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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
Liposarcoma
- Thigh, retroperitoneum
Myosisitis Ossificans
a. Muscle tissue changes to bone during healing after trauma

b. Affects horse riders on the inner thigh
Hereditary Bone Disorders (Polydactyly, Syndactyly, Absence of bone)
- HOMEOBOX (HOXD13) gene muation
Achondroplasia
a. Dwarfism

b. FGFR3 mutation-> Imparired proliferation of cartilage at growth plate

c. Only limbs are affected
Thanatophoric dwarfism
a. Gain of function mutation in FGFR3 (fibroblast growth factor receptor-3)

b. Die due to Resp insufficiency
Osteogenesis imperfecta (brittle bone disease)
a. AD congenital defect of bone resorption resulting in weak bone

b. Alpha-1/2 chains of collagen type 1 gene mutation

c. Type 1 (combatible w/ life, AD); Type 2 (lethal; AR)

d. CF: Osteopenia (recurrent fractures), blue sclera, deafness, easy bruisability, dental imperfections
Osteopetrosis (aka. Marble Bone/Alberg's Schonberg Disease)
a. Inherited defect of bone resorption resulting in abnormally thick, heavy bone that fractures easily-> due to poor osteoclast function

b. Children: AR gene defect in Carbonic anhydrase 2-> Impaired ability of osteoclast to maintain acidic environment-> failure of normal bone resorption

c. Adult: AD less severe defect in osteoclasts ("too much bone")

d. CF: patholoic fractures, CN compression (Infancy), Hydrocephalus

e. Treatment= B.M. transplantation

f. X-Ray= Erlenmeyer flask deformity (broadened epiphysis of long bones); Bone-in-Bone appearance
6. Paget Disease (Osteitis Deformans)
a. Disorder of increased, but disordered and structurally unsound, bone mass

b. Cause= paramyxovirus

c. Can be divided into 3 phases
i. Intial phase of osteoclastic resorption of bone
ii. Late phase of increased osteoblastic bone formation
iii. Final Burned-out quiscent osteosclerotic stage

d. CF: bone pain/deformity, chalk stick fractures

e. Risk of osteogenic sarcomas + high-output HF

f. Microscopy= Mosaic pattern; haphazard arrangement of cement lines

g. Lab= increase in Alkaline phosphatase; normal calicum/phosphorus levels
Osteoporosis
a. Decreasesd bone mass that is severe enough to increase the risk of fracture

b. RF: estrogen defeciency in Post-menopausal women

c. Pathogenesis= decreased estrogen-> increased cytokines and increased apoptoic activity by osteoclasts

d. CF (cancellous bone)= Bone pain and fractures in weight-bearing areas such as the vertebrae (leads to loss of height and kyphosis), hip fractures (femoral neck), and distal radius (colles fracture)

e. X-ray= osteopenia

f. Lab= Ca/Phosphorus/Alk phosphatase are normal (not helpful in diagnosis)

g. Dual energy x-ray absorptiometry

h. Cortiocsteriods worsen osteoporosis
Decreased mineralization of newly formed bone
a. Defect in Vit D metablism due to dietary deficiency, intestinal malabsorption, lack of sunlight, renal and liver ds

b. Lab findings: serum Ca2/ phosphorus decrease, alkaline phosphatase increase
9. Rickets/Osteomalacia
a. Are manifestations of Vit D deficiency/metablosim

b. Rickets (children)-> interference w/ deposition of bone in the growth plates
i. Crainotabes, Rachitic rosary, pectus carinatum, lumbar lordosis, bowing of legs

c. Osteomalacia (adult)-> bone formed during remodeling is undermineralized resulting in predisposition to fractures

d. Diffuse radiolucency on X ray
Hyperparathyroidism
a. Primary hyperparathyroidism
i. Caused by parathryoid ademoma/hyperplasia-> leads to increased osteoclast activation and bone resorption

b. Secondary hyperparathyroidism-> leads to prolonged states of hypocalcaemia

c. Morph: cortical bone thinning w/ loss of lamina dura around teeth

d. Can lead to osteoporosis (cystic spaces in bone), brown tumors (cystic enlargement of bone + fibrosis + hemorrhage), osteitis fibrosa cystica

e. X-ray= radiolucency
Renal osteodystrophy
a. Describe the skeletal changes that occur in Chronic Renal Disease

b. Chronic renal failure results in phosphate retention and hyperphosphatemia-> increased PTH secreation

c. Complication= long term hemodialysisc can lead to Beta-2 microglobulin amyloid deposition in bone and periarticular structures
Avascular (aseptic) necrosis of bone
a. Disruption of microcirculation causes bone infarctions

b. Most common location: femoral head, scaphoid bone, digits

c. Causes include trauma or fracture (most common), steroids, sickle cell anemia

d. X-Ray= will not see fracture
Osteomyelitis
a. Inflammation of bone/marrow due to infection

b. Organisms may reach the bone by hematogenous spread

c. MC= Metaphysis

d. Cause= Staph aureus (90%), Salmonella paratyphi (only osteomyelitis in sickle cell), Klebsiella/E.coli (IV drug abusers)

e. Neutrophils enzymatically destroy bone (dead bone is called Sequestrum)

f. Involucrum-> new bone that surrounds dead bone (Sequestrum)

g. Complication= Squamous cell carcinoma in draining sinus tracts to the skin
Tuberculous Osteomyelitis (Pott's disease)
- Hematogenous spread from lung targeting vertebral column
Osteochondrosis (Legg-Calve-Perthes disease)
a. Aseptic necrosis involving the femoral head ossification center

b. Boys 3-10 yrs

c. Secondary osteoarthritis is common
Bone tumor metastasis
- Metastasizes from prostate, breast, lung, thyroid, kidney
Osteoma
a. Benign tumor of skull bones

b. Associated w/ Gardner's polyposis syndrome
Osteoblastoma
- similar to osteoid osteoma but is larger (> 2 cm), arises in vertebrae, and presents as bone pain that does not respond to aspirin
Osteoid osteoma
a. Benign tumor of osteoblasts

b. Nocturnal pain relieved by aspirin
Osteochondroma (exostosis)
- Cartilage capped tumor
Enchondroma
a. Benign tumors of hyaline cartilage that arise within the medullary caviity of small bones in hands and feet

b. Multiple enchondromas can appear in Ollier disease and Maffucci syndrome

c. Risk for chondrosarcoma

d. X-ray= radiolucent nodule w/ pathological fracture
Giant Cell tumor
a. Soap bubbe appearance

b. Neoplastic mononuclear cell
Aneurysmal bone cyst
a. Tumor found in the Metaphyses of long bones

b. Micro= multinucleate osteoclast like giant cells
Osteogenic sarcoma
a. is a malignant tumor in which the cancerous cells produce osteoid matrix or mineralized bone

b. Primary osteosarcoma= mutation in RB and p53 gene

c. Tumors usually arise in the Metaphysis of the distal femur and proximal tibia

d. X-ray= sunburst appearance (spiculated pattern from calcified malignant osteoid)

e. Codman's triangle (tumor lifting periosteum)

f. Metastize to lung
Chondrosarcoma
a. Malignant tumors that produce cartilage

b. Arise in the pelvic bones and proximal femur

c. Composed of atypical anaplastic chondrocytes w/ multiple nuclei in lacuna

d. Metastatsize to lung
Ewing's sarcoma
a. is a malignant bone tumor characterized by primitive round cells without obvious differentiation

b. contain a (11;22) (q24;q12) translocation

c. Arise in the diaphysis of proximal femur or rib

d. X-ray= onion skin (appearnce of deposited bone layers from periosteal reaction)
Fibrous dysplasia
a. Benign tumor that cause developmental arrest where all of the components of normal bone are present, but they do not differentiate into mature structures

b. Femur, ribs, cranial bones of children most commonly affected

c. Multiple bone involvement is associated w/ Albright's syndrome (café-au-lait spots on skin + precocious sexual development
Chinease letter patern-> fibrous tissue between the trabuclae
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