)

Question 54

Answer 54

Circinate balanitis - reiter's syndrome (reactive arthritis)

Question 55

Answer 55

Small vessel vasculitis

Question 56

Saddle nose as a result of GPA

Question 57

Answer 57

Cavitating nodules as a result of GPA

Question 58

Answer 58

ANCA patters (i.e. cANCA (GPA) and pANCA (MPO and EGPA))

Question 59

Answer 59

Gottons sign - dermatomyositis

Question 60

Answer 60

Heliotrope rash - dermatomyositis

Question 61

Answer 61

Shawl sign - dermatomyositis

Question 62

Answer 62

Malar rash + subacute cutaneous lupus associated with SLE

Question 63

Answer 63

Jaccoud's arthritis - deforming arhtropathy (associated with SLE)

Question 64

Answer 64

Livido reticularis - associated with anti-phospholipid syndrome

Question 65

Answer 65

Sclerodactyly - associated with systemic sclerosis

Question 66

Answer 66

Telangectasia - associated with systemic sclerosis

Question 67

Answer 67

Cauda equina syndrome

Question 68

Answer 68

Blounts disease

Question 69

Answer 69

Legg-Calve-)Perthes disease - flattened, sclerotic

Question 70

Answer 70

Slipped upper femoral epiphysis (SUFE)

Question 71

Answer 71

CAM deformity (FAI)

Question 72

Answer 72

Left = normal Right = torn labrum

Question 73

Answer 73

Avascular necrosis \* Left - hanging rope sign \* Middle - MRI showing oedema \* Right - secondary OA

Question 74

Answer 74

ITOH x-ray Normal density on left, on right there is osteopenia (almost transparent)

Question 75

Answer 75

ITOH - MRI Oedema like in AVN