Ch 26: Joints Flashcards Preview

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Flashcards in Ch 26: Joints Deck (53):
2

What is the difference between a synovial joint and a synarthrosis?

synovial joints provide movement, whereas synarthrosis are joints with little/no movement (solid joints) such as those between cranial bones. Synarthroses include: symphysis, synchondrosis, syndesmosis, synostosis

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What is the structure and function of the synovium?

structure: not true membranes (no basement), 1-3 layers of either type A (macrophages) or B (secrete hyaluronic acid)function: diffusion in/out of joint, ingestion of debris, secretion of enzymes, lubrication of joints

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What is arthrogryposis

retardation of joint development due to lack of movement. can rarely cause joint fusion

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Function of articular cartilage

dual role of shock absorption and lubrication of movable joints

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Tangential/gliding zone

closest to articular surface, contain elongated chondrocytes, collagen type II as "skin" of articular cartilage

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Transitional Zone

Below tangential zone: collagen transverse to articular surface, chondrocytes more spread out

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Radial Zone

below transitional zone: small chondrocytes arranged in short columns. separated from calcified zone by TIDE MARK

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Calcified zone

below radial zone: small chondrocytes in heavily calcified matrix. separated from radial zone by TIDE MARK

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Tidemark

separation between mineralized and unmineralized cartilage. below the tidemark calcified cartilage is nourished by epiphyseal BV. This is also where cartilage cells are renewed

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Subchondral bone plate

supports articular cartilage. is deep to calcified zone, directly contiguous with the cancellous bone of the epiphysis

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OsteoarthritisDifference between primary and secondary?

slowly progressive destruction of articular cartilage. Occurs in elderly or trauma related in youngprimary: intrinsic defects in articular cartilage. "wear and tear arthritis/degenerative joint disease"secondary: known underlying cause (congenital, metabolic, infection, crystal deposits, etc

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Chondromalacia

subcategory of osteoarthritis: affects patellar surface of femoral condyles in young. causes pain and stiffness

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Causes of osteoarthritis?

1. increased unit load2. decrease in resilience of articular cartilage (less water binding)3. stiffness of subchnodral course cancellous bone beneath calcified zone (decrease in shock absorbing microfractures)

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COL2A1

Gene associated with early onset osteoarthritis

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osteophytes

large peripheral growths of bone and cartilage (bone spurs)

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Sequence of histological changes seen in osteoarthritis

Death of chondrocytes, crack in articular cartilage, leakage of synovial fluid, cartilage is progressively worn away and new vessels form. fibrocartilage is deposited, forming a plug, which is then worn away, exposing subchondral bone (becomes thick and eburnated/ivory like). Leakage of synovial fluid into marrow causes "subchondral bone cyst"

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Heberden and Bouchard nodes

osteophytes at the DIP and PIP joints, respectively

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Clinical hallmarks of Osteoarthritis

Joint stiffness in the morning that worsens during the day, as well as deep/achy joint pain following activity

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Joint mice

fragments of cartilage floating in the joint space from disruption on articular surface

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Neuropathic joint diseaseMost common cause?

rapid and severe form of secondary osteoarthritis, due to neurologic disorder that will fragment the joint. Most common cause today is Diabetic peripheral neuropathy. Previously it was Charcot joint (destruction of knee joints in pts with syphilitic tabes dorsalis)

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Rheumatoid Arthritis

systemic, chronic inflammatory disease with polyarthritis. It has been contributed to genetic factors, humoral/cellular immunity, infection, and local factors

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HLA-DR4

gene associated with predisposition to RA

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Seropositive rheumatoid arthritis

positive for rheumatoid factor (RF): many antibodies (mostly IgM, some G+A). directed against Fc portion of IgG. RF is also found in many nonrheumatic disorders such as SLE, collagen vascular disease, dermatomyositis

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EBV and RA

EBV can stimulate the production of RF, and RA patients will have increased numbers of EBV-infected B cells

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Pannus

Seen in RA. "cloak." forms from mast cells moving over the surface of the articular cartilage and adjacent structures, lymphocytes aggregate and form follicular centers. 8-10 layers deep with multinucleated giant cells. It will erode the articular cartilage (from actions of collagenases).

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Ankylosis

destruction of the joint leading to fibrous fusion. Bony ankylosis: bony bridging of joint

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Rheumatoid nodule

extra-articular lesion (usually skin and visceral organs). central zone of necrosis surrounded by epithelioid histiocytes

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Acute necrotizing vasculitis

associated with RA, many organs can be involved

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Clinical hallmarks of RA

morning stiffness that improves with activity. Can be acute, slow progressing,

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Treatment of RA

NSAIDs, corticosteroids, DMARDs (disease modifying antirheumatic drugs)

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Spondyloarthropathies

seronegative for RF, ASSOCIATED WITH HLA-B27ankylosing spondylitis, Reiter syndrome, psoriatic arthritis, and arthritis associated with inflammatory bowel diseaseCommon features: Asymmetric involvement of only a few peripheral joints, sacroiliac/vertebral involvement, tendency to inflame periarticular tendons and fascia, system involvement, preferential onset in young men

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Ankylosing spondylitis

arthropathy of sacroiliac and vertebral column, can cause bony fusion of vertebrae ("bamboo spine". Patients have low back pain. Associated with AA amyloidosis, aortitis, and uremia

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Reiter syndrome

(reactive arthritis. "can't see, can't pee, can't climb a tree"). triad of arthritis, urethritis, conjunctivitis.

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Keratoderma blennorrhagica

associated with about 50% of reiter syndrome pts: mucocutaneous lesions similar to those of pustular psoriasis on palms, soles, and trunk

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psoriatic arthritis

HLAB27 islinked to psoriatic spondylitis, and HLADR4 has been linked to a more RA etiology

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Enteropathic Arthritis

proposed to be associated with bacterial proteins that are structurally related to HLA-B27, causing abnormal antigen presentation to T-cell receptors. Seen in ulcerative colitis, chron's, and whipple disease

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Infectious Arthritis

causes: S. aureus and N gonorrhoeae. Classically involves a single joint

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Juvenile arthris

"Still disease" any inflammatory arthritis of childhoodCan include seropositive arthritis, polyarticular disease with or without systemic symptoms, and pauciarticular arthritis (only a few large joints)

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Lyme arthritis

Borrelia burgdorferi infection. chronic Lyme disease complication that is identical to RA

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Primary Gout

hyperuricemia without any other disease

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Secondary Gout

occurs in association with other illness that results in hyperuricemia

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Causes of hyperuricemia

increased de novo purine synthesis, increased cell turnover, decreased purine salvage, decreased uric acid excretion by kidnyes

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PP-ribose-P

elevated in gout, as it is not used by HGPRT to aid in purine salvation. This leads to hyperuricemia

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Secondary gout causes

leukemia/myeloproliferative disorders (increased cell turnover), Lesch-Nyan syndrome (X-linked deficiency of HGPRT), Renal insufficiency, Saturnine gout (lead nephropathy), accelerated ATP catabolism, ethanol intake

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Tophus

white, chalky aggregates of uric acid crystals, with fibrosis and giant cell reaction in soft tissue and joints. Associated with gout

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Podagra

exquisitely painful and red arthritis of the great toe. Seen in about half of patients with acute gout

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Gout treatment

Colchicine and allopurinol

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PseudogoutPseudo-RA, pseudo-OA, pseudoneurotrophic disease

CPPD (calcium pyrophosphate dehydrate) deposition in synovial membranes. acute onset of gout like symptoms. These other pseudos are mimics of clinical symptoms, and due to CPPD deposition

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Crystals found in synovial fluid: gout vs pseudogout

needle shaped and negative birefringence under polarized light (yellow) vs rhomboid shaped and weakly positive birefringence under polarized light (purple)

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Hemophilia/hemochromatosis/ochronosis

blood, iron, and ochronotic pigment involvement in the joints, leading to destruction of articular cartliage

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Baker cyst

herniation of synovium of knee joint into popliteal space. Seen with various forms of arthritis

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synovial chondromatosis

benign, self limiting. hyaline cartilage nodules form in synovial fluid. "grains of sand between gears." Stimulates synovium to secrete increased fluid and bleeding. If cartilage nodules undergo endochondral ossification --> synovial osteochondromatosis

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Tenosynovial giant cell tumor

benign neoplasm, most common of synovium and tendon sheath. Occurs aslocalized or diffuse (PVNS...pigmented vilonodular synovitis)invades joint and erodes the bone