Investigation of Joint Disease

Question 1

What types of synocviocytes are there?

Answer 1

Type A - phagocytic

Type B - Fibroblastic

Question 2

What is joint fluid?

Answer 2

Dialysate from plasma (filtered via vascular endothelium and synovaial interstitium) and contains proteins, electrolytes, enzymes, water and hyaluronic acid

Question 3

What causes are there for non-inflammatory arthritis?

Answer 3

Trauma
DJD
Haemathrosis

Question 4

What causes are there for non-infectious, imflammatory athritis?

Answer 4

Immune based (erosive-rheumatoid arthritis, polyarthritis; non-erosive SLE, polyarthritis)

Non-immune based
(crystals, neoplasia)

Question 5

Where should you perform arthrocentesis if you suspect a single arthropathy compared to polyarthropathy?

Answer 5

Single arthropathy - just that joint

Polyarthropathy - sample at least 3 joints

Question 6

What can joint fluid help us distinguish between?

Answer 6

Non inflammatory causes of arthritis (DJD) and inflammatory (infectious/non-infectious)

Macrophages - non inflammatory
Neutrophils - inflammatory

Question 7

What can we analysis in joint fluid?

Answer 7

Cell counts
Number and type present

Cytology
Macrophages - noninflammatory
Neutrophils - inflammatory
Presence of bacteria, fungal hyphae etc

Chemical analysis
Decreased glucose - septic arthritis
Increased TP - inflammatory arthritis

Culture

Question 8

Outline the infectious joint dieases, giving causes, aetiology and diagnosis.

Answer 8

Bacterial (staph, strep, pasteurella - all more commonly cause septic arthritis), viral, fungal, rickettsial, protozoal, borrelial, mycoplasmal.

Direct penetration, spread from adjacent tissues, haematogenous, osteoarthritis

Diagnosis:
+ Joint fluid - septic inflammatory (may be degenerate neutrophils), rarely bacteria but with positive culture
+ Rads - acute=effusion; chronic=degenerative changes
+ Serology - look for infectious agents (lyme disease, ehrlichiosis, leishmaniasis)

Question 9

How can you differentiate between erosive and non-erosive immune-based joint disease?

Answer 9

Erosive - bony changes (rads) and collapse of joints, high rheumatoid factor (antibodies against IgG)

Non-erosive - No bony changes and high antinuclear antibody titres (eg for SLE)

Question 10

What are the subtypes of immune-mediated polyarthritis?

Answer 10

I - idiopathic
II - infection
III - GI disease
IV - neoplasia

Question 11

How do you grade patellar luxation?

Answer 11

Grade 1: luxation, no clinical signs

Grade 2: dynamic luxation, clinical signs

Grade 3: luxation permanent, reducible

Grade 4: luxation permanent, non-reducible