Topics In MSK Jaynstein (Exam 2) Flashcards
Avascular Necrosis (AVN)/Osteonecrosis is what?
Necrosis of bone secondary to an interruption of blood supply
AVN risk factors?
Trauma Obstruction of blood supply: coag disorders, alcoholism (fat emboli), sickle cell disease, pregnancy Long-term steroid use Auto-immune dz and immunosuppression, chemo and radiation therapy
Most common bone for AVN?
Head of femur or humerus Scaphoid (bone of wrist) Neck of talus (tibia sits on this in foot)
What do you look for on XR that would indicate AVN of femoral head?
Crescent sign at head of femur
AVN sxs?
Progressive pain over weeks/months Early dz process: pain w/ activity/wt bearing, decreased ROM Late dz process: pain at rest with sig decreased ROM
AVN/osteonecrosis Dx?
Early xrays may be normal: unfortunately dx is usually late Eventually xrays will show bone destruction/collapse CT, MRI, and bone scan can all reveal AVN
AVN/osteonecrosis Tx?
Ortho referral for ALL! Tx directed at bone involved Hip/shoulder: almost all require replacement Scaphoid: depends on degree, may attempt to surgically restore blood supply (debride and re-align) or bone graft
Osteomyelitis is?
Inflammation and infection of bone
What can cause osteomyelitis?
Viruses, parasites, bacteria, fungi
What bug is most responsible for osteomyelitis?
S aureus is 80-90% Sickle cell pts “sickle cellmonella”
Osteomyelitis bugs from GU tract infections or IV drug users?
E coli Pseudomonas Klebsiella
Osteomyelitis risk factors?
Children IVDU DM Sickle cell Open wounds H/o hardware
Bones most often effected by osteomyelitis?
Long bones and vertebral bodies most commonly involved Toes/feet affected in DM
How does Osteomyelitis present clinically?
Acute systemic illness with malaise, fever, chills, leukocytosis and throbbing pain over affected site, pain with active and passive ROM
Osteomyelitis work up?
Labs: CBC, ESR, CRP, LDH, BCx, wound Cx, Bone Bx (Ca, phos, alk phos usually normal) Xray: STS, periosteal elevation, cortical erosion/lysis> necrotic bone (bone changes lag infection by 10-14 days; 30-50% of bone demineralization before it’s seen on xray) Bone scan, CT, and MRI are useful (MRI first if possible)
Osteomyelitis Tx?
Combination of abx and surgical drainage is usually curative Empiric Abx: Vanco+Ceftriaxone or Cirpo or Cefepime
Osteomyelitis complications?
Pathologic fx, endocarditis, sepsis, amputation
Chronic osteomyelitis can develop, but in which pt population?
Immunocompromised and DM Eventually a sinus tract breaks through skin and drains externally Tx with abx and open debridement Osteomyelitis top dxd for pt with DM with open would you can probe bone
Osteoma definition?
Benign lesions of bone that in many cases represent developmental or reactive growths rather than true neoplasms
Osteoma locations most common?
Facial bones (nose, ears) and skull
Osteoma age group?
40-50
Osteomyelitis age group?
Bimodal peaks 20yoa and 65yoa
Do osteomas undergo malignant change?
No
Osteosarcoma definition?
An aggressive malignant mesenchymal tumor in which the cancerous cells produce bone matrix
Osteosarcoma is the most common bone cancer in?
Kids
Osteosarcoma common sites?
Long bones (proximal humerus, proximal and distal femur, proximal tibia) and mandible
Osteomyelitis: how long will pts be on IV abx?
6 weeks
Osteosarcoma presentation?
Painful and progressively enlarging masses; occasionally pathologic fx is first symptom
Osteosarcoma work up?
CBC, ESR, CRP, xrays, CT/MRI/PET scan
Approx. 20% of osteosarcoma patients have what kind of mets at time of dx?
Pulmonary mets
Osteosarcoma tx?
Excision, radiation (Paulson Onc 2 ppt says radio resistant), chemo
Osteosarcoma prognosis?
5yr survival 60%
OsteoStarcoma on imaging?
Sunburst appearance on bone scan Also Codman’s triangle
What is osteochondroma?
A benign cartilage growth that is attached to the underlying skeleton by a stalk
Osteochondroma more commonly involve the metaphysis of what bones in the 10-30yr age group?
Long tubular bones (like distal femur)
When do osteochondromas stop growing?
At the time of growth plate closure
Ewing Sarcoma definition?
Malignant neoplasm of bone that occurs predominantly in children-second most common malignancy after osteosarcoma Highly aggressive M:F 1.6:1 Peaks at 10-20yrs