Flashcards in Investigating Joint Disease (La Fuente) Deck (33):
What is joint fluid?
Dyalisate from plasma
- 2 filters, vascular endothelium and synovial interstitum
- contains proteins , electrolytes, enzymes, water and HA
- cells- synovial lining cells
How does a healthy joint differ from an inflamed joint? LOOK AT SLIDE
- excessive synovial fluid in joint cavity
- surrounding soft tissue inflammation
-WBCs and inflammatory mediators released into synovial fluid via inflamed synovial membrane
- normal articular cartilage
Which inflammatory cell is more commonly seen in joint fluid?
Macrophages more than neutrophils
What aspects of the Hx are important for joint dz?
- single v multiple limb
- intermittent v before/after excercise
- excercise tolerance
- travel Hx
- systemic disease (IMHA, ITP etc)
What clues may the signalment give for joint disease?
- puppies: instability
- senior: OA
- GSD hip dysplaisa
- Labrador elbow dysplasia
- greyhounds erosive joint disease
What type of lameness does crucial element rupture give?
Weight bearing (unless traumatic)
How may poly arthritis cases sit?
Not flexing any joints - sit on lateral aspects of HLs
What clinical signs may be seen with joint dz?
- one or multiple limbs
- specific posture
>systemic signs (variable)
> orthopeadic examination
- joint effusion/buttress/muscle atrophy
- pain/heat/decreased ROM
- instability (CCLR, CHD) crepitus
> neuro exam
- normal v deficits
What is a buttress?
Swelling medial aspect of the stifle d/t cruciate rupture and joint capsule swelling
Dxx for joint dz
- joint capsule and space (look for cloudy joint effusion)
- bony relationships
- bone density
- subchondral bone
- osteophytes and enthesiophytes
- single affected joint
- or suspected polyarthropathy (at least 3 joints)
- sedation or GA
- sterile procedure
- slides, EDTA, blood culture (may be false negatives for septic arthritis, blood culture medium ^ chances of success)
> and analysis of joint fluid
What is the cut off point for WBC in joint fluid?
Above this = immune mediated poly arthritis OR septic
- positive culture to prove septic (rarely see bacteria in joint tap) though culture also gives false negatives
What is analysed of the joint fluid?
- cell count
- chemical analysis (TP, glucose)
- culture (R/o inflammatory septic v nnonseptic autoimmune)
What cells can be seen on cytology?
- degenerate v non-degenerate
- non-inflammatory (DJD)
> bacterial/fungal hyphae
What chemical analysis can be carried out on joint fluid?
- fluid: blood = 0.8-1 normal
- decreased in septic arthritis
If septic OA is suspected but culture negative what can be done?
How can culture give false results? How can this be improved?
- false negative as culture doesn't grow bacteria present (number too low??)
- false positive with contamination (check cell count)
> improve by sample into special culture media
> OR synovial membrane biopsy
What is the most common type of infectious inflammatory OA? Aetiologies?
- dogs with OA pdf spontaneous SEPTIC OA (non weight bearing)
- direct penetration
- spread from adjacent tissues
What bacteria are most commonly involved in some tic arthritis?
How long does OA take to develop radiographic signs?
What is seen in septic arthritis on joint tap and radiography?
> joint fluid
- septic inflammation (though not always degenerate neutrophils)
- rare bacteria
- positive culture
- acute (effusion)
- chronic (degenerative changes)
Tx septic arthritis
6 weeks Abx BS
What forms of infectious immune-mediated arthritis are possible and how can you r/o?
> Serology and travel hx (esp Mediterranean) (NB these do not have to infect the joint, the immune complexes cause the damage)
- infectious arthritis when suspecting immune-mediated polyarthritis
> Borrelia Burgdorfory (Lyme disease)
- borrelial arthritis
> Ehrlichia canis (Ehrlichosis)
- rickettsial arthritis [tick not endemic UK]
> Leishamania Infantum (Leishmaniasis)
- Protozoal arthritis [not endemic UK]
What are the 2 forms of immune based arthritis ?
Erosive v non-erosive
How does septic arthritis differ in presentation to immune mediated?
- One joint affected septically usually
- if immune mediated = poly arthritis
Is erosive poly arthritis common? Subtypes? Most common subtype?
- Rheumatoid most common within this subset
- PA greyhounds
- feline chronic progressive PA
What is rheumatoid arthritis?
Auto Ab against IgG
- causes erosive poly arthritis
- radiographic changes must be present too
What is SLE?
Systemic lupus erythematosis
- causes NONerosive polyarthritis
What are the 4 MAIN types of immune mediated polyarthritis and how can these be r/o?
type 1: Idiopathic immune mediated poly arthritis (most common, 50% cases)
- need to r/o other subtypes)
type 2: infection (25%)
type 3: GI dz
type 4: Neoplasia
- imaging body cavities
- depending on sigs CSF/Muscle biopsy etc.
What test can r/o SLE?
ANA ( antinuclear antibodies)
- high titres with SLE, though other infectious/inflame processes can -> low titres
What 2 types of synoviocytes ?
Type a and b
Criteria for diagnosing rheumatoid arthritis in dogs
> 7 out of 11 criteria
- stiffness after rest
- pain 1+ joint
- stiffnes 1+ joint
- swelling in 1 additional joint within 3 months
- symmetric joint swelling
- subcut nodules over bony prominences of extensor surfaces of only rticular regions
- radiographic evidence of destructive lesions
- positive RF serum (titre >1.8)
- poor mucin content of synovial fluid
- characteristic histopath changes in synovial membranes
- characteristic histopath changes in subcut nodules
What are the 5 main types of NON erosive immune mediated (non-infectious) inflame arthritis?
- idiopathic PA
- PA/PM syndrome
- PA/meningitis syndrome
- PA akitas