E2L18-19 Joints Pathoma

Question 1

What kind of collagen makes up articular cartilage?

Answer 1

Type II

Question 2

What is the fluid in synovial joints and where does it come from?

Answer 2

Synovium lines the joint capsule and secretes synovial fluid which is made of hyaluronic acid

Question 3

How do osteoarthritis and rheumatoid arthritis differ as far as how they feel throughout the day?

Answer 3

Osteoarthritis: stiff morning, worse throughout the day, remember this is a wear and tear problem so using it will make it worse
Rheumatoid: stiff in morning but better throughout the day and with use

Question 4

Patient has pain in hips and knees and DIP/PIP joints that feels worse the more they use them. What would be seen on the articular surfaces of these bones?

Answer 4

These are S/Sx of degenerative joint disease or OA

Articular surfaces would show disrupted cartilage (making joint mice), eburnation (polishing), osteophyte formation

Question 5

Patient has nodules forming on DIP and PIP joints and the joints are painful. What is the disease and what are these nodules called?

Answer 5

Osteoarthritis (OA)
DIP= Heberden Nodes
PIP= Bouchard Nodes

Question 6

What joints tend to be affected by OA?

Answer 6

Hips, Knees, Spine (Load bearing areas)

DIP, PIP

Question 7

Who tends to get rheumatoid arthritis?

Answer 7

Middle-aged women

This corresponds well with the fact that this is an autoimmune disease.

Question 8

What disease is associated with HLA-DR4?

Answer 8

Rheumatoid arthritis

Question 9

What is the hallmark of Rheumatoid arthritis?

Answer 9

Synovitis that leads to the formation of Pannus
Pannus: inflammed granulation tissue that has myofibroblasts which contract and pull the joint together (causing ankylosis) or cause the joint to deviate

Question 10

What joints are involved with rheumatoid arthritis?

Answer 10

PIP, wrists, elbows, ankles, knees

DIP are spared

Question 11

What other Sx might accompany RA besides joint problems?

Answer 11

This is an immune reaction and therefore there are also Sx of fever, malaise, weight loss, myalgia
Also can have vasculitis, Baker’s cyst, pleural effusions, LAD, interstitial lung fibrosis

Question 12

What are rheumatoid nodules?

Answer 12

Found in skin and visceral organs

Area of central necrosis and surrounding epithelioid histiocytes

Question 13

What are the labs assoc. with rheumatoid arthritis?

Answer 13

Most significant finding is rheumatoid factor which is an IgM antibody against the Fc region of IgG
Will also find neutrophils and high protein content in the synovial fluid

Question 14

What are the potential complications of rheumatoid arthritis?

Answer 14

Anemia of chronic disease

Secondary amyloidosis caused by deposition of AA that is derived from SAA which is made in the liver

Question 15

What is a seronegative arthropathy?

Answer 15

A disease of the joint that is negative for rheumatoid factor (IgM against Fc of IgG), involves the axial skeleton, is assoc. with HLA-B27

Question 16

Patient is a young male patient complaining of back pain, x-ray shows “bamboo spine”
What disease does he have and what are the possible complications?

Answer 16

Ankylosing spondyloarthritis
Involves the sacroiliac joints and spine
Can lead to a fusing of the spine (ankylosis) which is called bamboo spine
Complications: Uveitis, Aortitis

Question 17

Young male recently infected with Chlamydia or had a GI infection and now is experiencing joint pain.
What syndrome does he have and what other Sx classically accompany it?

Answer 17

Reiter’s syndrome classically follows GI or Chlamydia infection in a young male
Triad of Sx: Arthritis, Urethritis, Conjunctivitis
(Can’t see, pee, or climb a tree)

Question 18

Patient has history of scaly rash that is incurable and develops pain in the joints.
What disease, joints, and classic description?

Answer 18

Psoriasis can cause Psoriatic Arthritis in 10% of cases
Typically involves axial and peripheral joints including the DIP of hands and toes leading to the classical description of “sausage” fingers/toes

Question 19

Young adult recently Dx with N. gonorrhoeae infection develops swollen, red and painful knee.
What is the disease and what is the 2nd most common causative agent?

Answer 19

Infectious arthritis: involved one joint, usually the knee, warm, limited ROM, fever, increased WBC’s and ESR

Other agent is S. aureus which usually infects older kids and adults

Question 20

Patient diagnosed with gout, what would be found in a sample of the synovial fluid?

Answer 20

Monosodium Urate Crystals

Needle-shaped, negative birefringence under polarized light (demonstrated by crystals that are lying down being yellow)

Question 21

Describe formation of uric acid

Answer 21

Uric acid is the breakdown product of purines
Purines become AMP, GMP
AMP becomes hypoxanthine
GMP becomes guanine
HX and G become xanthine
Xanthine becomes UA by enzyme Xanthine Oxidase

Question 22

What are the causes of gout?

Answer 22

Hyperuricemia from either increased production of uric acid or decreased clearance by the kidney

1) Leukemia & Myeloproliferative: high cell turnover causes increased production of UA
2) Lesch-Nyhan syn.: x-linked deficiency of HGPRT which is an enzyme that salvages Purine breakdown products before they become UA, patient also mentally retarded
3) Renal insufficiency

Question 23

What is podagra?

Answer 23

fancy name for the inflamed great toe seen in gout

Question 24

What makes gout worse?

Answer 24

Ingestion of alcohol or meat

Question 25

What are some signs of chronic gout?

Answer 25

Formation of Tophi which are uric acid aggregates that deposit in soft tissues and joints, they are white and chalky and surrounded by fibrosis
Renal failure is also a result of chronic gout

Question 26

What is pseudogout?

Answer 26

Gout Sx, but deposit of calcium pyrophosphate dihydrate instead of monosodium urate
These crystals are rhomboid instead of needles and they are weakly positive birefringent under polarized light