33 and 34 - Soft Tissue Infections Flashcards
3 clinical patterns of infection
- Cellulitis
- Abscess
- Necrotizing fasciitis
Cellulitis
o Skin and connective tissue infection and inflammation WITHOUT necrotic or purulent collections
o Cellulitis can start out as just inflammation then become as an abscess, but by definition, cellulitis is NOT purulent in nature
Abscess
o Deep tissue infection WITH necrotic tissue and or purulent collections
o Involving tissue compartments, joints, tendon sheaths or deep spaces
Necrotizing fasciitis
o Extremely rapid progression
o Life and limb threatening
NOTE: not really going to talk about this today
Clinical signs and symptoms of cellulitis
o Erythema, edema
o Pain, fever, chills, malaise
o In diabetics with neuropathy, they will not have pain
Clinical signs and symptoms of abscess
o Erythema, edema
o Fluctuance, purulence, necrosis (coming from the inside out)
o Treat with antibiotics
o Pain, fever, chills, malaise
Clinical signs and symptoms of necrotizing fasciits
o Rapid wide spread necrosis
o Severe systemic symptoms (sepsis)
o CANNOT just treat with antibiotics, NEED to debride the necrosis
Common organisms
- NOTE: you need to know what the most common organism is to start antibiotic therapy
o For cellulitis, there is no opening in the skin to culture, so we need to assume
Common organisms in cellulitis
Strep. Group A, Staph. aureus
Most common organism in abscess and post-operative infections
Staph. aureus
Common organisms in a puncture wound
o Staph. aureus
o P. aeruginosa (osteomyelitis)
MOST common organism in diabetic infections
o **Staph aureus ** (staph is almost ALWAYS present)
o Can be POLYMICROBIAL (challenging to treat)
Community vs hospital acquired infections in terms of antibiotic resistance
- Community acquired infection has less antibiotic resistance
- Hospital acquired infection has more antibiotic resistance
- Healthy person is less likely to have an abx resistant infection (community acquired)
- If a NH patient comes in with an infection, we assume methicillin resistance
Effect of long standing antibiotic therapy on antibiotic resistance
- Patients on long standing antibiotic therapy select out resistant organisms
- *****Prophylactic antibiotics should be limited in timing and spectrum (1 dose 30 min prior to surgery for staph) – Should NOT be doing 2 weeks of prophylactic antibiotics after surgery
- You can’t put everyone on abx just to be safe – that will cause more problems in abx resistance
Polymicrobial infections
- Diabetic infections are in many cases poly-microbial
MRSA
- MRSA is a major player in community and institutional acquired infections
Clinical findings associated with soft tissue infection
- Fever
- Leukocytosis
- Lymphadenopathy
- Lymphangitis
- Bullae, purpura and other skin changes
- Increased ESR or C-reactive protein (Erythrocyte sedimentation rate and C-reactive protein measure overall inflammation in the body)
- Bacteremia (+ blood cultures)
Fever
- > 100.5 degrees F
- Exogenous and endogenous pyrogens
- Individual variation and diurnal variation
Fever patterns
o Continuous o Intermittent (spiking fever – common in abscess) o Remittent (parasitic – goes away, comes back few days later)
Immunocompormised patient’s fever
- **NOTE ** If the patient is immunocompromised they may not mount a febrile reaction – A diabetic with renal failure will NOT have a high fever, even with a limb-threatening infection
White blood count
WBC
o Leukocytosis > 12K
“With diff” - differential
o PMN percentage
o Left shift (immature WBCs, band cells, in blood stream)
o In immuno-compromised, you will not see a huge peak in WBC, but you will see slight elevation that will start to come down once abx therapy has been initiated
Timing of sed rate and WBC increase in infection
o For sed rate, there is a lag time… You may see the sed rate continue to peak following WBC decline post-abx therapy, but the sed rate will start to come down after that
o Not as easy as just looking at the numbers – need to relate it to the patient
Lymphatic involvement in soft tissue infection
- Inflammatory reaction in lymph channels
- Erythematous lymphatic streaking
- Palpable or painful lymph nodes
- Example: you can see red line coming down the leg, inguinal lymph nodes would likely be swollen, painful
Blood cultures in soft tissue infection
- Identification of bacteremia
- Important to consider with profound systemic symptoms
- May be helpful to identify pathogen when local culture material is not available
- May be difficult to obtain positive culture with intermittent bacteremia of cellulitis and abscess
Sepsis
Sepsis is a systemic response to a local infection
Example
o Foot ulcer (red hot swollen) and meet the criteria for SIRS = SEPSIS
Why is sepsis important to evaluate for?
VERY IMPORTANT TO UNDERSTAND***
o Need to know this because it determines admittance to the hospital
Systemic Inflammatory Response Syndrome (SIRS)
o Temp 100.5
o HR > 90
o Respirations > 20
o PaCO2 12K
Need 2-3 criteria
Types of sepsis (4)
KNOW THIS ***
Sepsis
o SIRS + Documented Infection
Severe Sepsis
o Sepsis + Organ dysfunction
o 25-30% Mortality
Septic Shock
o Sepsis + Acute persistent circulatory Failure
o 40-70% Mortality
Multi Organ Failure Syndrome
Organ dysfunction
- Altered mental status
- Edema
- Cardiac index > 3.5
- Acute oliguria
- Arterial hypoxemia
- High CR
- INR > 1.5
- Platelet count 1
What are the disease states that will contribute to a soft tissue infection?
- THESE WILL ALTER THE PATIENT’S SYMPTOMS AND IMMUNE RESPONSE*
- Elderly
- Diabetes
- Transplant and HIV
- Steroid use
How does diabetes contribute?
o Immune-suppression
o Altered immune response (Fever, WBC, SIRS)
o PVD (Poor healing)
o Neuropathy (Reduced patient perception)
How does HIV and transplant contribute?
o Immune-suppression
How does steroid use contribute?
o Altered immune response
o Blunted clinical symptoms
General treatment guidelines for infection
- Cellulitis can be treated with empiric antibiotics
- *Incision and Drainage must be priority if abscess or necrosis are present - do not leave isolated pockets of necrosis or purulence
- Delayed closure in most cases (open it and leave it open to drain)
- Culture deep tissues
Post I&D Antibiotics based on clinical scenario and patient health factors…
o Institutionalized patients may have MRSA
o Diabetic infections may be poly-microbial
Culture technique
- Superficial swipe is inaccurate for identification of deep pathogens
- Avoid skin contact to limit confusion of skin flora and pathogens
- Tissue is better than pus for culture material – DEEP TISSUE*
- Aerobic, anaerobic, fungal, acid fast
- Quantitative cultures
Antibiotic selection
Empiric choice first followed by culture directed drug of choice
***Best guess of the likely pathogens based on the patient medical history and clinical circumstances of the infection
Characteristics to look for in the drug of choice
o Highest specificity
o Lowest risk
o Lowest cost
Oral vs. IV antibiotics
o Oral drugs can have very good tissue penetration
o Do not always need IV in otherwise healthy
Duration
This will vary based on the patient’s health status
IDSA guidelines for CELLULITIS
Very good guidelines to reference
Community Acquired:
o Strep. / Staph.
o Nafcillin – Cefazolin - Clindamycin
MRSA Suspected:
o TMP/SMZ - Clindamycin
Nosocomial (hospital-acquired)
o Vancomycin
IDSA guidelines for DIABETIC FOOT INFECTIONS
Mild (with no previous antibiotics)
o Dicloxacillin – Cephalexin – Clindamycin
o Nafcillin – Cefazolin - Clindamycin
Moderate (or with previous antibiotics)
o Ampicillin / Sulbactam – Clindamycin + Levaquin
Diabetic foot infections
- Poly-microbial (Aerobes, Anaerobes, G+, G-)
- Multi-system disease (Cardiac, Renal, PAOD, Neuropathy, Immunosuppression)
- Less amenable to out-patient care
- Patient may not exhibit symptoms* (No pain – Neuropathy, low white count and fever – Immunosuppression)
IDSA guidelines for animal and human bites
- Non allergic (Ampicillin / Sulbactam)
- PCN allergy (Clindamycin + Levaquin)
- Most common organism in a dog bite = Pasturella
Paronychia - general
o Superficial nail fold infection
o Has characteristics of both cellulitis and abscess
o Well localized, usually not very deep or proximal infections
o In immunocompromised, it will be much more severe
Paronychia - clinical characteristics
Pain, erythema, purulence, granuloma, usually well localized, nail changes
Paronychia - treatment
o Incision & drainage is the mainstay
o Antibiotics rarely needed except for compromised host
o Culture only in special situations
o Staph., **Strep., Candida (= most common)
o We don’t usually even need abx
o NEED SURGICAL TREATMENT – ABX WILL NOT BE ENOUGH**
Cellulitis - clinical characteristics
o NO PURULENCE
o Erythema, warmth, pain, fever, chills, malaise, leucocytosis with left shift, contiguous source, no necrosis or pus
Cellulitis - treatment
o Empiric antibiotics, most commonly strep and staph
o Culture is usually not possible
o Admit to the hospital if the patient has profound symptoms, compromised host or failure of out-patient therapy
Criteria for hospital admission
- Profound clinical symptoms (Sepsis)
- One or more contributing disease states
- Antibiotics requiring inpatient monitoring
- Failure of out-patient therapy
- Suspicion of abscess requiring I&D
ISDA guidelines for admission
They revolve around SEPSIS
- Hypotension
- Increased creatinine
- Low bicarb
- Increased CPK
- Significant left shift
- C-reactive protein > 13
Monitoring recovery of soft tissue infections
We look at all of this to determine the next steps in treatment (debride again, send home, keep them in hospital, etc.) o Clinical appearance o Temperature o Symptoms (pain, chills) o WBC and differential o ESR or C reactive protein o Serial cultures???
Describe the controversy regarding serial cultures
- Some say 3 clean cultures before you can close the wound
- MOST wounds will not have clean cultures ever, so need to look at more than this – whole patient approach
Deep infections
- Includes: abscess and puncture wound
Abscess - clinical characteristics
o Pain, cellulitis, lymphangitis, spiking fever, fluctuance, focal collection of necrotic material
Abscess - treatment
o I&D/Culture – every hour we are not opening it up, more tissue is dying
- THERE ARE TEST QUESTIONS ON THIS – Incision and drainage is the MOST IMPORTANT THING
o Empiric antibiotics
o Medical Evaluation
o Vascular and other Testing
o Directed antibiotics after cultures are available
o Open wound management
o Delayed closure or reconstruction – do NOT close this right away
What do you NEED to remember about an abscess?
ALWAYS INCISION AND DRAINAGE FIRST – EMERGENT* (I&D) TEST QUESTION*
o “There will be test questions on this”
o Take culture at the same time
o If you start antibiotics before you take a culture, you have just altered the culture
Open wound management goals
Used for most infections after I&D to:
o Promote granulation
o Sequentially remove necrotic and infected tissue.
o Manage dead space
o Prevent subsequent sequestration
Basics of open wound management
- Continuously wet bandaging
- Serial debridement (have to be able to continue debriding the wound in the office or OR)
- Complete when granulation occurs and cellulitis and other signs resolved
CASE STUDY I
- 27 y/o healthy male just back from a camping trip, foot has been red for 3 days
- Severe pain, sweats and chills, tender in groin, oral temp 101.8, WBC 15.6K, ESR 32
- Draining for 1.5 days*** (tells you it is an abscess and not cellulitis), X-ray negative
- Diagnosis and plan: Abscess – I&D RIGHT NOW**
- Diagnosis is abscess in the foot with systemic sepsis because he has systemic symptoms as well
Criteria for hospital admission (recall from above)
- Abscess requiring I&D
- Profound clinical symptoms (sepsis)
- One or more contributing disease states
- Antibiotics requiring inpatient monitoring
- Failure of out-patient therapy
Plan for CASE STUDY I
- Plan: Hospital Admission, Emergent I&D, empiric antibiotics until cultures complete, medical optimization, saline bandages until the wound is clean and systemic symptoms have resolved, delayed closure when wound clean and granular
Delayed wound closure
- Primary closure vs. skin graft?
- Antibiotics after closure?
PLAN:
o Continue antibiotics for 5 days in otherwise healthy patient responding to treatment
o May need to consider longer course of abx if diabetic or if osteomyelitis
- 3 days later skin has recovered, wound is granular and very healthy looking
CASE STUDY II
- 70 y/o female with RA and DM, callus broke open 1 week ago and has been draining
- Painful in arch and ankle, feels weak
- N&V this AM, “thinks she has the flu”
- Oral temp 100.6 (can’t make a decision based on this due to immunocompromised)
- WBC 9.5K (can’t make a decision based on this due to immunocompromised)
- They think it is the flu and they are not associating it with the foot because it is not painful
- Arch compression yields drainage
- Plan: hospital admission, emergent I&D, empiric antibiotics until cultures complete, medical evaluation and optimization, vascular evaluation, directed antibiotics, saline bandages until wound is clean and systemic symptoms are resolved
CASE STUDY III
- 64 y/o male with NIDDM x 15 years
- Redness x 10 days, starting to drain, feels like he is getting the flu
- Oral temp 99.6, WBC 8.4K, blood sugar 270, non-palpable pulses
- Diagnosis is abscess with necrosis – NO vascular supply, so AFTER we halt the infection, we will get a vascular consult ASAP (I&D tonight, vascular consult tomorrow)
- Plan: hospital admission, emergent I&D, medical evaluation, empiric abx until cultures complete, vascular testing, advanced imaging, saline bandages until wound is clean and systemic symptoms have resolved
CASE STUDY IV
- 47 y/o IDDM with ulcer for 6 months, recent swelling in 2nd toe & forefoot
- No pain, feels fine, has had multiple past ulcers
- Temp 99.2, WBC 6.7K, ESR 55, x-ray shows extensive bone destruction, pulses palpable
- Most important factors in this patient is the multiple past ulcers, bone destruction, swelling in toe – Now we have an abscess in the toe
- Probably traveled up the tendon sheath – now you have a closed space infection, an abscess
- Plan: hospital admission, I&D, medical evaluation, empiric antibiotics, advanced imaging, directed abx, serial debridement and wound care
- Once infection has cleared, need to figure out how to close the wound – toe flap
- Eventually needed a transmetatarsal amputation, which removed the deforming forces to treat the ulcer as well as the infection – it was a functional amputation stub
CASE STUDY V
- 54 y/o female IDDM x 25 years, redness and swelling 5 days after twisting ankle
- No pain, feels fine, oral temp 98.5, WBC 8.9, HgA1c 9%, palpable pulses, swelling to the knee both extremities
- Ankle sprain or abscess? They made an incision and it was highly purulent, lots of drainage
CASE STUDY VI
- 62 y/o male with multiple episodes of gout, current episode x 7 days
- Severe pain, not responding to indomethacin, no response to oral abx, getting blisters on toes
- Fever and chills, oral temp 101.5, WBC 11K, tender in arch
- This is an abscess due to gout with necrosis of the toe, which is spreading proximally – the gout was traveling with the infection so there were crystals
- This is a deep space abscess in a single compartment of the plantarfoot
- Plan: admission, emergent I&D, medical evaluation, empiric abx, advanced imaging, serial debridement and wound care, reconstruction
- Gout – sodium urate tophi which “eats everything in its path” – there was no tendon capsule or bone left, just the sodium urate accumulation which can become acutely infected
CASE STUDY VII
- 75 y/o IDDM male with redness and L calf pain @ rest, acute onset 10 days ago, seen by two other doctors and treated with 2 courses of oral antibiotics
- Not responding to oral antibiotics and colchicine, uric acid 4.0, no open lesions, oral temp 99.0, WBC 5.0K, pulses not palpable, extensive heart disease history
- Diagnosis: PAD – occlusive vascular disease, determined this by testing for dependent rubor and elevation pallor
CASE STUDY VIII
- 67 y/o female admitted for cellulitis not responding to broad spectrum antibiotics
- Leg pain, temp 98.6, WBC 8.0, ESR 12, history of DVT
- Diagnosis: venous stasis – elevation makes it better, not the antibiotics
Puncture wound - general concepts
- Must determine the specific circumstances of trauma – environment, object, force of injury, timing of presentation, retained foreign body
- Get a detailed PMHx
- Initiate immediate treatment
- A lot of the same concepts as abscesses
Puncture wound treatment
- *****The aggressiveness of treatment is based on the zone of involvement
- *****I&D is the cornerstone of treatment
- Antibiotics are carefully considered
- Timing is extremely important
- Suspect Pseudomonas in osteomyelitis
- Always get X-ray
Puncture zones and risk associated
- Zone 1 - High risk***
- Zone 2 - Low risk (Zone 2 is a low risk because there is a lot of distance to the bone, muscle, tendon, etc.)
- Zone 3 - Mod risk
Clinical characteristics of puncture wounds
- History of trauma, pain
- Physical exam does not always tell the whole story
- Remember diabetics may have no symptoms or not be aware of trauma
- Should be treated aggressively before signs of cellulitis or abscess begin
- Everything is the same – don’t need to belabor this
- Depends on the environment of the injury***
- Depends on zone ***
Zone 1 puncture wounds
- Aggressive I&D and lavage in all cases, open management is necessary
- Antibiotics not mandatory unless high risk environment, compromised host, definite bone contact or fracture
- All injuries with bone penetration are treated with aggressive I&D
- Example: Puncture wound on the bottom with infection on the top – we know there is abscess because it has travelled to the joint – only way it can get to the top of the foot
Zone 2 and 3 puncture wounds
Local I&D, antibiotics carefully considered
Open management if:
o Deep penetration / Bone contact
o Contaminated environment
o Compromised host
Zone 2 in a Healthy Patient o Local anesthesia o Mini I&D o Extensive lavage o open
Zone 2 in a Patient with Systemic Complication
o Aggressive I&D
o Antibiotics
o Leave open
General concepts in the treatment of puncture wounds
- The aggressiveness of treatment is based on the zone of involvement
- I&D is the cornerstone of treatment
- Antibiotics are carefully considered
- Timing is extremely important
- Always get X-ray
- KEY – EVERYTHING we learned about in infection plus ZONE OF INVOLVEMENT***
