Primary Bone Tumors Flashcards
What are the s/sx of hyperparathyroidism?
- Bones
- Stones
- Abdominal Groans
- Psychiatric overtones
What is the effect of PTH on ca resorption in the renal tubules?
Increases Ca resorption, and increases phosphate secretion
What is the effect of PTH on Vit D?
Increased synthesis of active form
What happens to Serum Ca and phosphate levels with PTH excess?
Increased
What is the most common cause of excess PTH?
Primary hyperparathyroidism
What is the tunneling reabsorption seen in Hyper PTH?
Lines on x-ray r/t osteoclast resorption 2/2 PTH
What are the brown tumors seen in hyperparathyroidism?
Collection of fibrous tissue, giant cells, and hemosiderin in bones that appear as areas of hypo-lucency on x-ray
What is renal osteodystrophy?
Chronic renal failure causes decrease in 1,24 (OH) D3 deficiency and associated secondary increase in PTH
What causes the osteomalacia with dialysis and renal osteodystrophy?
Metabolic acidosis, and increased PTH
What are the complications from renal osteodystrophy?
Osteitis fibrosa cystica
Osteomalacia
what is the pathophysiology behind Paget’s disease of the bone?
- Aggressive osteoclast-mediated bone resorption and
2. Imperfect osteoblast mediated bone repair
What is the progression of the pathophysiology of paget’s disease of the bone?
First aggressive osteoclast resorption is more prominent, then imperfect osteoblast rapri becomes the larger factor
What is the supposed infectious etiology of Paget’s disease?
Paramyxovirus increases expression of RANK receptor
What are the three major stages of Paget’s disease of the bone?
- Osteolysis
- Osteoblastic
- Osteosclerosis
Pt complaining of hat size changes = ?
Paget’s disease of the bone
What are the histological findings of Paget’s disease of the bone?
- Sclerosis of the bone with wide trabeculae
- Large amounts of osteoid
What happens to the osteoclasts with Paget’s disease of the bone?
Increased size
What is the definition of scurvy?
Defective osteoid synthesis and collagen support of the blood vessels
What are the characteristic hair findings of scurvy?
Corkscrew hairs and petechiae
Where does hydroxylation of proline take place within a cell?
rER
What are some major complications of scurvy?
Subperiosteal hemorrhages
What, generally, is avascular necrosis?
Infarction of bone and marrow 2/2 ischemia
What are the common mechanisms that lead to avascular necrosis? (4)
- Fracture (mechanical vascular interruption)
- Corticosteroids
- Idiopathic
- Sickle cell disease
What are the gross characteristics of AVN?
Wedge shaped infarct in the bone, with separation of the subchondral area from the periosteum
Why is the femoral head particularly susceptible to avascular necrosis?
Hip fracture can shear off blood supply
What is the blood vessel that supplies the head of the femur?
Branch of the obturator artery
What are the two blood vessels that supply the neck of the femoral head?
Medial and lateral circumflex arteries
What is the first thing to happen when a bone is fractured?
Organization of a hematoma into a procallus
What happens with a fractures after a procallus has formed?
Conversion of the procallus to fibrocartilaginous callus caused by deposition of woven bone
What happens with a fracture after a fibrocartilaginous callus has formed
Replacement of the mesenchymal cells by osseous callus, with bone remodeling along stress lines
What is the order of calluses that occurs with fractures? (3)
Procallus
Fibrocartilaginous callus
Osseous callus
How much more common are fractures relative to primary bone tumors?
3000-4000x
What are greenstick fractures?
Incomplete fractures with closed skin, with bowing on the opposite side
What are stress fractures?
Fractures that develop slowly over time following a new repetitive stress
What are pathological fractures?
Diseased bone–non-traumatic
What is a compound fracture?
fracture where a part of the bone breaks through the skin
What is the enzyme that is defective with Gaucher’s disease?
Defect in glucocerebrosidase
What is happening in the 0-3 day timeframe of fracture healing?
Hemorrhage, inflammatory infiltrate, and granulation tissue
What is happening in the 3-7 day timeframe in fracture healing?
Chronic inflammation with granulation tissue and osteoclastic activity
What is happening in the 7-35 day time frame of fracture healing?
Progressive increase in cartilage woven bone and cartilage formation
What is happening in the 35+ day time frame of fracture healing?
Secondary callus, and replacement of woven bone by lamellar bone
What are the five major impediments to fracture healing?
- infection
- non-union
- Poor circulation
- Drugs
What is osteomyelitis?
Inflammation of the bone and marrow caused by infection
What are the bacteria that commonly cause osteomyelitis in sickle cell patients?
Salmonella
What are the three major routes of spread for osteomyelitis?
- Hematogenous
- Direct extension
- Open fracture or surgery
What is the most common bacterial cause of osteomyelitis in general?
Staph aureus
What usually follows initial osteonecrosis with osteomyelitis?
Subperiosteal pyogenic abscesses
What is the sequestrum with chronic osteomyelitis?
Residual necrotic bone
What is the involucrum with chronic osteomyelitis?
Rim of reactive bone around sequestrum
What is a brodie abscess?
Walled off abscess in bone by sclerotic bone
True or false: viable organisms may persist in brodie abscesses
True
What are some complications of chronic osteomyelitis?
Draining sinuses to the skin, which may serves as a nidus for sepsis or cancer
What cancer do patients with chronic osteomyelitis have an increased risk for?
Osteosarcoma
What usually causes tuberculosis osteomyelitis?
Hematogenous spread, but can be direct extension
What bones in particular are affected with tuberculous osteomyelitis?
Vertebrae and long bones
What is Pott’s disease?
TB of the vertebral bodies, producing a gibbus deformity (loss of vertebral body encroaches on spinal cord)
Why is there a resurgence of tuberculous osteomyelitis in developed countries?
Immigration and immunosuppressed people
What is the general progression of tuberculous osteomyelitis?
Starts in the synovium, then progresses to the epiphysis and through the medullary cavity
