Musculoskeletal System (lecture 1 and 2) Flashcards
1
Q
What is the main mineral in bones?
A
Main mineral–Calcium Hydroxyapatite
- Bones are mostly inorganic
- Calcium and phosphorus homeostasis
– Bones are 65% mineral and 35% organic
– Contain 99% of body calcium and 85% of phosphorus
2
Q
What type of cell is primary bone forming?
- Synthesize and secrete osteoid (bonematrix)
- Initiate mineralization
A
Osteoblasts
3
Q
What type of cell are responsible for remodeling and dissolving minearlized bone?
- Giant cells, derived from macrophages
- Breakdown bone and remodel it for what is needed
A
Osteoclasts
4
Q
What is the name for the head of the bone?
- part closest to growth plate?
- shaft?
A
- Epiphysis
- Metaphysis
- diaphysis
5
Q
What is this congenital disease?
- Hereditary disorder–impaired cartilage maturation in growth plate of long bones
- problem in physis = growth plate
- Autosomal dominant; 80% of cases are new mutations
- Morphology–clustered, disorganized chondrocytes in growth plate
- arranged in a completely disorganized fashion
Clinical
- Major cause of dwarfism
- Marked shortening of proximal extremities
- Bowing of legs
- Lordotic (“sway-backed”) posture
- Most problems are with proximal extremitites
A
Achondroplasia
6
Q
What is this congenital disease?
- Defective synthesis of Type 1 collagen
- type 1 collagen composes most bone
- Autosomal dominant or recessive
- Clinical features:
- Bone fragility; multiple fractures
- Blue sclerae; abnormal dentition; deafness
- Wide spectrum of clinical severity, from death in perinatal period to normal life expectancy
A
Osteogenesis Imperfecta
“Brittle Bone Disease”
7
Q
What is this metabolic/nutritional disease?
- Any disorder which causes decrease in bone mass
- Mostly in older females
- Morphology
- Thinning and wide spacing of trabeculae of medullary bone
- X-ray changes–late in course of disease
- Increased susceptibility to fractures
- Vertebral compression fractures–decreased height
- Hip and pelvic fractures–prolonged immobilization
A
Osteoporosis
Risk Factors for Osteoporosis:
- Hormonal–lack of estrogen in women
- Decreased peak bone mass
- Dietary factors
- Decreased physical activity
- Genetic factors–vitamin D receptor
8
Q
What is this metabolic/ nutritional disorder in children?
• Defect in bone mineralization due to Vitamin D deficiency
A
Rickets
9
Q
What is this metabolic/nutritional disorder in adults?
- Defect in bone mineralization due to Vitamin D deficiency
A
Osteomalacia
10
Q
What is this metabolic/nutritional bone disease?
- Principal direct PTH effect on bone is increase in osteoclast activity
- Secondary osteoporosis
- Fibrosis (“osteitis fibrosa cystica)
- Fractures with hemorrhage and reactive fibrosis
- more fibrosis and hemorrhage!
- ”brown tumor”
- more fibrosis and hemorrhage!
A
Hyperparathyroid Bone Disease
11
Q
What hormone?
- Polypeptide hormone, regulates calcium and phosphorus metabolism
A
Parathyroid Hormone
12
Q
What is primary hyperthyroidism caused by?
A
parathyroid tumors or hyperplasia
- something directly affecting the gland so that it oversecretes
13
Q
What is secondary hyperparathyroidism caused by?
A
chronic renal disease
- other factors!
- chronic renal disease leads to low levels of calcium in the blood and this leads to an overactive parathyroid gland!
- something outside leads to this
14
Q
What is this metabolic/nutritonal disease where
- Skeletal manifestations of chronic renal disease
- Hyperparathyroid effects
- Increased osteoclast activity
- Osteoporosis
- Osteomalacia-like effect
- Vitamin D converted into active form in kidney
- Defect in bone mineralization
A
Renal Osteodystrophy
15
Q
What is this infectious/inflammatory disease?
- Infection of bone
- Caused by pyogenic bacteria
- Staphylococcus aureus--most common
- Enteric pathogens–Klebsiella, Pseudomonas, E. Coli
- Hemophilus and Strep in neonatal period
- Salmonella in sickle cell anemia patients
- Causative organism unknown in 50% of cases
- Caused by pyogenic bacteria
- Pathogenesis:
- Hematogenous spread of infection to bone
- Direct spread from adjacent soft tissue or joint infection–most common!!!
- Traumatic (or iatrogenic) implantation
- Clinical features
- Pain, fever, malaise, leukocytosis
A
Pyogenic osteomyelitis
- Osteomyelitis = bone, medullary, inflammation
Diagnosis and treatment:
- Clinical signs localizing to bone may be subtle
- X-ray signs may not be present initially
- Nuclear medicine (bone scan) often helpful
- Treatment–aggressive, prolonged antibiotic treatment necessary
- difficult to get antibiotics into bone
16
Q
What is this infectious/inflammatory bone disease?
- Caused by Mycobacterium tuberculosis
- Usually hematogenous spread–complicates 1-3% of pulmonary TB cases
- Very destructive; difficult to treat
- Common locations
- Long bones, especially around knees and hips
- Vertebrae (Pott’s disease)
A
Tuberculous Osteomyelitis
17
Q
What is this infectious/inflammatory bone disease?
- “Osteitis Deformans”-deforming of certain parts of the bone
- Pathogenesis–three stages
- Osteolytic stage–increased osteoclast activity
- Mixed osteoclastic/osteoblastic stage
- Sclerotic stage–characteristic mosaic pattern
- bone overgrows
- Usually asymptomatic–incidental x-ray finding
- Most common sites–pelvis, hips, vertebrae, skull
- axial skeleton
- Symptoms related to bone deformity and inability to adapt to mechanical stresses
- Headache, visual and hearing loss
- Back pain; bowing of legs
A
Paget’s Disease
Complications
- Fractures
- Osteoarthritis
- Malignant transformation
- Osteogenic Sarcoma
- About 1% percent of cases
18
Q
What is this bone complication?
- Bone infarct–ischemic necrosis due to:
- Fracture
- Steroid therapy
- Radiation damage (Osteoradionecrosis)
- Idiopathic
- Most common site is head of femur
- Complications: osteoarthritis, fractures
A
Avascular Necrosis
19
Q
- Benign–histologically same as normal bone
- Most common in head and neck–solitary, hard “bump” on surface of bone “Mandible/maxilla”
- Important only because of cosmetic or mechanical reasons
- Do not undergo malignant transformation
- Dont have to remove unless getting in the wya of something else
A
Osteoma (Torus)
- “bone” “benign”
20
Q
Tumor of young men
– Long bones around knee; less than 2 cm
– Quite painful; distinctive xray appearance due to reactive, sclerotic bone around tumor
A
Osteoid osteoma
21
Q
Tumor of young men
- –vertebra; >2cm; dull pain
- dull annoying back pain
A
Osteoblastoma
22
Q
- Malignant, bone-forming tumor; tumor cells by definition produce osteoid
- Large, bulky tumors arising in and destroying bone
- Metastasis common; most often to lungs
A
Osteosarcoma (Osteogenic Sarcoma)
23
Q
What is this type of osteosarcoma?
- Arises about knee (or proximal arm) of adolescent
- metaphysis
- About 70% of all osteosarcomas
- Enlarging, painful mass or pathologic fracture
- Painful swelling occuring around knee, shoulder, ect; usually a young individual
- Very invasive tumors and large and bulky!
- imaging is extremely important in making this diagnosis
A
Conventional Osteosarcoma
24
Q
What type of osteosarcoma is this?
- Arises in diseased bone–arises because of some other disease process
- Radiation therapy
- Paget’s disease
- About 20 percent of cases
- Prognosis worse
- Sites (pelvis, vertebrae, jaws) harder to resect
- arise more often in axial skeleton which makes thme worse
- Pain from underlying disease delays diagnosis
- More resistant to chemotherapy
- Sites (pelvis, vertebrae, jaws) harder to resect
A
Secondary Osteosarcoma
25
What are the most common sites of orign for malignant bone tumors?
Most common sites
* Breast
* Lung
* Thyroid
* Kidney
* Prostate
* BLT w/ Kosher Pickle
26
* Benign tumor of mature cartilage
* hard to tell because just looks like mature cartilage
* Most commonly in medullary cavity of long bones of hands or feet; 20-50 years
* Usually solitary--no malignant transformation
* May be multiple
* Ollier’s disease; Maffucci’s syndrome
* Malignant transformation possible, but rare
Enchondroma (Chondroma)
27
* Bony tumor with a cartilaginous cap; may be sessile or pedunculated
* both bone and cartilage!
* Arise near growth plate of long bones; young adults
* Usually solitary; rarely multiple (hereditary exostosis)
* Malignant transformation rare; only in multiple lesions
* malignant portion would most likely be the cartilagonous part
Osteochondroma (Exostosis)
28
* Malignant tumor of cartilage
* Older adults (age 50-70)
* Most common sites proximal extremities, pelvis, ribs
* axial skeleton
* Prognosis related to histologic grade and resectability
* Aggressive tumors; destroy bone; metastasize to lungs
* hard to distinguish between benign cartilage
Chondrosarcoma
29
* 20% of all benign bone tumors
* arises right at the end of long bone
* so you see a lot of hemorrhage
* Osteoclast-like giant cells and histiocytes
* Epiphyses of long bones of young adults
* Clinical features
* Present with pain; may simulate arthritis
* Benign, but often recur locally if not completely resected. Metastasis rare.
* will slowly grow and take over most of the bone
Giant Cell Tumor of Bone
30
* Malignant bone **tumor of children**
* Preferred sites--diaphysis of long bones and pelvis
* right in the middle
* Histology--**”small round blue cell tumor”**
* Histogenesis uncertain; thought to be of neuroectodermal origin
* **chromosomal translocation**
* Treated by surgery and chemotherapy; 5-year survival now 75 percent
* neural cells drive this tumor!
Ewing’s Sarcoma
aka Primitive Neuroectodermal Tumor (PNET)
31
* Benign, tumorlike condition
* Replacement of bone by **combination** of fibrous tissue and malformed bone
* nonneoplastic swelling of the bone
Fibrous Dysplasia
32
What is this type of fibrous dysplasia?
* Adolescence; usually asymptomatic
* Ribs (most common), long bones of legs, skull, jaws
Monostotic Fibrous Dysplasia (70%)
33
What is this type of fibrous dysplasia?
* Children; craniofacial involvement common
* May cause deformities and pathologic fractures
Polyostotic Fibrous Dysplasia (25%)
34
* Most common joint disease in U.S.
* “Degenerative joint disease” is a better name
* Primary defect is degeneration of articular cartilage
* Splitting and fissuring of articular cartilage
* Erosion of articular cartilage
* Sclerosis and polishing (“eburnation”) of underlying bone
* Fragments of bone and cartilage (“joint mice”) in synovial cavity
* Fissuring of underlying bone
* Bone cysts
* Reactive synovial inflammation--late in course
* Carliagonous cap is eventually just worn away
Osteoarthritis
* Risk Factors
* Age
* Mechanical stress (joint deformity, extreme obesity, athletes)
* Clinical
* Gradual onset--usually elderly persons unless significant risk factors presen
* Common joints--knees, hips, vertebra, fingers Symptoms--dull pain, morning stiffness, decreased range of motion
* Second most common cause of long-term disability in U.S.
* Treatment--Joint replacement
35
* Systemic autoimmune disorder primarily affecting joints
* Morphologic features
* Chronic, proliferative synovitis
* Predominantly lymphocytes and plasma cells
* Pannus formation--fibrous mass of proliferating synovium, eventually filling synovial cavity
* End stage--ankylosis (obliteration of synovial cavity)
* \*mostly synovial joints
Rheumatoid Arthritis
Clinical
* Diagnosis based mostly on clinical features
* Morning stiffness
* Most commonly affects hands and feet
* Several joints affected
Radiographic and laboratory findings
36
* Systemic disease caused by precipitation of excessive concentrations of uric acid in and around synovial space
* Uric acid metabolism:
* End product of purine nucleotide metabolism
* Primary accumulation (90% of cases) due to enzyme deficiency
* Secondary accumulation :
* Increased cell turnover (e.g.,leukemia therapy)
* Decreased excretion (chronic renal disease)
Gout
* Uric acid crystals in synovial fluid
* Birefringent, needle-shaped crystals
* in and around joint space
37
Chalky white accumulations of uric acid in joint and surrounding tissues
* In chronic gout
Gouty tophus
38
Precipitation of uric acid in renal tubules
Gouty nephropathy
39
– Sudden, very painful onset of swelling and redness
* pain at an 8 or 9
– Usually one joint-- great toe most common
* isolated joint
– Diagnosis-- demonstration of urate crystals in synovial fluid
* try and get some of the joint fluid out
* look for uric crystals in fluid
Acute gouty arthritis
40
Result of multiple acute gout attacks
* more swelling from accumulation of urate acid
Chronic Tophaceous Arthritis
41
* Pyogenic bacterial infection of joint
* fluid may look a little yellow
* Fever, malaise, local pain, pus in joint
* Gonococci, staph, strep most common agents
* Prompt antibiotic treatment necessary to prevent joint damage
Acute suppurative arthritis
42
* Chronic infectious disease involving primarily skin and joints
* Most common arthropod-borne disease in U.S.
* Vector is deer tick (VECTOR born disease)
* Agent is spirochete, Borrelia burgdorferi
* first affects other places of body and then comes and affects your joints
Lyme Disease
* Acute stage
* Redness, induration at site of tick bite
* Lasts a few weeks
* Secondary stage
* Skin lesions distant from tick bite
* Cardiac symptoms, meningitis
* Late stage
* Arthritis in 80%
* Knees, shoulders, elbows
* multiple larger synovial joints
43
* Very common
* Small (1-2 cm) cyst near joint or tendon sheath
* Caused by degeneration of fibrous tissue surrounding joint
•Wrist area most common
* cystic swelling--remove it surgically and pts dont have any new problems
Ganglion Cyst
44
* Most common neoplasm of joint space
* Benign proliferation of synovial cells forming villous projections of synovium
* Usually one joint affected; knee in 80%
* Clinical: pain, stiffness, “locking” of joint
* Eventually, decreased range of motion
* occurs within joint space
* not an inflammatory disease
Villonodular Synovitis
