Investigating joint disease Flashcards
What are the 2 types of joint synoviocyte?
- A (like macrophage)
- B (like epithelial cell)
What are the 2 filters for joint fluid?
- vascular endothelium
- synovial interstitium
Joint fluid - contents
- proteins
- electrolytes
- enzymes
- water
- HA
- cells: synovial lining cells
What is the first main catergory of canine arthritis?
- Non- inflammatory (3000 WBC, PMNs e.g. neutrophils)
Categories of non-inflammatory arthritis?
- traumatic
- DJD
- hemarthrosis
Categories of inflammatory arthritis.
- infectious
- non-infectious
What are the categories of inflammatory, non-infectious canine arthrtiis?
- immune-based
- non-immune based (rare)
Name 2 types fo non-immune based arthritis
- crystal
- neoplastic
- both rare
Name 2 categories of immune-based arthritis
- erosive
- non-erosive
Examples - inflammatory, non-infectious, immune-based, erosive arthritis
- rheumatoid arthritis (RA)
- polyarthritis (PA) of greyhound
- feline progressive PA
Examples - inflammatory, non-infectious, immune-based, NON-erosive arthritis
- SLE
- Idiopathic PA
- PA/PM syndrome
- PA meningitis syndrome
- PA akitas
Age presentation of arthritis
- puppies (unstable)
- senior (OA)
What breed predispositions are there?
- GSD
- lab
- greyhound
- GAS: hip dysplasia
- Lab: elbow dysplasia (also cruciate dz)
- Greyhounds: erosive
Aspects of hx to include in workup
- # limbs affected
- relation to exercise/ intermiited
- exercise tolerance
- travel hx
- parasites
- systemic dz (IMHA, ITP etc)
Define ITP
Idiopathic thrombocytopenic purpura
Aspects of lameness to consider
- # limbs
- severity
- specific postures /mvts
Systemic signs of arthritis
- variable
- fever
- lethargy, aanorexia
- collapse
How can endocarditis lead to polyarthritis (PA)?
can lead to immune-mediated polyarthritis
How can tumours cause arthritis?
can lead to immune-mediated polyarthritis
What to look for on PE with suspect arthritis?
- fever
- heart murmur
- masses
Aspects of orthopaedic exam for suspect arthritis
- joint effusion, buttress, mm atrophy
- pain/ heat/ decreased ROM
- Instability (CCLR, CHD = Canine Hip Dysplasia), crepitus
What should you determine on neuro exam of suspect arthritis?
whether there are deficits or not
What areas to look for on radiograph when looking for arthritis
- joint capsule
- joint space
- bony relationships
- bone density
- subchondral bone
- calcification
- osteophytes and enthesiophytes
Where to perform arthrocentesis
- affected joint (single arthropathy)
- at least 3 joints (suspected polyarthropathy)
Method - arthrocentesis
- sedation/ GA
- landmarks
- sterile (gloves, clip and scrub)
- small syringe and needle
- slides, EDTA tube, blood culture media
Most common joints to tap for arthrocentesis - 3
- carpus
- tarsus
- stifle
- (elbow and hips possible but more difficult)
Aspects of joint fluid analysis
- cell count
- cytology
- chemical analysis (TP, glu)
- culture (if suspect septic)
What does joint fluid analysis allow you to differentiate?
Non-inflammatory (DJD) vs. inflammatory (infectious vs/ non-infectious)
What do different cells on cytology suggest?
- synoviocytes - normal
- neutrophils - inflammatory (degenerate vs. non-degenerate)
- macrophages = non-inflammatory
- bacteria/fungi = septic
Chemical analysis - joint fluid
- glucose (fluid: blood = 0.8-1 normal): decreased in septic arthritis
- TP (
Culture - joint fluid
- 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
What is the most common infectious inflammatory arthritis of canines?
- BACTERIAL
- d/t direct penetration, spread from adjacent tissues, haematogenous, OA (since poor synovial membrane integrity)
- Skin bacteria: Staph, Strep and Pasteurella
In a septic joint fluid analysis, are the neutrophils always degenerate?
No
Radiograph - acute./ chronic signs of arthritis
- acute: effusion
- chronic: degenerative changes (but you can’t r/o septic arthritis based on this)
What are the 3 main agents that are tested for when suspecting infectious agents?
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)
How are the different types of immune-based arthritis differentiated (i.e. erosive and non-erosive)
by radiography
What tests are done when suspecting erosive polyarthritis (i.e. Rheumatoid arthritis most commonly)?
RHEUMATOID FACTOR:
- Abs against IgG
- high titres in RA (up to 70%)
- radiographic changes too
What tests are done when suspecting non-erosive immune-mediated polyarthritis ?
- ) ANA titre = antinuclear Ab
- high titres in SLE (90%)
- other inflammatory or infectious processes can lead to low titres - ) image body cavities
- ) other (depending on CS - CSF, mm biopsy etc)
List the 4 subtypes of immune-mediated polyarthritis
- ) idiopathic (50%), diagnosis of exclusion
- ) infection (25%)
- ) GIT dz
- ) neoplasia
