Chapter 23 Musculoskeletal And Soft Tissue Disorders

Front 1

Osteogenesis imperfecta ("brittle bone disease")

Back 1

AD defect in type 1 collagen synthesis; the basic abnormality in all form of osteogenesis imperfecta is too little bone

Clinical findings: pathologic fractures at birth (skeletal fragility), blue sclera (reflection of underlying choroidal veins), deafness in some patients; treatment is bisphophonates (bind bone and inhibit osteoclasts)

Front 2

Achondroplasia (dwarfism)

Back 2

AD but ~80% spontaneous; increased mutations with paternal age

Mutation in fibroblast growth factor receptor gene causing constitutive activation of FGFR3 thereby suppressing growth (normal function of FGFR3 is to inhibit cartilage proliferation)

Shortened arms and legs; normal IQ, fertility, GH and IGF-1 levels, relatively normal lifespan

Front 3

Osteopetrosis ("marble bone" disease)

Back 3

Deficiency of osteoclasts resulting in reduced bone resorption and diffuse skeletal sclerosis ("too much bone"); AR form more severe than AD

Clinical: pathologic fractures (bone is brittle like chalk), anemia (replacement of marrow cavity), cranial nerve compression (visual & hearing loss)

Front 4

Osteomyelitis

Back 4

Inflammation of bone & marrow (virtually synonymous with infection)

Usually caused by pyogenic bacteria and mycobacteria, but can be caused by viruses, fungi and parasites

Front 5

Osteomyelitis in children and adults

Back 5

Staphylococcus aureus (90%) is most common cause, usually from hematogenous spread to bone; metaphysis is most common site (esp tibia and fibula in children); other pathogens: Streptococcus pyogenes and Haemophilus influenzae

Front 6

Osteomyelitis in sickle cell anemia

Back 6

Most often due to Salmonella paratyphi (Goljan says you need the spleen to get rid of Salmonella)

Front 7

Tuberculous osteomyelitis

Back 7

Hematogenous spread from a primary lung focus; targets the vertebral column (Pott's disease)

Front 8

Albers-Shonberg disease

Back 8

Osteopetrosis

Front 9

Pott's disease

Back 9

Extrapulmonary TB infection of the vertebral column

Front 10

Pseudomonas aeruginosa osteomyelitis

Back 10

Most often due to puncture of foot through rubber ware

Front 11

Sequestra

Back 11

Devitalized (ie dead) bone; term used in osteomyelitis

Neutrophils enzymatically destroy bones

Front 12

Involucrum

Back 12

Reactive bone formation in periosteum (ie a sleeve of living bone around the devitalized bone)

Occurs with chronic osteomyelitis

Front 13

Draining sinus tracts can occur in osteomyelitis. These have a risk of developing what?

Back 13

Squamous cell carcinoma at the orifice of the sinus tract

Front 14

Clinical findings, diagnosis, & treatment of osteomyelitis

Back 14

Clinical: fever, bone pain

Dx: CT scan or MRI (findings of a lytic focus surrounded by a zone of sclerosis)

Treatment: antibiotics + surgical drainage/debridement

S. aureus: vancomycin + ceftazidime

Salmonella paratyphi: ciprofloxacin

Front 15

Osteoporosis

Back 15

Porous bones and reduced bone mass

More common in women than men (men have greater bone mass to being with, so it takes longer to develop)

Risk is osteoporosis-related fracture, which is more common in women >65 (50%) compared to men > 65 (20%)

Primary: post-menopausal (most common), senile (age-related) or idiopathic (children & young adults)

Secondary: hypercortisolism, drugs like heparin, hypogonadism (hypopituitarism), malnutrition (anorexia nervosa), space travel

Front 16

Cause of senile osteoporosis

Back 16

Age-related decrease in osteoblast activity

Front 17

Cause of post-menopausal osteoporosis

Back 17

Due to estrogen deficiency, resulting in increased resorption of bone by osteoclasts and decreased formation of bone by osteoblasts

Front 18

Clinical findings, diagnosis, treatment in osteoporosis

Back 18

Clinical: bone fractures; compression fractures in vertebral bodies is most common; Colle's fracture of distal radius; Dowager's hump (thoracic kyphosis)

Diagnosis: dual energy x-ray absorptiometry (DEXA) scan is best test; measures bone mineral density

Tx: bisphosphonates, calcitonin

Front 19

Dowager's hump

Back 19

Thoracic kyphosis due to anterior wedging of thoracic vertebrae in osteoporosis

Front 20

Prevention of osteoporosis

Back 20

1. Calcium & vitamin D supplements

2. Stop smoking (inhibits osteoblast activity)

3. Weight-bearing exercise (need stress on bones): weight-lifting, vigorous walking; excludes swimmming which decreases bone stress

Front 21

Aseptic (avascular) necrosis of bone

Also called osteonecrosis

Back 21

Disruption of microcirculation causing bone infarcts; ischemia underlies all forms of bone necrosis

Femoral head & condyle is most common site and corticosteroids are most common cause

Other causes: alcohol, idiopathic, fractures

Other sites: humeral head, scaphoid (navicular) and lunate bones in wrist, talus bone (located between the calcaneus and the tibia and fibula)

Front 22

Femoral head asceptic necrosis

Back 22

Fracture in elderly persons

Subcapital fracture (ie just below head of femur) disrupts retinacular arteries from the medial circumflex femoral artery, resulting in aspetic necrosis

Pertrochanteric fractures do not compromise blood supply to the femoral head

Other causes of femoral head asceptic necrosis include sickle cell anemia and corticosteroids

Front 23

Scaphoid bone asceptic necrosis

Back 23

Scaphoid bone is the most commonly injured bone in wrist fractures and has a poor blood supply normally

Front 24

Clinical findings, diagnosis & tx in aseptic necrosis

Back 24

Clinical: asymptomatic; localized pain exacerbated by movement; functional limitation of activity

Dx: MRI most sensitive for early detection of osteonecrosis (double line sign)

Tx: core decompression (drill a small hole is necrotic region so it can fill with blood & tissue and maybe regrow); bone graft; joint replacement

Front 25

Osteochondrosis

Back 25

Asceptic necrosis of ossification centers in children

Front 26

Legg-Calve-Perthes disease

Back 26

Osteochondrosis of the femoral head

Boys 3-10 yrs old, present with pain in the knee or a limp

Secondary osteoarthritis is common

Front 27

Osteochondritis dissecans

Back 27

Osteochondrosis limited to the articular epiphysis (subchondral bone) resulting in breakdown & fragmentation of bone, and resultant loss of support for the overlying articular cartilage

Most common joint is the knee & the medial surface of the lateral femoral condyle is the most common site

Clinical findings of localized pain, stiffness & swelling; catching & locking of the joint; tenderness

Another typical scenario is insidious onset of elbow pain in adolescent baseball pitchers ages 11-15

Front 28

Osgood-Schlatter disease

Back 28

Painful swelling of the tibial tuberosity in boys ages 11 to 15

Inflammation of proximal tibial apophysis at insertion of patellar tendon

Pain with squatting, walking up stairs, knee extension with resistance

Permanent knobby knees

Front 29

Paget's disease of bone (osteitis deformans)

Back 29

A unique skeletal disease resulting in a net gain of architecturally unsound bone mass

Early blastic phase of osteoclastic resorption of bone causing shaggy-appearing lytic lesions

Late phase of increased osteoblastic bone formation, leading to a quiescent osteosclerotic phase, producing a thick, weak bone (mosaic pattern of weakened bone on histology) that is prone to fractures and a markedly increased alk phos

Clinical: bone pain, fractures, risk of osteosarcoma, risk of high output heart failure

Dx: shaggy areas of radiolucency, markedly elevated alk phos w/ normal calcium and phos

Tx with bisphosphonates and calcitonin

Front 30

Fibrous dysplasia

Back 30

A benign tumor that results from a defect in osteoblastic differentiation and formation, resulting in replacement of medullary bone with fibrous tissue with cyst formation

Can be monostotic (involving a single bone) or polyostotic (involving multiple bones)

Polyostotic may also have cafe au lait spots and precocious puberty

Ribs>femur>tibia or craniofacial bones

Clinical: bone pain, bone swelling, cherbism if in facial bones, fractures, and risk of osteogenic sarcoma or fibrosarcoma

Dx w/ imaging, tx w/ surgery

Front 31

Albright's Syndrome

Back 31

Occurs in fibrous dysplasia

1. Polyostotic bone involvement
2. Cafe au lait spots (usually same side of body)
3. Precocious puberty

Front 32

Most common malignancy of bone

Back 32

Metastasis; breast cancer is most common primary site

Front 33

Primary malignant disorders of bone in descending frequency

Back 33

Multiple myeloma > osteogenic sarcoma > chondrosarcoma > Ewing sarcoma

Treatment for primary bone tumors is surgery

Front 34

Benign bone tumors

Back 34

Osteochondroma, enchondroma, osteoma, osteoid osteoma, osteoblastoma, giant cell tumor

Front 35

Malignant bone tumors

Back 35

Chondrosarcoma, osteogenic sarcoma, Ewing's sarcoma

Front 36

Osteochondroma

Back 36

Benign tumor of metaphysis of distal femur

Males 13-30yr, solitary or multiple

Outgrowth of bone (exostosis) capped by benign cartilage

Most common benign tumor

Front 37

Enchondroma

Back 37

Medullary location -small trabecular bones in hands and feet

Benign; male=female; 20-50yrs; solitary or multiple

Risk for chondrosarcoma

Front 38

Osteoma

Back 38

Benign; facial bones; males of any age

Associated with Gardner's polyposis syndrome (aka familial colorectal polyposis)

Front 39

Osteoblastoma

Back 39

Benign; vertebra; males 10-20 yr; similar to osteoid osteoma

Front 40

Osteoid osteoma

Back 40

Benign; cortex of proximal femur; males 10-20 yr

Radiographic finding: radiolucent focus surrounded by sclerotic bone

Nocturnal pain relieved by aspirin

Front 41

Giant cell tumor

Back 41

Females 20-40 yr; benign; epiphysis of distal femur or proximal tibia

Reactive multinucleated giant cells resemble osteoclasts

Neoplastic mononuclear cells

Front 42

Chondrosarcoma

Back 42

Males 30-60 yr; pelvic bones or proximal femur

Grade determines biologic behavior

Metastasizes to lungs

Front 43

Osteogenic sarcoma

Back 43

Males 10-25 yr, risk factors: Paget's disease, familial retinoblastoma, irradiation, fibrous dysplasia

Metaphysis of distal femur, proximal tibia

Malignant osteoid

Radiographic findings: sunburst appearance (spiculated pattern from calcified malignant osteoid); Codman's triangle (tumor lifting the periosteum)

Metastasizes to lungs

Front 44

Ewing's sarcoma

Back 44

Males 10-20 yrs; pelvic girdle, diaphysis and metaphysis of proximal femur or rib

Small, round cell tumor; possible fever and anemia

Radiographic finding: onion skin appearance around bone (periosteal reaction)

t 11;22

Front 45

Monosodium urate crystals

Back 45

Cause gout

Needle shaped, negatively birefringent (yellow)

Front 46

Calcium pyrophosphate crystals

Back 46

Cause pseudogout

Monoclinic like or rhomboid; positive birefringence (blue)

Front 47

Mucin clot test

Back 47

Acid added to synovial fluid clots hyaluronic acid

Poor clot formation reflects decreased hyaluronic acid suggesting joint inflammation

Front 48

Ochronosis (alkaptonuria)

Back 48

autosomal recessive deficiency of homogentisic acid oxidase, resulting in accumulation of homogentisic acid (urine turns black when exposed to air & oxidized)

Homogentisic acid deposits in the intervertebral disks, causing osteoarthritis and other systemic findings

Front 49

Articular cartilage

Back 49

Type II collagen that provides tensile strength; proteoglycans

Front 50

Osteoarthritis

Back 50

Non-inflammatory progressive degenration of articular cartilage. Cytokines activate metalloproteinases that degrade proteoglycans and type II collagen in articular cartilage

Pain is most common complaint; joint stiffness after inactivity

Heberden's nodes (osteophytes) - enlargement of distal interphalangeal joints (DIPs)

Bouchard's nodes (osteophystes) - enlargement of proximal interphalangeal joints (PIPs)

Heat, NSAIDs, acetaminophen
Oral chondroitin sulfate, glucosamine (viscosupplementation)

Front 51

Rheumatoid arthritis

Back 51

A chronic, systemic vascular disorder that principally attacks the joints

HLA-DR 4 association

More often in women 30 - 50 yrs

Pathologenesis: B cells triggered to produce RF (an IgM anti-Fc portion of IgG) by synovial cells -> immune complex formation and complement (C5a) activation -> cytokine mediated destruction of articular cartilage

Front 52

Pannus

Back 52

Granulation tissue formed within the synovial tissue by fibroblasts and inflammatory cells

Front 53

Clinical findings in RA

Back 53

1. Prominent swelling of the second and third metacarophalangeal joints and PIP joints
2. Ulnar deviation
3. Swann neck deformity - (a) Flexion of DIP joint (b) extension of PIP joint
4. Boutonniere deformity - (a) extension of DIP joint (b) flexion of PIP joint

heart, lungs, hematologic, cervical spine, oither findings

Popliteal (Baker's) cyst behind the knee joint

Front 54

Sjorgens syndrome

Back 54

Female dominant autoimmune destruction of the minor salivary glands and lacrimal glands

clinical;
1. RA
2. Keratoconjunctivitis sicca - dry eyes describe as "sand in my eyes"
3. Xerostomia (dry mouth)

Labs: Anti-SS-A/Anti-SS-B antibodies; postive serum ANA; postive serum RF

Front 55

Still's disease

Back 55

JRA

Fever, rash, polyarthritis