MUSCULOSKELETAL PATHOLOGY - 4 Flashcards
What’s the pathogenesis of the condition described?
triad of arthritis, nongonococcal urethritis or cervicitis, and conjunctivitis
autoimmune reaction initiated by prior infection of the genitourinary system (Chlamydia) or the gastrointestinal tract (Shigella, Salmonella, Yersinia, Campylobacter)
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

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

The allele assoc with 50% cases of Rheumatoid arthritis
HLA-DRB1
2 antibodies assoc with Rheumatoid arthritis
Rheumatoid factor
Autoantibodies against citrullinated peptides (Anti CCPs)
See the attached image
Gout or Pseudogout?

Pseudogout.
Rhomboid; Positively birefringent
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

- Osteoarthritis
-
Radiographic features include:
a. Narrowing of joint space
b. Subchondral sclerosis
c. Subchondral boen cyst
What roles do TNF and IL-1 play in the pathogenesis of RA?
Stimulate synovial cells to secrete MMPs(matrix metalloproteases) that destroy hyaline cartilage
What crystals deposit in Pseudogout?
Calcium pyrophosphate crystals
Clinical consequence of cervical spine involvement in rheumatoid arthritis
Subluxation of the atlantoaxial joint
What are the radiographic findings assoc with the condition described?
Sudden onset of severe pain in the great toe
Localized hyperemia, warmth, Fever
Hyperuricemia
Juxta-articular erosion with overhanging edges

What’s your diagnosis?
14 year old with knee pain
Lasts for 6 weeks
ANA positive
Juvenile idiopathic arthritis
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
needle shaped
negatively birefringent
(yellow when aligned with the compensator filter and blue when perpendicular to the filter)

List the seronegative spondyloarthropathies
Psoriatic arthritis
Ankylosing spondylitis
Inflammatory bowel disease associated arthritis
Reactive arthritis
(PAIR)
List causes of gout based on mechanism of hyperuricemia

form of noninflammatory arthritis characterized by progressive joint destruction due to a primary neurologic disorder
Charcot Joint (Neuropathic joint disease)
bony outgrowths at lateral portions of the joints, capped by fibrocartilage and hyalone cartilage
Osteophytes
Characteristic radiographic findings in Rheumatoid arthritis
juxta-articular osteopenia with erosions
narrowing of the joint space
Describe the morphologic appearance of a rheumatoid nodule
necrotizing granulomas with a central zone of fibrinoid necrosis surrounded by a prominent rim of activated macrophages and numerous lymphocytes and plasma cells

List the locations where rheumatoid nodules are commonly found
the extensor surface of the fingers, forearms, and pressure points (Achilles tendon, olecranon process) and in the lungs
Microscopic description of calcium pyrophosphate deposition disease (CPPD/Pseudogout) deposits in soft tissues
amorphous basophilic oval blue-purple aggregates.

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

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

Examples of enteropathic arthritis
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
Describe the morphologic finding most likley to be seen in osteoarthritis

near-complete loss of articular cartilage. Subchondral cysts

Microscopic features of Rheumatoid arthritis
- Synovial cell hyperplasia
- Prominent lymphoid follicles composed of §CD4+ helper T cells, B cells, plasma cells, dendritic cells, and macrophages
- Pannus

Most common extra-articular manifestation of ankylosing spondylitis
Anterior uveitis
OA/RA?
Describe what you see in the attached image.

RA
Boutonniere deformity with marked flexion of the PIP joint and extension of the DIP joint
Important clinical consequence of the finding shown in the attached image

Kyphosis—>interferes with chest wall movement —>limitation of chest expansion—>hypoventilation
Describe a tophus
large aggregations of urate crystals surrounded by an intense inflammatory reaction of foreign body giant cells

2 dermatologic manifestations of Reactive arthritis
Keratoderma blennorhagicum
Circinate balanitis

OA /RA?
See the attached photomicrograph

OA
The photomicrograph shows Fibrillation of the articular cartilage
Describe the gross appearance shown in the attached image.

Eburnated bone (Ivory like bone) characteristic of osteoarthritis
Radiographic findings assoc with the condition described below:
Nail pitting, onycholysis
Sausage shaped digits
Salmon colored plaques on skin with positive Auspitz sign
erosion of the distal end of the interphalangeal joint with bony proliferation at the proximal end of the affected joint.

(Pencil in cup deformity)
List few causes for Charcot joints
Diabetes mellitus
Leprosy
Syringomyelia
Tabes dorsalis
What is Rheumatoid factor?
IgM (mostly) or IgA autoantibodies that bind to the Fc portion of the patient’s own IgG.
OA/RA?
prominent osteophytes at the distal interphalangeal joints

OA
(Heberden’s nodes)
List the 4 cytokines/substances elaborated in RA
Interferon gamma
IL-17
TNF and IL-1
RANK L
OA/RA?
malaise, fatigue, and generalized musculoskeletal pain
swollen, warm, painful
Particularly stiff when rising in the morning
Rheumatoid arthritis
rheumatoid nodules lung + pneumoconiosis
Caplan Syndrome
What is the pathogenesis of the condition described?
75 year old
deep, achy pain in the knees and hips that worsens with use
crepitus
degeneration of the articular cartilage and its disordered repair
(The condition described is osteoarthritis)
Unifying features of seronegative spondyloarthropathies
- Pathologic changes in the ligamentous attachments rather than synovium
- Involvement of sacroiliac joints, with or without other joints
- Absence of rheumatoid factor
- Association with HLA-B27
Desribe the composition of pannus
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
Renal complications of gout
uric acid nephrolithiasis
pyelonephritis