Quiz 4, Skeletal Flashcards
What is defective in osteogenesis imperfecta?
There is a genetic deficiency of normal type-1 collagen which forms bone matrix
What is Legg-Calve-Perthes syndrome characterized by?
Idiopathic avascular osteonecrosis of the epiphysis of the femoral head leading to an interruption of the blood supply of the head of the femur close to the hip.
What are two causes of Rickets?
Predominantly, a vitamin D deficiency.
Also, dietary calcium deficiency.
What term is used for the condition similar to Rickets in adults?
Osteomalacia
What deformity do toddlers with Rickets typically develop?
Genu varum (bowed legs)
What deformity to older children with Rickets typically develop?
Genu valgum (knock-knees)
What is the term used for patients with Rickets who develop prominent knobs of bone at the costochondral joints?
Rachitic rosary (beading of the ribs)
What conditions can cause osteoporosis?
Malabsorption disorders
hyperthyroidism
hyperparathyroidism
(generalized loss of bone)
Differentiate primary vs. secondary osteoporosis.
Primary = osteopenia from age/menopause Secondary = other medical conditions
What is largely responsible for the increased osteoclast activity in osteoporosis?
Increased levels of cytokines
IL-1, IL-6, TNF-alpha
What are some risk factors for osteoporosis?
Female Low body mass Age Fmhx Hx of fractures after age 50 Low bone mass Hx of fracture in 1st degree relative Estrogen deficiency Amenorrhea Low testosterone (men) Anorexia nervosa Low lifetime calcium intake Vit. D deficiency Inactive lifestyle Smoking ETOH Caucasian/Asian Medications
What postural change is commonly seen in patients with osteoporosis, due to compression fractures of vertebrae?
Kyphosis
What’s the other name for Paget’s disease of bone?
Osteitis deformans
What is Paget’s characterized by?
High bone turnover with accelerated osteoclast and osteoblast activity.
What lab marker is elevated in Paget’s?
Serum alkaline phosphatase
What is the histological hallmark of Paget’s?
MOSAIC pattern of LAMELLAR bone which likened in appearance to a jigsaw puzzle
Unlike osteoPETROSIS which presents at birth, when does Paget’s develop?
4th decade
What is the x-ray appearance of a patient’s skull who has Paget’s?
Area of sclerotic bone and areas of lucency (cotton ball appearance)
What is the first warning sign of Paget’s?
Pain in or over the area of affected bone or a pathologic fracture. Involved area can feel warm.
Does Paget’s affect one bone or multiple?
Either, multiple is more common
How do bones affected by Paget’s typically break?
Linear fracture (straight across)
What is a rare inherited disorder whereby the bones harden and become more dense?
Osteopetrosis
What is a rare inherited bone disease characterized by reduced or dysregulated activity of osteoclasts, resulting in generalized osteosclerosis.
Malignant infantile osteopetrosis (MIOP)
What organism is most commonly isolated from all forms of osteomyelitis?
Staphylococcus aureus
With osteomyelitis, which bones are usually affected in children vs. adults?
Children - long bones
Adults - vertebrae and pelvis
What is the second most common organism causing osteomyelitis in the vertebrae, which used to have its own name (Pott’s Disease)?
Tuberculosis
What is the most common cause of osteomyelitis in adults? (not the organism)
Injury that exposes the bone to local infections
What term describes all of the skeletal changes of chronic renal disease?
Renal osteodystrophy
A fracture that has no associated soft tissue injury is called what?
Closed or Simple (Open or Compound if there is soft tissue injury)
What kind of fracture does the bone not align?
Displaced
What term describes a fracture when the bone is splintered or crushed?
Comminuted
What do you call a fracture occurring in bone already altered by a disease process?
Pathologic fracture
What is a slowly developing fracture that follows a period of increased physical activity?
Stress fracture
Where do solitary bone cysts predominantly occur?
The distal ends of long bones such as the humerus and femur
What does an x-ray of a solitary bone cyst reveal?
Smooth thin cortex in close proximity to the epiphysis
Symmetrical appearance
Bone diameter may be increased at site of cyst
The cavity is filled with clear or bloody fluid
Where are aneurysmal bone cysts most common?
The metaphysis of long bones and also vertebrae
What does an aneurysmal bone cyst look like on x-ray?
Honey-combed appearance
What benign condition involves a bone-forming neoplasm characterized by a small area of neoplastic tissue surrounded by a wide zone of mature, reactive bone?
Osteoid osteoma
Osteoid osteoma are usually solitary. If there are multiple lesions what condition is likely?
Gardner syndrome
What is the x-ray appearance of an osteoid osteoma?
A small, well circumscribed lesion that is round or oval, located near the cortex and surrounded by densely sclerotic bone. May have radiolucent and radiopaque aspects.
What is the gross appearance of an osteoid osteoma?
Area of gritty, cherry red tissue, surrounded by dense sclerotic bone.
What is the primary malignant tumor of bone?
Osteosarcoma
Where do most osteosarcomas occur?
Distal femur or around the knee
Osteosarcomas can occur at any age, but 75% of them happen in what age group?
10-20
What does classic osteosarcoma demonstrate?
Rapid growth and high risk of local spread
“Skip lesions” metastasis within the bone and/or contiguous soft tissues
Pulmonary metastasis is common
What is the microscopic appearance of osteosarcoma?
Atypical cells with large nuclei and small amount of cytoplasm
Osteoid formation
Where are fibrosarcomas usually found?
Knee in either the distal femur and/or proximal tibia
What does a fibrosarcoma produce?
Collagen matrix (not osteoid or chondroid)
What is microscopically characteristic about fibrosarcoma?
Sheets of spindle shaped cells
What condition is usually only present in patients over 20 and is an aggressive tumor composed of oval cells and multinucleated cells that are uniformly distributed throughout the lesion?
Giant cell tumor
What is seen on x-ray of a giant cell tumor?
Destructive radiolucent lesion that is oval shaped and centered in the epiphysis
Causes cortical erosion and thinning which expands the bone contours without a border of new bone formation and sclerosis
What condition is a malignant tumor of bone composed of small, rounded cells that are uniform in size and densely packed? They occur mainly in children.
Ewing sarcoma
What does an x-ray of Ewing sarcoma look like?
Mottled “moth eaten” destructive lesion. Often infiltrates medullary cavity, penetrates the cortex, or extend beyond the bone into surrounding soft tissue
What condition is a malignant disease of monoclonal plasma cell overgrowth in the bone marrow which produces monoclonal immunoglobulin or paraprotein?
Multiple myeloma
What is a common concomitant with multiple myeloma?
Pathological fractures
Bone pain, especially in the back
What is the “ivory vertebra sign”?
Indication of either metastatic cancer or Paget’s disease
What is the most common type of joint disease?
Osteoarthritis
What is osteoarthritis characterized by?
Progressive erosion of articular cartilage
The cellular basis of osteoarthritis can found in what cells?
Chondrocytes
What do chondrocytes produce that inhibits the synthesis of both type 2 collagen and proteoglycans?
Cytokines, including IL-1, IL-6 and TNF-alpha