Musculoskeletal Flashcards
Osteogenesis Imperfecta is a group of hereditary bone disorders with abnormal synthesis of ___________
type I collagen
T/F: Most forms of OI are autosomal dominant
true
what are the 2 hallmark signs of Osteogenesis Imperfecta?
1) Blue sclera
2) opalescent teeth
T/F: the opalescent teeth of Osteogenesis imperfecta are indistinguishable from dentinogenesis imperfecta
True
what does the PROGNOSIS of Osteogenesis imperfecta depend on?
depends on:
1) type of OI
2) expression of the gene
Osteopetrosis is a goup of rare hereditary bone disorders with defective _______________
bone remodeling (osteoclast dysfunction)
what are the characteristics of bone affected with Osteopetrosis ?
Affected bone is dense, but structurally unsound and weak
Patients with Osteopetrosis are susceptible to what complications?
Prone to:
1) fractures
2) cranial nerve compression
3) infections
why can bone marrow transplants help people with Osteopetrosis?
transplantation may re-populate functional osteoclasts (derived from monocyte precursors)
_____________ is defined as “Increased porosity of the skeleton resulting from reduced bone mass”
osteoporosis
what conditions will increase the risk for osteoporosis?
** reduced estrogen in women
- lower androgens in males
- low physical activity
- old age (causes drop in hormone levels)
half of women will sustain a bone fracture by what age?
90
what are the most common sites for bone fractures as a result of osteoporosis?
A) vertebral bodies
B) pelvis
C) femoral neck
what are the 3 types of PRIMARY osteoporosis?
1) Postmenopausal
2) Senile
3) idiopathic
the primary treatment for osteoporosis includes:
- adequate dietary calcium intake
- vitamin D supplementation
- regular weight-bearing exercise
- hormone therapy (estrogen)
Paget disease (osteitis deformans) is characterized as:
Abnormal, dense bone formation which is structurally weak and prone to fracture
T/F: Pagets disease often affects multiple bones
TRUE
85% of cases are “polyostotic “
most cases of Pagets disease show what clinical signs?
NONE
- most are asymptomatic, only detected on radiographs
what is the osteolytic stage of Pagets disease?
frenzied, regional osteoclastic activity and bone resorption
what is the mixed osteoclastic-osteoblastic stage of Pagets disease?
exuberant osteoblastic activity and bone formation
what is the osteosclerotic stage of Pagets disease?
apparent exhaustion of cellular activity
name the 3 “stages” of Pagets disease:
1) osteolytic stage
2) mixed osteoclastic-osteoblastic stage
3) osteosclerotic stage
what is the net clinical result of the abnormal/dysfunctional bone mass created during Pagets disease?
skeletal deformation caused by accumulation of excessive amounts of abnormal, unstable bone
___________ lesions are those involving only one bone. What percent of Pagets disease cases show this pattern?
- monostotic
- accounts for 15% of pagets disease cases
polyostotic lesions (those involving more than 1 bone) account for ____% of paget’s disease
85%
_______ bone is the HISTOLOGICAL pattern of bone found in paget’s disease?
this is one of the “hallmarks” of Paget’s
mosaic
In Paget’s disease, the RADIOGRAPHIC features form a _____ pattern of bone
cotton-wool pattern
what is leontiasis ossea?
- complication of Paget’s disease
- “lion face”
- characterized by an overgrowth of the facial and cranial bones
what % of Paget’s disease patients are asymptomatic? how is Paget’s diagnosed?
- 80-90% are asymptomatic
- The diagnosis is made secondary to the radiographic and microscopicappearances
what substance is elevated in the urine of people with Page’ts disease? what is elevated in the serum?
- URINARY hydroxyproline (⇑bone resorption)
- SERUM alkaline phosphatase (⇑bone apposition)
Patients with Paget’s disease are at a higher risk to develop what form of cancer?
osteosarcoma
how does PTH effect calcium homeostasis?
1) osteoclast activation
2) increased calcium resorption by the kidneys
3) increased synthesis of vitamin D (kidneys) resulting in increased calcium absorption from the gut.
patients with Hyperparathyroidism often develop skeletal changes (bone appears ground glass and osteoporotic) due to _____________
activation of osteoclasts
Primary hyperparathyroidism is an important cause of ____________
hypercalcemia
In more than 95% of cases, primary hyperparathyroidism is caused by what?
parathyroid adenomas
or
hyperplasia (less commonly by parathyroid carcinoma)
** what is the most common manifestation of PRIMARY hyperparathyroidism? **
an increase in serum calcium due to an increased level of PTH.
what symptoms are associated with primary hyperparathyroidism?
painful bones, renal stones, abdominal groans, and psychic moans
Secondary Hyperparathyroidism is caused by what?
any condition associated with a chronic depression in the serum calcium level
in secondary Hyperparathyroidism, low serum calcium leads to compensatory over-activity of ___________
the parathyroid glands
____________ is by far the most common cause of secondary hyperparathyroidism
renal failure
decreased phosphate excretion (during kidney failure) will lead to what
hyperphosphatemia
which has more severe clinical manifestations: Primary, or secondary, hyperparathyroidism?
Primary
__________ refers to an infection spreading through the medullary spaces of a bone
Osteomyelitis
what are the 3 ways in which bacteria can invade the bone?
3 causes of osteomyelitis
- Hematogenous spread
- Contiguous infection (i.e. odontogenic infections)
- Direct traumatic introduction (i.e. compound fractures, surgical procedures)
Hematogenous osteomyelitis is caused mostly by what bacteria?
Staphylococcus aureus
With progression of osteomyelitis, ill-defined areas of radiolucency develop and may be intermixed with radiopaque ________
sequestra
__________ is a disorder characterized by progressive replacement of bone by a proliferation of fibrous tissue intermixed with unorganized, woven bone
Fibrous Dysplasia
name the 3 types of fibrous dysplasia:
- Monostotic fibrous dysplasia (one bone)
- Polyostotic fibrous dysplasia without endocrine involvement
- Polyostotic fibrous dysplasia in association with endocrinopathies
Polyostotic fibrous dysplasias are often associated with what 2 characteristics?
café-au-lait spots*
occasionally with endocrine disorders
Jaffe-Lichtenstein Syndrome is what form of fibrous dysplasia?
Polyostotic fibrous dysplasia WITHOUT endocrine involvement
- arises in early childhood, can continue into adulthood
- NO endocrine involvement/disorder
what are Cafe-au-lait spots?
= melanin pigmentation spots of the skin
- found in POLYostotic Fibrous dysplasias
(both Jaffe-lichtenstein and McJune-Albright)
which form of Fibrous dysplasia effects more females than males?
Polyostotic fibrous dysplasia in association WITH endocrinopathies
= McCune-Albright syndrome
Histopathological, AND radiographic features of Fibrous dysplasia:
*** Radiograph: “Ground Glass” looking areas of increased radiopacity
Histopath: Chinese characters
Outside of lymphoproliferataive diseases, __________ is the most common primary malignant tumor of bone
osteosarcoma
who is at higher risk for osteosarcomas? what region of bones are most at risk?
- patients are younger than age 20 (mean age 18yrs)
- metaphyseal region of long bones in the extremities is the most frequent site
60% occur in the knee
___________ is a bone producing malignancy. what is the 5-year survival rate of these disorders?
Osteosarcoma
- 5 yr = 60% survival
what is the most common clinical presentation for osteosarcomas? what are the radiographic characteristics?
- clinical: A painful enlarging mass
- radiograph: radiolucent-radiopaque lesion that may present with a “sunburst” appearance
the _____________ is a characteristic feature of osteosarcomas, and is the formation of an acute angle between the neoplastic bone and the cortex
Codman’s triangle
T/F: osteosarcomas are associated with “sunburst” radiographs, and the formation of Codman’s triangle
true
_____________ (degenerative joint disease) is the most common disorder of the joints and is a very frequent, if not inevitable, part of aging.
Osteoarthritis
The fundamental feature of osteoarthritis is:
degeneration of the articular cartilage
T/F: unlike rheumatoid arthritis, osteoarthritis is not primarily an inflammation of the joint
true
what are the most important factors for osteoarthritis?
aging and mechanical effects
- mechanical stress = major role in development
T/F: a PRIMARY feature of osteoarthritis is a structural change in the underlying bone of effected joints
FALSE
- bone changes are secondary to degeneration of articular cartilage
what are the steps in the progression of osteoarthritis?
- the cartilage cap develops vertical fissures
- With time, these fissures extend through the full thickness to the subchondral bone
- portions of the cartilage are eroded completely with exposure of the underlying bone
what are the symptoms of osteoarthritis?
- after age 50
- crepitus (grating or popping sensation) & joint stiffness
- deep, aching pain
- pain, deformity, and limitation of motion develop late
during osteoarthritis: At the margins of the joint, small bony outgrowths termed _________ arise and help to further inflame the surrounding synovial membrane
osteophytes
In contrast to rheumatoid arthritis, ___________ of the joints does not occur in osteoarthritis
fusion
Gout is a disorder caused by tissue accumulation of excessive amounts of _______
uric acid
in patients with Gout, crystallization of the uric acid can cause recurrent bouts of _______
arthritis
high uric acid in body fluids leads to precipitation of __________ that trigger a chain of events that culminate in joint injury
sodium URATE crystals
Gout can result in what 3 things?
1) episodic, acute arthritis
2) tophus (tophi) formation
3) kidney damage
what joint is effected in 90% of gout patients? are men or women more likely to suffer from gout?
- great toe
- more common in males
(Peripheral joints like the hands and feet are affected more frequently)
what is a “tophus”?
- feature of Gout
- Tophus = a layer/deposit of crystals
- Urate Crystals become encrusted on the articular surface and even penetrate deeply into surrounding bone and soft tissue
During CHRONIC arthritis from gout, erosion and progressive destruction of the joint occurs secondary to tophi (mult tophus) and resembles _____________
advanced osteoarthritis
Sodium Urate crystals in the joints of Gout sufferers will trigger the chemotaxis of what cell type? what does this cause?
neutrophils & monocytes
- neutrophils release inflammatory signaling molecules
treatments for gout:
1) Diet modification
2) Colchicine, allopurinol
3) NSAIDs for pain
what disease constitute a group of inherited abnormalities of muscle which vary from mild motor weaknesses to severe life-threatening alterations
muscular dystrophies
what is the most common (and devastating) form of muscular dystrophy?
Duchenne muscular dystrophy
characteristics of Duchenne muscular dystrophy:
- X-linked recessive disorder
a) predominantly in the male offspring - caused by the absence of a structural protein
- The initial signs appear in childhood
- death usually ensues before age 30 due to cardiac/respiratory involvement
what protein is missing in patients with Duchenne dystrophy? what is the function of this protein:
dystrophin
- Dystrophin attaches portions of the muscle fibers to the cell membrane
clinical progression of Duchenne muscular dystrophy:
- affected muscles undergo progressive degeneration
- process begins in the pelvis and shoulder girdles
a) eventually spreads to extremities
why are the leg muscles are often enlarged in patients with Duchenne?
enlarged secondary to pseudohypertrophy
replacement of lost muscle with fibrofatty tissue
what is Myasthenia gravis?
- autoimmune disease
- results in destruction of acetylcholine receptors in the neuromuscular junction
manifestation of myasthenia gravis:
weakness and prominent fatigability of voluntary muscles
- most active muscles generally are the most severely affected (eyes, face, chewing, swallowing, breathing)
are males or females more likely to have myasthenia gravis?
FEMALES
ANY AGE
inset often insidious
many sufferers of myasthenia gravis are also likely to have abnormalities of what organ?
thymus abnormalities
common clinical signs of Myasthenia Gravis:
A) ptosis: drooping of eyelids
B) diplopia: double vision
Treatment and prognosis for Myasthenia Gravis:
TREATMENTS
A) Cholinesterase inhibitors, immunosuppression, thymectomy may induce remission
B) sometimes disease spontaneously stops
PROGNOSIS
- 5-year survival is 95%
what are the available for treatments for Paget’s disease of bone?
- bisphosphonates
- calcitonin
**no permanent solution exists
Osteitis Fibrosa Cystica (a condition caused by hyperparathyroidism), is characterized as:
formation ofcyst-like ___________ of bone
brown tumors
what is a “involucrum “? what disease is it associated with?
- rim of new bone growth around “sequestrum” (dead bone)
- found in osteomyelitis
Problems with eye muscles and muscles of mastication may be initial presentation for what disease?
Myasthenia Gravis
muscles that get worked more will show symptoms sooner
