OA, Gout, Osteoporosis Flashcards
Osteoarthritis Defined
Progressive disease can result in chronic pain, restricted ROM, and muscle weakness, especially if a weight-bearing joint such as knees, hips, cervical or lumbar spine, distal interphalangeal (DIP) joints, and carpometacarpal joint (base of the thumb) is affected.
Osteoarthritis Forms Defined
Primary or Idiopathic: Arises from physiologic changes that occur with normal aging
Secondary: results from traumatic injuries or inherited conditions and may present as hemochromatosis, chondrodystrophy, or inflammatory OA.
Osteoarthritis Pathophysiology
OA must be differentiated from other forms of arthritis because the physiologic changes specific to the condition dictate disease management.
Although most forms of arthritis, including OA, result in degeneration of articular cartilage, the subsequent formation of new bone is a change specific to OA.
Osteoarthritis Diagnostic Criteria: Hand
Pain, aching, or stiffness and three of the following:
Hard tissue enlargement of >2 joints; Hard tissue enlargement of >2 DIP joints; <3 swollen metacarpophalangeal joints; deformity of >1 selected joint
Osteoarthritis Diagnostic Criteria: Hip
Pain and two of the following:
Erythrocyte sedimentation rate (ESR) <20 mm/h; Radiographic femoral or acetabular osteophytes; Radiographic joint space narrowing
Osteoarthritis Diagnostic Criteria: Knee
Knee pain and three of the following:
>50-year-old; stiffness <30 minutes; crepitus; bony tenderness, Bony enlargement; no palpable warmth
OA Diagnostic Criteria: Clinical and Radiographic Diagnosis
Knee pain and osteophytes and one of the following:
>50-year-old; stiffness <30 minutes; crepitus
OA Diagnostic Criteria: Clinical and Laboratory diagnosis
Knee pain and 5 of the following:
Age >50 years; stiffness <30 minutes; crepitus; bony tenderness; bony enlargement; no palpable warmth; ESR <40 mm/h; RF <1:40; synovial fluid signs of OA (clear, viscous, or WBC count <2,000/mm3)
OA Topical NSAID’s Indications
Topical therapy is preferred over systemic therapy by the European League Against Rheumatism (EULAR) and the Osteoarthritis Research Society International (OARSI).
Topical nonsteroidal antiinflammatory drugs (NSAIDs) are strongly recommended by the American College of Rheumatology (ACR) for knee osteoarthritis and conditionally for hand osteoarthritis. Due to concerns with absorption in hip osteoarthritis, topical therapy is typically not recommended.
Systemic therapy may be more effective depending on the number and location of joints affected. Topical therapy is an attractive option due to the relatively benign side effect profiles.
OA NSAID Indications
2nd line therapy = oral NSAIDs
NSAIDs further classified according to their chemical structure, all exhibit cyclooxygenase (COX) inhibition.
A practitioner is prescribing a medication for a patient recently diagnosed with OA. What is the recommended first line of treatment for OA?
Acetaminophen. First-line pharmacotherapy for OA is geared toward analgesia, specifically with acetaminophen (Tylenol). Due to acetaminophen’s cost effectiveness and safety, it is currently the first-line treatment recommended in guidelines by the ACR, the EULAR, and others.
Diclofenac (Voltaren) MOA
The mechanism of action for topical diclofenac is the same as for oral
NSAIDs. The benefit is that minimal diclofenac is absorbed when applied topically, which then
decreases the risk of adverse events. Data have shown that only 6% to 10% of the topical gel and
2% to 3% of the solution is absorbed.
Diclofenac (Voltaren) Dosage
LE’s: 4 g should be applied four times a day; if used on the UE’s: 2 g should be applied four times a day. The entire total daily dose should not exceed
32 g/d.
Diclofenac (Voltaren) Contraindications
Topical diclofenac carries the same warnings and contraindications as oral
NSAIDs, although the risk is less. Also, topical diclofenac is contraindicated on non-intact or
damaged skin.
Diclofenac (Voltaren) Adverse Events
pruritus, rash, dry skin, pain, and exfoliation.
Capsaicin MOA
Depletes substance P.
Initially, capsaicin releases substance P from the peripheral sensory
neurons.
With time, substance P becomes depleted, and capsaicin prevents
reaccumulation of substance P.
What is Substance P?
Substance P is a chemomediator responsible for pain
transmission from the periphery to the central nervous system (CNS).
Capsaicin Dose
Capsaicin is available as an over-the-counter (OTC) product in a patch, cream, gel,
liquid, or lotion.
Effect seen after 2-4 weeks of use
Capsaicin Contraindications, Adverse Events
Contraindication: None.
SE: burning and irritation at the application
site.
Oral NSAID MOA
One is by
inhibiting the conversion of arachidonic acid to prostaglandin, prostacyclin, and thromboxanes—
all of which are mediators of pain and inflammation. The other is by interfering with protein
kinase activation (especially when taken at higher doses).
Most non-selectively inhibit COX-1 and COX-2
What is COX?
The enzyme that converts arachidonic acid to prostaglandin G2.
What does COX-1 do?
COX-1 enzymes are found in
the gastrointestinal (GI) tract and kidney and produce protective prostaglandins,
What does COX-2 do?
COX-2 produces protective prostaglandins in
the kidney that are responsible for maintaining adequate blood perfusion via vasodilation of the
afferent arteriole.
Inhibition of COX-2 produces antiinflammatory
and analgesic effects without affecting the GI tract.
NSAID Contraindications
Pregnant women
Caution with liver or kidney disease
Aspirin allergy
EtOH dependence
all NSAIDs carry a black box warning emphasizing that they are contraindicated for
perioperative pain treatment in patients undergoing coronary artery bypass graft surgery and
should be avoided in patients with cardiovascular disease or risk factors.