Rheumatology: Rheumatoid arthritis

Question 1

In what demographic is rheumatoid arthritis more common?

Answer 1

Females (2.5:1 female to male ratio)

Question 2

What components of blood tests are expected to be present and/or elevated in RA?

Answer 2

RF factor is present in 85% of cases.
The ESR and CRP may also be elevated
Anti-CPP antibodies are more indicative of RA than RF is (there’s a notecard on this later)

Question 3

T or F?
The joint distribution of RA is usually symmetrical and is common in the small joints of hands and feet, spares the PIP, and also commonly involves the lumbar spine.

Answer 3

False.
It’s true that it’s usually symmetrical, as well as common in hands and feet, but it spares the DIP, not the PIP, and commonly involves the cervical spine, not the lumbar spine.

Question 4

What would be the expected synovial joint fluid findings in RA?

Answer 4

Inflammatory (>2000 WBC/mm) with predominant neutrophils as well as low complement and glucose.

Question 5

What are some of the extra-articular symptoms of RA?

Answer 5

Rheumatoid nodules are present in 20-25% of people with RA. Organs such as the eyes, lungs, pericardium or peripheral nerves may be affected in about 20% of people with RA

Question 6

What genetic factor is associated with RA?

Answer 6

MHC Class II HLA-DR4 (in about 50% of people with RA), but only 30% concordance in monozygotic twins.

Question 7

What is the primary source of inflammation in RA?

Answer 7

The synovium

Question 8

Generally describe the pathology of RA

Answer 8

It starts with mild inflammation of synovium along with microvascular injury. Eventually you see an increase in the synovial lining cells as well as increased fibroblast proliferation. The synovial fluid will show a prevalence of polymorphonuclear neutrophils

Question 9

What short sequence in the DRB1 gene is important in RA?

Answer 9

The QKRAA sequence

Question 10

What are the two separate compartments of pathogenesis in RA and which is more important in the disease state?

Answer 10

1) The fluid phase
2) The synovial tissue-in the form of pannus, this is responsible for joint tissue destruction.
* The synovial tissue events are more important in the disease process

Question 11

Which pro-inflammatory cytokines are released by macrophages in the synovial tissue?

Answer 11

IL-1, TNF-alpha, IL-6, IL-17

Question 12

T or F?

Mast cells and osteoclasts are involved in disease processes in the synovial tissue in RA

Answer 12

True

Question 13

Which anti-inflammatory cytokines and substances are released by macrophages in the synovial tissue?

Answer 13

IL-1RA (a receptor agonist to IL-1)
Soluble receptors for IL-1 and TNF-alpha.
The net result depends on how much pro-inflammatory vs. anti-inflammatory is present in the synovium.

Question 14

What is the primary lymphocyte involved in RA? What is the minor one?

Answer 14

CD4+ memory T cells.

Th17 cells also play a minor role

Question 15

How are RF and IgG related?

Answer 15

RF interacts with the Fc portion of IgG, form an immune complex which may lead to complement activation.

Question 16

What are the 3 most common treatment options for RA?

Answer 16

1) NSAIDS
2) DMARDS
3) Biologics in conjunction w/ the 2 above
* physical therapy is also recommended, and in extreme cases surgery may be performed

Question 17

What is bony resorption associated with in RA?

Answer 17

It’s associated with the RANK receptor on osteoclast precursors. IL-17 is involved in activating this receptor and stimulating osteoclast activity in RA.

Question 18

RF is not very specific for RA. What is?

Answer 18

Anti-CCP antibodies (Anti-cyclic citrullinated peptide antibodies). This isn’t the etiology of RA but they do play a role in propagating the disease.