Musculoskeletal Disorders

Terms Definitions
Genu Varum
Gull-wing Deformity
Tendon inflammation
Wegener's Granulomatosis
Tendon degeneration
freq involves skull
hyperostosis frontalis interna: osteoma extends into orbit or sinuses
pathology: dense nl bone 
Sjogren's Syndrome
Multiple osteomas
Gardener Syndrome
Positively birefringent
CPPD crystals
produces osteoid and bone
most common bone tumor
M>F, usua 2nd-3rd decade
assoc c Paget dx in older pts
presents c localized pain, swelling, weight loss, anemia
XR: Codman triangle (periosteal elevatoin) + bone destruxn
Pathology: large, necrotic, hemorrhagic mass
poor prog, met to lungs common 
Painful, progressively enlarging masses in the central portion of the skeleton including pelvis, shoulders and ribs
Ulnar Deviation of Fingers
RA, Giant Cell Arteritis
bony metaphyseal projections capped with cartilage
Gardner syndrome: exostoses and colonic polyps -> may become carcinomas
cartilaginous masses w/n medullary cavity of bone

ollier dx: non-hereditary, multiple, most commonly hands and feet
present with pain and fx -> may undergo malignant transformation

Maffuci syndrome: familial; enchondromas and hemangiomas of skin
degenerative joint dx
incidence inc with age (80% 70 y.o. in one jt)
aging or wear and tear most important mech
insidious onset with joint stiffness, dec ROM, and effusions
XR: narrowing of joint space due to loss of cartilage and osteosclerosis
joints: vertebrae, hips, knees, DIP jts of fingers
subchondral cysts, eburnation, osteophytes, Heberden's nodes (DIP),Bouchard's nodes (PIP) 
Capital femoral epiphysis
AKA Femoral Head
Painful, aggressively enlargin masses, soft-tissue swelling, Codman's triangle, pulmonary metastases
A widespread granulomatous inflammatory reaction leading to stenosis in the walls of medium and large size vessles (typically involves the aortic arch and its branches)
Takayasu Arteritis
Overactive osteoclastic bone resorption with resultant new bone formation
Paget's Ds
Infiltration by inflammatory cells (CD4, T+ B cells),release of cytokines IL-1 & TNF-alpha, increased vascularity, aggregation of fibrin - formation of pannus
Receptor Activator of Nuclear Factor-KB; chr. 18; a factor critical in controlling osteoclast function - assoc. with Paget's Ds
AD form of dwarfism
abnl cartilage synthesis
mutation of FGFR3 (receptor) 
giant cell tumor
malignant, uncommon
ages 20-50
arises in epiphyseal region of long bones
present as bulky mass c pain and tenderness
XR: expanding area of radiolucency without sclerotic rim 
Paget disease
excessive bone resorption c replacement by soft, poorly mineralized matrix (woven) -> XR: enlarged, radioluscent bones
presents c pain, deformity, fxs
Lab: high high! alk phos
polyostotic: skull, pelvis, femur, vertebrae
alternates osteolytic -> osteoblastic phase
may cause bone hypervascularity c inc warmth of overlying skin 
suppurative arthritis
tender, red swollen ("hot knee")
monoarticular - high PMN count in joint fluid

Reiter syndrome: arthritis, uveitis, and conjunctivitis - possibly due to Chlamydia (can't pee, can't see, can't climb a tree)
Necrotizing vasculitis of arterioles, capillaries and venules (commonly involves the lung and kidney)
Microscopic polyangitis
Benign tumor of interosseous hyaline cartilage
Amyloid associated protein - secreted by liver
A mesenchymal tumor involving the overproduction of bone matrix
Autosomal dominant disorder of skeletal development with deficient/ imperfect ossification of bones such as the clavicle, cranium and pelvis
Cleidocranial dystosis
Vascular infarction leading to the cellular death of bone tissue
MSU gout of the big toe
Fibrotic proliferation and formation of metaplastic bone in skeletal muscle (usually following a trauma)
Myositis ossificans
Rare, aggressive, malignant tumors of skeletal m.
A chronic inflammatory myopathy that also involves dermatologic manifestations
osteitis fibrosa cystica 
osteoclasts resorb bone, kidney wastes Ca++
more common in primary hyperparathyroidism
presents c bone pain and fracture (fx)
fibrous replacement of marrow -> cystic spaces in bone and "brown tumors" 
chondromyxoid fibroma
benign, rare
affects young M
firm mass w/n metaphyseal marrow cavity of the tibia or femur
contains fibrous and myxomatous tissue 
dec in bone mass (esp postmenopausal F)
RF: estrogen deficiency, low density of orig bone, lack of exercise
all bones affected (XR: generalized radiolucency)
weight-bearing bones predisposed to fx 
Treatment for sarcoidosis
First line- glucocorticoids; second line- methotrexate (MTX)
Skin thickening confined to fingers, forearms and face, accompanied by CREST Syndrome
Limited Scleroderma
Most common soft tissue sarcoma of childhood and adolescence
Arthritis, uveitis in a child under 16
RA, splenomegaly, abnormally low WBC count (granulocytopenia)
Felty's Syndrome
Congenital contractures and rigid jt deformities of multiple jts (LE>UE)
Arthrogryposis multiplex
Heliotropic rash in upper eyelids and periorbital edema that can worsen with sun exposure, B/L symmetrical proximal muscle weakness, erythema of knuckles with raised scaly eruptions (Grotton Lesions)
Calcium phosphate crystals, often deposited on vessels
Calcium Apatite Gout
Accumulation of iron in body tissues (esp. liver and pancreas) accompanied by osteoarthritis-like sxs
Causes of in-toeing
Metatarsus adductus(most common cause in kids 3yrs)
Cause of ~10% of scoliosis cases
Congenital scoliosis
Scoliosis appearing during or right after a growth spurt (ex: ~10 y/o)
Congenital Scoliosis
Secondary Amyloidosis
Involves AA; reactive amyloidosis due to chronic disease
ankylosing spondylitis
mostly young M & +HLA-B27
assoc c IBD
involves SI joint + spine 
fibrous dysplasia
focal fibrous replacement of bone that begins in medullary cavity and remains encased in cortical bone.
esp male teenagers
affects long bones, ribs, skull, facial bones -> pathologic fx

McCune-Albright syndrome: assoc of polyostotic fibrous dysplasia, cafe-au-lait spots, and sexual precocity in W
Avascular necrosis of the femoral head in kids
Legg-Calve-Perthes Disease
Anti-Jo1 Antibody
Seen in pts with Polymyositis and Dermatomyositis (more specific for PM than DM)
Grade II Legg-Calve-Perthes Ds
Rarified bone, avascular segment, Gage's Sign (a small osteoporotic region on radiographs that forms a transradiant V on the lateral side of the epiphysis), Metaphyseal rarefaction
An aggressive, malignant tumor that usually arises in the musculature of the proximal extremities or in the mediastinum
Malignant fibrous histiocytoma
ANA, anticentromere antibodies
Seen in patients with Limited Scleroderma
"Hatchet Face"
Associated with Myotonic Dystrophy - a narrowing of the face due to loss of mass in the masster mm.
Adduction of the forefoot (causing the lateral border of the foot to appear convex)
Metatarsus adductus
Pain, joint locking and recurrent swelling of the knee; a tangled mat of red-brown folds is seen in the synovium
Pigmented Villonodular Synovitis
Degeneration of the anterior longitudinal ligament followed by ossification of the ALL; spans at least 4 segments
Diffuse Idiopathic Skeletal Hyperotosis (DISH)
Results from a lack of Vit. D
Osteomalacia/ Rickets
Rose Bengal Score or Lissamine Green Dye Test
Sjogren's Syndrome
Asymmetric arthritis of the DIP joints in a pt with nail pitting
Psoriatic Arthritis
Pathophysiology of gout
MSU crystals are chemotaxic to leukocytes, cytokines are released, inflammation follows; phagocytosis of crystals leads to cell repture and release of lysosomal enzymes furthering the inflammation(/ redness/ warmth?)
Associatd with consumption of red meat and EtOH
MSU gout
juvenile RA (still dx)
peak 1-3 yrs
often preceded by acute febrile illness
sxs: periarticular swelling, LA, hepatosplenomegaly, neg RF
var course; resolution possible 
Baker Cyst
A synovial cyst that develops in the popliteal space, often in the setting of an arthritis
Bouchard's Nodes
Osteophytes in the PIP jts of patients with OA
Heberden's nodes
Osteophytes in the DIP jts in patients with OA
Gradual onset of vague pain in jt, catching/ locking of the joint, possibly jt effusion
Osteochondritis dissicans
Associated with ANKH gene
Hereditary pseudogout; ANKH is a transmembrane inorganic pyrophosphate transport channel
Loss of flexibility in the spine, loss of chest expansion
Ankylosing Spondylitis
Fever, chills, rash and acute onset of monoarthritis of the knee in a 27 y/o sexually active female
Gonococcal Arthritis
Benign tumor of fat
Lipoma - soft, mobile and painless
Pathophysiology of OA
Early changes involve a decrease in proteoglycans and an increase in water content with weakening of the collagen; IL1, TNF alpha and NO levels increase in the cartilage; chondrocyte apoptosis of the articular cartilage; eventually - thinning of the cartilage, subchondral sclerosis and osteophyte formation
Causes of Congenital Scoliosis
Partial or complete failure in vertebral formation; partial or complete failure in body segment formation
Congo Red Staining
Performed on bx specimens to dx amyloidosis
A less common, later onset and slower progressing form of muscular dystrophy than Duchenne's Muscular Dystrophy
Becker Muscular Dystrophy
A benign tumor of smooth m.
Leiomyoma - think uterine fibroids
Weakness, poor endurance, discomfort, exertional dyspnea and tachycardia
S/S of Mitochondrial Myopathy - mitochondrial myopathy is a myopathy due to mutations occurring in the mitochondrial genome
Grade III Legg-Calve-Perthes Ds
Most of the epiphysis is avascular, viable bone posterior and anterior, metaphyseal changes
Cause of Cleidocranial Dystosis
A mutation in the transcription factor CBFA1, which controls osteoblast differentiation
Lab Tests for Osteomalacia/ Rickets
Serum vit. D, PTH, Calcium, phosphorous and alk.phos. levels
Insidious, progressive jt/ back pain in a patient with a positive PPD
Tuberculous Arthritis (Pott's Ds when spinal involvement)
5 Most common primary origins of neoplastic metastasis to bone
Lung, Breast, Thyroid, Kidney, Prostate
Dry eyes, Dry Mouth, B/L Parotid gland swelling
Sjogren's Syndrome (Sicca Syndrome)
Test for ANA, dsDNA, Smith, SSA and SSB antibodies
Dx testing for SLE
Most common cause of Pyogenic Osteomyelitis
S.aureus (followed by H.influenza and GBS)
Delayed motor milestones, marfanoid body type
Late Infancy- Early Childhood form of Centronuclear Myopathy
Obese teenage male presents with knee pain
Slipped Capital Femoral Epiphysis (SCFE)
Small interosseous abscesses involving the cortex of bone that are walled off by reactive bone
Brodie Abscesses - seen in pyogenic osteomyelitis
Symmetric arthritis of the LEs in a pt. with Chron's ds
Arthritis of Inflammatory Bowel Ds
Onset of mild, non-progressive limb weakness in the second or third decade of life
Late childhood- Early Adult form of Centronuclear Myopathy
ESR > 50 mm/h with normochromic, normocytic anemia
Seen in 50% of polymyalgia rheumatica patients
Microscopic polyangitis
Boutonniere Deformity
malignant tumor
30-60 yrs
de-novo or from pre-existing enchondroma
slower growing than osteosarcomas
presents c pain and swelling
involves spine, pelvic bones and upper extremities 
Bamboo Spine
Ankylosing Spondylitis
Harrison groove
Osteomalacia/ Rickets
Swan Neck Deformity
Housemaid's Knee
Prepatellar bursitis
Golfer's Elbow
Medial Epicondylitis
Small (
Osteoid Osteoma
calcium pyrophosphate crystal deposition
assoc with multiple dx (Wilson dx, hypothyroidism, DM)
pos birefringence, rhomboid appearance 
Ankylosing Spondylitis, Reactive Arthritis
Mushroom-shaped bony cartilage-capped growth
Associated with Sarcoidosis
Erythema nodosum
Sjogren's Syndrome
hyperuricemia -> deposition of monosodium urate crystals (needle-shape, neg birefringent) in jts -> recurrent bouts of arthritis
primary gout: 90%: due to inborn error of purine metabolism, usua from unknown enzyme deficiency (rare: Lesh-Nyhan)
secondary gout: unrelated to purine metabolism (example: leukemia) 
hypertrophic osteoarthropathy
etiology: intrathoracic carcinoma, cyanotic congenital heart dx, IBD
presents as idiopathic painful swelling of wrists, fingers, ankles, knees or elbows
periosteal inflammation, new bones form at end of long bones, MC and MTs
arthritis often seen with digital clubbing 
solitary cartilaginous growth with spongiosa of bone
solitary growths similar to those in multiple form (ollier) 
Most common neoplasm in women
Hypergammaglobulinemia and positive Hep B surface antigens in 30% of patients
Polyarteritis nodosa
Negatively birefringent under polarizing light microscope
MSU crystals
A dysraphism involving complete destruction of the SC
Osf2/ Cbfa1
Osteoblast specific transcription factor 2/ core binding factor activity 1 - two genes associated with Cleidocranial dysotsis; located on Chr. 6p21
Asymmetrical sterile arthritis following a GU or GI infection
Reactive Arthritis
Osteoclastic activity in underlying bone driven by RANKL from T-cells and synovial fibroblasts
felty syndrome
polyarticular RA assoc with HLA-B27
with splenomegaly + leukopenia 
Rheumatoid Arthritis (RA)
progressive arthritis
F>M; 20-60 yrs
autoimmune rxn with formation of circulating Ab (Rheumatoid Factor)
sxs: low grade fever, malaise, fatigue, AM stiffness
PE: joint swelling, redness, warmth
SF: inc cells (PMNs) + poor mucin
inc ESR and hypergammaglobulinemia
XR: erosions and osteoporosis
starts in small jts of hands & feet; symmetrical 
ewing sarcoma
malignant , rare
usual adolescents, often M
from mesenchymal cells
presents as pain, tenderness and early widespread dissemination
commonly affects pelvis, metaphysis of long tubular bones
similar to osteoid osteoma
BUT large, painless
often involves vertebrae
may be malignant 
osteoclasts unable to resorb bone
inc density of cortex with narrowing of erythropoeitic medullary cavities
presents with
brittle bones
CN palsies

AR: affects children -> early death (via anemia and infxn)
AD: affects adults -> fx 
Insidious onset of shortness of breath, cough, chest pain and hemoptysis; may also see constitutional s/s, eye involvement, splenomegaly & hepatomegaly
Slow-growing benign tumor located on the subperiosteal or endosteal surfaces of skull or facial bones
Proliferation of synovial lining; contains chromosomal abnormalities
Villonodular Synovitis
Generalized mm. pain increased with exertion, fatigue, perception of swollen jt not present on PE
Seen in patients with Diffuse Scleroderma
Most common adult muscular dystrophy
Myotonic Dystrophy
Fever, malaise, weakness, arthralgias, anorexia + wt loss, persistent pneumonia, chronic sinusitis
Wegener's granulomatosis
Pencil-in-cup appearance of phalanges on X-ray
Psoriatic Arthritis
Symmetric proximal muscle weakness in the UE and LE, muscle pain/ tenderness, fatigue
spread by direct inoculation of bone or hematologenous seeding
Staph aureus
Haem. influenzae
Salmonella (sickle cell dx)
Pseudomonas (IV drug users and diabetics)
Mycobac tuberculosis (Pott dx - spine)
presents with fever, localized pain, erythema and swelling
osteoid osteoma
affects diaphysis of long bones (often tibia or femur)
causes pain worse at night and relieved by ASA
XR: central radiolucency surr by sclerotic rim
Pathology: brown nodule surrounded by dense sclerotic cortical bone 
Deep, achy joint pain that worsens with use; jt enlargement; involvement of the DIP + PIP jts with MCP sparing
Often associated with Polymyalgia rheumatica
Giant Cell Arteritis
Wide-spread skin thickening and rapid progression to fibrosis of visceral organs (GI, heart, kidneys, skeletal muscle and lungs)
Diffuse Scleroderma
An autosomal dominant disorder that manifests with fragility of the skeletal system due to structural or quantitative defects in collagen type I
Osteogenesis Imperfecta
Light chain amyloid - derived from plasma cells and contains immunoglobulin light chains
Rare, aggressive neoplasm of the soft tissue
Patient initially presents with an area of pain and swelling in the muscle, that evolves into a painless mass and may eventually calcify to become a painful mass in the muscle
Myositis ossificans
Acute onset (hours) of monoarthritis of the first MTP jt - typically at night, accompanied by intense redness, heat and swelling
MSU gout
A necrotizing vasculitis most commonly affecting the respiratory and renal systems
Wegener's Granulomatosis
Disease progresses rapidly at first, then halts after 1-2 years, alowing for long-term survival
Takayasu Arteritis
Triad of acute necrotizing granulomas of the mucosa in the upper and lower respiratory tract, necrotizing granulomatous vasculitis affecting small to medium sized vessels,and focal necrotizing renal disease
Wegener's Granulomatosis
Severely degenerated joints secondary to loss of innervation to the joint
Neuropathic (Charcot) Joints
Inflammation of the thin inner synovial lining surrounding the tendons of the adductor policis longus and extensor policis brevis as they pass thru a common sheath at the base of the thumb and distal end of the radius
DeQuervain's tenosynovitis
Abnormally high-positioned scapula
Sprengel Deformity- congenital, may see webbing of skin btwn neck and scap.; may be assoc. with a Klippel-Feil Abnormality (fusion of any 2 cervical vert.)
osteomalacia and rickets
Vitamin D deficiency due to:
chronic renal insufficiency
intestinal malabsorption
dietary deficiency

osteoid produced in nl amounts, but cannot calcify properly -> diffuse radiolucency on bone films
lo Ca++ and P, high alk phos

Rickets: children, prior to closure of epiphyses -> "rachitic rosary", bowing of legs and fxs

Osteomalacia: impaired mineralization of nl osteoid matrix; fx and deformities
osteogenesis imperfecta
defect in type I collagen charac by
fragile bones
blue sclera
lax ligaments

Type 1: AD - mild to mod dx
Type 2: AR - stillborn infant - generalized crumpled bones

Type 3: AR - prog severe deformity; white sclera
Type 4: AD - var severity; nl sclera
Necrotizing vasculitis of small and medium sized vessels, typically involves renal and other visceral organs (NO lung involvement)
Polyarteritis Nodosa (PAN)
Grade IV Legg-Calve-Perthes Ds
Total epiphyseal involvement, diffuse metaphyseal changes, no viable bone posterior, epiphyseal consolidation
Defect in this gene (for type II collagen) is seen in familial cases of osteonecrosis
Most common site for leiomyosarcomas
Retroperitoneum or intra-abdominal; other common places include skin and deep soft tissue of extremities (typically associated wtih vv.)
Most common form of systemic vasculitis in adults
Giant Cell Arteritis
Increase tryptophan containing foods
May help prevent fibromyalgia flares
Lab Studies for Polymyositis
Serum CK, LDH, Alanine Aminotransferase, Aldolase, CBC (leukocytosis or thrombocytosis), elevated ESR, ANA positive in 1/3 of patients, Anti-Jo1, Anti-signal recognition particles (Anti-SRP)
PAX3- FKHR gene fusion dysregulating m. differentiation
Pathogenesis of Rhabdomyosarcoma
Galeazzi Sign
A test for hip dysplasia invovling flexing the infant's knees while they're supine so that the feet are flat on the table; looking to see if the knees are level - unlevel knees = positive test
3 common LE congenital abnormalities
1)fibular deficiency; 2)tibial deficiency; 3)longitudinal deficiency of the femur
Barlow Test
A Test for hip instability with dislocation occurring with flexion, adduction and a posterior force/ push
Ortolani Test
A test for hip dysplasia involving abduction and anterior pressure/ pull; "click/ clunk"
ABCDEs of Arthritis
Alignment of bones, Bone integrity, Cartilage/ jt space, Deformities, Erosions, Soft Tissue involvement
Acute onset of a symmetrical small joint arthralgia that is self-limiting
Viral Arthritis
Fragile bones, blue sclera, and early deafness
Ostogenesis imperfecta
Benign bone tumors that produce a dull pain unresponsive to ASA
psoriatic arthritis
similar to RA, but no RF
assoc with HLA-B27 
Deep, achy pain referred to the paraspinal region that doesn't radiate and worsens on extension of the spine
Facet Joint Syndrome
Pathogenesis of Scleroderma
Abnormal immune response from CD4 T cells and TH2 cells - abnl secretion of growth factors & cytokines, t-cell mediated fibrogenesis and vascular injury, abnl humeral response
Elevated alk.phos level, pain, facial deformities and fractures
Seen in Paget's Ds
Foot exhibits: plantar flexion (equines) of the ankle, adduction (varus) of the heel/ hindfoot, high arch (cavus), and adduction of the forefoot
Talipes Equinovarum (AKA Club Foot)
Grade I Legg-Calve-Perthes Ds
Less than 1/3 of epiphysis involved, cystic appearance, epiphyseal height maintained, viable tongue of epiphysis
Newborn with more folds on one leg than the other
Congenital Hip Dysplasia
Most common causes of viral arthritis
Parvovirus B19, Rubella (including following a rubella vaccine), Hep B or C
Patient presents between ages 3 and 5 with delayed motor milestones with progressively worsening loss of strength and Gower's Sign, and joint contractures
Duchenne's Muscular Dystrophy
Tests for Congental Hip Dysplasia
Barlow Test, Ortolani Test, Galeazzi Sign
Lab studies for Dermatomyositis
CPK, Aldolase, LDH, SGOT, SGPT, RF, ANA, Anti-Jo1, Anti-pMi-2,Anti-SRP
Severe hypotonia and weakness at birth
Neonatal form of centronuclear myopathy
A cyst arising from a cystic or myxoid degeneration of CT; the cystic cavity lacks a true lining of cells
Ganglion Cyst
Cause of the pain in Osteoid Osteomas/ the reason the pain is relieved by ASA
Production of PGE2
Malignant tumor of fat
Liposarcoma - one of the most common sarcomas of adulthood
Acute onset of tender, nodular, erythematous eruption usually found on the extensor aspects of the LEs
Erythema nodosum - associated with sarcoidosis
B/L low/ absent longitudinal arch; arch flattens when weight bearing and foot becomes pronated
Hypermobile Pes Planus (rigid flat feet indicates a more concerning pathology)
Benign, aggressive tumor containing multinucleated giant cells that look like osteoclasts
Giant Cell Tumor - typically involves the knee
4 common UE congenital Limb Abnormalities
1)hypoplasia or absence of the thumb; 2)radial deficiency; 3) ulnar deficiency; 4)transverse deficiency of the forearem (complete absence fo the hand and wrist can occur)
Dx of Duchenne's Muscular Dystrophy
Serum CK levels, EMG and a bx (Western blot demonstrating decreased dystrophin)
Why distal joints are more affected by gout than proximal ones
Temperature - distal jts have a lower temp, so the MSU crystals precipitate out easier there
Reason the nucleus is in the center of the m. in Centronuclear Myopathy
Most likely involves a defect in the cytoskeleton of the m. cells, preventing marginalization of the nucleus
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