Osteoarthritis Flashcards
What is arthritis?
joint disorder involving one or more joints
-over 100 different forms (OA, RA, psoriatic, septic, etc)
What is osteoarthritis?
chronic, progressive disorder characterized by the loss of articular cartilage primarily in hands, knees, hips, and spine
-not simply a degenerative joint disease
What is the most common form of arthritis?
osteoarthritis
What is the relationship between osteoarthritis and age?
prevalence increases with age
-peak onset is 50-60 yrs
Describe the etiology of osteoarthritis.
MOA not completely understood
-primary: no identifiable factor
-secondary: other metabolic factors identified
genetic component likely
joint trauma is a factor
-biochemical and mechanical changes –> loss of functionality –> changes in cartilage, joint capsule, subtracheal bone
Explain the pathogenesis of osteoarthritis.
imbalance between cartilage maintenance and destruction
-malfunction of chondrocyte (responsible for cartilage breakdown)
-end result is loss of proteoglycans and water
-formation of osteophytes (bony outgrowths)
role of inflammatory cytokines and MMP
What are the risk factors for osteoarthritis?
modifiable:
-obesity
-joint trauma
non-modifiable:
-age
-sex
-genetics
-joint deformity/misalignment
What are the clinical features of osteoarthritis?
gradual onset
initial absence of inflammation or joint swelling
mono-articular at first
pain and swelling with activity
no systemic sx
crepitus
tenderness
limited ROM
bony swelling
joint deformity
instability
Describe the pain associated with osteoarthritis.
stages:
-1: predictable, sharp pain brought on by activity
-2: becomes more constant; episodes of stiffness
-3: constant dull/ache; chronic stiffness; intense episodes
worse later afternoon/early evening
may have a neuropathic quality
Which joints are commonly affected by osteoarthritis?
PIP, DIP, thumb
cervical and lumbar spine
hip, knee, metotarsophalangeal
How is osteoarthritis often diagnosed?
often diagnosed without radiography or lab tests
in general, diagnosed if:
-persistent usage-related pain
-age > 45yrs
-little morning stiffness; more evening stiffness
When is additional testing needed for osteoarthritis?
younger individuals
atypical signs/sx
weight loss
What is the role of imaging in the diagnosis of osteoarthritis?
x-ray can be helpful for diagnostic clarification or monitoring
x-ray does not necessarily correlate with pain
What is the role of laboratory tests in the diagnosis of osteoarthritis?
perhaps to rule out other conditions
What are the treatment goals for osteoarthritis?
focus on specific lifestyle changes
reduce pain
maintain or improve joint mobility
limit functional disability
improve self-management
What are the 4 pillars of treatment for osteoarthritis?
- patient education
- rehabilitation
- medications
- referrals
What are some key points about osteoarthritis to educate patients about?
importance of exercise, joint protection, strengthening of muscles and supporting joint
importance of weight control
What is the role of exercise in osteoarthritis management?
introduction of at home or structured exercise is a key initial management strategy
-ROM, strengthening, aerobic activity
-physiotherapy
What amount of exercise is too much for osteoarthritis?
pain lasting > 2 hrs after exercise
What are some environmental adaptations that can be made for osteoarthritis?
raised toilet seats
supports, splints, braces
walkers, canes
supportive footwear
What is the most effective intervention for osteoarthritis?
non-pharmacological interventions
-most effective but underutilized
What is pharmacotherapy aimed at for osteoarthritis?
pain relief
How should pharmacotherapy be initiated for osteoarthritis?
monotherapy prn and add/substitute medications as needed
Which medications are options for osteoarthritis?
acetaminophen
topical NSAIDs
other topicals (capsaicin, A535)
oral NSAIDs
opioids
duloxetine
injectable joint replacement fluid
injectable glucocorticoids
What is the role of acetaminophen for osteoarthritis?
historically was the initial DOC
-recent evidence shows negligible, non sig clinical effect on pain
-guidelines do not strongly recommend anymore
1g QID (max 4g/24h), trial 2-3 wks at max dose then use LED
What is the MOA of acetaminophen?
acts within CNS, prevents PG synthesis by blocking COX
What are safety concerns of acetaminophen?
does NOT cause liver disease at normal doses
risk is from consuming from multiple sources
lower dose: liver dx, LBW, malnutrition, advanced age
What are the drug interactions of acetaminophen?
warfarin
isoniazid
continued alcohol use
Which NSAIDs are available as topicals?
diclofenac
ketoprofen
What is the MOA of topical NSAIDs?
thought to inhibit COX-2 at the site of action
What is the role of topical NSAIDs for osteoarthritis?
knee/hand/foot OA
-analgesic effect in hrs, full effect may take a couple wks
-60% achieve a 50% pain reduction
-safety issues and drug interactions are unlikely
What is the MOA of capsaicin?
depletes substance P and down regulates nociceptive fibers
What is the use of capsaicin for osteoarthritis?
knee OA
How should capsaicin be used for OA?
TID-QID to affected joint
must be used consistently for 2-4wks to see improvement
What are the side effects of capsaicin?
initial burning and sensitivity
systemic effects are rare, case reports of severe burns
What is the MOA of methyl salicylate?
topical counter irritant
What is the role of methyl salicylate in osteoarthritis?
limited evidence
What are the safety concerns of methyl salicylate?
avoid in ASA allergic patients
potential warfarin interaction
What is the MOA of oral NSAIDs?
bind to COX and prevent the production of PGs
What is the role of oral NSAIDs for osteoarthritis?
more effective than acetaminophen
preferred if failed topical NSAID, multiple joints affected, or hip or spine OA
What are the concerns with oral NSAIDs?
- CV: risk is with all, effect is dose related
- GI: assess risk and consider prophylaxis
- renal: risk is with all
- drug interactions
Which oral NSAID is preferred for osteoarthritis?
if concerned about GI toxicity:
-celecoxib or other NSAID + PPI
How should oral NSAIDs be used for osteoarthritis?
low doses and slow escalation’
switching may help if one failed
What are some “other” side effects of NSAIDs?
CNS
-dose related, respond to decreased dose
minor or serious skin reactions, pruritis
What are the monitoring parameters if oral NSAIDs are used long term?
blood pressure
electrolytes
renal function
CBC
INR if on anticoagulants
What is the MOA of opioids?
bind opioid receptors in CNS and PNS, alters perception and response to pain
What is the use of opioids for osteoarthritis?
only select patients/last line therapy
-modest benefit at best
-viable option if severe pain or CI to other treatment
-smallest effective dose, shortest duration
What are the concerns with using opioids for osteoarthritis?
AEs: sedation, nausea, constipation, resp dep, tolerance
fall risk and confusion in elderly
What is the MOA of tramadol?
binds mu opioid receptors
inhibits reuptake of serotonin and norepinephrine
What are the concerns with tramadol?
risk of serotonin syndrome
drugs that lower seizure threshold
QT prolongation
requires 2D6 to metabolize
What is the role of tramadol for osteoarthritis?
guidelines endorse as an option, preferable to opioids
-similar efficacy to oral NSAIDs but more AEs
What is the MOA of duloxetine?
SNRI
What is the role of duloxetine for osteoarthritis?
2nd line agent, esp if neuropathic pain
-indications: knee OA (off-label: hip OA)
What is the onset of duloxetine for osteoarthritis?
improvement may be noted in 1-4 weeks
What are the adverse effects of duloxetine?
headache
dizziness
dry mouth
constipation
sweating
appetite loss
sedation
fatigue
BP and HR increase at higher doses
What are the warnings for duloxetine?
GI bleed risk
CNS depression
fracture risk increase
orthostasis
serotonin syndrome
sexual dysfunction
What are the contraindications of duloxetine?
narrow angle glaucoma
ESRD and hepatic impairment
seizure history
What are the drug interactions of duloxetine?
risk of serotonin syndrome with SSRIs
clearance decreased by 1A2 and 2D6 inhibitors
What is the MOA of injectable corticosteroids?
interrupt inflammatory cascade at several levels
What is the use of injectable corticosteroids for osteoarthritis?
can be considered in hip, knee, shoulder OA
Describe the efficacy of injectable corticosteroids for osteoarthritis.
short term relief, no long term benefit
pain reduced by average of 1-2 points on 10 point scale
What is the onset and duration of injectable corticosteroids?
rapid onset
effects typically last 4-8 wks
What are the adverse effects of injectable corticosteroids?
may accelerate cartilage destruction
post-injection flare
local skin changes
infections
What are the warnings for injectable corticosteroids?
limited to 3-4 injections in one joint per year
may worsen joint instability or weakness
minimize joint activity for 2-3 days
What is the available injectable joint fluid replacement?
hyaluronic acid
What is the MOA of hyaluronic acid?
component of synovial fluid
What is the use of hyaluronic acid for osteoarthritis?
indicated for knee OA; other types off-label
-efficacy: uncertain benefit, costly
What are the adverse effects of hyaluronic acid?
arthralgia
injection site pain/reaction
post-injection flare
What is glucosamine?
precursor to proteoglycan
What is the role of glucosamine for osteoarthritis?
no official approval, evidence is mixed
not recommended in tx guidelines
How long is an adequate trial of glucosamine?
need to use for 3 months before results
What are the safety concerns of glucosamine?
good safety profile
increased INR, bleed risk
What is the role of chondroitin for osteoarthritis?
less data than glucosamine
What are the safety concerns of chondroitin?
good safety profile
increased INR, bleed risk
