Skeletal Disorders Flashcards
1
Q
Bone matrix is osteoid made of this
A
Type I collagen
2
Q
These cells form new bone on surface of osteoid
A
Osteoblasts
3
Q
These cells become osteocytes when senescent
A
Osteoblasts
4
Q
These cells secrete acids into resorption pit to absorb bone and release calcium
A
Osteoclasts
5
Q
Osteoclasts are derived from this
A
Hematopoietic cells, monocyte/macrophage
6
Q
Type of bone formation that occurs in long bones
A
Endochondral
7
Q
Fibroblast growth factor 3 promotes differentiation of these
A
Chondrocytes
8
Q
Type of bone formation where growing cartilage at epiphyseal plates have provisional mineralization
Apoptotic chondrocytes are replaced by ingrowth of osteoblasts
A
Endochondral
9
Q
Fibroblast growth factor 3 promotes this type of bone formation
A
Endochondral
10
Q
Type of bone formation that occurs in flat bones
A
Intramembranous
11
Q
Type of bone formation where mesenchymal cells differentiate into osteoblasts and pre-existing matrix undergoes mineralization
A
Intramembranous
12
Q
Before remodeling, initial bone is of this type
A
Woven
13
Q
These cells are activated by WNT/Beta-catenin signaling
A
Osteoblasts
14
Q
Calcium deposition is mediated by this
A
Alkaline phosphatase
15
Q
Alkaline phosphatase mediates the deposition of this
A
Calcium
16
Q
Osteoblasts are activated by signaling of this
A
WNT/Beta-catenin
17
Q
Parathyroid hormone stimulates these cells
A
Osteoclasts
18
Q
Stimulation of RANK receptor activates these cells
A
Osteoclasts
19
Q
Osteoclasts are activated by stimulation of this receptor
A
RANK
20
Q
These cells are activated by M-CSF
A
Osteoclasts
21
Q
What effect does estrogen have on bone mass?
A
Is protective
22
Q
What effects does Vitamin D have on Calcium?
A
Increases renal Ca reabsorption
Increases bone deposition of Ca
23
Q
Vitamin D increases bone deposition of Ca via osteoblast production of this calcium binding protein
A
Osteocalcin
24
Q
This increases bone deposition of Ca via osteoblast production of the Ca binding protein osteocalcin
A
Vitamin D
25
Vitamin D increases bone deposition of Ca via these cells producing osteocalcin (Ca binding protein)
Osteoblast
26
Alkaline phosphatase is increased when this is occuring
Increased in bone deposition/turnover
E.g. tumor
27
What effect does Parathyroid Hormone have on bone resorption?
Causes bone resorption
28
These are precursors to osteoblasts
Mesenchymal cells
29
Osteoblasts or Osteoclasts?:
Eccentric nuclei
Osteoblasts
30
Osteoblasts or Osteoclasts?:
On osteoid surface
Osteoblasts
31
Osteoblasts or Osteoclasts?:
Mineralize bone with alkaline phosphatase
Osteoblasts
32
Osteoblasts or Osteoclasts?:
Osteocyte is senescent form
Osteoblasts
33
Osteoblasts or Osteoclasts?:
Monocytes are precursors
Osteoclasts
34
These are precursors to Osteoclasts
Monocytes
35
Osteoblasts or Osteoclasts?:
Multinucleated
Osteoclasts
36
Osteoblasts or Osteoclasts?:
Form resorption pits
Osteoclasts
37
Osteoblasts or Osteoclasts?:
Release Ca and P into serum
Osteoclasts
38
Type of bone:
Newly formed bone, disorganized, not as strong
woven bone
39
Type of bone:
Mature bone after remodeling, increased strength, compact bone cortex, cancellous in medullary cavity
Lamellar bone
40
Bone marrow fills this part of bone
Medullary cavity
41
What effect does RANK/RANK-L have on bone?
Stimulates bone resorption by osteoclasts
42
RANK/RANK-L stimulates bone resorption by these
Osteoclasts
43
Decoy molecule that inhibits bone resorption
Protects bone
Osteoprotegerin
44
This promotes osteoclast mediated bone resorption via increased RANK/RANK-L
PTH
45
This decreases RANK/RANK-L, increases osteoprotegerin
Estrogen
46
Most common form of dwarfism
Achondroplasia
47
Inheritance pattern of Achondroplasia
Autosomal dominant
48
Condition caused by a gain of function in FGF3 receptor
Most are new sporadic paternal mutations (advanced paternal age)
Achondroplasia
49
Gain of function in this can cause Achondroplasia
FGF3
50
What effect does Achondroplasia have on long bones?
Promotes endochondral ossification, so there is presence of shortened long bones - short extremities
Normal flat bones
51
More severe, lethal form of dwarfism
Thanatophoric dysplasia
52
What causes Achondroplasia?
Gain of function in FGF3 receptor
53
What causes Thanatophoric dysplasia?
Gain of function FGF3 mutation with greater effect
54
This condition has similar features as Achondroplasia, but death occurs in neonatal period due to respiratory insufficiency
Thanatophoric dysplasia
55
What causes Osteogenesis Imperfecta?
Switch of glycine with non-gly amino acid in type I collagen
Impairs formation of triple helix
56
Condition caused by a switch of glycine with a non-gly amino acid in collagen, impairing the formation of the triple helix
Osteogenesis Imperfecta
57
What type of collagen is affected in Osteogenesis Imperfecta?
Type I
58
What is the inheritance pattern of Osteogenesis Imperfecta?
Dominant negative
59
Condition that is also called Brittle bone disease
Osteogenesis Imperfecta
60
Condition where fusion of conductive ossicles may occur, leading to conductive hearing loss
Osteogenesis Imperfecta
61
Condition that can have thin, transparent sclera with visualization of underlying choroid vasculature = blue sclera
Osteogenesis Imperfecta
62
Blue sclera is seen in this condition
Osteogenesis Imperfecta
63
Diffuse skeletal sclerosis due to defective osteoclast absorption
Osteopetrosis
64
Osteopetrosis is diffuse skeletal sclerosis due to a defect in this
Osteoclast absorption
65
Condition where defective osteoclast absorption results in no bony remodeling
Osteopetrosis
66
Carbonic Anhydrase deficiency may cause this skeletal condition
Osteopetrosis
67
Why can Carbonic Anhydrase deficiency cause Osteopetrosis?
Deficiency results in lack of acidic environment in resorption pit
(also results in renal tubular acidosis)
68
Condition were there is a lack of bone resorption, so bone is DENSE
Osteopetrosis
69
Condition where neural foramen may be occluded, causing cranial nerve defects
Osteopetrosis
70
Condition where there is extremely sclerotic bone with no medullary cavity for hematopoiesis, leading to low platelet, WBC, etc. counts
Osteopetrosis
71
What is the treatment for Osteopetrosis?
Bone marrow transplant
72
What are the levels of platelets and WBCs in Osteopetrosis?
Low
Extremely sclerotic bone has no medullary cavity for hematopoiesis
Extramedullary hematopoiesis may occur
73
Condition described by a bone density less than 2.5 std below mean peak bone density of young adults
Osteoporosis
74
What race is most affected by Osteoporosis?
Caucasians
Much less common in African races
75
Risk of Osteoporosis is determined by these two factors
Peak bone mass at early adulthood
Rate of age-related bone loss
76
Primary or secondary Osteoporosis?:
Senile - males especially
Post-menopausal (estrogen deficiency)
Primary
77
Primary or secondary osteoporosis:
Can be caused by hyperparathyroidism, neoplasm, intestinal disorders with malabsorption, chronic steroid use, hypogonadism
Secondary Osteoporosis
78
Chronic steroid use increases risk of this condition
Secondary Osteoporosis
79
Condition where there is normal bone but less of it
Most significant change at lumbar/thoracic vertebral bodies
Osteoporosis
80
What are the levels of Ca, PTH, and Alkaline phosphatase in Osteoporosis?
All normal
81
Biphosphonates inhibit these and can be used as treatment for Osteoporosis
Osteoclasts
82
Biphosphonates inhibit osteoclasts and can be used as treatment for this condition
Osteoporosis
83
Condition characterized by normal amount of bone matrix but inadequate mineralization
Rickets/Osteomalacia
Usually caused by Vitamin D deficiency
84
In children, does Rickets affect endochondral or membranous bone?
Both
85
What are the levels of Ca, Phosphate, Alk phos, and PTH in Rickets/Osteomalacia?
Low/normal Ca
Low phosphate
High alk phos
High PTH
86
Normal levels of Ca, PTH, and alk phos but with low bone density indicate this condition
Osteoporosis
87
Low/normal levels of Ca, low phosphate, and high Alk phos and PTH are typical labs seen in this condition
Rickets/Osteomalacia
88
Epiphyseal cartilage overgrowth due to inadequate mineralization and failure of chondrocyte maturation is seen in this condition
Rickets
89
Growth plate cartilage and osteoid continues to expand laterally but does not mineralize or mature into bone is seen in this condition
Rickets
90
Skeletal deformation due to lack of structural rigidity is seen in this condition
Windswept deformity, bowing of legs (varus and valgum deformities), Pigeon breast, lumbar lordosis
Rickets
91
Condition where radiographs show widening of growth plates and fraying of collagen
Rickets
92
Fraying of cartilage as seen on radiograph indicates this condition
Rickets
93
Looser zones that are transverse areas of lucency due to microfractures and/or vascular channel erosion are seen on radiograph in this condition
Rickets
94
A row of beadlike prominences at the junction of a rib and its cartilage (i.e., enlarged costochondral joints), resembling a rosary, is seen in this condition
Rickets
95
Most characteristic diagnostic features of Rickets are seen in this type of bone
Long bones
Does still affect bones with intramembranous ossification though (frontal bossing of skull)
96
Vitamin D dependent rickets (type 1) is caused by a deficiency in this
1 alpha hydroxylase
97
A deficiency in 1 alpha hydroxylase causes this condition
Vitamin D dependent rickets (type 1)
98
Inheritance pattern of Vitamin D dependent rickets (type 1)
Autosomal recessive
99
Vitamin D dependent rickets (type 1) involves this gene
CYP2R1
100
CYP2R1 gene is involved in this condition
Vitamin D dependent rickets (type 1)
101
Type of Rickets where patients develop the condition by age 1 year
Vitamin D dependent rickets (type 1)
102
Vitamin D supplements help this type of Rickets
Vitamin D dependent rickets (type 1)
103
Type of Rickets caused by VDR mutations (Vit D receptor)
Vitamin D dependent rickets (type 2)
104
Mutations in VDR (Vit D receptor) cause this condition
Vitamin D dependent rickets (type 2)
105
Inheritance pattern of Vitamin D dependent rickets (type 2)
Autosomal recessive
106
Type of Rickets where patients develop the condition in adolescence usually
Vitamin D dependent rickets (type 2)
107
When do patients with Vitamin D dependent rickets (type 2) develop the condition?
In adolescence usually
108
When do patients with Vitamin D dependent rickets (type 1) develop the condition?
By age 1 year
109
IV calcium helps this type of Rickets
Vitamin D dependent rickets (type 2)
110
Type of Rickets caused by PHEX mutation on X chromosome
X-linked hypophosphatemia (Vit D resistant Rickets)
111
PHEX mutation on the X chromosome causes this condition
X-linked hypophosphatemia (Vit D resistant Rickets)
112
What are the levels of Ca and phosphate in X-linked hypophosphatemia (Vit D resistant Rickets)?
Normal/high Ca
VERY LOW phosphate
113
What are the levels of Alk Phos and PTH in X-linked hypophosphatemia (Vit D resistant Rickets)?
HIGH alk phos
normal PTH
114
What is the effect of X-linked hypophosphatemia (Vit D resistant Rickets) on males?
Early rickets
115
What is the effect of X-linked hypophosphatemia (Vit D resistant Rickets) on females?
Isoalted hypophosphatemia usually
116
2 supplements used to treat X-linked hypophosphatemia (Vit D resistant Rickets)
1,25 dihydroxy vitamin D and phosphate
117
Loss of 1ɑ hydroxylase activity in proximal renal tubules leads to this
Chronic renal disease
118
Condition where renal dysfunction leads to loss of phosphate, glucose, bicarbonate, amino acids
Results in renal tubular acidosis (Rickets/osteomalacia)
Fanconi syndrome
119
Fanconi syndrome can lead to this condition due to its associated hypophosphatemia
Rickets/osteomalacia
120
Condition of inadequate mineralization of bone in remodeling of mature skeleton due to low Vitamin D
Osteomalacia
121
Areas of overgrowth in weak bones are seen in Rickets or Osteomalacia?
Rickets
122
Morphological widening of osteoid seams (gap between new collagen and zone of mineralization) is seen in this condition
Osteomalacia
123
This condition causes excess production of PTH resulting in excess bone resorption
Hyperparathyroidism
124
Hyperparathyroidism causes excess production of this, resulting in excess bone resorption
PTH
125
Type of Hyperparathyroidism due to autonomous (neoplastic) secretion
Primary
126
Type of neoplasm that most commonly causes primary Hyperparathyroidism
Parathyroid adenoma
127
Levels of calcium in Primary Hyperparathyroidism
High
128
Type of Hyperparathyroidism that is a response to renal loss of calcium in chronic renal disease
Secondary
129
Levels of calcium in Secondary Hyperparathyroidism
Low
Low Ca leads to high PTH, which compensates and causes normalish Ca
130
Type of Hyperparathyroidism that is a secondary form which has become autonomous
Tertiary
131
Level of alk phos in Hyperparathyroidism
High
132
Brown tumors of bone are complications of this condition
Hyperparathyroidism
133
Microfractures resulting in reactive hypervascularity, hemorrhage and fibrosis and osteoclast accumulation
Brown tumors
Seen in Hyperparathyroidism
134
Osteoporosis with cystic change
Form brown tumors (due to hemosiderin)
Seen in Hyperparathyroidism
Osteitis Fibrosa Cystica
135
Osteitis Fibrosa Cystica is a complication of this condition
Hyperparathyroidism
136
Constellation of skeletal changes due to chronic renal failure
Renal Osteodystrophy
137
Secondary hyperparathyroidism, osteopenia/osteoporosis, and osteomalacia are changes due to chronic renal failure seen in this condition
Renal Osteodystrophy
138
How does secondary hyperparathyroidism occur due to renal failure in Renal Osteodystrophy?
1. renal Ca loss secondary to tubular dysfunction
2. compensatory PTH secretion
3. Ca/P resorbed from bone = fibrosis and cyst formation (Osteitis Fibrosa Cystica)
139
How does Osteopenia/osteoporosis result from chronic renal failure in Renal Osteodystrophy?
1 of 3 ways:
1. high PTH
2. renal Ca loss
3. renal tubules don't excrete H+ (= metabolic acidosis = Ca is resorbed as a buffer)
Generalized loss of Ca from bone
140
How does Osteomalacia result from Renal Osteodystrophy?
Renal failure results in inability to convert inactive Vitamin D to active 1,25 Vitamin D form
(leads to inability to mineralize osteoid)
141
Condition characterized by increased, but dysfunctional, bone mass due to increased osteoclast activity and osteoblast response
Paget disease
142
Condition where morphology shows bone resorption with increased numbers of large, multinucleated osteoclasts
Paget disease
143
Condition characterized by bone deposition without remodeling
Paget disease
144
Condition characterized by thick lamellar bone with prominent cement lines
Paget disease
145
Thick lamellar bone with prominent cement lines are seen in this condition
Paget disease
146
Mosaic pattern of lamellar bone is seen in this condition
Paget disease
147
Morphology of Paget disease involves increased numbers of this cell type with increased numbers of nuclei
Osteoclasts
148
Do osteoblasts or osteoclasts initially have increased activity in Paget disease?
Osteoclasts
Then compensatory increase of osteoblast activity
149
Condition that may initially be due to osteoclastic viral infection or increased RANK or NFk-B activity
Paget disease
150
Condition characterized by the following 3 phases:
Osteolytic, Mixed osteoclastic-osteoblastic, osteosclerotic
Paget disease
151
Condition involving:
1. increased osteoclast activity and bone resorption
2. compensatory increased osteoblast activity and bone deposition
3. burnt out osteoclasts with continued bone deposition by osteoblasts
Paget Disease
152
In Paget disease, there is increased bone density with no remodeling, leading to this type of bone
Weaker woven bone
153
Radiographs showing thickened cortices, cotton wool appearance and bowing of weight bearing bones is seen in this condition
Paget disease
154
Cotton wool appearance of bones seen radiographically are characteristic of this condition
Paget disease
155
A patient with a history of increasing hat size or hearing loss may have this condition
Paget disease
156
Paget disease is relatively common in these populations
European/Anglo
157
Bone enlargement and weakness are seen in this condition
Also bowing of weight bearing bones and compression of nerve roots or cranial contents
(skull, femur, axial skeleton are common sites)
Paget disease
158
Levels of Alk phos in Paget disease
Elevated
159
Levels of Ca and P in Paget disease
Both normal
160
Osteosarcoma and Osteoblastic hypermetabolic state are complications of this condition
Paget disease
161
Complication of Paget disease due to increased blood flow requirement causing increased demand on heart
Exacerbates heart disease and may produce high output cardiac failure in extensive disease
Osteoblastic hypermetabolic state
162
This condition may exacerbate heart disease and produce high output cardiac failure in extensive disease
Paget disease
163
Rupture of blood vessels forms this during healing of a fracture
Hematoma
164
In the healing of a fracture, formation of granulation tissue produces this scaffold
Fibrin scaffold
Fibroblasts, WBCs, capillaries grow into hematoma
165
During fracture healing, osteoid is deposited similar to this type of ossification during the formation of soft callus
Intramembranous
166
During fracture healing, chondroid matrix is ossified similar to this type of ossification during the formation of soft callus
Endochondral
167
This is the final stage of fracture healing
Remodeling
168
Why is resumption of weight bearing so critical during healing of fractures?
Non-stressed parts of callus are resorbed
Stressed parts of callus are remodeled to new lamellar bone
Physical stress on bone helps bone remodel to produce new bone
169
In a fracture with non-union, ingrowth of synovium may produce this
Pseudoarthrosis
170
Type of fracture:
Overlying skin is intact
Simple (closed)
171
Type of fracture:
Bone communicates with skin surface
Risk of osteomyelitis
Compound (open)
172
Type of fracture:
Bone is fragmented
Comminuted
173
Type of fracture:
Fracture along long axis
Associated with torsional injuries
Spiral
174
Type of fracture:
Fracture due to axial load
Compression (impacted)
175
Type of fracture:
Fracture perpendicular to long axis
Transverse
176
Type of fracture:
Tendinous insertion pulled off bone
Avulsion
177
Type of fracture:
Ends of bone are not aligned
Displaced
178
Type of fracture:
Slow developing fracture due to repeated trauma and microfractures
Stress
179
Type of fracture:
Fracture extends partially through bone
Mostly in pediatrics
Greenstick
180
Why is it called a Greenstick fracture?
Fracture extends partially through bone
Like a green twig - bends but does not break through full thickness
181
Type of fracture:
Fracture of bone weakened by underlying bone disease
Pathologic
182
Infarction of bone and marrow
Avascular necrosis
Aka Osteonecrosis
183
What is the most common site of Avascular necrosis?
Femoral head
184
Avascular necrosis resolves with this, resulting in dense bone seen on radiology
Ingrowth of new bone
185
Avascular necrosis is repaired by this
Creeping substitution
186
Condition with empty lacunae, bone that often appears denser, and subchondral linear lucency later
Avascular necrosis
187
How does bone appear in Avascular necrosis?
Often appears denser
Subchondral linear lucency later
188
Idiopathic avascular necrosis of femoral head epiphysis
Legg-Calve-Perthes Disease
189
Who is more likely to have Legg-Calve-Perthes Disease, male or female?
Male, 4:1
190
What does a patient with Legg-Calve-Perthes Disease present with?
Limp +/- pain
Pain often present at thigh or knee
191
What is the treatment for Legg-Calve-Perthes Disease?
Leg immobilization
Allows remineralization so that femoral head heals to conform to shape of acetabulum
192
Legg-Calve-Perthes Disease is idiopathic avascular necrosis of this
Femoral head epiphysis
193
Legg-Calve-Perthes Disease is uncertain etiology of this
Avascular necrosis
194
Infection of bone and bone marrow
Osteomyelitis
195
2 routes by which Osteomyelitis may occur
Hematogenous
Direct extension or traumatic implantation
196
This is the most common route of Osteomyelitis in pediatrics
Hematogenous
197
This is the most common location of Osteomyelitis in pediatrics
Metaphysis (due to slowing of circulation)
198
Most common organism that causes Osteomyelitis in pediatrics
S. aureus
199
Direct extension causing Osteomyelitis in pediatrics may occur with these 2 things
Otitis, open fractures
200
Most common route of Osteomyelitis in adults
Direct extension
201
Hematogenous route of Osteomyelitis in adults tends to occur in this part of the body
Vertebra (bodies)
202
Most common organism that causes Osteomyelitis in all populations
S. aureus
203
Common organism that causes Osteomyelitis in IV drug users
S. aures
204
Common organism that causes Osteomyelitis in Sickle Cell anemia
Salmonella
205
Salmonella can cause Osteomyelitis in patients with this
Sickle Cell anemia
206
3 Common organisms that cause Osteomyelitis in UTI/GI
E. coli
Pseudomonas
Klebsiella
207
Common organism that causes Osteomyelitis in Potts disease
M. tuberculosis involvement of vertebra
208
M. tuberculosis involvement of vertebra is a common cause of Osteomyelitis in patients with this
Potts disease
209
Necrotic focus of infected bone as seen in Osteomyelitis
Sequestrum
210
Sclerotic reactive bone that surrounds sequestrum, as seen in Osteomyelitis
Involucrum
211
Complication of Osteomyelitis that is a persistent infection in an involucrum
Brodie Abscess
212
Brodie Abscess is a persistent infection in an involucrum and is a complication of this
Osteomyelitis
213
Condition where radiology may show lucency with surrounding sclerosis or dense central nidus
Osteomyelitis
214
This may become Chronic Osteomyelitis
Due to inadequate antibiotic duration or type, inadequate debridement, delayed diagnosis
Pyogenic Osteomyelitis
215
Brodie abscess/sequestrum may form and recur, sometimes decades later, from this condition
Chronic Osteomyelitis
216
Draining sinuses, AA amyloidosis, and malignancy are complications of this
Chronic Osteomyelitis
217
AA amyloidosis is a complication of this condition
Chronic Osteomyelitis
218
This is the most common, classic location for Tuberculosis Osteomyelitis
Vertebral bodies
219
This condition is more destructive and difficult to eradicate that pyogenic osteomyelitis
Tuberculosis Osteomyelitis
220
Type of Osteomyelitis established by metastatic spread, usually from lung
Tuberculosis Osteomyelitis
221
Long term infection with Osteomyelitis may result in malignancy, such as this
Squamous cell carcinoma of draining sinus tract
222
Squamous cell carcinoma of draining sinus tract is a malignancy that can be a complication of this condition
Chronic Osteomyelitis
223
Potts disease is another name for this
Tuberculosis Osteomyelitis
