LEC 5: Infections & Tumors

What is osteomyelitis?

bone infection which classically occurs from hematogenous seeding or direction infection m/c from trauma

What bacteria are typically responsible for osteomyelitis?

strep, staph, enterococcus, pseudomonas

What antibiotics are prescribed to patients with osteomyelitis from dog/cate bites?

augmentin

alt- clindamycin

How does acute osteomyelitis classically present?

sinus tract with abscess formation

Acute osteomyelitis in the spine is m/c seen in this population.

IV drug abusers

When should a dog/cat bite be re-checked?

24-48 hours

What is a biofilm-bacteria complex?

extracellular matrix with a glycocalyx (glycoprotein & glycolipid layer surrounding cell membrane)

What is the greatest barrier to treatment & eradication of musculoskeletal infections?

mature biofilm complex

What is the gold standard for diagnosing acute osteomyelitis?

culture/biopsy

How is acute osteomyelitis treated?

IV abx for 6-8 weeks, may do surgical irrigation & debridement (if abx response is not rapid)

What is considered the cornerstone of treatment for osteomyelitis?

surgical debridement

What is chronic osteomyelitis?

occurs with untreated OM, when tx fails, necrotic bone becomes walled off by fibrous tissue

Why would chronic osteomyelitis present with normal labs?

patient was already treated with abx previously

What is the treatment for chronic osteomyelitis?

IV abx, irrigation & debridement, removal of hardware if present; may need plastic surg/amputation!!

What organisms m/c causes septic arthritis?

N. gonorrhea

What are the symptoms of septic arthritis?

warm, painful, swollen joint with decreased range of motion

How is septic arthritis diagnosed?

joint fluid aspiration= gram stain, C&S, acid fast bacilli, cell count >100k, glucose, check for crystals to r/o gout

How is septic arthritis treated?

irrigation & debridment, IV abx (cephalosporins if gonorrhea)

What is a benign bone tumor like?

well defined sclerotic border, lack of soft tissue mass, solid periosteal reaction, geographic bone destruction

What is a malignant bone tumor like?

interrupted periosteal reaction, moth-eaten or permeative bone destruction, soft tissue mass, wide zone of destruction

How are benign bone tumors treated?

depends, but: observation, aspiration & injection, curettage, surgical adjuvants, excision/resection

How are malignant bone tumors treated?

MUST be removed with well demarcated margins, chemo, radiation

What is an osteoid osteoma?

distinctive, painful, benign osteoblastic bone tumor, 5-30 y/o, M>F

Describe the pain of a person with an osteoid osteoma.

dull, aching, nocturnal pain relieved by NSAIDs/ASA

What is the m/c site of an osteoid osteoma?

proximal femur

What imaging should be done for an osteoid osteoma?

bone scan & CT

What are the treatment options for an osteoid osteoma?

ASA/NSAIDs, surgical excision, radiofrequency ablation

What is an osteoblastoma?

a rare, aggressive, benign osteoblastic tumor, M>F, 10-30 y/o

What is the m/c site of an osteoblastoma?

spine, sacrum, long bones

Describe the pain of a person with an osteoblastoma.

slow, progressive, pain not nocturnal & NOT relieved by NSAIDs

What are the treatment options for an osteoblastoma?

must have surgical tx- curettage of lesion +/- bone grafting

What is the m/c bone tumor of the HAND?

enchondroma

What is an enchondroma?

centrally located, benign tumor composed of mature hyaline cartilage in the medullary cavity, most pts between 20-50 y/o

What is the m/c site of an enchondroma?

small tubular bones of hands and feet

Describe the pain of an endochondroma.

no pain! asymptomatic, usually an incidental finding

What does an endochondroma look like on an x-ray?

classic rings & stippled calcifications

What is the treatment for an endochondroma?

no treatment unless symptomatic

What is the most frequent cause of pathologic fracture in children after minor trauma?

solitary bone cyst

What is a unicameral/solitary bony cyst?

a common, serous, fluid-filled bone lesion, most pts. usually <20 y/o

What is the m/c location of a solitary bone cyst?

proximal humerus, proximal femur

What does a solitary bone cyst look like on an x-ray?

soap-bubble appearance, fallen leaf

What is the treatment for a solitary bone cyst?

just watch & wait for it to heal on its own, can give steroid inj, only curettage if it does not heal

What is an anneurysmal bone cyst?

a destructive, expansive, reactive bone lesion filled with multiple blood filled cavities, most pts <20 y/o

What is the m/c location of an anneurysmal bone cyst?

distal femur, proximal tibia, pelvis, spine

What are the symptoms of an anneurysmal bone cyst?

pain & swelling

What is the treatment for an anneurysmal bone cyst?

curettage & bone grafting

What is a giant cell tumor?

benign, aggressive bone tumor consisting of distinct undifferentiated mononuclear cells, pts 30-50 y/o, F>M

What is the m/c location of a giant cell tumor?

about the knee (distal femur/proximal tibia)

What are the symptoms of a giant cell tumor?

pain and swelling x 2-3 months, decreased ROM at the joint

What does a giant cell tumor look like on an x-ray?

lytic lesion located in epiphyseal-metaphyseal end of long bone, lesions extend in to subchondral surface without a sclerotic rim

What is the treatment for a giant cell tumor?

curettage/high speed burr - adjuvant phenol, hydrogen peroxide, or liquid nitrogen (helps to prevent local recurrence)

What is a chondroblastoma?

a rare, benign bone tumor differentiated from

giant cell tumor by its chondroid matrix, pts 10-20 y/o

What does a chondroblastoma consist of?

“chicken wire” calcifications in a lace like pattern

What is the m/c location of a chondroblastoma?

epiphysis of distal femur/proximal tibia

What are the symptoms of a chondroblastoma?

pain that is progressive at location of tumor, usually close to joint→ may have associated decreased ROM, limp, muscle atrophy, bony

tenderness

What does an x-ray of a chondroblastoma look like?

small round lytic tumor with sharp sclerotic rim/margin, 25-40% have central stipple or flocculated calcification

What is the treatment of a chondroblastoma?

curettage, bone graft, surgical adjuvants phenol, liquid nitrogen (decrease local recurrence)

What is an osteosarcoma?

classic intramedullary malignant bone-

forming tumor, m/c malignant bone tumor in children, m/c in second decade of life

What is the m/c location of an osteosarcoma?

distal femur, proximal tibia, proximal humerus, and pelvis

What are the symptoms of an osteosarcoma?

pain at site before tumor is noticeable,

intermittent pain progressing to constant pain unrelieved by medication, dilated veins in overlying skin

As an osteosarcoma grows outside of the bone, what will you see?

sunburst pattern

What type of imaging is used to stage an osteosarcoma?

MRI

What is the treatment for an osteosarcoma?

high dose chemotherapy followed by surgical resection (limb sparing vs amputation) followed by additional chemotherapy

What is the m/c site of osteosarcoma metastases?

lungs

What is a chondrosarcoma?

malignant cartilage-producing

tumor that arises de novo or secondary to other lesions, occurs in adults 40-75 y/o

What is the m/c location of a chondrosarcoma?

pelvis

What are the symptoms of a chondrosarcoma?

minimal pain over several years prior to diagnosis, bowel and bladder symptoms may develop, slow growing firm mass (surface lesion)

What is the treatment of a chondrosarcoma?

surgical removal

What is an ewing sarcoma?

a malignant bone tumor composed of small round blue cells, M/F, second M/C primary malignant bone tumor in kids

What is the m/c location of an ewing sarcoma?

pelvis followed by diaphysis of long bones and scapula

What are the symptoms of an ewing sarcoma?

PAIN, swelling, limp, decreased ROM are variable, frequent fever, occasional erythema

What will be seen on an x-ray of an ewing sarcoma?

onion skin pattern

What is the treatment for an ewing sarcoma?

chemo, +/- radiation, resection

What is the M/C primary tumor of the bone in the United States?

multiple myeloma

What is multiple myeloma?

systemic disease; neoplastic proliferation of plasma cells producing a monoclonal protein, M>F, pts > 40 y/o, AA>whites

What will be seen on an x-ray of multiple myeloma?

punched out lytic lesions

What will be seen in urine electrophoresis of multiple myeloma?

“Bence Jones” protein

What is the treatment for multiple myeloma?

high dose chemotherapy with autologous stem cell support