MUSCULOSKELETAL PATHOLOGY - 4

Question 1

What’s the pathogenesis of the condition described?

triad of arthritis, nongonococcal urethritis or cervicitis, and conjunctivitis

Answer 1

autoimmune reaction initiated by prior infection of the genitourinary system (Chlamydia) or the gastrointestinal tract (Shigella, Salmonella, Yersinia, Campylobacter)

Question 2

What is synovial fluid examination from the involved joint likely to show?

Sudden onset of severe pain in the great toe

Localized hyperemia, warmth, Fever

Hyperuricemia

Answer 2

Monosodium urate crystals , both free and within the phagosomes of neutrophils

Question 3

The allele assoc with 50% cases of Rheumatoid arthritis

Answer 3

HLA-DRB1

Question 4

2 antibodies assoc with Rheumatoid arthritis

Answer 4

Rheumatoid factor

Autoantibodies against citrullinated peptides (Anti CCPs)

Question 5

See the attached image

Gout or Pseudogout?

Answer 5

Pseudogout.

Rhomboid; Positively birefringent

Question 6

1. See the attached radiograph. What is it characteristic of?

75 year old

deep achy pain that worsens with use

Synovial fluid - decreased vsicosity, WBC 900 cells/mm³, Neutrophils 20%

2. Enumerate the radiographic findings

Answer 6

1. Osteoarthritis
2. Radiographic features include:
   a. Narrowing of joint space
   b. Subchondral sclerosis
   c. Subchondral boen cyst

Question 7

What roles do TNF and IL-1 play in the pathogenesis of RA?

Answer 7

Stimulate synovial cells to secrete MMPs(matrix metalloproteases) that destroy hyaline cartilage

Question 8

What crystals deposit in Pseudogout?

Answer 8

Calcium pyrophosphate crystals

Question 9

Clinical consequence of cervical spine involvement in rheumatoid arthritis

Answer 9

Subluxation of the atlantoaxial joint

Question 10

What are the radiographic findings assoc with the condition described?

Sudden onset of severe pain in the great toe

Localized hyperemia, warmth, Fever

Hyperuricemia

Answer 10

Juxta-articular erosion with overhanging edges

Question 11

What’s your diagnosis?

14 year old with knee pain

Lasts for 6 weeks

ANA positive

Answer 11

Juvenile idiopathic arthritis

Question 12

Properties of the crystals assoc with this condition , when viewed with a polarizing filter

Sudden onset of severe pain in the great toe

Localized hyperemia, warmth, Fever

Hyperuricemia

Answer 12

needle shaped

negatively birefringent

(yellow when aligned with the compensator filter and blue when perpendicular to the filter)

Question 13

List the seronegative spondyloarthropathies

Answer 13

Psoriatic arthritis

Ankylosing spondylitis

Inflammatory bowel disease associated arthritis

Reactive arthritis

(PAIR)

Question 14

List causes of gout based on mechanism of hyperuricemia

Answer 14

Question 15

form of noninflammatory arthritis characterized by progressive joint destruction due to a primary neurologic disorder

Answer 15

Charcot Joint (Neuropathic joint disease)

Question 16

bony outgrowths at lateral portions of the joints, capped by fibrocartilage and hyalone cartilage

Answer 16

Osteophytes

Question 17

Characteristic radiographic findings in Rheumatoid arthritis

Answer 17

juxta-articular osteopenia with erosions

narrowing of the joint space

Question 18

Describe the morphologic appearance of a rheumatoid nodule

Answer 18

necrotizing granulomas with a central zone of fibrinoid necrosis surrounded by a prominent rim of activated macrophages and numerous lymphocytes and plasma cells

Question 19

List the locations where rheumatoid nodules are commonly found

Answer 19

the extensor surface of the fingers, forearms, and pressure points (Achilles tendon, olecranon process) and in the lungs

Question 20

Microscopic description of calcium pyrophosphate deposition disease (CPPD/Pseudogout) deposits in soft tissues

Answer 20

amorphous basophilic oval blue-purple aggregates.

Question 21

OA/RA?

Describe what you see in the attached image.

Answer 21

RA

Swan neck deformity - hyperextension of the proximal interphalangeal (PIP) joints and hyperflexion of the distal interphalangeal (DIP) joints

Question 22

Examples of enteropathic arthritis

Answer 22

Arthritis assoc with Ulcerative colitis and Crohn disease

Arthritis assoc with Whipple disease

After certain bacterial infections of the gut - Yersinia, Salmonella, Shigella, and Campylobacter

Question 23

Describe the morphologic finding most likley to be seen in osteoarthritis

Answer 23

near-complete loss of articular cartilage. Subchondral cysts

Question 24

Microscopic features of Rheumatoid arthritis

Answer 24

1. Synovial cell hyperplasia
2. Prominent lymphoid follicles composed of §CD4+ helper T cells, B cells, plasma cells, dendritic cells, and macrophages
3. Pannus

Question 25

Most common extra-articular manifestation of ankylosing spondylitis

Answer 25

Anterior uveitis

Question 26

**OA/RA?** **Describe what you see in the attached image.**

Answer 26

RA Boutonniere deformity with marked flexion of the PIP joint and extension of the DIP joint

Question 27

Important clinical consequence of the finding shown in the attached image

Answer 27

Kyphosis**---\>**interferes with chest wall movement **---\>**limitation of chest expansion**---\>**hypoventilation

Question 28

Describe a tophus

Answer 28

large aggregations of urate crystals surrounded by an intense inflammatory reaction of foreign body giant cells

Question 29

2 dermatologic manifestations of Reactive arthritis

Answer 29

Keratoderma blennorhagicum Circinate balanitis

Question 30

**OA /RA?** See the attached photomicrograph

Answer 30

OA The photomicrograph shows Fibrillation of the articular cartilage

Question 31

Describe the gross appearance shown in the attached image.

Answer 31

Eburnated bone (Ivory like bone) characteristic of osteoarthritis

Question 32

**Radiographic findings assoc with the condition described below:** Nail pitting, onycholysis Sausage shaped digits Salmon colored plaques on skin with positive Auspitz sign

Answer 32

erosion of the distal end of the interphalangeal joint with bony proliferation at the proximal end of the affected joint. ## Footnote ***(Pencil in cup deformity)***

Question 33

List few causes for Charcot joints

Answer 33

Diabetes mellitus Leprosy Syringomyelia Tabes dorsalis

Question 34

What is Rheumatoid factor?

Answer 34

IgM (mostly) or IgA autoantibodies that bind to the Fc portion of the patient's own IgG.

Question 35

**OA/RA?** prominent osteophytes at the distal interphalangeal joints

Answer 35

OA | (Heberden's nodes)

Question 36

List the 4 cytokines/substances elaborated in RA

Answer 36

Interferon gamma IL-17 TNF and IL-1 RANK L

Question 37

**OA/RA?** malaise, fatigue, and generalized musculoskeletal pain swollen, warm, painful Particularly stiff when rising in the morning

Answer 37

Rheumatoid arthritis

Question 38

rheumatoid nodules lung + pneumoconiosis

Answer 38

Caplan Syndrome

Question 39

**What is the pathogenesis of the condition described?** 75 year old deep, achy pain in the knees and hips that worsens with use crepitus

Answer 39

degeneration of the articular cartilage and its disordered repair (The condition described is osteoarthritis)

Question 40

Unifying features of seronegative spondyloarthropathies

Answer 40

1. Pathologic changes in the **_ligamentous attachments_** rather than synovium 2. Involvement of **sacroiliac joints**, with or without other joints 3. **Absence of rheumatoid factor** 4. Association with **HLA-B27**

Question 41

Desribe the composition of pannus

Answer 41

a mass of **edematous synovium, inflammatory cells, granulation tissue, and fibroblasts** that grows over the articular cartilage and causes its erosion leading to **bony ankyloses**

Question 42

Renal complications of gout

Answer 42

uric acid nephrolithiasis pyelonephritis