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MSK path

Terms in this set (44)

Osteoarthritis
a. Characterized as a chronic noninflammatory joint disease in which there is degeneration of cartilage accompanied by new bone formation subchondrally and at the margins of the affected joint

b. Joint Findings:
i. Polished, ivory-like appearance of bone, resulting from erosion of overlying cartilage-> cartilage breaks free into the joint space
ii. Subchondral cysts
iii. Osteophytes at joint margins
iv. No fusion of bones (unlike Rheumatoid Arthritis)

c. CF:
i. Bouchard nodes-> osteophytes at the PIP joints
ii. Heberden nodes-> osteophytes at the DIP joints
iii. Joint stiffness in the morning that worsens throughout the day (contrast w/ RA), Crepitus (sound of joints)

d.X-ray= decreased joint space
Rheumatoid Arthritis
a. Autoimmune disorder (type 3 hypersensitivity) that most commonly affects peripheral joints

b. Autoantibodies (IgM antibodies) called Rheumatoid factor against Fc fragment of IgG (TNF is the key cytokine mediator)-> deposit in the joint

c. raised levels of anti-CCP antibodies contribute to the disease becoming chronic

d. Morphology:
i. Synovial cell hyperplasia
ii. Pannus-> granuation tissue that extends over articular catilage and causes its erosion
iii. Subcutaneous rheumatoid nodules
iv. Ankylosis-> fusion of the 2 bones (contrast w/ osteoarthritis)

e. CF: swelling of the joints and stiffness that improves w/ activity, raial deviation of wrist and ulnar devaiton of fingers, Swan neck/Boutenneiere deformities

f. Most often involves PIP and metacarpophalangeal joints
Extraarticular manifestions= Caplan Syndrome, Felty Syndrome (splenomegaly, neutropenia, and rheumatoid arthritis)
Juvenile Rheumatoid Arthritis
a. Below 16 years of age

b. Persists for min of 6 weeks

c. Oligoarthritis + RF negative polyartritis

d. Often preceded or accompanied by generalized lymphadenopathy and hepatosplenomegaly and an acute onset marked by fever
Seronegative arthritis
a. HLA-B27 (+)

b. Types: Ankylosing spondylitis, Reiter's syndrome, Arthritis (associated w/ ulcerative colitis, shigellosis, psoriasis
Ankylosing spondylitis
a. Intially target sacroiliac join and then eventually vertebral column ("bamboo spine"-> forward curvature)

b. Complications: Aortitis w/ aortic regurgitation, Uveitis (blurring of vision), Amyloidosis
Reiter's syndrome
a. Urethritis due Chlamydia trachomatis

b. HLA B27

c. "I can't see, I can't pee, and can't bend my knees following sexual encounter"
Psoriatic arthritis
a. Sausage-shaped DIP joints of fingers or toes

b. X-ray= Pencil-in-cup deformity
Septic arthritis
a. Causes:
i. Staph aureus
ii. Neisseria gonorrhoes
- Young women
- Deficiency of C5-C9 predisposes to dissemination

b. CF= painful sweelling of joint
Diag= joint aspiration will show increased neutrophils; Gram stain
Lyme Disease
a. Cause:
i. Spirochete= Borrelia burgdorferi
ii. Arthropod borne= Tick (Ixodes ricinus complex)

b. CF= skin rash (erythema chronica migrans), migratory arthrits (knees, shoulders, elbows), CNS/Cardiac involvement
Gout
a. Deposition of monosodium urate (MSU) crystals in joints

b. MSU phagocytosed by neutrophils in synovial fluid

c. Most often caused by under excretion of uric acid in the kidneys or HGPRT deficiciency

d. Seconday causes-> increased nucleated cell turnover (leukemia), decreased renal excreation (lead poisoning, alcoholism)

e. Podagra-> acute gout causing swelling, erythema and extreme pain and tenderness of the first metatarsal joint

f. Gouty tophus: An aggregate of dissolved urate crystals is surrounded by reactive fibroblasts, mononuclear inflammatory cells, and giant cells.


g. Clinical condiation associated w/ gout= urate nephropathy, renal stones, hypertenstion, coronary artery disease, interstitial nephritie (caused by lead poisioning)

h. Lab= hyperuricemia, joint aspitation is confirmatory
Chronic Gout
- Production of Tophi (deposits of MSU in soft tissue around joints causing granulomatous reaction w/ multinucleated giant cells-> causing erosive arthritis
Chondrocalcinosis (aka Calcium Pyrophosphate Crystal Deposition Disease/ Pseudo-Gout)
a. Involves knee

b. Crystal produce linear deposits in articular carilage

c. Associated w/ diabetes, hypothyroidism, ochronosis
Rhabdomyosarcoma
- Most common skeletal muscle tumor in children
Synovial Sarcoma
a. Malignant tumor seen adjacent to joints in lower extremities

b. Are morphologically monophasic or biphasic

c. Biphasic type contains spindle cells and epithelial cells
Lipoma
- Most common benign tumor in adults
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