Osteoarthritis and Infectious Arthritis

Question 1

Pathology of Osteoarthritis

Answer 1

Multiple causes (internal derangement, infections, trauma, etc); Most commonly from repetitive joint insults. 
Repeat insults release of proteolytic and collagen-degrading enzymes. Destruction of collagen and proteoglycans increased bone formation (osteophytes). 
OA results from inadequate repair of cartilage-bone injury

Question 2

Natural History of Osteoarthritis

Answer 2

Etiopathogenesis of OA: Mechanical insults to joint; OA is a manifestation of attempts to heal the joint. OA process often results in a stable, painless joint

Question 3

Clinical Features of Osteoarthritis

Answer 3

Pain in involved joints that is worse with activity, improving with rest. Morning stiffness (if present)( < 30 min). Stiffness after periods of immobility (gelling). Joint enlargement and instability with a limitation of joint mobility. Periarticular muscle atrophy and crepitus.

Pain at rest or during the night indicates severe disease.

Question 4

Primary and Secondary OA Problems

Answer 4

Primary Problems: Synovium, Bone, Ligaments, Periarticular muscles, Meniscus and Nerves. There is no Common Pathophysiological Pathway, BUT there is a final common end stage.

Secondary Problems: Synovial inflammation caused by joint particles.

Question 5

Treatment of Osteoarthritis

Answer 5

General principles of OA treatment:

1. Analgesic and Anti-Hyperalgesic Rx
2. Physical /Occupational Therapy (Maintaining and/or improving function)
3. Acetaminophen, NSAIDs, Opioids
4. Duloxetine (Cymbalta)
5. Weight Reduction and limiting physical disability

Alternative and Experimental Therapies: Viscosupplementation, Synvisc, Euflexxa, Supartz, Surgery, Knee osteotomy, Joint replacement (arthroplasty)

Question 6

Diagnosing Osteoarthritis

Answer 6

The diagnosis of OA almost always can be made by history and PE and confirmed by plain radiography.
ESR is typically WNL
RF is negative
ANA is negative
Synovial  fluid
-- high viscosity
--color is clear and yellow
--WBC< 1000-2000/mm3
--no crystals and negative cultures

Question 7

Lab/Tests for Osteoarthritis

Answer 7

Clinical diagnosis of OA can be confirmed with radiographs of the affected joints.
Bony proliferation (osteophyte formation or spurs)
Asymmetric joint space narrowing (decrease in interbone distance)
Subchondral bone sclerosis
Subchondral cysts

CT or MRI, US

Question 8

Distribution of Non-Gonococcal Arthritis

Answer 8

Knee-

Question 9

Causes of Bacterial/Infectious Arthritis

Answer 9

S. Aureus, Gonococcal, and Non-Gonococcal

Question 10

Predisposition of Infectious Arthritis

Answer 10

Non-Gonococcal- kids, elderly and immunosuppressed.

Question 11

Clinical Features of Infectious GC Arthritis

Answer 11

Migratory polyarthralgias, Tenosynovitis, Dermatitis and Purulent arthritis all with No GU Symptoms.

Question 12

Clinical Features of Infectious Non-GC Arthritis

Answer 12

(Patient is either very young, elderly or immune-compromised); Usually monoarticular with accompanying fever, chills, and positive blood culture.

Question 13

Treatment of Infectious Arthritis

Answer 13

Treat the causative agent. Then same as OA.

Question 14

Diagnosing Infectious Arthritis

Answer 14

Synovial Fluid Aspiration

Question 15

Epidemiology of OA

Answer 15

Most common joint disorder in the United states and throughout the world. 60% of adults older than 60 yrs have radiographic evidence of significant OA. One of the leading causes of disability and pain in the elderly.

Question 16

OA’s predilection

Answer 16

OA commonly affects the cervical and lumbar spine. OA predilection is for weight-bearing joints in the leg, PIP and DIP joints of the hand.

Question 17

Who is OA most common in?

Answer 17

Before age of 50, men are more likely to have OA than women. After age of 50, women are more likely to be affected.

Question 18

Risk Factors of OA

Answer 18

Local factors: Injury and occupation, Excess weight (obesity) and Developmental deformities

Systemic factors: Sex, Genetic susceptibility and Racial differences

Question 19

Osteoarthritis

Answer 19

Definition: Gradual change of articular unit with a loss of cartilage. Thickening of subchondral bone. Bone marrow edema (on MRI). Bony outgrowths(osteophytes) at the joint margins. Mild chronic nonspecific synovial inflammation.

Question 20

Typical OA patient

Answer 20

Overweight, Middle-aged or elderly, Pain and stiffness of joints and has limited function.

Question 21

Cardinal Feature of OA

Answer 21

PAIN is the cardinal feature of OA. Major determinant of disability and functional impairment. Pain, however is frequently absent in patients with radiographic features of OA.

Question 22

Joint involvement in OA

Answer 22

Acromioclavicular joint of shoulder, DIP joints of the hands, PIP joints of the hands, First carpometacarpal joints of the hands, Hips, Knees, First metatarsophalangeal (MTP) joints of the feet, Facet (apophyseal) joints of the cervical and lumbosacral spine.

Question 23

Heberden’s nodes

Answer 23

Located at the DIP joints. Ten times more frequent in women than in men.

Question 24

Bouchard`s nodes:

Answer 24

Located at the PIP joints

Question 25

Erosive OA

Answer 25

A subset of primary OA. Occurs primarily in women(>50yrs)

DIP, PIP, 1st CMC. “Gull wing” or inverted T appearance. Joint inflammation superimposed on degenerative OA symptoms.

Question 26

Causes of Secondary OA

Answer 26

Congenital disorders: Hip (Legg-Calve-Perthes,…), Dysplasias (Epiphyseal Dysplasia,…) …….. Metabolic diseases, Endocrine disorders, Neuropathic joints, Other (Osteonecrosis, Paget`s disease)

Question 27

Advanced Therapies of Cartilage Defects

Answer 27

Drill holes creating Microfractures to stimulate bone growth; Ostechondra allograft; Autologous chondrocyte implantation (ACI) using a collagen membrane.

Question 28

Conclusions on OA

Answer 28

OA is the most common diarthrodial joint problem. Distinct joint involvement. Think of alternative underlying diseases if OA in unusual location or age-group. Conservative management followed by pharmacotherapy.

Question 29

Acute Monoarthritis is aka ________________ and is considered a ____________.

Answer 29

Infectious Arthritis; A Medical Emergency

Question 30

T/F: Synovial fluid aspiration is essential when septic arthritis is in the differential.

Answer 30

True

Question 31

Dx of Infectious Arthritis Conclusions

Answer 31

Joint aspiration is most often diagnostic. Gram stain & Cultures also helpful. Always consider GC arthritis in sexually active individuals.

Question 32

Tx of Infectious Arthritis Conclusions

Answer 32

Joint drainage and antibiotic therapy