Necrotizing Fasciitis Dolan Wenner, D.O. Internal Medicine Lecture Series 1/31/07.

Necrotizing FasciitisNecrotizing Fasciitis

Dolan Wenner, D.O.Dolan Wenner, D.O.

Internal Medicine Lecture SeriesInternal Medicine Lecture Series

1/31/071/31/07

Necrotizing FasciitisNecrotizing Fasciitis

Definition – commonly referred to as Definition – commonly referred to as “flesh-eating bacteria,” it is a rare infection “flesh-eating bacteria,” it is a rare infection of the deeper layers of the skin and of the deeper layers of the skin and subcutaneous tissue (fascia) subcutaneous tissue (fascia)

Organisms Organisms

Most common associated organism is Most common associated organism is group A group A beta-hemolytic streptococcibeta-hemolytic streptococci

Other isolated organisms: Staph. aureus, Other isolated organisms: Staph. aureus, Clostridium perfringens, Staph. Epidermidis, Clostridium perfringens, Staph. Epidermidis, enterococci, Enterobacteriaceae species, E. coli, enterococci, Enterobacteriaceae species, E. coli, Proteus mirabilis, Klebsiella pneumonia, Proteus mirabilis, Klebsiella pneumonia, Pseudomonas aeruginosa, Pseudomonas aeruginosa, Bacteroides/Prevotella species, anaerobic gram-Bacteroides/Prevotella species, anaerobic gram-positive coccipositive cocci

PathophysiologyPathophysiology

Organisms spread from the subcutaneous tissue Organisms spread from the subcutaneous tissue along the superficial and deep fascial planes along the superficial and deep fascial planes facilitated by bacterial enzymes and toxins facilitated by bacterial enzymes and toxins M1 and M3 surface proteins – increase M1 and M3 surface proteins – increase adherence of streptococci to the tissues, also adherence of streptococci to the tissues, also protects bacteria against neutrophilic protects bacteria against neutrophilic phagocytosisphagocytosisStreptococcal pyrogenic exotoxins (SPEs) A, B, Streptococcal pyrogenic exotoxins (SPEs) A, B, C and streptococcal superantigens (SSA) – lead C and streptococcal superantigens (SSA) – lead to the release of cytokines and produce clinical to the release of cytokines and produce clinical signs such as hypotensionsigns such as hypotension

PathophysiologyPathophysiology

Deep infection can causeDeep infection can cause Vascular occlusionVascular occlusion IschemiaIschemia Tissue necrosisTissue necrosis Nerve damageNerve damage Septicemia (systemic toxicity)Septicemia (systemic toxicity)

Necrotizing Fasciitis syndromesNecrotizing Fasciitis syndromes

Type I (polymicrobial)Type I (polymicrobial)

Type II group A beta-steoptococcalType II group A beta-steoptococcal

Type III gas gangrene (clostridial Type III gas gangrene (clostridial myonecrosis)myonecrosis)

NF – Type INF – Type I

PolymicrobialPolymicrobialTypically occurs after surgery or traumaTypically occurs after surgery or traumaCan be mistaken for simple wound cellulitisCan be mistaken for simple wound cellulitisMay also be observed with urogenital or May also be observed with urogenital or anogenital infectionsanogenital infectionsAerobic and anearobic bacteria usually found in Aerobic and anearobic bacteria usually found in combination combination work synergistically work synergisticallyVariant of NF – saltwater NF, usually minor skin Variant of NF – saltwater NF, usually minor skin would contaminated with saltwater that contains would contaminated with saltwater that contains Vibrio speciesVibrio species

NF – Type IINF – Type II

So-called “flesh-eating bacterial infection”So-called “flesh-eating bacterial infection”

MonomicrobialMonomicrobial

Caused by group A beta-streptococcusCaused by group A beta-streptococcus

Varicella infection and use of non-steroidal Varicella infection and use of non-steroidal anti-inflammatory drugs may be anti-inflammatory drugs may be predisposing factorspredisposing factors

NF – Type IIINF – Type III

Gas gangrene (clostridial myonecrosis)Gas gangrene (clostridial myonecrosis)

Usually caused by Usually caused by Clostridium perfringensClostridium perfringens

When this type occurs spontaneously, When this type occurs spontaneously, Clostridium septicum most likely etiologic Clostridium septicum most likely etiologic agent agent usually occur in association with usually occur in association with colon CA or leukemiacolon CA or leukemia

Skeletal muscle infection may be Skeletal muscle infection may be associated with recent surgery or traumaassociated with recent surgery or trauma

NF – History and Physical ExamNF – History and Physical Exam

HistoryHistory Fever and chillsFever and chills Erythema notedErythema noted Supralesional vesiculation or bullae formationSupralesional vesiculation or bullae formation Serosanguinous fluid drainageSerosanguinous fluid drainage Recent history of skin biopsy, illicit drug use, Recent history of skin biopsy, illicit drug use,

frostbite, chronic venous stasis ulcers, open frostbite, chronic venous stasis ulcers, open bone fractures, insect bites, surgical wounds, bone fractures, insect bites, surgical wounds, and skin abcessesand skin abcesses

History of DiabetesHistory of Diabetes

NF – History and Physical ExamNF – History and Physical Exam

Physical Exam Physical Exam Rapidly advancing erythemaRapidly advancing erythema Painless ulcersPainless ulcers Black necrotic eschar may be evident at the Black necrotic eschar may be evident at the

borders of the affected areasborders of the affected areas Vesiculation or bullae formation may be notedVesiculation or bullae formation may be noted Sepsis/shock Sepsis/shock Gas may be evident (crepitus)Gas may be evident (crepitus) Pain out of proportion to examPain out of proportion to exam

Cellulitis vs. NFCellulitis vs. NF

The following may suggest NFThe following may suggest NF Rapid progressionRapid progression Poor therapeutic responsePoor therapeutic response Blistering necrosisBlistering necrosis CyanosisCyanosis Extreme local tendernessExtreme local tenderness High temperatureHigh temperature TachycardiaTachycardia HypotensionHypotension Altered level of consciousnessAltered level of consciousness

Lab StudiesLab Studies

Elevated WBCsElevated WBCsHyponatremiaHyponatremiaElevated BUNElevated BUNAnemiaAnemiaHypocalcemiaHypocalcemiaAcidosisAcidosisThrombocytopeniaThrombocytopeniaProlonged PT associated with higher mortality Prolonged PT associated with higher mortality raterate

Imaging StudiesImaging Studies

Standard radiographs – little value unless Standard radiographs – little value unless free air is depicted, as with gas-forming free air is depicted, as with gas-forming infectionsinfectionsCT – can show subcutaneous airCT – can show subcutaneous airT2-weighted MRIs may show well-defined T2-weighted MRIs may show well-defined regions of high signal intensity in the deep regions of high signal intensity in the deep tissues tissues sensitivity exceeds specificity sensitivity exceeds specificityCT and MRI may be useful in directing CT and MRI may be useful in directing rapid surgical debridementrapid surgical debridement

Other TestsOther Tests

Excisional deep tissue biopsyExcisional deep tissue biopsy is gold is gold standardstandard

Gram staining (can help delineate Gram staining (can help delineate between Type I and Type II)between Type I and Type II)

CulturesCultures

TreatmentTreatment

Transfer pt to ICU or Surgical ICUTransfer pt to ICU or Surgical ICUMaintain hemodynamic parametersMaintain hemodynamic parametersSurgical DebridementSurgical DebridementCombination antibiotic therapyCombination antibiotic therapySingle antibiotic therapySingle antibiotic therapyVancomycinVancomycinHyperbaric oxygen (HBO) Hyperbaric oxygen (HBO) may reduce may reduce mortality rate, but no literature to supportmortality rate, but no literature to supportIVIG IVIG anecdotal evidence anecdotal evidence

TreatmentTreatment

Surgical DebridementSurgical Debridement Incisions should be deep and extend beyond Incisions should be deep and extend beyond

the areas of necrosis until viable tissue is the areas of necrosis until viable tissue is reachedreached

Wound should be well irrigatedWound should be well irrigated Hemostasis should be maintainedHemostasis should be maintained Wound should be kept openWound should be kept open Debridement and evaluations should be Debridement and evaluations should be

repeated on a daily basisrepeated on a daily basis

TreatmentTreatment

Antimicrobial therapyAntimicrobial therapy Ampicillin (Principen, Omnipen)Ampicillin (Principen, Omnipen) Gentamicin (Garamycin, Jenamicin)Gentamicin (Garamycin, Jenamicin) Clindamycin (Cleocin)Clindamycin (Cleocin) Metronidazole (Flagyl)Metronidazole (Flagyl) Imipenem and cilastatin (Primaxin)Imipenem and cilastatin (Primaxin) Ampicillin and sulbactam (Unasyn)Ampicillin and sulbactam (Unasyn) Piperacillin-tazobactam (Zosyn)Piperacillin-tazobactam (Zosyn) VancomycinVancomycin Amphotericin BAmphotericin B

NF – ComplicationsNF – Complications

Sepsis and renal failureSepsis and renal failure

Metastatic plaques may occurMetastatic plaques may occur

Septicemia leads to severe system toxicity Septicemia leads to severe system toxicity and rapid death unless treated quickly and and rapid death unless treated quickly and appropriatelyappropriately

NF - PrognosisNF - Prognosis

Poor prognosis linked to certain Poor prognosis linked to certain streptococcal strainsstreptococcal strains

Mortality rate can be as high as 25%Mortality rate can be as high as 25%

Cases of NF with renal failure and sepsis Cases of NF with renal failure and sepsis have mortality rate as high as 70%have mortality rate as high as 70%

Early recognition and appropriate Early recognition and appropriate treatment can help ensure better treatment can help ensure better prognosisprognosis

Thank you!Thank you!

Question 1Question 1

What is the most common organism What is the most common organism associated with necrotizing fasciitis associated with necrotizing fasciitis (“flesh-eating disease”)?(“flesh-eating disease”)?

A.A. E. coliE. coli

B.B. Group A beta-hemolytic streptococciGroup A beta-hemolytic streptococci

C.C. Pseudomonas aeruginosaPseudomonas aeruginosa

D.D. Proteus mirabilisProteus mirabilis


What test is considered the “gold What test is considered the “gold standard” for diagnosis of necrotizing standard” for diagnosis of necrotizing fasciitis?fasciitis?

A.A. MRIMRI

B.B. CT scanCT scan

C.C. Excisional deep tissue biopsyExcisional deep tissue biopsy

D.D. Cultures Cultures


What is the organism that is most What is the organism that is most commonly associated with Type III commonly associated with Type III necrotizing fasciitis?necrotizing fasciitis?

A.A. Group A beta-hemolytic streptococciGroup A beta-hemolytic streptococci

B.B. Proteus mirabilisProteus mirabilis

C.C. Clostridium perfringensClostridium perfringens

D.D. Staphylococcus aureusStaphylococcus aureus

The EndThe End

Necrotizing Fasciitis Dolan Wenner, D.O. Internal Medicine Lecture Series 1/31/07.

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