Exam 1--Sec. 1 Musculoskeletal Pathologies Flashcards
What is the term for a disorder of bony development, which commonly results in defective ossification of the skeletal system?
Dysostosis
What are some examples of Dysostosis?
- polydactyly
- syndactyly
- aplasia (absense of bodily structure)
- cleidocranial dysostosis
- Klippel-Feil Syndrome
Following what irregularity does dysostoses develop after?
following irregular mesenchymal cell migration, during embryogenesis
What is Dysplasia?
a musculoskeletal pathology resulting from a mutation that interfers with the body’s ability to perform normal growth or regulate normal musculoskeletal homeostasis
What are examples of dysplasia?
- type 1 spondylolisthesis (the dysplastic type)
- osteogenesis imperfecta
- osteopetrosis
- achondroplasia
~could be isolated or widespread
What is dwarfism?
a description of stunted growth; does not achieve mature height of at least 4’11’’
What are some pathologies that may result in dwarfism?
- Turner syndrome
- osteogenesis imperfecta
- achondroplasia
- hypopituitarism
What is a form of skeletal dysostosis that involves congenital abnormalities of bones and teeth with clavicles that are underdeveloped or absent?
cleidocranial dysostosis
What is the frequency that cleidocranial dysostosis occurs?
1 in a million inds.
What occurs with the skull bones in someone with cleidocranial dysostosis?
have delayed fusion, result in delayed closure of cranial sutures, causing enlarged frontanelles (“soft spots”), typically have normal intelligence though
About 70% of inds. with cleidocranial dysostosis have a mutation in what gene? What does that gen involve? How is it inherited?
mutation in RUNX2 gene; involves cartilaginous and osseous tissue development; is “master switch” and regulates other genes
inheritence: autosomal dominant
What syndrome is a skeletal dysostosis and is defined by presence of two or more cervical vertebrae having abnormal fusion?
Klippel-Feil Syndrome
Occurs ~ 1 in 40,000
What abnormalities in the neck and other places in the body does Klippel-Feil syndrome cause?
- shortened neck height and low-appearing hairline and limited motion in cervical spine
- cause cervical neck pain and headaches
Other: - renal abnormalities, cardiac abnormalities, and hearing problems
~Sprengel’s deformity
What is Sprengel’s Deformity and what other disorder is it characteristically ass. with?
is a skeletal abnormality of the scapula due to failure of scapula to descend during embryogenesis –> may involve congenital bony fusion (ankylosis) b/w scapula and lower C or upper T spine
ass. with Klippel-Feil syndrome
What is the most common form of skeletal dysplasia and what gene is involved?
Achondroplasia; a gain-of-function mutation in FGFR3 gene; usually the gene suppresses endochondral growth; these affects long bone elongation of extremity bones
How does achondroplasia occur?
- inherited ~10% cases, autosomal dominant
- most are a sporadic mutation in FGFR3 gene w/in father’s sperm
What increases the risk of one having achondroplasia due to a spontaneous FGFR3 gene?
advanced paternal age increases the risk of father’s sperm developing the spontaneous mutation
What are characteristics of achondroplasia?
- short extremity bones
- trident hand appearance
- stenosis of foramen magnum
- frontal bossing
- midface hypoplasia
- lumbar spinal stenosis
- bullet vertebrae (scoliosis and extreme kyphosis or lordosis)
- lower extremity radiculopathy (from lumbar stenosis)
- normal intelligence
What is the most common form of lethal dwarfism that is incompatible with postnatal life and how common is it? How is the thorax affected?
Thanatophoric dwarfism (~ 1 in 20,000)
Severely underdeveloped thorax does not provide enough space for normal heart and lung development
What is severely diminished in Thanatophoric dwarfism? What gene is mutated?
chondrocyte activity–resulting in inhibited endochondral ossification
same FGFR3 gene mutation as in traditional achondroplasia
What is the most common cause of death of thanatophoric dwarfism?
respiratory failure (due to underdeveloped thorax)
What dysplasia disorder is due to mutation in formation of type 1 collagen, causing it to take on irregular shape resulting in premature breakdown?
Osteogenesis imperfecta (AKA brittle bone disease, type 1 collagen disease, or OI)
What tissues are affected in osteogenesis imperfecta, which tissues are prominently affected??
all tissues containing type 1 collagen; esp. bones, teeth, eyes, skin, and joints
~hearing issues, small teeth
What are two unique features of osteogenesis imperfecta?
- severely under-mineralized bony tissues = very prone to fracture
- “blue sclerae”–> due to more translucent sclerae of eyes and vascular choroid layer showing bluish color
T/F. Type I Osteogenesis imperfecta is incompatible with life.
False. it IS compatible with life
How is Type I osteogenesis imperfecta most commonlly recognized?
in childhood due to multiple fractures, bowing of weight-bearing lower extremity bones, dwarfism, or scoliosis
What do we need to keep in mind with patients with Type I osteogenesis imperfecta?
severe skeletal fragility and DO NOT use HVLA adjusting
Is Type II osteogenesis imperfecta compatible with post-natal life? why or why not?
NO! Due to extreme skeletal fragility and ind. suffers multiple fracture in utero or during birth process and usually causes lethal intracranial hemorrhage
Children that are treated with bisphosphonates for their osteogenesis imperfecta will have what bone appearance on x-ray?
Zebra Stripe Sign
What describes a group of conditions that are characterized by reduced osteoclast formation/activity? What does it result in?
Osteopetrosis (AKA marble bone disease)
Results in widespread skeletal sclerosis
What does sclerosis mean?
abnormal hardening of a body tissue
What are the affects to the bone in osteopetrosis?
increased skeletal density, and therefore more prone to fractures due to ridged and inflexible
“chalk stick” pathological fractures, straight across
What are some clinical features of someone with osteopetrosis?
bone marrow mineralizes—therefore reduced hematopoiesis
- decreased RBCs = anemia
- decreased WBCs = infections
- Erlenmeyer flask deformity
- CN defects due to foraminal stenosis
What is osteoporosis?
a common condition involving a severe reduction in bone mineral density, defined as being at least -2.5 standard deviations from normal mineralization
What is the primary complication from osteoporosis and where does that most commonly occur?
fractures in trachecular bone (VBs of spine, femur, or calcaneus)
How is bone mineral density evaluated?
DEXA scan determines how many standard deviations patient’s bone mineralization is away from normal of a 25 yr old = “T-score”
What is a T-score vs a Z-score?
T-score = compare you to age of same sex of optimal time period
Z-score = compare you to inds your age, sex, and weight and where they are at
What is osteopenia?
a term used for bone mineralization below normal, but not yet severity of osteoporosis; therefore b/w 1 and 2.5 standard deviations below normal
When does bone mineralization peak and what happens to it after that?
young adulthood, age 25-30, then decreases ~0.5% every year after
What factors influence inds bone mineral density?
genetic factors, diet, lifestyle choices (smoke/drink), level of physical activity, muscle strength, age, hormones
What is the term for when osteoblast activity decreases with age and there is age-related loss in bone mineralization? Why does this occur?
senile osteoporosis
- older adults more likely to be inactive
- after menopause rates increase of osteoclast activity and due to reduced estrogen levels
T/F. Osteopenia and osteoporosis are asymptomatic.
True. Until there is a fracture
Where are the MC locates for osteoporosis-related fractures?
- femoral neck
- VBs–> cause compression fracture MC in thoracolumbar
What is the term for a loss of overall height observable with advanced osteoporosis?
“Dowager’s hump”
What are complications from osteoporosis-related fractures?
- immobility
- spinal deformity (lateral curve in T/L or lordosis in L)
- pneumonia
- pulmonary embolism
How can one help prevent osteoporosis?
- max. deposition of bone mineralization in childhood/young adulthood
- regular physical exercise
- diet rich in Vit. D and get UV exposure
- good vision and hearing
What medication can be used to help decrease osteoclast activity?
bisphosphonates
What are two metabolic bone disease that develop after Vitamin D deficiency?
Rickets and Osteomalacia
What is Rickets?
develpos in children due to deficiency in Vit. D; reduced bone deposition in epiphyseal region (growth plate); causes stunt growth, bowing of legs, and increased risk of fractures, and abnorm spinal curvatures
What is osteomalacia?
- develops in adults due to Vit. D deficiency
- faulty bone turnover and bone left under-mineralized
- increases risk of fracture
- less severe than Rickets
- mimics osteoporosis
What is hyperparathyroidism?
involves elvated PTH, which regulates blood calcium levels by stimulating osteoclast activity which release Ca++ into blood
T/F. Primary hyperparathyroidism involves other processes in the body that causes increase PTH production.
False, (this is describing secondary hyperparathyroidism)
primary– involves parathyroid glands overproducing PTH
What is the primary cause of primary hyperparathyroidism? and who is most likely to develop it?
adenoma of parathyroid gland
women around age 50
What does Secondary hyperparathyroidism involve?
other processes in body that cause increase production of PTH
What is the primary cause of secondary hyperparathyroidism?
chronic kidney disease–> which causes hypocalcemia–> and parathyroid gland response by elevating PTH production
What is a less common cause of secondary hyperparathyroidism?
vitamin D deficiency–> which interfers with calcium homeostatsis–> causes hypocalcemia–> stimulates PTH levels
What is the MC sign of hyperparathyroidism? What is the MC symptom?
MC sign = hypercalcemia
MC symptom = kidney stones
What are some other conditions patients with hyperparathyroidism may experience?
- weakness
- depression
- abdominal pain
- peptic ulcer
- nausea
- anorexia
- short-term memory loss
- bone pain
- myalgia (muscle pain)
- joint pain
- anorexia
- body-wide osteoporosis
T/F. Skeletal changes ass. with hyperparathyroidism involve resorption of cortical and trabecular bone?
true. and is widespread
Hyperparathyroidism does affect the skeleton in a widespread manner, but what are the most characteristically affected areas?
- phalanges
- VBs
- calvaria
- femurs
- tibias
For hyperparathyroidism, what are the radiological appearances for these locations:
- VBs
- Phalanges
- Calvaria
- Long bones of lower extremeties
- Rugger jersey spine
- Resorption of cortex on radial side of middle and distal phalanges
- salt and pepper skull
- osteitis fibrosa cystica
What is the brown “tumor” characteristic of? How is it caused?
hyperparathyroidism
- develop following localized osteolysis –> one weakens and hemorrhage occurs–> macrophages come–> fibrotic tissue fills area
Localized areas of osteolysis in hyperparathryroidism may cause brown “tumor”, but what else may it cause?
osteitis fibrosa cystica–> areas of “cystic degeneration”
What are the three stages of Paget’s Disease?
- Osteolysis stage
- mixed osteoclastic-osteoblastic stage
- osteosclerotic (burned-out) stage
What are the results of the the three stages of Paget’s Disease?
increased bone mass, but structurally weak
Who does Paget Disease seem to effect and what geographic locations? How common?
(males 2x as likely) Caucasian males around age 70; in North America, AUS< New Zealand, Europe
~1%, but up to 10% if older than 80yrs
T/F. Most patients with Paget Disease are asymptomatic and diagnosis is discovered incidentally.
True, ~80%
What is elevated in serum of someone with Paget’s Disease?
levels of alkaline phosphatase–> represents osteoblastic activity
If Paget’s disease is symptomatic, what are some symptoms?
- back and neck pain (MC)
- bony deformation (bowing)
- increased fracture risk
- headache
- CN compression
- “ivory vertebra sign”
What are the three things that can cause an “ivory vertebra sign”?
- Paget Disease
- Metastatic cancer (prostate)
- lymphoma
How is the bone of an x-ray described for Paget’s disease?
“shaggy” appearance. irregular mosaic or “jigsaw puzzle” pattern
Where is Paget’s disease most likely to develop on the skeleton?
axial skeleton and proximal femurs
- pelvis, sacrum, skull(increase density)
What percentage of Paget’s disease cases transform into cancer and what is usually the prognosis?
~1% or less transition into osteosarcoma–and is very aggressive and has a high mortality rate
What is the etiology of Paget’s Disease?
idiopathic
What is a fracture?
abbreviated Fx.
- is complete or partial loss of bone integrity
Describe a complete fracture.
fracture completely separates; complete separation of bones cortex
When is a complete fracture MC?
at site of pathological fracture in older adults
Describe an incomplete fracture.
does not separate the fragments of fractured bone
Where and when are incomplete fractures MC?
in long bones in pediatric inds
What is a fracture called when the skin overlying the fracture remains intact?
Closed (simple) fracture
- decreases risk of inf.
What is a compound (open) fracture?
fracture is in communication with overlying skin; increases risk of inf.
What is fracture called when it is splintered into multiple fragments? When does this characteristically occur?
comminuted fracture; typically due to high-velocity forces
What is a displaced fracture?
when ends of bones at fracture site are not in alignment
Describe a stress fracture.
slowly-developing fracture following increased physical activity and repetitive loading
What makes a fracture painful?
the disruption of sensitive periosteum
What are the optimal steps of a fracture healing?
Begins immediately and hematoma forms Week 1: soft callus Week 2: bony callus and woven bone Weeks 6-8: endochondral oss. and bony callus ~lifetime of remodeling
What 6 things can delay a fracture from healing?
- nonunion
- splintered
- not immobilized
- infected
- ind. malnourished
- older adult
What are fractures called that involve the epiphyseal growth plate and what individuals can they occur in?
Salter-Harris Fractures (SHF); ind. must have “open” or active growth plates–limited to pediatrics who have not reached skeletal maturity
How common are Salter-Harris Fractures?
occur in about 15% of all pediatric longbone fractures
Describe a Type I Salter-Harris Fracture. What is the prognosis?
extends through entire growth plate (physis)
- favorable prognosis
Describe a Type II Salter-Harris fracture. What is the prognosis?
extends from growth plate into metaphysis
- favorable prognosis
Describe a Type III SHF. What is the prognosis
extends from growth plate into epiphysis
- limited prognosis, due to joint involvement
Describe a Type IV SHF. What is the prognosis?
extends through growth plate, metaphysis, and epiphysis
- poor prognosis
Describe a Type V SHF. What is the prognosis?
compression fracture of growth plate
- poor prognosis
From Type 1 - Type V, what are the prevalence of each when it comes to all SHFs?
Type I - 5% Type II - 75% Type III - 10% Type IV - 10% Type V - <1%
What type is the most common Salter-Harris fracture?
Type II (extends from growth plate into epiphysis)
What is Avascular Necrosis (AVN)?
a site of necrosis due to reduced blood supply (ischemia)
Avascular Necrosis (AVN) may occur following a fracture or joint dislocation. What are some other causes?
- autoimmune vasculitis (Type III hypersensitivity)
- prolonged use of corticosteroids
- ionizing radiaton
- blood clots
- blood disorders increasing clotting
About _____ percent of all Avascular Necrosis (AVN) are ______.
25%; idopahthic
T/F. Many Avascular necrosis (AVNs) are asymptomatic.
True
and heal via “creeping substitution”
What may occur with a subchondral Avascular necrosis (AVNs) that collapse?
may cause surface irregularities at joint, which accelerate osteoarthrities = secondary osteoarthritis
What is the term given to an Avascular necrosis (AVN) that develops at the subchondral area of a joint?
Osteochondritis dissecans
-is pain due to death of osseous and cartilaginous tissues
What are the MC locations for osteochondritis dissecans?
knee and hip joints
What age do most Avascular necrosis (AVN) cases occur?
ages 30-50
What is a site of bone marrow inflammation, due to an infection?
osteomyelitis (bacterial inf.)
In osteomyelitis, what is the term used for the site of infected bone that dies?
sequestrum
In osteomyelitis, what do you call the irregular bone surrounding the sequestrum?
invelucrum
Many cases of ______ will produce pus, which exits the site via a _____ ______.
pyogenic; draining sinus
What are the two types of osteomyelitis?
- Pyogenic osteomyelitis
2. Mycobacterial osteomyelitis (TB osteomyelitis, or skeletal TB)
What are the three way that an infection reaches the bone marrow in Pyogenic osteomyelitis?
- (MC) hemoatogenous spread
- extension from nearby inf.
- direct implantation form trauma or compound fx.
What are the MC sites of Pyogenic Osteomyelitis?
long bones of extremities
What is the MC bacterial microbial origin for Pyogenic Osteomyelitis?
Staph. aureus ~90% all cases
In neonates, what are the two MC bacterial microbes to cause Pyogenic osteomyelitis?
E. coli and Group B Strep.
Inds. with sickle cell disease are most likely to develop Pyogenic osteomyelitis from what bacterial microbe?
Salmonella spp.
What is it called when TB causes the bone marrow infection?
Mycobacterial Osteomyelitis, or TB Osteomyelitis, or Skeletal TB
Where does Mycobacterial Osteomyelitis usually develop from?
in patients with pulmonary TB, inf. begins in lungs and spread to lymph and blood
Is what percent of all cases of pulmonary TB does Mycobacterial osteomyelitis develop?
3%; usually in ind. with suppressed immune system
What symptoms can Mycobacterial osteomyelitis cause?
- severe destruction and caseous granulomas
- low-grade fever
- chills
- chachexia
Where is the inf. in Mycobacterial osteomyelitis MC occur?
long bones of extremities and VBs
When the vertebral bodies are involved are destructed over time in Mycobacterial osteomyelitis, what is it called?
Pott’s disease
T/F. Mycobacterial osteomyelitis is MC results of acute infection.
False; MC due to a chronic inf.
What is congenital kyphosis?
results from abnormalities occurring during embryogenesis, regarding formation or segmentation of spinal column
Is Type I or Type II congenital kyphosis more common?
Type I (involving incomplete formation of VB)
What type of congenital kyphosis involves failed segmentation of VBs?
Type II
Where does congenital kyphosis occur? What can it cause?
thoracic spine; cause compression of spinal cord–> paraplegia
