04-08 Skin, Soft Tissue and Bone Infx Flashcards
(27 cards)
Spreading infx is usually from _______ which is treated with _______.
- If 2° to trauma add ____
**distinguish focal vs. spreading**
Spreading infx (e.g. cellulitis) is usually from GROUP A STREP (a.k.a. STREP PYOGENES) which is treated with PENICILLIN to which it’s “exquisitely sensitive”.
—I.E. you DON’T NEED KEFLEX! (Overkill)
—Usuallly 2° to microtrauma (zipper, toenail infx, surgery)
If 2° to trauma, add Rx for MSSA/MRSA
Focal skin/soft tissues infx are usually caused by _________ and treated with ______.
we’re talking boils/furuncles/carbuncles
- usually caused by STAPH AUREUS.
- Treatment: Apply heat and drain if > 1cm; often sufficient.
- Add abx if pt is sick or cellulitis is surrounding focus; cover for MRSA “unless you have a culture cooking”
- best options: TMP/SMX > doxy > clinda
- vanco if hospitalized
What is this?
- bug?
- tx?
impetigo
- usually strep
- Treatment
- mild: topical mupirocin
- more severe: cephalexin +/- TMP/SMX depending on likelihood of staph
What is this?
- presentation?
- causal organism?
- tx?
Erysipelas
- Well-demarcated, uniform erythema w/ systemic sx
- Cause: Group A strep
- Tx: penicillin
Cat bite infections
Pasturella
Human bite infxs
Eikenella
Fresh water trauma worry about…?
Aeromonas
Salt water trauma worry about…
Vibrio vulnificus
Rose gardener w/ nodular lesions worry about…
Spoptrichosis (fungal)
Fish tank owner w/ skin/soft tissue infx worry about…
Mycobacterium marinum
Name the tissue layers and the infections that occur at each level.
See image below
Treatment for pts w/ recurrent MRSA?
Nasal mupirocin, bleach baths, chlorhexidine washes
Necrotizing Faciitis
- Presentation
- Dx
- Causative Bugs
- Tx strategy
- Presentation: rapidly spreading soft tissue infx, can be accompanied w/ systemic shock sx
- Dx: MRI + culture
- Bugs: usu Grp A Strep or Staph
- more rare: Gm negs
- Tx: often surgical debridement plus
- broad spectrum abx
- PLUS clinda (ribosomal inhib) to stop toxin elaboration
Paronychia
- Presentation?
- Tx?
Inflamm around nail bed
- usually tx w/ “moist head” is enough
- rarely drainage +/- abx
Folliculitis
- Causal org?
- Tx
Usu staph
tx w/ topical abx (e.g. Polymyxin B or mupirocin)
Anthrax presentation
- bug name?
painless eschar in someone w/ exposure to animal hides or terrorists
- Bacillus anthracis
Lyme
- Derm finding name?
- non-derm findings?
- should you check serology?
- Erythema chronicum migrans
- Non-Derm Findings
- septic, monoarticular arthritis
- facial nerve (CN VII) palsy
- meningitis
- complete heart block
- If pt has ECM, no need for serology
- also no need if suspected “chronic Lyme”
Two ways of osteomyelitis spreading
- heamtogenous
- contiguous
Contiguous Osteomyelitis
- Pt population?
- Risk factors?
- w/o vasc insuff vs. w/ vasc insuff
- s/sx differences between two
- Common sites?
- Pathogens?
- Dx?
Contiguous focus infections and those due to vascular insufficiency are most common in those over 50 years old, reflecting increased likelihood of precipitating factors:
- Surg, ortho surg (e.g., knee, hip replace)
- History of DM and/or PVD
- Trauma, incl open fxs
Hematogenous Osteomyelitis
- Presentation
- Pt population?
- Risk factors?
- Which bone(s)?
Hematogenous Osteomyelitis
- Presentation: local sx + systemic sx
- Pt population: children
- Risk factors?
- Which bone(s): usually single, long bone
Vertebral Osteomyelitis:
- Pathophysiology
- Most common bug?
- Others in adults?
- Old men?
- IVDUs?
- Sickle Cell pts?
- Risk Factors?
- S/Sx
- Dx
Pathophys
- Organisms reach the well-perfused vertebral body via spinal arteries.
- Most often involves the lumbar or thoracic spine.
- Infection spreads from end plate into disk space.
Most common bugs (95% single org)
- Most common: 50% S. aureus
- other adult paths: Viridans streptococci, including S. milleri;
- E.coli and other enterics in~25%
- Old men: Enterococci
- IVDUs: S. aureus, P. aeruginosa, Serratia
- Sickle: Salmonella spp., S. aureus
Risk Factors
- Age > 50
- Sickle cell
- DM
- Hemodialysis
- Endocarditis
- IVDU
- Nosocomial bacteremia
- Long-term vascular access
- UTI, esp. elderly men
- Preceding minor trauma or fall
S/Sx
- Often starts insidious -> subacute or chronic
- May have hx of fever +/- rigors weeks b4 presentation w/ back pain
- Presents as back or neck pain (>90%)
- Fever often low-grade or absent (50%)
- Constitutional symptoms: anorexia, malaise
- Percussion tenderness of spine and paraspinal muscles, with spasm (85%)
Dx
- Cultures
- Plain films: irregular erosions in end plates of adjacent vertebral bodies and narrowing of intervening disk space – virtually diagnostic
- CT/MRI: may show epidural, paraspinal, retropharyngeal, mediastinal, retroperitoneal, or psoas abscess originating in the spine
Treatment for General Osteomyelitis
See Slides 32 and 33
Most sensitive and specific test of osteomylelitis?
MRI
Tx for acute hematogenous osteo
- Duration of therapy typically 4 to 6 weeks
- Home therapy (OPAT) is appropriate for motivated and stable patients
- Drugs with a long half-life, such as ceftriaxone vancomycin, and ertapenem, facilitate OPAT.
- Children can be switched from parenteral to oral therapy after 5 to 10 days if signs of infection have resolved.
- Few data support the use of oral therapy in adults except with quinolones (for GNRs) and possibly linezolid.
