Pathoma: Joint

Question 1

Synovial joints usually have _____________ over the end of the bone.

Answer 1

articular cartilage (type II collagen)

Question 2

The synovium along the internal edge of the joint capsule secretes ________________ to lubricate the joints.

Answer 2

hyaluronic acid

Question 3

Degenerative joint disease usually presents as stiffness in the morning that _____________ throughout the day.

Answer 3

worsens

Question 4

List the three classic histologic pathologies that present with degenerative joint disease.

Answer 4

• Destruction of the articular cartilage
• Eburnation (aka polishing) of the subchondral bone
• Osteophyte formation

Question 5

Osteophytes classically present in the ______________.

Answer 5

DIPs and PIPs

Question 6

Rheumatoid arthritis is classically associated with what HLA subtype?

Answer 6

HLA-DR4

Question 7

The hallmark histologic pathology of rheumatoid arthritis is ______________.

Answer 7

synovitis that leads to destruction of the underlying

Question 8

A pannus is a thick ___________ tissue layer.

Answer 8

granulation

Question 9

What cells mediate ankylosis?

Answer 9

Ankylosis is fusion of joints. This is mediated by myofibroblasts in granulation tissue that contract and pull the joint together.

Note: if this fusion happens asymmetrically, it can produce distortion of the joint (such as a finger deviating off to one side).

Question 10

The classic symptom of rheumatoid arthritis is joint stiffness that ____________ throughout the day.

Answer 10

improves

This occurs because of movement pushing the inflammatory infiltrate out.

Question 11

List some of the extra-articular manifestations of rheumatoid arthritis.

Answer 11

• Rheumatoid nodules (necrotic granulomas in any tissue of the body)
• Vasculitis
• Pleural effusions
• Pulmonary fibrosis
• Baker cyst (inflammation of the knee bursa on the posterior aspect of the leg)

Question 12

List the serum findings of rheumatoid arthritis.

Answer 12

• Rheumatoid factor (anti-IgG IgM) –very sensitive, not specific
• Anti-citrullinated peptide antibodies –very specific, not sensitive

Sattar didn’t mention the second one, but there is a UWorld question about it so it’s probably worth knowing.

Question 13

Joint aspiration will show _____________ in rheumatoid arthritis.

Answer 13

neutrophils and protein… no bacteria

Question 14

What are some long-term complications of rheumatoid arthritis?

Answer 14

• Anemia of chronic disease (from the chronic inflammatory state inducing hepcidin and subsequent iron-deficiency anemia)
• Amyloidosis: RA induces serum amyloid A –another inflammatory marker –that gets converted to amyloid in the periphery and can accumulate in deposits

Question 15

The spondylopathies notably lack what serum marker?

Answer 15

Rheumatoid factor

This is why ankylosing spondylitis is called a “seronegative” arthropathy.

Question 16

What two extra-articular manifestations are common in ankylosing spondylitis?

Answer 16

• Uveitis

* Aortitis (increased risk of aortic aneurysm and aortic insufficiency)

Question 17

Give a brief rundown on reactive arthritis.

Answer 17

• Associated with HLA-B27
• Usually presents one to two weeks after a GI infection (Campylobacter) or Chlamydia trochomatis infection
• Signs include uveitis, urethritis, and arthritis (“Can’t see. Can’t pee. Can’t climb a tree.”)

Question 18

What joints are affected in psoriatic arthritis?

Answer 18

• Axial
• Appendicular
• Fingers

Basically everything. The DIP is common and presents with a swollen, “sausage” finger.

Question 19

Which two organisms are commonly implicated in septic arthritis?

Answer 19

• N. gonorrhoeae (young adults)

* S. aureus (children, older adults, and IV drug users)

Question 20

What are the signs and symptoms of infectious arthritis?

Answer 20

• Single joint affected
• Limited range of motion
• Fever
• Leukocytosis

Question 21

GMP gets broken down to guanine and AMP gets broken down to ___________.

Answer 21

hypoxanthine

Question 22

The most common cause of gout is ____________.

Answer 22

idiopathic increase in uric acid

Question 23

Lesch-Nyhan disorder results from a defect in the _____________ pathway.

Answer 23

purine salvage

Question 24

List three causes of secondary gout.

Answer 24

• Leukemia and other myeloproliferative disorders (because of increased turnover of cells and consequent increased purine degradation)
• Lesch-Nyhan (inability to salvage purines leads to increased conversion to xanthine)
• Chronic renal failure (inability to excrete uric acid)

Question 25

Why do alcohol and meat induce gout attacks?

Answer 25

*  Meat intake: increased RNA and DNA from food leads to increased uric acid *  Alcohol competes with uric acid for secretion in the kidney, so alcohol leads to increased uric acid

Question 26

Tophi are described as __________________________.

Answer 26

"white chalky deposits"

Question 27

Pseudogout is made from ___________ crystals.

Answer 27

calcium pyrophosphate