Exam 6 Bone Pathology Flashcards
List different non-neoplastic bone diseases
Fractures, osteoporosis, osteomalacia, osteomyelitis, avascular bone necrosis/infarction, Paget’s disease, congenital bone disorders
What is the differential diagnosis of osteopenia?
Osteoporosis, osteomalacia, malignancy, rare hereditary disorders
What are neoplasms involving bone?
Metastatic tumors to skeleton, hemic malignancies that usually infiltrate bone
What is a pathological fracture?
fracture through diseased bone- usually refers to fracture through tumorous or tumor-like bone
What does PTH do to osteoclasts?
Increases their activity resulting in increased calcemia
Where does vitamin D come from?
Diet and skin synthesis (from sun)
What stimulates the release of PTH and increased conversion of vitamin D into it’s active form in the kidneys?
Hypocalcemia, hypophosphatemia
What is needed for healthy bones in an adult?
Calcium and phosphorous, vitamin D, good absorption at gut, good vit D conversion in kidneys, parathyroid hormones
What is the first thing that happens at a fracture site?
Blood clot
What happens when the periosteum experiences stress?
In can differentiate into osteoblasts and lay down new bone
What are some complications of a fracture through healthy bone?
Mal-alignment, non-union/mal-union/pseudoarthritis, osteomyelitis, growth disturbances, arthritis, FAT embolism, immobilization complications
What is osteoporosis
osteopenia caused by an imbalance of the bone remodeling process
What usually happens to give a patient a diagnosis of osteoporosis?
Typically a fracture of a bone is the first clinical manifestation
What is the bone density level of people with osteoporosis?
2.5
What are different diseases associated with osteoporosis?
postemenopausal women, excess corticosteroids, hyperparathyroidism, hypertheyroidism, poor nutrition/malabsorption, immobilization, hypogonadism
What can osteoporosis of the spine lead to?
kyphosis
What is the best prevention of osteoporosis?
maximize peak bone mass, encourage weight-bearing exercises and calcium supplementation
What does primary hyperparathyroidism cause?
Hypercalcemia
What can cause hypercalcemia?
primary hyperplasia of parathyroid gland, or neoplastic enlargement
What causes secondary hyperparathyroidism?
renal disease
T/F: most hypercalcemia is caused by a malignancy?
TRUE
Define osteomalacia
decreased bone mineralization with excess osteoid
What is associated with osteomalacia?
environmental problems (rickets), instestinal malabsorption, liver or renal disease, rare congenital errors of metabolism
What is the biochemical profile of osteomalacia?
Increased serum alkaline phsophatase, low serum calcium, decreased urinary calcium, increased PTH, decreased vit D
What is the childhood version of osteomalacia? What causes it?
Rickets; poor diet
What is the classical presentation of rickets?
Widened/distorted growth plates, bowed legs due to softened bone, fractures
What causes renal osteodystrophy/osteomalacia?
Progressive destruction of second hydroxylation step of vit D, often secondary hyperparathyroidism and abnormal mineralization
Define osteomyelitis
infection of a bone
What is the primary, secondary, and direct ways of acquiring osteomyelitis?
Primary: spread from often occult source, Secondary: spread to bone from adjacent infection, direct: compound fractures
What is the most common bacteria that causes osteomyelitis? What are others?
Staphylococcous aureus, Streptococcus, salmonella in sickle cell patients
Are xrays good at detecting early osteomyelitis?
NO, often not detectable before 10 days after initial infection
what is the best way to detect early bone infection?
Bone scans and MRI
Where do most osteomyelitis start?
Metaphyseal marrow space
What are long term complications of suppurative (bacterial) osteomyelitis?
Suppurative arthritis in adjacent joints, sinus tracks to skin, growth disturbances (children), deformity, amyloidosis
what is the most common cause of osteomyelitis in adults?
direct extension from adjacent infections, or injection of bugs
What are associations of bone infection in adults?
Compound fractures, contamination during orthopedic surgical procedures,
What is the treatment of suppurative osteomyelitis?
Need high index of suspicion for early/timely diagnosis, Aggressive abx treatment, surgical drain/debride, maybe amputation
What are complications of a reactivation of tuberculosis?
Osteomyelitis of the spine (Pott’s disease) and long bones
What population is most likely to have Pott’s disease in the US?
Immigrants from third world countries
Where does osteomyelitis often start?
In the lungs, spreads via blood stream
What are the most common causes of avascular bone necrosis/infarction?
Fractures, corticosteroids, alcoholism
What bone does avascular bone necrosis/infarction usually affect?
Femoral head (femoral neck fractures)
What diseases/incidents are associated with avascular bone necrosis?
CORTICOSTEROID THERAPY, Fractures, Legg-calve-perthes disease (random osteonecrosis of femoral head), alcoholism, Gaucher’s disease, SLE, sickle cell anemia, Caisson’s disease
What does avascular bone necrosis often present as clinically?
Subchondral infarcts (pain w/ activity), medullary infarcts (often silent), Multiple infarcts (corticosteroid therapy)
What are complications of avascular bone necrosis?
Secondary degenerative joint disease, bone growth deformities (childhood), pathologic fracture
What population most commonly gets Paget’s disease (osteitis deformans) of bone?
Middle-aged and elderly anglo-saxon adults
What is the current theory of Paget’s disease (osteitis deformans)?
Due to latent viral infection of osteoclasts in genetically susceptible person
What are the three phases of Paget’s disease?
Lytic (osteoclasts), Mixed (osteoclasts and osteoblasts), sclerotic (osteoblastic)
What are clinical/imaging features of Paget’s disease?
Widening/bowing of long bones, distorted/widened pelvic bones, general weakening of affected bone causing fractures
What are the symptoms of Paget’s disease?
Principally pain due to fractures, compression of spinal nerves, sometimes skin overlying affected bone is warm during lytic/vascularization
What are the biochemical hallmarks of Paget’s disease?
Older person with increased alkaline phosphatase, normal serum calcium, no hepatobiliary disease
What are hallmarks of congenital bone disorders?
Localized absence or duplications of bones, malformation of craniospinal axis, achondroplasia, osteogenesis imperfect, osteopetrosis
What is the basis for osteogenesis imperfecta?
congenital disorders of type 1 collagen
What information do x rays give for bone tumors?
likelihood of primary v metastatic lesion (w/ age), ability to subtype primary bone tumors by location and x-ray character, can separate benign and malignant
What are the classifications of bone tumors x rays can give you?
osteolytic, osteoblastic, mixed
What is a classic example of purely osteolytic malignancy?
myeloma
What is a classic example of largely osteoblastic malignancy?
metastatic prostate cancer
Where is the most common site for metastatic tumor to skeleton from?
Visceral cancers: lung, breast, prostate cancer
T/F: Most bone cancers are caused by metastasis
True
What are hemic malignancies affecting bone?
Classic myeloma, plasmacytoma of bone, lymphoma (non-hodgkin’s), Leukemia
Where does leukemia always affect?
Bone marrow, can cause diffuse multifocal bone/joint pain
Where do most primary tumors arise in bones?
Metaphyses
What are most common benign tumors seen in bones?
Osteochondroma, giant cell tumor, chondroma, osteoid osteoma, fibroma
What are most common malignant tumors seen in bone?
Osteosarcoma, chondrosarcoma, lymphoma, Ewing’s sarcoma, chordoma
What is the most common primary malignant tumor in children/young adults?
Osteosarcoma
What is the most common malignancy in middle-age/older adults?
Chondrosarcoma
What is the treatment for primary bone tumors?
Pre-surgical chemotherapy, surgery, chemotherapy and radiation post surgery
T/F: giant cell tumors are malignant?
False but some can be… it’s a gray area
What is the most common bone lesion?
Metaphyseal fibrous defect (fibroma, fibrous cortical defect)
What can osteosarcoma be secondary to?
Paget’s, prior irradiation, old bone infarcts
What are the most lethal variants of chondrosarcoma?
Dedifferentiated and mesenchymal
Where is chondrosarcoma often found?
Long bones and central skeleton (pelvis)
what is the most aggressive and lethal bone tumors?
Ewing’s sarcoma
What age group is typically affected by Ewing’s sarcoma?
peripubertal ages
