4/9 Review: Skin, Soft Tissue, Osteomyelitis

Question 1

If you have an abscess that you are unable to completely drain, when should you refer to surgery or derm?

Answer 1

• concern for disfigurement
• consider location; some locations easier to open than others, some are more likely to heal better than others
• size: if 6-7 cm cut + probably some stitches, refer to someone else

Question 2

PO treatment options for boils?

Answer 2

A. TMP/SMX (Bactrim) (because bactrim is CHEAP)

B. Clindamycin

C. Cephalexin (but not good for MRSA)

Why Bactrim over clinda? There is more commonly resistance to clindamycin. Some resistance to Bactrim, but less.

Clinda is MORE TOXIC –> worry about diarrhea from C Diff because it kills anaerobes, allows C Diff to proliferate

Question 3

IV treatment options for boils?

Answer 3

A. vancomycin

B. TMP/SMX
C. Oxacillin

Vanco is the default IV drug for MRSA infections (or if could be staph, could be strep, unknown). Can use empirically. Not as cidal as oxacillin, but oxacillin doesn’t work as well for this.

Question 4

Treatment for recurrent boils?

Answer 4

• Hygiene – make sure pt is doing laundry regularly etc
• Treat contacts (People don’t have to have a boil to transmit)
• MSM, sports teams, prisoners –> groups in high contact with each other can have outbreaks
• Nasal carriage - treat with Mupirocin in the nose

Question 5

Why are cat bites so nasty? what is treatment?

Answer 5

Cats have sharp teeth: penetrate far down into synovium

(Dog bites crush more than penetrate.)

Treatment for cat bite: Augmentin -
covers gram-negs (like Pasteurella) &
covers for anaerobes (like oral flora)

Question 6

Necrotizing Fasciitis: what are s/s that you have this rather than just cellulitis?

how would you diagnose?

Answer 6

Clinical clues:

• Fever + shock are unusual with cellulitis -> clue towards necrotizing fasciitis
• Pain out of proportion to numbness also a clue.

Diagnosis:

• Use MRI to diagnose for sure, helps determine the extent of the lesion.
• PE can give you a good clue and raise your level of suspicion, but you don’t want to start deep surgical debridement without confirmation.

Question 7

Contiguous osteomyelitis:

most common patients?

likely microbes?

Answer 7

Most common in 50+ people with vascular disease and diabetes
Likely to be polymicrobial – the ulceration becomes a portal for the bugs. But most prevalent org - S aureus

Question 8

What are some patient scenarios that would suggest hematogenous osteomyelitis?

Answer 8

• Sickle cell pts
• Kids are more susceptible (remember single bone, at metaphyseal plate)
• Some high grade bacteremia, much more likely to metastasize
• Dialysis patients
• Any patient with a line, catheter, central line
• Immunecompromised
• Pts with vertebral osteo
• Sternoclavicular joint trauma (very vascularized, concern for bacteremia from this source)

Question 9

What type of scenarion would suggest vertebral osteo from E Coli?

Answer 9

• Perforated bowel
• Decubitous ulcer (bowel contamination of abscess, ulcer)
• BPH (benign prostatic hypertrophy) pt, outlet obstruction, UTI, pyelonephritis, instrumentation of the urinary tract….etc

Question 10

Imaging for osteomyelitis:

• what imaging is best?
• what can you see with CT?
• when do you not need imaging?

Answer 10

-MRI best for diagnosis (Plain radiography not the best because it will be time before you see the destruction (takes 2-3 weeks))

• On MRI, can see soft tissue way better than plain film and C; can also see bony destruction
• CT is in-between: can see soft tissues better than plain film. But worse than MRI view of soft tissue
• No need for MRI to diagnose if you can tell based on probing tissue to bone (may still do MRI for surgical planning)

Question 11

How can I distinguish Lyme Dz from Erythema Multiforme?

Answer 11

Erythema multiforme can involve mucosa

Lyme NEVER involves the mucosal tissues

Question 12

A few Lyme pearls:

What causes it?

If you can see the ECM, should you do serology?

Answer 12

-What causes it? Borellia burgdorferi

• Do not need serology if you can see the ECM
• Dr. Lahey is crazily adamant that you should NOT do a Lyme serology for chronic malaise or other non-specific symptoms

-These pts may be positive for no good reason, but then may be treated for Lyme inappropriately

Question 13

What are the classic non-derm syndromes associated w Lyme?

Answer 13

• Bell’s palsy
• Arthritis (MONOarticular septic arthritis, usually in knee)
• Meningitis (aseptic)
• Myocarditis (heart block, not due to heart failure)

-BAMM

Question 14

Antibiotic Mix and Match:

_Conditions to treat: _

MRSA, Group A Strep cellulitis, Vibrio vulnificus/Aeromonas, Pasteurella, MSSA

_Antibiotics: _

TMP/SMX, Penicillin, Ciprofloxacin, Amoxicillin/clavulanate, Oxacillin

Answer 14

TMP/SMX –> MRSA

Penicillin –> Group A Strep (cellulitis)

Ciprofloxacin –> Vibrio vulnificus or Aeromonas (gram neg rods)

Amoxicillin/clavulanate –> Pasturella multocida

Oxacillin –> MSSA