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
2
Q
Manifestations of Bone disease
A
- Disability
- Deformity
- Pain
- Electrolyte imbalance
- Anemia/ Pancytopenia
- Neurological dysfuction
3
Q
Composition of Bone
A
Extracellular matrix
- Osteoid
- Minerals
Cells
- Osteoblast
- Osteoclast
- Osteocytes
4
Q
Components of Osteoid
A
- Type 1 collagen
- GAGs
- Osteocalcin (Protein like osteopontin)
5
Q
Mineral components in bones
A
Hydroxyapatite [Ca10(PO4)6(OH)2]
- Bone hardness
Repository for:
- 99% body calcium
- 85% body phosphorus
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
7
Q
Normal Growth & Development
A
- Pre-modeled in cartilage OR Direct production
- Mesenchymal condensation
8
Q
Osteoclast
A
- Bone removing- release proteolytic enzymes & bone resorption
- Derived from Hematopoietic progenitor cells
- Multinucleated
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
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
11
Q
Lamellar Bone
A
- Collagen arranged in parallel sheets –> Resist unidirection force
- Facilitates weight bearing
12
Q
Endochondral ossification
A
Bone formed after replacing cartilage anlagen
- Formation of most bones
pg 12 Mesenchymal condensation =
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
14
Q
Layers of Growth Plate (Endochondral ossification)
A
- Reserve zone
- Proliferative zone
- Hypertrophic zone
- Mineralization zone
- Primary spongiosa zone
15
Q
Reserve zone
A
Chondroblasts resting (inactive)
16
Q
Zone of proliferation
A
Chondroblasts proliferates (multiply) & contribute to lengthening of the plate
17
Q
Zone of hypertrophy
A
Chondroblasts hypertrophy, secrete matrix & more longitudinal growth
18
Q
Zone of Mineralization
A
Chondroblasts apoptose & cartilage matrix mineralizes
19
Q
Primary spongiosa zone
A
BV innervate & brings osteoprogenitor cells that replace mineralized cartilage w/ bone
- Fist layer of spongy bone formed
20
Q
Bone modeling
A
Formation & growth of individual bones
- Longitudinal growth = Childhood & Adolescents
- Appositional growth = Adulthood
- Osteoblast & osteoclast work independently
21
Q
Bone remodeling
A
Constant replenishment of bone during the lifetime
- Occurs due to Osteoblast & Osteoclast working together
- Highly regulated microscopic process
22
Q
Mineralization
A
Osteoid ——- (10-15 days) —-> Bones
23
Q
Special features of Growth plate zones
A
Zones 1-3 = Maintaining cartilage
Zones 4-5 = Bone formation
24
Q
Etiology of Achondroplasia
A
- AD
- Gain of function mutation of FGFR3 gene
Normally FGF binds FGFR3 –> Inhibits Endochondral ossification
25
CFs of Achondroplasia
- 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
26
Clinical diagnosis of Achondroplasia
- Disproportionate dwarfism & normal intelligence
- Bones w/ endochondral ossification (long bones)
- Usually have normal parents
27
DDx of Achondroplasia
1. Cretinism (thyroid deficiency)
2. Growth hormone deficiency
Intelligence & reproduction usually affected
Limbs & trunks, etc. are not disproportionate
28
Osteogenesis Imperfecta (OI)
Brittle bone disease
Connective tissue disorder
- Dec in Type 1 Collagen synthesis --> Extreme fragility
29
Etiopathogenesis of OI
30
CFs of OI
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
31
Osteopetrosis
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
32
Etiopathogenesis of Osteopetrosis
Mutation --> Impaired acidification of osteoclast resorption pit --> Impaired dissolution of Calcium hydroxyapatite within the matrix
33
Diagnosis of Osteopetrosis
X-ray
| Genetic analysis
34
Treatment of Osteopetrosis
Bone marrow transplant
35
Ehler Danlos Syndrome
Faulty collagen synthesis due to mutation in genes encoding Collagen or enzymes modifying collagen resulting in deficient collagen synthesis
36
CFs & Molecular Etiology of EDS
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
37
Marfan Syndrome (Etiopathogenesis)
AD connective tissue disorder affecting bones, heart, aorta & eyes
- Fibrillin (FBN1) gene mutation on Chr 15
- Fibrillin is a component of microfibrils
38
CFs of Marfan Syndrome
- 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)
39
MCC of death in pts. w/ Marfan Syndrome
Aortic rupture
40
Regulation of Bone Remodeling
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
41
Factors released by Osteocytes
- Sclerostin
42
Factors released by Osteoprogenitor cells
- Bone Morphogenic Protein (BMP)
43
Blood Borne factors
Hormones
- Vit D
- Cytokines
- Growth hormones
44
Intercellular signals involved in Bone remodeling
1. RANK & RANKL
2. Monocyte Colony Stimulating Factor (M-CSF)
3. Sclerostin
4. BMP
45
RANKL (Receptor Activator of NF-Kappa-B Ligand)
Expressed on Osteoblast
Binds to RANK on Osteoclast & precursors --> Activation
46
Upregulation of RANKL
1. PTH
2. IL-2
3. Vit D3
4. Some malignancies
47
Inhibition of RANKL
Osteoprotegerin (OPG) (TNF family)
| - Produced by Osteoblast when WNT proteins from the Osteoprogenitor cells binds to LRP 5/6 on the Osteoblast
48
Monocyte Colony Stimulating Factor (M-CSF)
Produced by Osteoblast
- Signals monocytes to differentiate into Osteoclast
49
Sclerostin
Produced by Osteocytes
Binds to LDL receptor proteins 5/6 on Osteoblast --> Inhibit Osteoprotegerin production
50
Bone Morphogenic Protein (BMP)
Produced by Osteoprogenitor cells
| - Stimulate osteoblasts & Inc Bone resorption
51
Osteoporosis
Osteopenia that is severe enough to significantly increase the risk of fracture
- Localized or Diffused
- Primary (Senile & Post-menopausal) or Secondary
52
Diagnosis of Osteoporosis
DEXA Scan
| - T-score =
53
Peak Bone Mass Determinants
1. Sex (m>f)
2. Physical activity
3. Genetics
4. Nutrition
5. Hormones
54
Rate of loss of bone mass in Senile Osteoporosis related to:
- Dec physical activity
- Hormones
- Dec reproductive age of Osteoblast & its precursors
- Dec synthetic activity of Osteoblast
- Dec Biological activity of matrix precursors
55
Pathogenesis of Post-menopausal Osteoporosis
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
56
Endocrine causes of Secondary Osteoporosis
- Hyperparathyroidism
- Hyperthyroidism - pts usually have Hypocalcemia
- DM
- Addison disease
- Pituitary disease
57
Neoplastic causes of Secondary Osteoporosis
- Carcinomatosis
- Multiple myeloma
- Paraneoplastic Disease = Squamous Cell Carcinoma of lung
58
GI causes of Secondary Osteoporosis
- Malnutrition
- Hepatic insufficiency
- Vit D/C deficiency
- Malabsorption
59
Drugs that cause Secondary Osteoporosis
- Chemotherapy
- Corticosteroids
- Alcohol
60
Other causes of Secondary Osteoporosis
Immobilization
61
CFs of Osteoporosis
Fracture or bone pain after trivial trauma
| - Elderly patients
62
Radiological diagnosis of Osteoporosis
- Plain radiograph- Fractures & loss of bone
| - DEXA scan/ CT scan- < 2.5 SD
63
Serum readings in Osteoporosis
Primary- Normal Calcium, Phosphate & Alkaline phosphatase
64
Complications of Osteoporosis
Fractures that heal slowly -
| Bone deformities
65
Causes of Hyperparathyroidism Bone disease
Primary- Tumors
Secondary- Vit D deficiency
Tertiary- Inc PTH despite correction of Ca & Vit D levels
66
Pathogenesis of Hyperparathyroidism Bone-disease
67
Paget Disease / Osteitis Deformans
Acquired disorder of bone remodeling due to unknown cause
68
Epidemiology of Paget Disease
- Adults (>40 years)
- M=F
- MC in whites
69
Etiology & RFs of Paget Disease
- Genetic (15% have FHx) --> Sqstm1 gene
| Environmental (Viral infection that may trigger Osteoclast activity)
70
Pathogenesis Of Paget Disease
Unregulated Osteoclastic activity --> Inc resorption --> Stimulates Inc Osteoblastic activity --> Abnormal haphazard bone deposition
71
Phases of Paget Disease
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
Osteolytic phase of Paget Disease
73
Mixed pHase of Paget Disease
74
Blastic phase of Paget Disease
75
Hallmark feature for diagnosis of Paget Disease
Mosaic/ Jigsaw patten of bone
| - due to dense sclerosis w/ irregular wavy cement lines
76
CFs of Paget Disease
77
Investigation for Paget Disease
- X-ray- Lytic or Sclerotic lesion
2. Inc serum ALP
3. Inc urinary Hydroxyproline (breakdown product of Collagen type 1)
78
Complications of Paget Disease
1. High-Output Cardiac failure (Osteoblastic phase)
| 2. Sarcoma
79
renal Osteodystrophy
Skeletal changes in pts w/ chronic renal disease including those w/ dialysis
80
Etiopathogenesis of Renal Osteodystrophy
Combination of:
1. Hyperparathyroidism - Inc Urinary Phosphate excretion
2. Tubular dysfunction- Impaired urinary Ca reabsorption
3. Dec biosynthetic function- Dec Vit D & Hypocalcemia
81
Features of Renal Osteodystrophy
- Osteopenia & Secondary osteoporosis
- Osteomalacia
- Secondary hyperparathyroidism
- Growth retardation (in children & adolescents)
82
Disease of abnormal Mineral metabolism
- Rickets
- Osteomalacia
- Hyperparathyroidism
83
Osteomalacia & Rickets
Disorders of abnormal mineralization due to Vit D deficiency
Rickets = children & Osteomalacia = adults
84
Etiology & RFs of Osteomalacia & Rickets
Inadequate synthesis or Dec absorption of vitamin D
- Malnutrition
- Malabsorption
- Receptor abnormalities
- Lack of sunlight exposure
85
Pathogenesis of Osteomalacia & Rickets
- Under-mineralized matrix
- Persistent hyaline cartilage
- Fractures & skeletal deformity
86
CFs of Rickets
- 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
CFs of Osteomalacia
88
Disease of Abnormal Matrix production
Scurvy
89
Scurvy
Signs & symptoms of Vitamin C deficiency
90
Etiopathogenesis of Scurvy
`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
CFs of Scurvy
- Microfractures & Bony deformities
- Impaired wound healing
- Vascular fragility --> Bleeding from skin & gums
92
Classifications of Bone tumors
- Bone forming
- Cartilage forming
- Unknown origin
- Hematopoietic
- Secondary tumors in children
- Secondary tumors in adults
93
Diagnosis of Bone tumors
Age + Site + Radiographic appearance + Histo appearance
94
General principles of Benign tumors
- Usually asymptomatic
- Usually small
- Well circumscribed lesions
- No destructive growth
- No soft tissue/ joint space invasion
95
General principles of Malignant bone tumors
- Aggressive w/ pain & pathological fractures
- Large destructive & invasive growths
- Usually high grade & poor prognosis
- Stage determines clinical outcome
96
Location of bone tumors
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
Types of Bone forming tumors
Benign
1. Osteoma
2. Osteoid osteoma (10-20)
3. Osteoblastoma (10-20)
Malignant
1. Osteosarcoma (10-20)
98
Osteoma
- Slow growing
- Bone islands
- Paranasal sinuses & calvaria
- FAP (colonic adenomas) in Gardner's syndrome
99
Similarities of Osteoid osteoma & Osteoblastoma
- Teens & twenties
- M >> F
- Nocturnal pain (more in Osteoid osteoma )
100
Differences between Osteoid osteoma & Osteoblastoma
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
Radiological features of Osteoid osteoma
Dense reactive sclerosis surrounding well-localized nidus
Nidus= Osteoid/ unmineralized bone
102
Osteosarcoma
- MC primary malignant bone tumor
- < 20 OR Older adults w/ Paget's disease
- M >> 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
Morphological & Histological features of Osteosarcoma
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
Cartilage forming tumors
Benign
1. Osteochondroma (10-30)
2. Enchondroma (30-50)
Malignant
1. Chondrosarcoma (40-60)
105
Similarities between Osteochondroma & Enchondroma
- Involves bones of endochondral origin
- Slow growing
- Painful if impinging a nerve
106
Features of Osteochondroma
- Late adolescents & early adults
- M >> 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
Enchondroma
- 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
Radiologic & Histo features of Osteochondroma
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
Histo features of Endochondroma
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
Chondrosarcoma
- >40
- M >> 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
Gross & Histo features of Chondrosarcoma
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
Bone tumors of Unknown origin
Benign
1. Giant cell tumor (Osteoclastoma) (20-40)
Malignant
1. Ewing's sarcoma/ Peripheral Neuroectodermal tumor (PNET) (10-20)
113
Giant Cell Tumor/ Osteoclastoma
- 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
Pathogenesis of Giant cell tumor/ Osteoclastoma
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
Radiologic & Histo features of Giant cell tumor/ Osteoclastoma
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
Ewing's Sarcoma/ Primitive Neuroectodermal tumor (PNET)
- <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
Pathogenesis of Ewing's tumor
Translocation resulting in EWSRE-FL1 fusion protein --> Proliferation w/o differentiation
- EWSR1 gene on Chr 22
- FL1 gene on Chr 11
118
Radiographic & Histological features of Ewing's tumor
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
Prognosis & treatment of Ewing's tumor
- Aggressive
| - Responds to neoadjuvant (before surgery) chemotherapy followed by surgical excision
120
Hematopoietic Bone tumors
Malignant
| 1. Multiple myeloma
121
Radiologic & Histo features of Multiple myeloma/ Plasma Cell Myeloma
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
Metastasis/ Secondaries to Bone
MC that primary tumors of bone
- Multifocal
- Axial skeletal >> (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
MC primary sites in Secondary bone tumor
- Breast
- Lung
- Thyroid
- Kidney
- Prostate
BLT- Kosher Pickle (mnemonic)
124
MC primary sites in Secondary bone tumors in children
- Osteosarcoma
- Wilm's tumor
- Neuroblastoma
- Ewing's sarcoma
- Rhabdomyosarcoma
OWNER (mnemonic)
125
Parts of the joint
1. Synovium
| 2. Articular cartilage
126
Synovium
- Mesenchymal
- Fibroblast-like cells = 1-4 cells thick
- Produces hyaluronic acid, proteins & synovial fluid
127
Articular cartilage
- 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
Function of Type 2 collagen organization in Articular Cartilage
- Transmit vertical stress
- Resist tensile force
- Spread load across the joint surface to allow the underlying bone to absorb shock
129
Causes of Arthritis (Joint inflammation)
1. Infections
2. Degenerative changes
3. Immune mediated
4. Crystal deposition = Gout (Uric acid) & Pseudogout (Calcium pyrophosphate)
130
Osteoarthritis (OA)
Degenerative disease of articular cartilage causing Asymmetrical Oligo/Polyarticular arthritis -- > Structural & functional failure of affected synovial joint
131
MC joint affected in OA
Weight bearing joints
132
CFs of OA
- 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
Etiopathogenesis of OA
Mechanical Wear & tear --> Cartilage damage --> Narrowing joint space & reactive bone changes
```
Primary = Age > 70 years
Secondary = Obesity or Metabolic diseases (DM or Hemochromatosis)
```
134
Gross morphological of OA
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
Imaging features of OA
Osteophytes- Bone overgrowths towards joint space
- joint pain
- morning stiffness <30 minutes
- nerve root compression - radicular pain, muscle atrophy & nerve
136
Histo features of OA
- Joint mice = Loose bodies of Cartilage that was sloughed off, join together and accumulate in the joint space
137
Rheumatoid Arthritis (RA)
Chronic autoimmune disease of joints casing non-suppurative proliferation & inflammatory symmetric arthritis
138
MC joints affects in RA
Small joints of hands & feet
- Polyarticular
- Episodic & progressive
139
Epidemiology of RA
- 20 -40 years
| - F >> M
140
Etiopathogenesis of RA
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
Pannus formation in RA
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
Articular CFs of RA
- 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
Extra-articular CFs of RA
```
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
Rheumatoid Nodule
- 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
Lab finding in RA
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
Imaging finding of RA
1. Diffuse osteopenia
2. Periarticular bony erosions
3. Marked loss of joint spaces of carpal, metacarpal, phalangeal & interphalangeal joints
147
Differences between OA & RA
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
Seronegative Spondyloarthropathies
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
Etiopathogenesis of Seronegative Spondyloarthropathies
- Young males
| - HLA B27 strong association
150
CFs of Seronegative Spondyloarthropathies
- Oligoarticular arthritis
- Axial skeleton & Sacroiliac joint
- Destruction of articular cartilage & subchondral bone
- Fibrosing ankylosis & Bony ankylosis
151
Ankylosing Spondylitis Etiopathogenesis
- 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
CFs of Ankylosing Spondylitis
- 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
Reactive Arthritis CFs
Triad of:
- Conjunctivitis + Urethritis + Arthritis
- "Cant see, cant pee & cant climb a tree"
Extra-articular symptoms:
- Ocular conjunctivitis, uveitis
- Mucocutaneous
154
Infections that may lead to Reactive Arthritis
GI infections - Salmonella, Shigella, Yersinia & Campylobacter
GU infections- Non-gonococcal Chlamydia
"She Caught Every Student Cheating yesterday & oveREACTed"
155
Psoriatic Arthritis
Associated w/ skin Psoriasis & nail changes
- Asymmetric
- Patchy involvement
- Dactylitis & "Pencil-in-cup deformity" on x-ray
156
Inflammatory Bowel Disease w/ Spondylarthritis
Ulcerative colitis or Crohn's disease w/ arthritis
