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Flashcards in week 8- MSk 3 Deck (66)
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• Osteoarthritis:

o Aka Degenerative Joint Disease
o Mc type of joint dz
o Dt breakdown of articular (hyaline) cartilage in synovial joints (actually entire joint organ)
o Mostly dt ↑wear and tear, or 2nd nonspecific inflammatory changes


• Prevalence of OA

o ↑ w age
o 20M in US; ↓45 M > F; >55 F > M
o using x-rays, >50% >65
o 80-90% >65 have evidence of OA


• OA etio:

o Multifactorial
o Local inflame
o Hx jt trauma
o Systemic hormones: esp E
o ↓proprioception
o Genetics
o Obesity: ↑mechanical stress
o Mineral def
o Biomechanical: post trauma; squatting, climbing stairs, excessive kneeling


• Pathology of OA:

o Metalloproteases: collagenase, stromelysin, gelatinase
o Cytokines: IL-2, IL-6, TNFa
o NO
o ↓ proteoglycans → cartilage softens, ↓elasticity
o ↓jt surface integrity → loss of jt space
o Proliferation of new bone & cartilage at jt margins (spurs or osteophytes)


• Subsets of OA:

o 1st or 2nd
o Local or general
o Hypertrophic or atrophic
o +/- diffuse idiopathic skeletal hyperostosis (DISH)
o +/- overt inflame
o +/- chondrocalcinosis
o Rate of progression


• 1st OA:

o Dt aging, idiopathic
o in previously intact joints, no apparent initiating factor
o usu C and L spine, PIPs, DIPs, base of thumb, hips, knees, 1st MTP


• 2nd OA:

o Predisposing: Trauma Congenital or developmental dos, CPPD,
o Osteonecrosis, RA, gouty arthritis, septic arthritis, Paget dz of bone
o DM, acromegaly, hypothyroid, neuropathic (Charcot) arthropathy, frostbite


• OA ssx:

o related pain, deep achy
o ↓ROM
o Crepitus
o Stiffness during rest (gelling)
o AM jt stiffness, usu ↓30 mins


• PE for OA:

o Heberden’s and Bouchard’s nodes
o Mild-mod firm jt swelling
o Crepitus
o ↓ROM
o Tender jt line, mb warm, effusion
o Wasting of mm assoc w jt
o Periarticular tenderness
o Deformities or instability in advanced dz


• Labs for OA:

o Not useful in dx
o RF (-)
o Eval synovial fluid
o xray
o cartilage degradation products


• Pt archetypes of OA:

o Menopausal/Erosive
o Charcot


• Menopausal/Erosive OA:

o Aka erosive or inflam OA
o Usu F beginning in menopause
o Pain, swelling, inflame, redness in hand IP’s
o Erythema subsides → enlarged, stiff, st deformed jt
o Boney erosions and cystic swellings
o DMARDs don’t help, settles down on its own in a few yrs



o Bridging enthesophytes in spine
o Osteophytes in peripheral jts
o ↓ ROM
o Metabolic syndrome, usu older obese M or DM


• Charcot OA:

o Dt denervation of jts
o Destructive form of OA
o Extensive new bone formation around jts
o Found in diabetic neuropathy


• Radiographs of OA:

o Jt space narrowing
o Osteophytes
o Sclerosis
o Deformity
o Gull wing/saw tooth
o Spurring
o Subchondral cysts


• OA ddx:

o PsA: dacylitis
o Onychodystrophy
o AS
o ReA
o EA
o RA- DIP unaffected, systemic ssx
o CPPD: crystals in jt fluid, calcification of cartilage, knee, brief attacks


• Crystal induced coditions:

o Gout
o Calcium Pyrophosphate Deposition (CPPD)


• Gout:

o deposition of monosodium urate crystal in and around jt
o M:F 9:1, most F post menopausal
o 40-60
o 3 clinical stages: asx hyperuricemia, acute intermittent, advanced (Chronic Tophaceous)


• Gout etio:

o Metabolic:
o 1st: ↑uric acid dt specific enzyme defects, def, overactivity
o 2nd: ↑uric acid dt ↑nucleic acid turnover: myelo-proliferative dos, chronic hemolytic anemia, psoriasis
o ↑intake dietary purines: rich foods, esp w alcohol
o Renal: ↓excretion dt Pb nephropathy, acute ethanol ingestion, toxemia of pg, drugs (salicylates, diuretics)


• Asx Hyperuricemia:

o Most ppl w ↑uric acid never → gout, tophi, KD stone
o ULN serum urate: 8.0-8.5mg/dL
o > 6.8mg/mL is > soluble concentration of monosodium urate in body
o =physiologically hyperuricemia


• Acute Intermittent Gout:

o Mc in primary care
o Rapid development of warmth, swelling, erythema and PAIN
o Pain escalates over 8-12 hrs
o Initial attack usu monoarticular, 1st MTP
o Other: midfoot, ankle, heel, knee
o → Walking difficult to impossible
o Lc: wrist, finger, elbow
o mb systemic sx (fever, malaise)
o Erythema may extend beyond involved jt , resemble bacterial cellulitis
o Attacks hrs-2 wks, gradual ↑ duration, freq; feel normal bw
o Synovial fluid has crystals even if asx


• Chronic Tophaceous Gout

o Usu after >10 yrs acute intermittent gout
o intercritical periods are no longer pain free
o Less painful then acute intermittent gout attacks bw attacks
o exquisite pain, more often, st every few wks
o mb diffuse, symmetrical involvement in hands, like RA
o Tophi around jts or other areas, fingers, wrists, ears, knees, olecranon bursa, Achilles tendon
o Microtophi inside synovial fluid, w MRI


• Dx of gout:

o ↑Serum uric acid
o Synovial fluid shows needle or rod shaped crystals, yellow one direction, blue the other
o WBCs 5000-80,000/mm3
o also culture to r/o infx


• Calcium Pyrophosphate Deposition (CPPD)

o Aka pseudogout: acute attacks of CPPD crystal-induced synovitis
o Aka Chondrocalcinosis: radiographic calcification in hyaline/fibrocartilage
o Aka Pyrophosphate arthropathy
o 1.3/ 1000, ~50% pop have xray changes of CPPD by 80
o M>F 1.5:1
o Assoc metabolic dos: hemochromatosis, hyperparathyroid, hypomagnesemia, hypophosphatasia, hypothyroid


• Clinical Manifestations of CPPD (sub-types):

o Asx (will have radiographic changes) may be found incidentally
o Pseudogout
o Pseudo-rheumatoid arthritis
o Pseudo-osteoarthritis
o Pseudo-neuropathic joint disease


• Pseudogout:

o = self-limited acute or subacute attacks of arthritis (mono or pauci) in extremities
o Provoked: Trauma, surgery, severe medical illness
o St both urate and CPPD crystals in a single inflammatory effusion
o Systemic: fever, leukocytosis w left shift, ESR


• Pseudo-rheumatoid arthritis

o nonerosive, asynchronous, inflame
o CPPD crystals in jt fluid
o Rarely mimics sepsis


• Pseudo-osteoarthritis

o 50% w sx CPPD show progressive jt degeneration
o knees, wrists, MCP’s, hips, shoulders, elbows, spine


• Pseudo-neuropathic joint dz:

o severe jt degeneration and disruption w of neuro do → jt denervation
o Charcot jt
o Underlying dos: DM (mc), tabes dorsalis, syringomyelia


• Imaging/Testing for CPPD:

o Synovial fluid: intracellular Ca pyrophosphate dehydrate crystal
o Chondrocalcinosis ("cartilage calcification")
o Degenerative changes
o Squared-off bone ends, hook-like osteophytes in MCP jts
o radiocarpal jt narrowing, navicular-lunate dissociation
o Notching or erosion of distal femoral cortex superior to patella
o subchondral cysts in small jts of spine and SIJ