November 20, 2015 - Monoarticular Arthritis

Question 1

Synovial Fluid Memory Chart

Answer 1

Question 2

Normal Synovial Fluid

Answer 2

Appearance - Clear colourless

Viscosity - High (because of hyaluronic acid)

Cell Count < 200 mm³

% Polyps - < 25%

Question 3

Type I Synovial Fluid

Answer 3

Non-inflammatory

Appearance - Clear straw

Viscosity - High

Cell Count 200-2000 mm³

% Polyps - < 25%

Question 4

Type II Synovial Fluid

Answer 4

Inflammatory

Appearance - Turbid yellow

Viscosity - Fair

Cell count - 5000-50000 mm³

% Polyps - >50%

Question 5

Type III Synovial Fluid

Answer 5

Septic

Appearance - Turbid yellow

Viscosity - Poor

Cell count - 50,000-200,000 mm³

% Polyps - >75%

Question 6

Type IV Synovial Fluid

Answer 6

Bloody

Appearance - Bloody or serosanguinous

Viscosity - Variable

Cell count - 200-10,000 mm³

% Polyps - >50%

Question 7

Causes of Type I Synovial Fluid

Answer 7

(Non-inflammatory)

Traumatic synovitis

Torn meniscus

Osteochondromatosis

Osteochondritis dessicans

Osteoarthritis

Spontaneous osteonecrosis knee (SONK)

Question 8

Causes of Type II Synovial Fluid

Answer 8

(Inflammatory)

Rheumatoid arthritis

Rheumatoid variants (panindromic rheumatism etc.)

Seronegative arthropathies (ankylosing spondylitis, psoriatic arthropathies, IBD, reactive arthropathies)

Crystal arthropathies (gout, pseudogout)

Question 9

Causes of Type III Synovial Fluid

Answer 9

(Septic)

Septic arthritis

Question 10

Causes of Type IV Synovial Fluid

Answer 10

(Bloody)

Traumatic hemarthrosis

Bleeding disorders

Pigmented villonodular synovitis

Synovial sarcoma (RARE)

Question 11

Osteoarthritis Dessicans

Answer 11

Can cause Type I Synovial Fluid.

Devitalized fragment of bone with its overlying articular cartilage seperates from the lateral portion of the medial condyle of the femur.

Affects adolescents and young adults.

May have recurrent effusions and sometimes “locking” of the joint.

Question 12

Torn Meniscus

Answer 12

Can cause Type I Synovial Fluid.

Following a twisting injury, the patient has knee on the anteromedial aspect of the knee. The following day there is swelling of the knee and an inability to extend completely. Usually subsides after 2 weeks.

Question 13

Osteochondromatosis

Answer 13

Can cause Type I Synovial Fluid.

Cause proliferation of osteochondromas (benign tumor of bone). Results in mild swelling, pain, and often limited ROM of the joint.

Question 14

Spontaneous Osteonecrosis of the Knee (SONK)

Answer 14

Can cause Type I Synovial Fluid.

Affects weight bearing surface of the medial femoral condyle. Tenderness and severe and sudden onset of pain can occur. X-ray appears normal, but will be visible on an MRI.

Question 15

Pigmented Villonodular Synovitis

Answer 15

Can cause Type IV Synovial Fluid.

Causes inflammation and overgrowth of the knee lining. It usually affects the hip or the knee. The synovium becomes swollen and grows which harms the bone next to the joint and creates extra fluid that causes swelling.

Synovial tissue is brown in colour due ot the hemosiderin-laden macrophages.