Investigating joint disease

Question 1

What are the 2 types of joint synoviocyte?

Answer 1

• A (like macrophage)

- B (like epithelial cell)

Question 2

What are the 2 filters for joint fluid?

Answer 2

• vascular endothelium

- synovial interstitium

Question 3

Joint fluid - contents

Answer 3

• proteins
• electrolytes
• enzymes
• water
• HA
• cells: synovial lining cells

Question 4

What is the first main catergory of canine arthritis?

Answer 4

• Non- inflammatory (3000 WBC, PMNs e.g. neutrophils)

Question 5

Categories of non-inflammatory arthritis?

Answer 5

• traumatic
• DJD
• hemarthrosis

Question 6

Categories of inflammatory arthritis.

Answer 6

• infectious

- non-infectious

Question 7

What are the categories of inflammatory, non-infectious canine arthrtiis?

Answer 7

• immune-based

- non-immune based (rare)

Question 8

Name 2 types fo non-immune based arthritis

Answer 8

• crystal
• neoplastic
• both rare

Question 9

Name 2 categories of immune-based arthritis

Answer 9

• erosive

- non-erosive

Question 10

Examples - inflammatory, non-infectious, immune-based, erosive arthritis

Answer 10

• rheumatoid arthritis (RA)
• polyarthritis (PA) of greyhound
• feline progressive PA

Question 11

Examples - inflammatory, non-infectious, immune-based, NON-erosive arthritis

Answer 11

• SLE
• Idiopathic PA
• PA/PM syndrome
• PA meningitis syndrome
• PA akitas

Question 12

Age presentation of arthritis

Answer 12

• puppies (unstable)

- senior (OA)

Question 13

What breed predispositions are there?

• GSD
• lab
• greyhound

Answer 13

• GAS: hip dysplasia
• Lab: elbow dysplasia (also cruciate dz)
• Greyhounds: erosive

Question 14

Aspects of hx to include in workup

Answer 14

• # limbs affected
• relation to exercise/ intermiited
• exercise tolerance
• travel hx
• parasites
• systemic dz (IMHA, ITP etc)

Question 15

Define ITP

Answer 15

Idiopathic thrombocytopenic purpura

Question 16

Aspects of lameness to consider

Answer 16

• # limbs
• severity
• specific postures /mvts

Question 17

Systemic signs of arthritis

Answer 17

• variable
• fever
• lethargy, aanorexia
• collapse

Question 18

How can endocarditis lead to polyarthritis (PA)?

Answer 18

can lead to immune-mediated polyarthritis

Question 19

How can tumours cause arthritis?

Answer 19

can lead to immune-mediated polyarthritis

Question 20

What to look for on PE with suspect arthritis?

Answer 20

• fever
• heart murmur
• masses

Question 21

Aspects of orthopaedic exam for suspect arthritis

Answer 21

• joint effusion, buttress, mm atrophy
• pain/ heat/ decreased ROM
• Instability (CCLR, CHD = Canine Hip Dysplasia), crepitus

Question 22

What should you determine on neuro exam of suspect arthritis?

Answer 22

whether there are deficits or not

Question 23

What areas to look for on radiograph when looking for arthritis

Answer 23

• joint capsule
• joint space
• bony relationships
• bone density
• subchondral bone
• calcification
• osteophytes and enthesiophytes

Question 24

Where to perform arthrocentesis

Answer 24

• affected joint (single arthropathy)

- at least 3 joints (suspected polyarthropathy)

Question 25

Method - arthrocentesis

Answer 25

- sedation/ GA - landmarks - sterile (gloves, clip and scrub) - small syringe and needle - slides, EDTA tube, blood culture media

Question 26

Most common joints to tap for arthrocentesis - 3

Answer 26

- carpus - tarsus - stifle - (elbow and hips possible but more difficult)

Question 27

Aspects of joint fluid analysis

Answer 27

- cell count - cytology - chemical analysis (TP, glu) - culture (if suspect septic)

Question 28

What does joint fluid analysis allow you to differentiate?

Answer 28

Non-inflammatory (DJD) vs. inflammatory (infectious vs/ non-infectious)

Question 29

What do different cells on cytology suggest?

Answer 29

- synoviocytes - normal - neutrophils - inflammatory (degenerate vs. non-degenerate) - macrophages = non-inflammatory - bacteria/fungi = septic

Question 30

Chemical analysis - joint fluid

Answer 30

- glucose (fluid: blood = 0.8-1 normal): decreased in septic arthritis - TP (

Question 31

Culture - joint fluid

Answer 31

- about 23% negative in spite of infection - care with false positive d/t contamination so check cell count - TO IMPROVE: special culture media or synovial membrane biopsy

Question 32

What is the most common infectious inflammatory arthritis of canines?

Answer 32

- BACTERIAL - d/t direct penetration, spread from adjacent tissues, haematogenous, OA (since poor synovial membrane integrity) - Skin bacteria: Staph, Strep and Pasteurella

Question 33

In a septic joint fluid analysis, are the neutrophils always degenerate?

Answer 33

No

Question 34

Radiograph - acute./ chronic signs of arthritis

Answer 34

- acute: effusion | - chronic: degenerative changes (but you can't r/o septic arthritis based on this)

Question 35

What are the 3 main agents that are tested for when suspecting infectious agents?

Answer 35

Serology for: - Borrelia burgdorfery (Lyme disease) - Ehrlichia canis (Ehrlichiosis = rickettsial arthritis, tick not endemic in the UK) - Protozoal arthritis = Leishmania infantum, not endemic in UK, other signs (skin, renal)

Question 36

How are the different types of immune-based arthritis differentiated (i.e. erosive and non-erosive)

Answer 36

by radiography

Question 37

What tests are done when suspecting erosive polyarthritis (i.e. Rheumatoid arthritis most commonly)?

Answer 37

RHEUMATOID FACTOR: - Abs against IgG - high titres in RA (up to 70%) - radiographic changes too

Question 38

What tests are done when suspecting non-erosive immune-mediated polyarthritis ?

Answer 38

1. ) ANA titre = antinuclear Ab - high titres in SLE (90%) - other inflammatory or infectious processes can lead to low titres 2. ) image body cavities 3. ) other (depending on CS - CSF, mm biopsy etc)

Question 39

List the 4 subtypes of immune-mediated polyarthritis

Answer 39

1. ) idiopathic (50%), diagnosis of exclusion 2. ) infection (25%) 3. ) GIT dz 4. ) neoplasia