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Pathology > Bones & Joints > Flashcards

Bones & Joints Flashcards

1
Q

Functions of the Skeleton

A
  • Body shape & size
  • Structural support
  • Protection of internal organs
  • Mechanical support for movement
  • Mineral homeostasis
  • Houses hemopoietic tissue
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2
Q

Manifestations of Bone disease

A
  • Disability
  • Deformity
  • Pain
  • Electrolyte imbalance
  • Anemia/ Pancytopenia
  • Neurological dysfuction
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3
Q

Composition of Bone

A

Extracellular matrix

  • Osteoid
  • Minerals

Cells

  • Osteoblast
  • Osteoclast
  • Osteocytes
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4
Q

Components of Osteoid

A
  • Type 1 collagen
  • GAGs
  • Osteocalcin (Protein like osteopontin)
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5
Q

Mineral components in bones

A

Hydroxyapatite [Ca10(PO4)6(OH)2]
- Bone hardness

Repository for:

  • 99% body calcium
  • 85% body phosphorus
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6
Q

Osteoblast

A
  • Bone producing- synthesize matrix proteins (collagen) - Osteoid
  • Initiates mineralization - Binding Calcium phosphate to Osteoid to make hard bone
  • Binds hormones - PTH
  • Regulates osteoclast
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7
Q

Normal Growth & Development

A
  • Pre-modeled in cartilage OR Direct production

- Mesenchymal condensation

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8
Q

Osteoclast

A
  • Bone removing- release proteolytic enzymes & bone resorption
  • Derived from Hematopoietic progenitor cells
  • Multinucleated
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9
Q

Types of bones

A

Mineralization

  • Non-mineralized/ Osteoid
  • Mineralized

Structure

  • Cortical/ Compact (Surface forming)
  • Cancellous/ Spongy (Inner trabecular)

Microscopic arrangement of matrix fibers

  • Woven / Immature
  • Lamellar/ Mature
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10
Q

Woven bone

A

Laid in fetal skeleton or disease states

  • Collagen arranged in random orientation –> Resist force in all directions
  • Forms quickly
  • Remodeled into Lamellar bone
  • Always pathological in adults
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11
Q

Lamellar Bone

A
  • Collagen arranged in parallel sheets –> Resist unidirection force
  • Facilitates weight bearing
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12
Q

Endochondral ossification

A

Bone formed after replacing cartilage anlagen
- Formation of most bones

pg 12 Mesenchymal condensation =

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13
Q

Intramembranous Ossification

A

Formation of bone w/o cartilage network
- mesenchymal condensation –> Differentiation of mesenchymal stem cells into Osteoblasts –> Direct bone synthesis on fibrous layer of tissue

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14
Q

Layers of Growth Plate (Endochondral ossification)

A
  1. Reserve zone
  2. Proliferative zone
  3. Hypertrophic zone
  4. Mineralization zone
  5. Primary spongiosa zone
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15
Q

Reserve zone

A

Chondroblasts resting (inactive)

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16
Q

Zone of proliferation

A

Chondroblasts proliferates (multiply) & contribute to lengthening of the plate

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17
Q

Zone of hypertrophy

A

Chondroblasts hypertrophy, secrete matrix & more longitudinal growth

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18
Q

Zone of Mineralization

A

Chondroblasts apoptose & cartilage matrix mineralizes

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19
Q

Primary spongiosa zone

A

BV innervate & brings osteoprogenitor cells that replace mineralized cartilage w/ bone

  • Fist layer of spongy bone formed
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20
Q

Bone modeling

A

Formation & growth of individual bones

  • Longitudinal growth = Childhood & Adolescents
  • Appositional growth = Adulthood
  • Osteoblast & osteoclast work independently
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21
Q

Bone remodeling

A

Constant replenishment of bone during the lifetime

  • Occurs due to Osteoblast & Osteoclast working together
  • Highly regulated microscopic process
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22
Q

Mineralization

A

Osteoid ——- (10-15 days) —-> Bones

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23
Q

Special features of Growth plate zones

A

Zones 1-3 = Maintaining cartilage

Zones 4-5 = Bone formation

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24
Q

Etiology of Achondroplasia

A
  • AD
  • Gain of function mutation of FGFR3 gene

Normally FGF binds FGFR3 –> Inhibits Endochondral ossification

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25
Q

CFs of Achondroplasia

A
  • Short stature (short extremities & normal trunk)
  • Large head w/ bulging forehead/ Frontal bossing
  • “Saddle nose” - Depression of nose root
  • Exaggerated lumber lordosis

Intelligence, reproduction & life expectance not affected

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26
Q

Clinical diagnosis of Achondroplasia

A
  • Disproportionate dwarfism & normal intelligence
  • Bones w/ endochondral ossification (long bones)
  • Usually have normal parents
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27
Q

DDx of Achondroplasia

A
  1. Cretinism (thyroid deficiency)
  2. Growth hormone deficiency

Intelligence & reproduction usually affected
Limbs & trunks, etc. are not disproportionate

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28
Q

Osteogenesis Imperfecta (OI)

A

Brittle bone disease
Connective tissue disorder
- Dec in Type 1 Collagen synthesis –> Extreme fragility

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29
Q

Etiopathogenesis of OI

A
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30
Q

CFs of OI

A

Dec bone matrix

  • Bone fragility = Recurrent fractures from birth to childhood
  • Deformities & disability
  • Short stature

Dec in other Connective tissue

  • Blue sclera - partial visualization of underlying choroid through translucent sclera
  • Hearing loss - abnormal middle & inner ear bones (sensorineural deficit + impeded conduction)
  • Small misshapen blue-yellow teeth - Dentin deficiency
  • Easy bruisability - Fragile capillaries
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31
Q

Osteopetrosis

A

Marble Bone disease
- Bones are brittle & fracture easily bc the new bone deposited is woven bone

  • Dec bone resorption due to deficient Osteoclast development or function
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32
Q

Etiopathogenesis of Osteopetrosis

A

Mutation –> Impaired acidification of osteoclast resorption pit –> Impaired dissolution of Calcium hydroxyapatite within the matrix

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33
Q

Diagnosis of Osteopetrosis

A

X-ray

Genetic analysis

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34
Q

Treatment of Osteopetrosis

A

Bone marrow transplant

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35
Q

Ehler Danlos Syndrome

A

Faulty collagen synthesis due to mutation in genes encoding Collagen or enzymes modifying collagen resulting in deficient collagen synthesis

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36
Q

CFs & Molecular Etiology of EDS

A

COL5A1 & COL5A2 (AD)

  • hypermobile joints
  • Stretchy skin
  • Joint dislocation
  • Easy bruising

COL3A1 (AD)

  • Affects BV & organs
  • Easy bleeding
  • Berry aneurysms & rupture
  • Aortic rupture
  • Uterine rupture in pregnancy / Other organ rupture

Lysyl hydroxylase enzyme deficiency (AR)

  • Congenital scoliosis
  • Ocular fragility
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37
Q

Marfan Syndrome (Etiopathogenesis)

A

AD connective tissue disorder affecting bones, heart, aorta & eyes

  • Fibrillin (FBN1) gene mutation on Chr 15
  • Fibrillin is a component of microfibrils
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38
Q

CFs of Marfan Syndrome

A
  • Tall w/ super long extremities & long, tapering fingers & toes (Excessive TGF-b signaling)
  • High arched palate, hyperflexible joints, kyphosis, scoliosis, pectus excavatum & Pectus carinatum (pigeon chest) (Loss of structural integrity)
  • Subluxation or dislocation of lens- Ectopia lentis (B/L)
  • Mitral valve prolapse –> CHF, Aortic root dilation –> A. regurgitation & A. dissection (Loss of elastic fibers in tunica media)
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39
Q

MCC of death in pts. w/ Marfan Syndrome

A

Aortic rupture

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40
Q

Regulation of Bone Remodeling

A

Coordinated activity of Osteoblasts & Osteoclasts
Osteoblast = Key regulatory cell
- Synthesize bone matrix (Collagen & other proteins)
- Initiates & maintains mineralization of matrix
- Responds to stimulation from factors released by Osteocytes
- Responds to stimulus from Blood borne factors
- Activates/ inactivates Osteoclast activity

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41
Q

Factors released by Osteocytes

A
  • Sclerostin
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42
Q

Factors released by Osteoprogenitor cells

A
  • Bone Morphogenic Protein (BMP)
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43
Q

Blood Borne factors

A

Hormones

  • Vit D
  • Cytokines
  • Growth hormones
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44
Q

Intercellular signals involved in Bone remodeling

A
  1. RANK & RANKL
  2. Monocyte Colony Stimulating Factor (M-CSF)
  3. Sclerostin
  4. BMP
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45
Q

RANKL (Receptor Activator of NF-Kappa-B Ligand)

A

Expressed on Osteoblast

Binds to RANK on Osteoclast & precursors –> Activation

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46
Q

Upregulation of RANKL

A
  1. PTH
  2. IL-2
  3. Vit D3
  4. Some malignancies
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47
Q

Inhibition of RANKL

A

Osteoprotegerin (OPG) (TNF family)

- Produced by Osteoblast when WNT proteins from the Osteoprogenitor cells binds to LRP 5/6 on the Osteoblast

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48
Q

Monocyte Colony Stimulating Factor (M-CSF)

A

Produced by Osteoblast

  • Signals monocytes to differentiate into Osteoclast
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49
Q

Sclerostin

A

Produced by Osteocytes

Binds to LDL receptor proteins 5/6 on Osteoblast –> Inhibit Osteoprotegerin production

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50
Q

Bone Morphogenic Protein (BMP)

A

Produced by Osteoprogenitor cells

- Stimulate osteoblasts & Inc Bone resorption

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51
Q

Osteoporosis

A

Osteopenia that is severe enough to significantly increase the risk of fracture

  • Localized or Diffused
  • Primary (Senile & Post-menopausal) or Secondary
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52
Q

Diagnosis of Osteoporosis

A

DEXA Scan

- T-score =

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53
Q

Peak Bone Mass Determinants

A
  1. Sex (m>f)
  2. Physical activity
  3. Genetics
  4. Nutrition
  5. Hormones
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54
Q

Rate of loss of bone mass in Senile Osteoporosis related to:

A
  • Dec physical activity
  • Hormones
  • Dec reproductive age of Osteoblast & its precursors
  • Dec synthetic activity of Osteoblast
  • Dec Biological activity of matrix precursors
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55
Q

Pathogenesis of Post-menopausal Osteoporosis

A

Dec Estrogen –> Inc inflammatory cytokine release by Monocytes (IL-1)

  • -> Inc Osteoclast activation & recruitment
  • -> Inc RANK-RANKL activity
  • -> Dec Osteoprotegerin
  • -> Dec Osteoclast apoptosis

= HIGH bone turnover & bone loss

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56
Q

Endocrine causes of Secondary Osteoporosis

A
  • Hyperparathyroidism
  • Hyperthyroidism - pts usually have Hypocalcemia
  • DM
  • Addison disease
  • Pituitary disease
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57
Q

Neoplastic causes of Secondary Osteoporosis

A
  • Carcinomatosis
  • Multiple myeloma
  • Paraneoplastic Disease = Squamous Cell Carcinoma of lung
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58
Q

GI causes of Secondary Osteoporosis

A
  • Malnutrition
  • Hepatic insufficiency
  • Vit D/C deficiency
  • Malabsorption
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59
Q

Drugs that cause Secondary Osteoporosis

A
  • Chemotherapy
  • Corticosteroids
  • Alcohol
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60
Q

Other causes of Secondary Osteoporosis

A

Immobilization

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61
Q

CFs of Osteoporosis

A

Fracture or bone pain after trivial trauma

- Elderly patients

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62
Q

Radiological diagnosis of Osteoporosis

A
  • Plain radiograph- Fractures & loss of bone

- DEXA scan/ CT scan- < 2.5 SD

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63
Q

Serum readings in Osteoporosis

A

Primary- Normal Calcium, Phosphate & Alkaline phosphatase

64
Q

Complications of Osteoporosis

A

Fractures that heal slowly -

Bone deformities

65
Q

Causes of Hyperparathyroidism Bone disease

A

Primary- Tumors
Secondary- Vit D deficiency
Tertiary- Inc PTH despite correction of Ca & Vit D levels

66
Q

Pathogenesis of Hyperparathyroidism Bone-disease

A
67
Q

Paget Disease / Osteitis Deformans

A

Acquired disorder of bone remodeling due to unknown cause

68
Q

Epidemiology of Paget Disease

A
  • Adults (>40 years)
  • M=F
  • MC in whites
69
Q

Etiology & RFs of Paget Disease

A
  • Genetic (15% have FHx) –> Sqstm1 gene

Environmental (Viral infection that may trigger Osteoclast activity)

70
Q

Pathogenesis Of Paget Disease

A

Unregulated Osteoclastic activity –> Inc resorption –> Stimulates Inc Osteoblastic activity –> Abnormal haphazard bone deposition

71
Q

Phases of Paget Disease

A
  1. Osteolytic
  2. Mixed
  3. Blastic/ Burned-out/ Sclerotic
    Mixed- Osteoblast need the blood w/ increased oxygen to provide substrates for osteoid formation
    Osteolytic phase - Inc urinary Hydroxyproline due to breakdown of Collagen type 1
72
Q

Osteolytic phase of Paget Disease

A
73
Q

Mixed pHase of Paget Disease

A
74
Q

Blastic phase of Paget Disease

A
75
Q

Hallmark feature for diagnosis of Paget Disease

A

Mosaic/ Jigsaw patten of bone

- due to dense sclerosis w/ irregular wavy cement lines

76
Q

CFs of Paget Disease

A
77
Q

Investigation for Paget Disease

A
  • X-ray- Lytic or Sclerotic lesion
    2. Inc serum ALP
    3. Inc urinary Hydroxyproline (breakdown product of Collagen type 1)
78
Q

Complications of Paget Disease

A
  1. High-Output Cardiac failure (Osteoblastic phase)

2. Sarcoma

79
Q

renal Osteodystrophy

A

Skeletal changes in pts w/ chronic renal disease including those w/ dialysis

80
Q

Etiopathogenesis of Renal Osteodystrophy

A

Combination of:

  1. Hyperparathyroidism - Inc Urinary Phosphate excretion
  2. Tubular dysfunction- Impaired urinary Ca reabsorption
  3. Dec biosynthetic function- Dec Vit D & Hypocalcemia
81
Q

Features of Renal Osteodystrophy

A
  • Osteopenia & Secondary osteoporosis
  • Osteomalacia
  • Secondary hyperparathyroidism
  • Growth retardation (in children & adolescents)
82
Q

Disease of abnormal Mineral metabolism

A
  • Rickets
  • Osteomalacia
  • Hyperparathyroidism
83
Q

Osteomalacia & Rickets

A

Disorders of abnormal mineralization due to Vit D deficiency

Rickets = children & Osteomalacia = adults

84
Q

Etiology & RFs of Osteomalacia & Rickets

A

Inadequate synthesis or Dec absorption of vitamin D

  • Malnutrition
  • Malabsorption
  • Receptor abnormalities
  • Lack of sunlight exposure
85
Q

Pathogenesis of Osteomalacia & Rickets

A
  • Under-mineralized matrix
  • Persistent hyaline cartilage
  • Fractures & skeletal deformity
86
Q

CFs of Rickets

A
  • Softening of skull bones “Craniotabes”
  • Frontal bossing & square forehead
  • Persistent hyaline cartilage & overgrowth of costochondral junction –>”Rachitic rosary”
  • Tugging of softened ribs & sternum by Diaphragm & respiratory muscles –> “Harrisons groove & pigeon chest deformity”
  • Lumbar lordosis
  • Legs bowing
  • Short stature
87
Q

CFs of Osteomalacia

A
88
Q

Disease of Abnormal Matrix production

A

Scurvy

89
Q

Scurvy

A

Signs & symptoms of Vitamin C deficiency

90
Q

Etiopathogenesis of Scurvy

A

`Dec vit C –> Dec hydroxylation of proline & lysine residues in collagen –> Impaired collagen fibrils cross linking –> Impaired triple helix formation of Procollagen –>Impaired Collagen Synthesis

91
Q

CFs of Scurvy

A
  • Microfractures & Bony deformities
  • Impaired wound healing
  • Vascular fragility –> Bleeding from skin & gums
92
Q

Classifications of Bone tumors

A
  • Bone forming
  • Cartilage forming
  • Unknown origin
  • Hematopoietic
  • Secondary tumors in children
  • Secondary tumors in adults
93
Q

Diagnosis of Bone tumors

A

Age + Site + Radiographic appearance + Histo appearance

94
Q

General principles of Benign tumors

A
  • Usually asymptomatic
  • Usually small
  • Well circumscribed lesions
  • No destructive growth
  • No soft tissue/ joint space invasion
95
Q

General principles of Malignant bone tumors

A
  • Aggressive w/ pain & pathological fractures
  • Large destructive & invasive growths
  • Usually high grade & poor prognosis
  • Stage determines clinical outcome
96
Q

Location of bone tumors

A

Epiphysis

  1. Chondroblastoma
  2. Giant cell tumor

Metaphysis

  1. Osteoblastoma
  2. Osteoid osteoma
  3. Osteochondroma
  4. Enchondroma
  5. Giant cell tumor
  6. Osteosarcoma

Diaphysis

  1. Ewing’s sarcoma
  2. Chondrosarcoma
  3. Enchondroma
97
Q

Types of Bone forming tumors

A

Benign

  1. Osteoma
  2. Osteoid osteoma (10-20)
  3. Osteoblastoma (10-20)

Malignant
1. Osteosarcoma (10-20)

98
Q

Osteoma

A
  • Slow growing
  • Bone islands
  • Paranasal sinuses & calvaria
  • FAP (colonic adenomas) in Gardner’s syndrome
99
Q

Similarities of Osteoid osteoma & Osteoblastoma

A
  • Teens & twenties
  • M&raquo_space; F
  • Nocturnal pain (more in Osteoid osteoma )
100
Q

Differences between Osteoid osteoma & Osteoblastoma

A

Osteoid osteoma

  • Cortex of femur/ tibia
  • < 2cm
  • Pain relieved w/ NSAIDs bc tumor cells produce PGE2
  • Reactive sclerosis

Osteoblastoma

  • Lamina & pedicle (posterior column)
  • > 2cm
  • No relief from NSAIDs bc pain is neuropathic
  • No Reactive sclerosis
101
Q

Radiological features of Osteoid osteoma

A

Dense reactive sclerosis surrounding well-localized nidus

Nidus= Osteoid/ unmineralized bone

102
Q

Osteosarcoma

A
  • MC primary malignant bone tumor
  • < 20 OR Older adults w/ Paget’s disease
  • M&raquo_space; F
  • Metaphysis of long bones - around the knee in distal femur or proximal tumor
  • Rb (hereditary germ cell mutation), p53, sporadic & Li Fraumeni syndrome, CDKN2a, MDM2 & CDK4; sporadic
103
Q

Morphological & Histological features of Osteosarcoma

A

RADIO

  • Raised periosteum
  • “Codman triangle”
  • “Sunburst appearance”

GROSS

  • Necrotic & hemorrhagic mass filling the medullary cavity
  • Mass infiltrating the surrounding soft tissue
  • Elevated periosteum
  • “Lace like osteoid deposition”
104
Q

Cartilage forming tumors

A

Benign

  1. Osteochondroma (10-30)
  2. Enchondroma (30-50)

Malignant
1. Chondrosarcoma (40-60)

105
Q

Similarities between Osteochondroma & Enchondroma

A
  • Involves bones of endochondral origin
  • Slow growing
  • Painful if impinging a nerve
106
Q

Features of Osteochondroma

A
  • Late adolescents & early adults
  • M&raquo_space; F
  • Exostosis- Bony stalk capped by a cartilage
  • 85% sporadic & solitary; 15% in AD Multiple hereditary Exostosis syndrome (Children)
  • EXT1 & EXT2 genes
  • Near growth plate of long bones near the knees
107
Q

Enchondroma

A
  • 30-50 years
  • M = F
  • Within the medullary cavity; no stalk
  • MC sporadic & solitary; Rarely in Non-hereditary multiple tumors in Olliers & Mafucci syndromes
  • IDH1 & IDH2 genes
  • Small bones of hands & feet
108
Q

Radiologic & Histo features of Osteochondroma

A

Radio
- Outgrowth from epiphyseal cartilage w/ Medullary cavity extending into stalk

Histo

  • Cartilaginous cap w/ disorganized growth plate like cartilage
  • Bony matrix w/ trabeculae
  • Medullary cavity extending into stalk
109
Q

Histo features of Endochondroma

A

Chondrocytes & cartilage matrix surrounded by ring of reactive bone tissue in medullary cavity of tubular bone
Ollier’s disease- disfiguring; 20% develop to Chondrosarcoma
Mafucci’s disease- Enchondroma & spindle cell hemangioma’ 20% develop in Chondrosarcoma & 100% develop another extra-skeletal malignancy like gliomas

110
Q

Chondrosarcoma

A
  • > 40
  • M&raquo_space; F
  • Axial skeletal - pelvis, shoulder, ribs
  • Symp- Painful progressive enlarging masses
  • IDH1 & IDH2, EXT1 & EXT2 & CDKN2a
  • Hematogenous metastasis to lungs in high grade lesions
111
Q

Gross & Histo features of Chondrosarcoma

A

GROSS

  • Nodules of hyaline & myxoid cartilage permeating through the medullary cavity
  • Invasion of the cortex into the sift tissue

HISTO

  • Anaplastic chondrocytes
  • Hyaline cartilage matrix
112
Q

Bone tumors of Unknown origin

A

Benign
1. Giant cell tumor (Osteoclastoma) (20-40)

Malignant
1. Ewing’s sarcoma/ Peripheral Neuroectodermal tumor (PNET) (10-20)

113
Q

Giant Cell Tumor/ Osteoclastoma

A
  • 20-50
  • Develops in epiphysis –> Spreads to metaphysis (MC around the knee in distal femur/ proximal tibia)
  • Symp= Arthritis-like symp. bc its near joints
114
Q

Pathogenesis of Giant cell tumor/ Osteoclastoma

A

Neoplastic osteoblast precursors w/ increased expression of RANKL –> Promotes differentiation & maturation of Osteoclast –> No normal feedback between Osteoclasts & Osteoblast –> Localized but highly destructive bone resorption

115
Q

Radiologic & Histo features of Giant cell tumor/ Osteoclastoma

A

RADIO

  • Overlying cortex destruction
  • Bulging soft tissue delineated by a thin shell of reactive bone
  • “Soap bubble appearance” - Expansile lytic lesion

HISTO

  • Neoplastic = Mononuclear stromal cells
  • Non-neoplastic = Osteoclast-like giant cells
116
Q

Ewing’s Sarcoma/ Primitive Neuroectodermal tumor (PNET)

A
  • <20
  • M > F
  • Whites > African/ Asian descent
  • Medullar cavity - diaphysis of long bones & flat bones of pelvis
  • Symp = Painful enlarging mass (tender, warm & swollen), fever, anemia, raised ESR, Leukocytosis
117
Q

Pathogenesis of Ewing’s tumor

A

Translocation resulting in EWSRE-FL1 fusion protein –> Proliferation w/o differentiation

  • EWSR1 gene on Chr 22
  • FL1 gene on Chr 11
118
Q

Radiographic & Histological features of Ewing’s tumor

A

RADIO

  • “Onion-skin appearance” bc of periosteal bone reaction
  • “Moth eaten appearance”

HISTO

  • Uniform, small, round cells w/ scant cytoplasm (PAS +ve due to glycogen)
  • “Homer- wright Rosettes” - Rounded cell clusters w/ a central fibrillary core –> attempted neuroectodermal differentiation
119
Q

Prognosis & treatment of Ewing’s tumor

A
  • Aggressive

- Responds to neoadjuvant (before surgery) chemotherapy followed by surgical excision

120
Q

Hematopoietic Bone tumors

A

Malignant

1. Multiple myeloma

121
Q

Radiologic & Histo features of Multiple myeloma/ Plasma Cell Myeloma

A

RADIO

  • Sharply “punched-out” areas of bone destruction
  • 1-5 cm
  • NO surrounding zone of sclerosis
  • Vertebrae, pelvis, ribs & skulls

HISTO

  • Clusters & sheets of plasma cells in bone marrow
  • Cells range from blasts to mature form

Inc monoclonal Ig serum or light chains in urine as “Bence Jones proteinuria

122
Q

Metastasis/ Secondaries to Bone

A

MC that primary tumors of bone

  • Multifocal
  • Axial skeletal&raquo_space; (Bc of rich capillary network in marrow
  • Blastic (prostate), lytic (kidney, lung, GIT & melanoma) or mixed.
  • Biopsy = confirm diagnosis when CFs are questionable
  • Morphology & ancillary studies = Confirm site of origin
123
Q

MC primary sites in Secondary bone tumor

A
  • Breast
  • Lung
  • Thyroid
  • Kidney
  • Prostate

BLT- Kosher Pickle (mnemonic)

124
Q

MC primary sites in Secondary bone tumors in children

A
  • Osteosarcoma
  • Wilm’s tumor
  • Neuroblastoma
  • Ewing’s sarcoma
  • Rhabdomyosarcoma

OWNER (mnemonic)

125
Q

Parts of the joint

A
  1. Synovium

2. Articular cartilage

126
Q

Synovium

A
  • Mesenchymal
  • Fibroblast-like cells = 1-4 cells thick
  • Produces hyaluronic acid, proteins & synovial fluid
127
Q

Articular cartilage

A
  • Shock absorber
  • Chondrocytes regulate matrix turnover
  • Synthesis = Type 2 collagen & Proteoglycans
  • Matrix degrading enzymes
  • 1-4 mm thick
  • Nourished by synovium
  • Maintains friction-free movement
128
Q

Function of Type 2 collagen organization in Articular Cartilage

A
  • Transmit vertical stress
  • Resist tensile force
  • Spread load across the joint surface to allow the underlying bone to absorb shock
129
Q

Causes of Arthritis (Joint inflammation)

A
  1. Infections
  2. Degenerative changes
  3. Immune mediated
  4. Crystal deposition = Gout (Uric acid) & Pseudogout (Calcium pyrophosphate)
130
Q

Osteoarthritis (OA)

A

Degenerative disease of articular cartilage causing Asymmetrical Oligo/Polyarticular arthritis – > Structural & functional failure of affected synovial joint

131
Q

MC joint affected in OA

A

Weight bearing joints

132
Q

CFs of OA

A
  • Pain in joint that is worse w/ activity (end of day) and relieved w/ rest
  • Morning stiffness <30 minutes
  • Nerve root compression by osteophytes - radicular pain, muscle atrophy & nerve
  • Bowleg because cartilage degradation occurs in the medial aspect first
  • Heberden nodes in DIP
  • Bouchard node in PIP
133
Q

Etiopathogenesis of OA

A

Mechanical Wear & tear –> Cartilage damage –> Narrowing joint space & reactive bone changes

Primary = Age > 70 years
Secondary = Obesity or Metabolic diseases (DM or Hemochromatosis)
134
Q

Gross morphological of OA

A

GROSS

  • Eburnation - smooth surface caused by bone rubbing together when joint space is narrowed
  • Subchondral Reactive Sclerosis - Remodeling attempt
  • Subchondral cyst - Synovial fluid seeps through cracks in bone surface
135
Q

Imaging features of OA

A

Osteophytes- Bone overgrowths towards joint space

  • joint pain
  • morning stiffness <30 minutes
  • nerve root compression - radicular pain, muscle atrophy & nerve
136
Q

Histo features of OA

A
  • Joint mice = Loose bodies of Cartilage that was sloughed off, join together and accumulate in the joint space
137
Q

Rheumatoid Arthritis (RA)

A

Chronic autoimmune disease of joints casing non-suppurative proliferation & inflammatory symmetric arthritis

138
Q

MC joints affects in RA

A

Small joints of hands & feet

  • Polyarticular
  • Episodic & progressive
139
Q

Epidemiology of RA

A
  • 20 -40 years

- F&raquo_space; M

140
Q

Etiopathogenesis of RA

A

HLA DR4 (genetic predisposition) + Smoking & Infections-E coli) (Environmental factors) –> Recruitment & activation of Th1, Th17, B-cells, Plasma cells & macrophages –> Proliferation of Synovial cells, Chondrocytes & Fibroblast –> Joint erosion

141
Q

Pannus formation in RA

A

When the immune system attack the Synovium it causes the proliferation of Synovial & inflammatory cells (mass of cells) called Pannus. These cells secretes cytokines which causes joint & bone erosions. Fibroblast in pannus will also cause fibrosis and joint fusion.

Inflammatory cells are mainly lymphocytes (chronic).

142
Q

Articular CFs of RA

A
  • Morning stiffness > 1hr & improves w/ use
  • Fever, malaise, Generalized MSK pain
  • Symmetric & small joint involvement = MCP & PIP
  • Boutonniere deformity = Flexed PIP & hyperextended DIP joints
  • Swan neck deformity = Hyperextended PIP & flexed DIP
  • Z/ Hitchhiker deformity of thumb
  • Ulnar deviation of MCP
  • Radial deviation of Wrist
143
Q

Extra-articular CFs of RA

A 
Lung= Progressive interstitial fibrosis
CVS = MI, stroke, HF
Brain= Fatigue, Dec cognitive function
Carpal tunnel syndrome
Vasculitis = Leucocytoclastic type
Uveitis & Keratoconjunctivitis (juvenile form)
Lymphoma
Kidney = Secondary systemic amyloidosis
144
Q

Rheumatoid Nodule

A
  • Firm, non-tender, Round-oval nodules
  • Ulnar aspect of forearm, elbow & occiput (subject to pressure)
  • Necrotizing granulomas w/ central zone of fibrinoid necrosis
  • Rim of activated macrophages, lymphocytes & plasma cells
145
Q

Lab finding in RA

A
  1. Rheumatoid factor = IgM & IgA Ab against Fc portion of IgG immunoglobulin
    - Non specific for RA bc its found in other disease
  2. ESR & CRP (non-specific inflammation markers)
  3. Ab against Citrullinated peptides (CCP) in joints like fibrinogen, Type 2 collagen, Alpha enolase, etc. = Anti Citrullinated Peptide Ab (ACPA)
  4. HLA DR4 gene association
146
Q

Imaging finding of RA

A
  1. Diffuse osteopenia
  2. Periarticular bony erosions
  3. Marked loss of joint spaces of carpal, metacarpal, phalangeal & interphalangeal joints
147
Q

Differences between OA & RA

A

OA

  • Morning stiffness < 30 mins
  • Worse w/ activity & better w/ rest
  • Weight bearing joints, PIP & DIP
  • Non-inflammatory
  • Asymmetric
  • Reparative activity

RA

  • Morning stiffness > 1 hr.
  • Better w/ activity
  • Wrist, MCP & PIP
  • Inflammatory & systemic
  • Symmetric
  • No reparative activity
148
Q

Seronegative Spondyloarthropathies

A

Heterogenous group of joint diseases; part of a systemic spectrum w/ arthritis
NO RF in serum

-Psoriatic arthritis, Ankylosing spondylitis, Inflammatory Bowel disease & Reactive Arthritis (PAIR)

149
Q

Etiopathogenesis of Seronegative Spondyloarthropathies

A
  • Young males

- HLA B27 strong association

150
Q

CFs of Seronegative Spondyloarthropathies

A
  • Oligoarticular arthritis
  • Axial skeleton & Sacroiliac joint
  • Destruction of articular cartilage & subchondral bone
  • Fibrosing ankylosis & Bony ankylosis
151
Q

Ankylosing Spondylitis Etiopathogenesis

A
  • HLA B27 association
  • Persist > 3months
  • Insidious onset back pain in the lower lumbar or buttock region
  • “Bamboo spine” –> Vertebral fusion in Costovertebral & Costochondral vertebrae.
152
Q

CFs of Ankylosing Spondylitis

A
  • Lower Back or buttock pian
  • Morning stiffness > 1hr that improves w/ activity
  • Pleuritic chest pain & Limited chest expansion = Secondary to Costovertebral & Costochondral junction inflammation & fusion
  • Peripheral arthritis - (large joints) may precede back pain
  • Tendinitis or plantar fasciitis
  • Aortic regurgitation
153
Q

Reactive Arthritis CFs

A

Triad of:

  • Conjunctivitis + Urethritis + Arthritis
  • “Cant see, cant pee & cant climb a tree”

Extra-articular symptoms:

  • Ocular conjunctivitis, uveitis
  • Mucocutaneous
154
Q

Infections that may lead to Reactive Arthritis

A

GI infections - Salmonella, Shigella, Yersinia & Campylobacter

GU infections- Non-gonococcal Chlamydia

“She Caught Every Student Cheating yesterday & oveREACTed”

155
Q

Psoriatic Arthritis

A

Associated w/ skin Psoriasis & nail changes

  • Asymmetric
  • Patchy involvement
  • Dactylitis & “Pencil-in-cup deformity” on x-ray
156
Q

Inflammatory Bowel Disease w/ Spondylarthritis

A

Ulcerative colitis or Crohn’s disease w/ arthritis

Pathology (7 decks)

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