Clin Med: Msk I - Lec 2

Question 1

Osteosarcoma Dx

Answer 1

• Incr LDH
• “Codman triangle”–> new rim of bone forming b/c tumor
• “Sunburst”–> inflammation & extra bony growth coming off bone
• Chest CT –> Staging (refer)

Question 2

Osteosarcoma Tx

Answer 2

• Immediate referral to a MSK oncologist
• Chemo
• Amputation
• Limb salvaging surgery (90%)

Question 3

Ewing’s Sarcoma Dx

Answer 3

• ESR – Elevated
• Bone marrow aspiration & tumor biopsy

X-ray
- Large lytic lesion of the metaphysis or diaphysis of a long bone
- Characteristic “onion skin” appearance

Question 4

Ewing’s Sarcoma Tx

Answer 4

• Refer immediately to a MSK oncologist
• Chemo & irradiation
• Possible surgical resection

Question 5

Chondrosarcoma Dx

Question 6

Chondrosarcoma Tx

Answer 6

• Refer for surgery***
• No chemo usually needed (don’t respond well b/c of slowly differentiating cells)

Question 7

Osteochondroma Dx

Answer 7

X-ray
- Compact, pedunculated protuberance of bone

Question 8

Osteochondroma Tx

Answer 8

May be left untx unless symptomatic

Question 9

What Orthopedic emergency did we discuss?

Answer 9

Compartment Syndrome

Question 10

Compartment Syndrome 5 Ps

Answer 10

• pain
• paresthesia (tingling)
• pallor
• pulselessness
• poikilothermia (inability to regulate body temp)

Question 11

Compartment Syndrome Dx

Answer 11

Calculate the delta pressure
– Diagnosis at > 30 mm Hg
– check it 2-3 times

– CPK & myoglobin

Question 12

What is the normal pressures within in body compartment?

Answer 12

< 10 mmHg

Question 13

Compartment Syndrome pressures

Answer 13

Pressures exceeding 30 - 50 mm Hg

Question 14

Compartment Syndrome Tx

Answer 14

Referral/Consult for immediate fasciotomy

While waiting
–> Remove restrictive casts & dressings
–> Place limb at level of the heart
–> Supplemental O2 & supporting the BP in the hypotensive pt

Question 15

How long does it take for permanent damage to occur w/ Compartment Syndrome?

Answer 15

> 8 hours

Question 16

Time frame for likely functional impairment in Compartment Syndrome?

Answer 16

6-8 hours

Question 17

Time frame for functional impairment to be unlikely in Compartment Syndrome?

Answer 17

w/n 6hrs

Question 18

Osteomyelitis Dx: Imaging

Answer 18

MRI – TEST OF CHOICE

X-rays (could be normal)
–> Soft tissue swelling
–> Osteopenia, bone resorption, new periosteal bone formation
- Bone scan – localize involvement
- CT – differentiate from other lesions

Question 19

Osteomyelitis Dx Aspiration if able…

Answer 19

1. Gram stain
2. Aerobic and anaerobic cultures
3. Acid-fast bacillus
4. KOH for fungus

via fine needle biopsy

Question 20

Osteomyelitis Abx Therapy Tx

Answer 20

• ID the organism (delay abx until cultures obtained if possible)

Abx therapy:
- Children < 3mo: IV oxacillin + cefoxatime
Children > 3mo: IV oxacillin ± vanc
–> PNC allergic: vanc alone
Adults: IV vanc + ceftriaxone
Usually IV abx for 5-10 days or until C&S is back
- Continue for 4-6 weeks
- Consult Infectious dz & Ortho

Question 21

Osteomyelitis Surgical Tx & indications

Answer 21

• Surgical debridement – more common in non-hematogenous
• Indications:
  –> Aspiration of frank pus
  –> Substantial bone resorption (decr in bone density on imaging)
  –> Failure of symptoms resolution after 36-48hrs of tx