Flashcards in Skeletal Pathology Deck (68):
What is our main concern with most bone pathologies?
-Increased feature risk.
How are fractures classified?
-Location (mid shaft, proximal, distal)
-Type (open/compound or closed, level of disruption, character of the pieces)
-Pattern of fracture
How do fractures present?
-PAIN, lack of mobility
-Diagnosis via XRAY
What are the 4 steps of fracture healing?
-Hematoma formation (1-2 days after injury). Blood clot forms from damaged tissues. Large clot forms in 2-5 days. Fibrosis begins at the end of week 1.
-Fibrocartilaginous callus (soft tissue) forms. Collagen is secreted by fibroblasts. Osteoblasts begin depositing osteoid into the matrix and edges of fibrocartilaghinous collar connects the bone fragments. Maximal girth in 2-3 weeks. Stabilizes fracture
-Bony callus formation: 3rd or 4th week. Osteogenic cells in area become osteoblasts and initially form trabecular.spongey bone. Radiographic union occurs when all of the fibrocartilage has become spongey bone. Cast may be taken off now.
-Remodeling. Dead bone is reabsorbed by osteoclasts. Osteoclasts re-establish medullary canal. Bone is reorganized along lines of mechanical stress. Compact bone forms along shaft.
What are the bone healing times for: kids, teens, adults?
-Kids: 4-6 weeks
-Teens: 6-8 weeks
-Adults: 10-18 weeks
What type of fractures heal the slowest?
Long bone, displaced, fractures with less surface area.
What is osteomyelitis, and when does it become chronic?
-Bone bacterial infection, >6-8 weeks is chronic.
What are the three routes of bone infection?
-Hematogenous: blood borne
-Contiguous: infection of tissue
-Exogenous: direct traumatic introduction from the external environment.
Who usually gets hematogenous osteomyelitis?
-Kids or adults with compromised immune systems.
What is the most common cause of HO? What are it's signs?
-Staphylococcus aureus, can bind to collagen and enter bone
-Signs are typical bacterial infection signs: fever, pain, erythema, swelling.
Where does HO usually present?
Metaphysis of bone due to the vascular supply there.
What is the traditional long term progression of HO?
-Infection progresses forming a pocket of puss in bone.
-This pus pocket decreases vascular supply to a portion of bone, resulting in necrosis.
-Fragmentation occurs (fragments are called sequestra) leading to more necrosis.
-New bone, called involcrum, forms around sequestra.
How is HO treated?
-Antibiotics, surgical drainage.
Who is likely to get contiguously spread osteomyelitis?
-People with diabetes and wounds on their feet.
-People with infected open wounds
-People with tuberculosis (most usually impacts the vertebra
What is osteonecrosis and what are some potential causes?
Bone death due to improper blood flow. Potential causes include:
-Infection of vasculitis
What is the most commonly involved site for osteonecrosis?
How is osteonecrosis treated?
Immobilization, limited weight bearing, hyperbaric oxygen, non steroidal anti-inflammatories, joint replacement.
What do neoplasms of bone most commonly occur as?
Primary or metastatic lesions.
What type of cancers commonly metastasize to bone?
-Prostate, lung, breast.
What can bone neoplasms involve?
Bone, marrow, cartilage.
What is a sarcoma?
A malignant bone neoplasm.
What is an osteoma? A chondroma?
Both are benign.
Osteoma is in bone.
-Chondroma is in cartilage.
What is an osteochondroma?
-Unusual lateral outgrowth of cartilage.
-Common in young individuals, makes up 35% of all benign tumors.
What are some characteristics of being neoplasms?
-Many are asymptomatic and go undiagnosed.
-Defined borders, slow growing.
What is the most common malignant bone tumor?
Osteosarcoma. Usually in teens
What are the risk factor for osteosarcoma?
What are characteristics of osteosarcomas?
-Presence of osteoid in the lesion
What are the signs of osteosarcoma?
-Pain with movement
What is the treatment for osteosarcoma?
-Amputation or limb salvaging.
What is Ewings Sarcoma?
-Second most common malignant bone neoplasm.
Who usually gets Ewings sarcoma?
-People under the age of 30
-27% of cases up to age 9, peeks in teens (64% in ages 10-19). 9% 20-29.
Where is the most common spot for Ewing Sarcoma?
Signs and symptoms of ES?
-Local palatable mass
How is ES treated?
Radiation, chemo, surgery. Bad prognosis after metastasis. (
What is metastatic bone disease?
-More common than primary neoplasms.
-Other cancers metastasize to bone .
-Commonly axial skeleton
-Patient presents with pain
What is the concern for us with MBD?
-Increased fracture risk.
What is a pathologic fracture?
A fracture that occurs as a result of metastatic bony lesions.
What is the treatment fir MBD?
-Radiation, pain management, surgical stabilization of bone at fracture site.
What is a common result of MBD?
-Hypercalcemia. Treated via hydration, loop diuretics, and bisphosphonates.
How much cortical bone turns over each year?
How much trabecular bone turns over each year?
T/F MBD results in balanced bone resorption.
FALSE. There is an imbalance of bone resorption as a result of MBD.
What is the rate of bone mineral density loss?
.5% for each year after 30, greater in women post menopause than men.
How is bone density measured?
dual energy Xray absorptiometry. (DXA)
What does a DXA test do?
compares your bone density to peak BMD of a 30 yo of your sex.
What is a Z score?
# of SDs below or above mean BMD for your age/sex.
What is a T score?
# os SD above/below peak BMD
Which score is used for Dx?
What is a normal T score?
What is osteopenia?
>1 SD below peak
What is osteoporosis?
>2-2.5 SD below peak
What is type 1 osteoporosis?
-Due to menopause
-Primary loss of trabecular bone
-Greatest risk of vertebral fracture.
Type 2 osteoporosis?
-aka senile osteoporosis
-occurs with aging (over 70)
-Related to calcium deficiency.
-Slow loss of both cortical and trabecular bone.
What is most at risk for Type 2?
-Hip, long bone, vertebrae
What is type 3 osteoporosis?
-Secondary due to another condition
What are some causes of type 3 osteoporosis?
What are general risk factors for osteoporosis?
-Caucasian race (light skin tone worse even within race)
What are the signs/symptoms of osteoporosis
-Low impact fractures
How is osteoporosis treated?
-Calcium and vitamin D supplement
-Estrogen/Phytoestrogens (interfere with PTH and osteoclasts)
-Weight bearing exercise and resistance training.
-Meds (bisphosphonates, SERMs (selective estrogen receptor modulators)
What type of meds specifically has a negative impact on bone health?
-Decrease calcium absorption, interferes with osteoblasts, increased PTH effects.
What is the difference between osteomalacia and rickets?
-Age. Rickets in kids, OM in adults
What are the causes of osteomalacia?
-poor calcium, phosphate, vitamin D intake.
-Lack of UV exposure
-Hyperparathyroidism (releases too much calcium from bone)
Signs and symptoms of osteomalacia?
-Soft bones (bowed legs, pigeon chest)
What is the treatment for osteomalacia?
-Treat nutritional deficiency
What is Paget disease?
Second most common metabolic bone disease. Characterized by increased breakdown of bone (osteoclast activity) in the tibia, pelvis, proximal femur, skull.
What causes paget disease and what is the progression?
-Unknown. Often follows viral infection.
-Increased risk with age. Osteoclasts initially so overactive that the bone is replaced with fibrous tissue.
What are the signs and symptoms of Paget's disease?
-If any, hearing loss if skull is involved,
-Cardiovascular failure in advanced cases (dilation of blood vessels above effected bones causing high output cardio failure).
-Ventilary complications due to malformed thoracic cage.