Common Small Animal Arthropathies Flashcards
define septic arthritis
a bacterial infection of a joint space with 3 routes of contamination
- hematogenous spread: young animals, infections right after birth, omphalophlebitis, strep phayrngitis, unterine/mammary infections of bitch/queen bacteremic conditions, pneumonia,
- direct penetration: surgical (iatrogenic), surgery (intra-articular injection), trauma (bite wounds)
- spread from surrounding tissues: uncommon
what are common clinical findings with septic arthritis? (5)
- lameness (acute or chronic) with palpable joint swelling/pain/warmth
- monoarthropathy: most common! may see polyarthropathy in immunocompromised
- larger joints most commonly affected: stifle, elbow, carpus
- local lymphadenopathy
- less common findings include pyrexia and systemic signs
describe the common bacterial etiology of septic arthritis
dogs: stap. intermedius and staph. aureus, or beta-hemolytic streptococci spp.
cats: pasturella multicoda and bacteroides spp.
describe septic arthritis diagnostics (3)
- arthrocentesis and cytology:
-turbid and highly neutrophilic with degenerative and toxic changes, +/- intracellular bacteria (pathognomonic) - synovial fluid culture and susceptibility should be attempted in all cased and blood culture media SHOULD be used
- PCR can be difficult to interpret and give false positive results
how do you diagnose septic arthritis in the real world?
probable diagnosis: history and clinical signs and synovial fluid cytology
definitive diagnosis would be from a positive bacterial culture but not always reliable! (add more info)
what are your 2 categories of treatment options for septic arthritis? describe
- medical
-systemic antibiotics, based on culture and sensitivity if possible, or empirically choose cephalosporins or amoxicillin-clavulanic acid for 30 days minimum - surgical
-joint irrigation or lavage; may not be tuly effective
-mechanical debridement: exploratory arthrotomy, not typically recommended
-surgical implant removal
describe etiology and clinical signs of tick-borne arthropathies (not LO)
etiology: borellia (lyme disease), ehrlichia, anaplasma
pathophysiology: synovial vasculitis and neutrophilic effects
clinical signs:
variable! +/- fever, painful shifting limb lameness, POLYARTHROPATHY
if you suspect a tick disease, IMPA should be on your rule-out list!
describe diagnosis and treatment of tick borne arthropathy (not LO)
diagnosis: arthrocentesisgive neutrophilic synovial fluid, nonspecific bloodwork (everything low), serology
treatment: doxycycline for 30d minimum
define immune-mediated arthritis pathophysiology; how it leads to the 2 types
- an autoimmune reaction causes immune complexes to deposit in the synovium
- this activates complement and inflammatory cascades, releasing inflammatory mediators and cytokines
- this leads to chronic inflammation of the synovial tissue lining - non-erosive IMA
can continue on to erosive IMA
- proliferation of synovial tissue (pannus)
- pannus invades cartilage and bone surface, leading to cartilage and bone erosion
- joint destruction
describe clinical signs of immune-mediated arthritis (early, intermediate, late)
early:
+/- joint paint and /or effusion
+/- multiple joint swelling (not always easily palpable)
lameness and general stiffness
intermediate:
depression
anorexia
pyrexia (fever of unknown origin = IMPA is most common diagnosis)
lympahdenopathy
late:
severe lameness
luxation/sub-luxation (erosive form)
what are the 4 key diagnostic steps of IMPA?
- history, physical exam, clinical signs
- synovial fluid analysis: sterile inflammatory joint fluid
- imaging: effusion, degenerative changes, erosion with erosive form
- rule out other diseases, know that elevation of RA factors CANNOT be used alone to make diagnosis or lack of RA also does not rule out
list 4 causes of non-erosive IMPA and 3 causes of erosive IMPA
non-erosive:
1. immune-mediated polyarthritis (IMPA) type 1- idiopathic
2. systemic lupus erythematosus
3. drug reactions
4. breed associated IMPA: shar-pei fever, juvenile akitas associated with aseptic meningitis
erosive:
1. rheumatoid arthritis (RA)
2. feline chronic polyarthritis: adult male cats 1-5 years old
3. erosive polyarthritis of greyhounds 3mos to 3 years
describe prevalence and breeds we most commonly see non-erosive IMPA type I, what joints are commonly involved, and what you should ALSO do if you see it
this is the most common immune-mediated arthritis in dogs!
large: german shepherds, dobies, retrievers
small: poodle, lhasas, yorkies
often the smaller joints are involved: carpus, tarsus, stifle, elbow
describe the incidence, signalment, and joints involved with erosive IM arthropathy
incidence: uncommon in dogs, rare in cats
signalment: no sex/breed predilection, can present at any age
joints involved: also smaller joints like tarsus, stifle, elbow
describe the etiology and prevalence of osteoarthritis
cartilage damage issue!
osteoarthritis is a disorder of moveable joints where cartilage damage is the initiating factor leading to gradual degeneration of articular cartilage resulting in subsequent changes to ALL joints
primary (cats more common): wear and tear, aging phenomenon
secondary (dogs more common):
-trauma (joint fracture)
-developmental conditions (hip or elbow dysplasia)
-mechanical joint instability
-endocrine disorders
-metabolic disorders
