Pathology

Question 1

What are the most important diseases affecting the joints?

Answer 1

The most important diseases affecting the joints are Osteoarthritis, also known as Degenerative Joint disease (DJD) and Rheumatoid Arthritis (RA), which together accounts for more than 90% of all cases in Rheumatologic practice.

Osteoarthritis is much more common than RA

Gout and Pseudogout are important metabolic causes of arthritis.

Question 2

What is the pathogenesis of osteoarthritis; pathology?

Answer 2

unknown but most favor wear and tear of articular cartilage to be the primary site of injury.

Affects primarily weight bearing joints

Pathology- articular cartilage undergoes Fibrillation with the formation of vertical clefts. Cartilage fragments shed into joint and bone exposed.

Question 3

What is Eburnation and what is it related to? Bone cysts? Osteophytes?

Answer 3

Sclerosis (stiffening) of the subchondral plate from pressure on the joint, which is associated with osteoarthritis.

Bone cysts result from bone degeneration under stress and are filled with synovial fluid

Osteophytes are bone spurs around a joint that can cause trauma, swelling, and inflammation of the tendons attached.

Question 4

What are the main pathologic findings of osteoarthritis?

Answer 4

Spine Involvement: most often affects the cervical or lumbar area. DJD involves primarily the intervertebral joint, which causes stiffness of the vertebral column due to osteophyte formation. This process is called lipping.

2. Hand Involvement- The nodular deformities of the DIP joints are called Heberden’s Nodules (the MOST COMMON manifestations of DJD), whereas those of the PIP joints are termed Bouchard’s Nodules.
   3. Feet Involvement- joint disease involving the 1st metatarsophalangeal joint, which leads to the formation of Bunions.

Question 5

RA primarily involves which joints? How does it progress? What cells indicate the disease in the joint?

Answer 5

Synovial joints

Begins as synovitis then inflammatory cells enter the joint cavity. The inflammation stimulates the in-growth of synovial cells. These transform into granulation tissue and form an pannus/cover over the joint cartilage. This pannus is rich in inflammatory cells secreting enzymes and cytokines which destroy cartilage and erode bone. Joint space becomes a collagenous scar causing Ankylosis, and the bone on both sides undergoes osteoporosis.

Cells: lymphocytes, plasma cells, PMNs. Also immunoglobulin

Question 6

What are the most commonly affected joints in RA?

Answer 6

PIP joints of the fingers
MCP joints
and the joints of the wrist.

Question 7

What are some characteristic findings of the wrist and fingers in RA?

Answer 7

Radial deviation of the wrist, fingers opposite direction &

Z-deformity/swan neck deformity (anterior slippage of the proximal phalanges)

Question 8

What are Rheumatoid Nodules?

Answer 8

These are nodules composed of central fibrinoid necrosis surrounded by macrophages and lymphocytes and are found in many places including joints.

Question 9

What is Pigmented Villonodular Synovitis

Answer 9

A benign tumor of the synovial lining.

Characterized by an exuberant proliferation of synovial lining cells with extension into the subsynovial tissue.

It usually involves a single joint, occurring in young adults,

The most common site is the knee (80%), but the hip, ankles, elbow, and tendon sheaths of fingers and toes may also be involved.

Question 10

Where does Pigmented villonodular synovitis arise from and what characteristic signs would you see microscopically?

Answer 10

These tumors arise from the synovium and invade the joint and erode the underlying bone

The synovium develops enlarged folds and nodular tubercule.

Microscopically, the tumor exhibits numerous mononuclear cells, pigmented and brown hemosiderin-laden macrophages, and several multinucleated giant cells.

Question 11

What is nodular tenosynovitis/giant cell tumor of the tendon sheath? picmonics tiny snowmen

Answer 11

variant of pigmented villonodular synovitis.
Involves tendon sheath of hands and feet.
MOST COMMON SOFT TISSUE TUMOR OF THE HANDS
location-middle or index fingers

Question 12

Hyperuricemia is defined as blood levels that exceed what concentration?

What % of the pop have this?

What gender is disproportionately at risk for gout?

Answer 12

7mg/dL Not sufficient for development of gout.

5-15%

95% patients with gout are men

Question 13

Gout is classified as primary or secondary. What types of primary gout are there and which cause is more prevalent?.

Answer 13

Metabolic= hyperproduction uric acid
Renal=underexcretion of uric acid

Most patients are metabolic

Question 14

what is secondary gout related to ?

Answer 14

another disease:
leukemia
hemolysis
obesity
ETOHism

cause hyperproduction or uric acid or undersecretion

Question 15

How long does gout take to develop and where are the common sites of uric acid deposition?

Answer 15

15-30 yrs

joints and periarticular connective tissue

Question 16

What is another name for the tarsometatarsal joint of the big toe as related to gout onset in 90% of cases?

Answer 16

Podagra-foot seizure

Question 17

What is a common cause of uric acid release from the joint capsule?

Answer 17

minor trauma

Question 18

What happens when uric acid enters the joint cavity from the capsule esp in the foot?

Answer 18

feet cold and reduce solubility of the uric acid and promote crystalization in the joint.

This occurs along joint surfaces and peri-articular CT and leads to acute inflammation within the joint.

Crystalization also activates complement and Kallikrein which promotes inflammation and pain

Question 19

Describe acute gout clinically

Answer 19

swollen joint, very painful, hyperuricemia, fever, leukocytosis, tachycardia and exhaustion.

Usually 2-3 day attack

As disease progresses asymptomatic periods become shorter.
(treat high dose NSAIDs acute attacks)

Chronic gout-less inflammation more bone deformities.

Question 20

What do you call subcutaneous deposits of uric acid? Where are you likely to find these?

Answer 20

Tophi- encapsulated and contain urate crystals-NOT PAINFUL. Surrounded by leukocytes

Fingers and toes
ALSO: ears, olecranon, patella, kidneys

Question 21

Describe renal complications with gout

Answer 21

Renal failure 1/4 patients

Uric acid stones 1/5 patients which can cause obstructive nephropathy or pyelonephritis.

Question 22

How is gout diagnosed?

Answer 22

clinical symptoms proof of hyperuricemia, big toe issues, tophi and bone errosion on x-ray

Question 23

What is pseudogout? What’s its etiology?

Answer 23

Calcium Pyrophosphate Dihydrate (CPPD) deposition disease refers to the accumulation of this compound in synovial membranes.

When CPPD deposits in the joint cartilage, it is called Chondrocalcinosis. It can also deposit in ligaments and tendons.

Etiology-trauma, metabolic disorder, idiopathic

Question 24

Characteristics of pseudogout

Answer 24

half of the population > 85 yrs

trauma and the aging process in cartilage promote the CPPD crystals.

excessive levels of inorganic pyrophosphate in the synovial fluid.

Question 25

Common deposit locations for pseudogout? Diseases associated with pseudogout?

Answer 25

CPPD-commonly found in the knees after trauma and after surgical removal of the meniscus.

hyperparathyroidism, hypothyroidism, hemochromatosis, and Wilson’s Disease.

WHHH-

Question 26

Compare and contrast uric acid crystals characteristic of gout with those of pseudogout

Answer 26

Pseudogout- short stubby rhomboid shaped crystals weakly birefringent/refractive using polarized light. Chalky white

Gout-needle shaped crystals easily see with polarized light

Question 27

How do you separate gout from pseudogout through clinical presentation?

Answer 27

psedogout acute attacks last
1 day-4wks (gout 2-3 days)
Metatarsophalangeal joints are spared (not spared in gout), Inflammation and swelling are similar, but gout is primarily hands and feet whereas pseudogout is in many major joints.