Joint Pathology

Question 1

Normal Joint

Architecture

Answer 1

Components of Cartilage:

• Chondrocytes
• Water
• Collagen
• Proteoglycans

Question 2

Osteoarthritis

Overview

Answer 2

“Degenerative Joint Disease”

• See deterioration and loss of articular cartilage
• Takes place over the course of many years
• Affects weight bearing joints
• Pathogenesis: biomechanical and biochemical theories
• Clinical course: insidious with progressive pain and disability
  
  • No constitutional signs, differential from RA
  • No specific preventative or maintenance therapy (as of now)

Question 3

Osteoarthritis

Morphology

Answer 3

• Loss of cartilage
• Exposure and eburnation of subchondral bone
• ± Subchondral cyst formation
• Osteophytes aka “Joint mice”
• Heberden’s nodes

Question 4

Osteoarthritis

Symptoms

Answer 4

• Joint pain associated with movement
• Limitation of motion
• Stiffness after periods of rest
• Referred pain

Question 5

Osteoarthritis

Clinical Manifestations

Answer 5

• Changes in shape of the joint
• Malalignment
• Limitation of motion
• Instability
• Spasm or atrophy of surrounding muscles
• Fine crepitation on joint motion

Question 6

Rheumatoid Arthritis (RA)

Overview

Answer 6

Systemic, relapsing, chronic destructive synovitis

• Etiology unknown, course unpredictable
• Women affected 3x more than men
• Diagnosis by physical exam and lab studies
• Shortened life expectancy, often due to complications of therapy
• Variants: juvenile RA, Felty’s syndrome, ankylosing spondylitis

Question 7

Rheumatoid Arthritis (RA)

Morphology

Answer 7

• Irregular, hypertrophied synovial membrane
  
  • ‘Villiform’ structure
  • Lymphoid inflammation
    
    • Can contain lymphoid follicles
• Chronic inflammation
• Pannus formation (scarring @ edges of joint space)
• Fibrous and bony ankylosis (bone fusion)

Question 8

Felty’s Syndrome

Answer 8

Constellation of sx:

• Rheumatoid arthritis
• Splenomegaly
• Neutropenia

Question 9

Rheumatoid Arthritis (RA)

Pathogenesis

Answer 9

Believed to be autoimmune disease.

(Theory that process can be initiated by a virus)

Question 10

Rheumatoid Arthritis (RA)

Course

Answer 10

Disease can follow various courses:

• Single episode followed by sustained remission
• Initial episode followed by complete remissions and exacerbations
• Acute illness with intercurrent milder disease activity
• Sustained disease activity

Question 11

Rheumatoid Arthritis (RA)

Intra-articular Manifestation

Answer 11

• Joints inflamed
• Progressive stiffness and ankylosis (fusion of the bones)
• Hand becomes claw-like with ulnar deviation

Question 12

Rheumatoid Arthritis (RA)

Extra-articular Manifestations

Answer 12

• Subcutaneous and subperiosteal nodules
  
  • Fibrin core surrounded by palisading histiocytes
• Constitutional sx (malaise, fatigue, diffuse pain, fever)
• Organs and Tissue involvement:
  
  • Pulmonary
  • Cardiac
  • Ocular
  • Neurological
  • Vascular
• RA pts often have Sjogren’s syndrome

Question 13

Rheumatoid Arthritis (RA)

Pulmonary Involvement

Answer 13

• Pleuritis
• Pleural effusion
• Pulmonary fibrosis
• Parenchymal rheumatoid nodules

Question 14

Caplan’s Syndrome

Answer 14

Peumoconiosis and rheumatoid arthritis

Question 15

Rheumatoid Arthritis (RA)

Vascular Involvement

Answer 15

• Digital Arteritis
  
  • Focal ischemic areas with pitting
  • Digital gangrene
• Raynaud’s phenomenon
• Leg ulcers
• Necrotizing systemic vasculitis
  
  • Mesenteric
  • Renal
  • Coronary

Question 16

Suppurative (Septic) Arthritis

Answer 16

• Destructive non-specific acute inflammatory reaction
• Hematogenous or direct spread to single large joints
• See Gonococci, Staph, Strep, Gram negative bacilli

Question 17

Tuberculous Arthritis

Answer 17

• Caseating granulomas similar to those seen in TB elsewhere
• Causes ankylosis, skin sinuses, or damage to spinal cord
• Insidious chronic disease in children
• Affects the spine, hip, etc
• Early diagnosis essential

Question 18

Lyme Disease

Answer 18

• Spirochetal infection
• Transmitted by deer ticks
• Progression:
  
  • First stage: skin lesion
  • Second stage: cardiac and nervous systems affected
  • Third stage: chronic disabling arthritis in 10% of cases
• Serologic diagnosis
• Abx therapy essential

Question 19

Gout

Overview

Answer 19

• Hyperuricemia
• Recurrent acute arthritis following asymptomatic intervals
• Deposition of tophi
• Renal impairment may occur
• Few with hyperuricemia develop gout
• Asymptomatic hyperuricemia does not require treatment
• 95% of cases in adult males, usually in great toe

Question 20

Gout

Pathogenesis

Answer 20

Pathogenesis relates to production and excretion of uric acid:

• Primary Gout
  
  • Due to overproduction of uric acid
  • Cause of overproduction generally unknown
• Secondary Gout
  
  • Can be due to reduced excretion
    
    • Glomerular or tubular defect or due to certain drugs
    • Lead poisoning of the kidneys in Victorian England
  • Can be due to increased production
    
    • Chemotherapy

Question 21

Gout

Morphology

Answer 21

• Acute arthritis due to precipitation of urates in joint fluid
  
  • Birefringent crystals phagocytized by neutrophils and MΦ ⇒ release of harmful products
  • Attack ends when crystals go back into solution
• Chronic arthritis is due to progressive precipitation of urates into synovium ⇒ destruction and ankylosis of joint
• Tophus: inflammatory mass of urates, pathognomonic
• Renal involvement by gout can include stones or urate deposits

Question 22

Gout

Clinical Phases

Answer 22

1. Asymptomatic hyperuricemia
2. Recurrent acute gouty arthritis
3. Chronic gouty arthritis

Diagnosis important because treatment is available

Question 23

Pseudogout

Answer 23

“Calcium pyrophosphate crystal deposition disease”

• Get precipitation of crystals in menisci and intervertebral discs
• Deposits can enlarge and rupture into the joint
• Produces inflammation
• Often asymptomatic

Question 24

Seronegative Spondyloarthropathies

Answer 24

• Ankylosing spondylitis
• Reactive arthritis
• Enteropathic arthritis
• Psoriatic arthritis

Question 25

Ankylosing Spondylitis

Answer 25

"Bechterew disease" * **Rare type of arthritis that causes pain and stiffness in the spine** * Most often affects sacroiliac joints * Lifelong condition * Seen in adolescent males * 90% have HLA B-27

Question 26

Reactive Arthritis

Answer 26

"Reiter syndrome" * _Triad of:_ * **Arthritis** * **Non-gonococcal urethritis or cervicitis** * **Conjunctivitis** * 80% are HLA B-27 * Autoimmune reaction to GI or GU infection

Question 27

Enteropathic Arthritis

Answer 27

* Induced by GI infection with Yersinia, Salmonella, Shigella, Campylobacter * Often HLA B-27

Question 28

Psoriatic Arthritis

Answer 28

* Form of arthritis that affects some pts with psoriasis * **Type of inflammatory arthritis** * **Affects DIP joints of hands and feet and large joints** * Symptoms include joint pain, stiffness, and swelling * Tx includes antiinflammatories, steroid injections, or joint replacement surgery

Question 29

Ganglion Cyst

Answer 29

**Fluid-filled sac arising from an adjacent joint capsule or tendon sheath** Most common mass that develops in the hand

Question 30

Nodular Tenosynovitis

Answer 30

* Common * More frequent in women * **Usually seen on hands and feet, more often proximally and on flexor surfaces** * May erode contiguous bone by pressure * _Pathogenesis_: Controversial, some view as reactive, others see it as neoplastic (but usually benign) * _Gross appearance:_ * **Single mass, usually 1–3cm diameter** * Fairly well-defined capsule * May be somewhat lobulated * Varies in color from whitish gray to yellowish brown * _Microscopic_: **dense, cellular tissue**