Final Exam - Osteoarthritis Flashcards
what percentage of adult animals are affected by OA?
20% of adult dogs & 60% of adult cats
what is the pathophysiology behind OA?
joint abnormalities from overload, instability, developmental abnormalities, or trauma
what are some predisposing factors of OA?
obesity, genetics, & age
what are examples of chronic overload causing OA?
obesity or an animal doing intense exercise
what are some examples of instability causing joint abnormalities leading to OA?
cranial cruciate ligament disease & loss of plantar/palmar support
what is an example of developmental abnormalities causing joint instability leading to OA?
hip dysplasia, elbow dysplasia
what are some examples of trauma causing joint instability leading to OA?
articular fractures & malunion fractures
why is obesity a predisposing factor for OA development? what is an example of breeds predisposed to this?
increased load on joints, abnormal loads, & chronic pro-inflammatory state leading to cartilage degradation
labs
why is increased age a predisposing factor for OA development?
decreased repair mechanisms, decreased cellular activity, & altered physical properties of cartilage
how can genetics play a role in being a predisposing factor for OA development?
genetic components to many developmental diseases
what is the pathogenesis of OA?
imbalance of repair & degradation of articular cartilage resulting in a loss of tensile strength, damaged collagen, & increased water content
increase in degradative/inflammatory markers - IL-1B, TNF-A, NO, PGE2, substance P, & MMPs
later will see osteophyte formation in the periosteum at junction of cartilage & bone, synovitis, capsular fibrosis, cartilage erosion - all irreversible changes
why is there pain seen with OA?
there are nerves present around & in the joint except for the articular cartilage
causes a dull aching pain - inflammatory mediators may sensitive nerves
what are the clinical changes an owner may see in their pet with OA?
decreased activity, ‘warm out of it’, decreased ROM, muscle atrophy, crepitus, joint effusion, lameness
how can you confirm a diagnosis of OA?
radiographs
what radiographic changes are consistent with a diagnosis of OA?
joint effusion, osteophyres/enthesiophytes, subchondral sclerosis, intra-articular mineralization, & subchondral cysts
why is it important to treat the patient & not the radiographs?
degree of OA doesn’t correlate with clinical function - could have an extremely painful animal with minimal radiographic changes
when may you use a joint fluid analysis for OA?
if the joints are excessively painful & there are multiple involved
need to rule out immune-mediated disease & infection
what is the medical management of OA?
- weight management
- medications - symptom & structure modifying
- joint supplements - nutraceuticals
- exercise modification & rehab
how may weight management be used as a treatment plan for OA?
prescription diets, low calorie treats, & honest owner assessment
what are the adverse effects of NSAIDs when treating OA?
gi signs - mild to life-threatening
renal disease
liver toxicity
what is your symptom modifying medication of choice for treating OA?
NSAIDs - carprofen, meloxicam, previcox, galliprant
what are the major take-home points for using NSAIDs when treating OA?
give it with food!!!!
educate owners about use & adverse effects
stop meds if you see adverse effects & be prepared with a back up plan
routine monitoring
what is the MOA of tramadol?
weak mu opioid agonist & serotonin reuptake inhibitor with variable absorption
what is the MOA of gabapentin?
not entirely known - voltage gated n-type calcium channel ion
what is the dosing for gabapentin?
10-30mg/kg by mouth every 8 hours - increase slowly
what is the MOA of amantadine?
NMDA receptor agonist dosed at 3-5 mg/kg every 24 hours
why can’t you use acetaminophen in cats?
cats are deficient in glucuronyl transferases and are therefore unable to sufficiently glucuronidate acetaminophen - will cause oxidative damage & heinz bodies
will also see severe methemoglobinemia, hematuria, and icterus
what is the MOA of acetaminophen?
central COX pathway inhibitor
what drug is used for structure modifying in dogs with OA? how does it work?
adequan - polysulfated glycosaminoglycan
maintains chondrocyte viability & prevents degradation
what is the dosing of adequan?
4.4mg/kg IM twice weekly for 4 weeks
what is the primary joint supplement recommended for treating OA?
omega 3 fatty acids - anti-inflammatory properties
what are some examples of exercise modification/rehab that can be used for treating OA?
low impact, controlled activity - leash walks, underwater treadmill
laser therapy & extracorporeal shock wave therapy
what are some subjective ways for assessing outcome in OA patients?
veterinarian lameness grading & owner assessment
what are some objective ways for assessing outcome in OA patients?
muscle mass measuring on a gulick II tape measure & ROM on a goniometer
T/F: there is a poor coorelation between subjective scales & force plate measurements
true - subjective may be better for severe lameness, and at best, 73% agreement with objective data
subjective data will differ among evaluators
what are some signs associated with OA in cats?
behavior changes - litter box changes & avoiding jumping
what is the treatment for OA in cats?
similar to dogs - weight loss & controlled activity
what are the recommended medications for treating OA in cats?
robenacoxib - onsior, FDA approved for cats
meloxicam
tramadol - increased activity seen in 2mg/kg BID dosing
T/F: OA is an irreversible condition often secondary to abnormalities within the joint
true
what are the 4 pillars of treatment of OA?
- weight loss
- pain meds
- joint supplements
- exercise modification
T/F: OA in cats is easy to diagnose
false - difficult to diagnose
T/F: surgical intervention is recommended to treat underlying conditions causing OA
true
what kind of drug is codeine?
alkaloid in opium poppy that is metabolized to other active compounds with variable effects
