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21 Cards in this Set
- Front
- Back
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Describe the pathological features of Necrotizing Fasciitis
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Extensive tissue destruction
thrombosis of blood vessels bacteria spreading through fascial planes few inflammatory cells in early process. |
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What are some ways to distinguish NF from cellulitis?
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pain out of proportion to the appearence of the skin affected
high fever toxic appearance Those at increased risk: Diabetics, abnormal periphery circulation immunocompromised traumatic wounds surginal incisions |
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Describe the causes of Type I NF
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DM, abdominal surgery, perineal infection
MIXED INFECTION: anaerobes, anaerobic strep, facultative organisms (synergistic nonclostridial myonecrosis) |
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Describe the causes of Type II NF
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Group A Strep (flesh eating strain)
Aeromonas hydrophilia Vibrio Vulnificans |
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What are some genereal characteristics of Type I NF?
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Resembles gas gangrene
significant gas formation copious seropurulent exudate @ 3-4 days. Unpleasent sour odor affected muscle reacts to stimulation |
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How is Type I NF diagnosed?
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Gram Stain - numerous streptococci, pleomorphic Gram - rods
Culture usually mixed anaerobic Strep Group A Strep or S. aureus enteric bacteria and bacteroides Leukocytosis w/ left shift elev. sed rate elev creatinine kinase hypocalcemia hypoalbuminemia |
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How is Type I NF treated?
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Meticulous Debridement
Large doses of antibiotics (Penicillin and aminoglycoside) |
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What are some general characteristics of Type II NF?
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Caused by Group A strep
Flesh eating strain due to high amount of lipase enzyme Rapid progression NO GAS FORMATION |
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How is Type II NF diagnosed?
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Gram stain and culture of infected tissue (rapid strep screen)
Lab tests: leucocytosis, ESU, creatinine phosphatase, electrolyte imbalance X-Ray or MRI: Check for gas (SHOULD BE ABSENT) inscisional or fascial biopsy |
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What is the preferred treatment of Type II NF?
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Surgical debridement with primpt antimicrobial therapy
Penicillin G |
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What are some characteristics of aeromonas hydrophilia myonecrosis? (AHM)
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Motile, gram negative rods found in fresh water
oxidase positive Rapid progression following penetrating trauma in fresh water resembles clostridial gas gangrene bacteremia frequently present |
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What is the treatment for AHM?
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Surgical debridement and prompt Ab therapy (fluoroquinelone, aminoglycosides, or trimeth/sulfa)
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What are some general characteristics of Gas Gangrene (clostridial myonecrosis)?
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rapidly progressing
life-threatening toxemic infection of tissue and skeletal muscle due to clostridia (usu. perfringens) Usu. due to traumatic injury |
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Describe the pathophysiology of tissue necrosis.
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Break in skin
Wound contamination eema and tissue hypoxia germination of anaerobic bacterial spores repease of exotoxins by bacteria necrosis of muscle, subcutaneous tissue, and fat decreased blood flow causing further hypoxia liquefaction necrosis of tissue due to enzymes produced by anaerobic bacteria |
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What are some predisposing factors of Gas Gangrene?
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Accidental traumatic injury w/ compound fracture
penetrating war wounds surgical wounds artery insifficiency in extremities -> diabetics. |
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What are some clinical findings for gas gangrene?
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incubation period 2-3 days, but could be as low as 6-8 hrs.
severe pain with rapid increasing intensity pt appears ill with a rapid pulse and falling BP -> shock and renal failure may follow process is rapid and often fatal |
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What is the general appearance of thewound/patient in Gas Gangrene?
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Wound has peculiar, foul odor
gas bubbles may be visible in discharge and crepitus may be present skin around wound is swollen and white, w/ some yellow discoloration blebs containing sero-sanguineous fluid develop on overlying skin, green-black areas of necrosis appear involved muscle undergoes disintegration and fails to contract upon stimulation fulminant cases develop rapidly 2-4hr |
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How do you diagnose GG?
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Gram stain of exudate reveals large gram - rods but few polys
C. perfringens isolated in 80-95% of cases. |
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How is GG usually treated?
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Emergency surgery for debridement
penicillin G and clindamycin hyperbaric oxygen |
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What is the etiology and general characteristics of spontaneous, non-traumatic GG?
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Etiology - C. septicum
assoc. w/ colon cancer, diverticulitis, and GI surgery Clinical presentation of bacteremia, pain, and fever. Treat similar to GG. |
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What are the general characteristics of myalgias?
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feature in a variety of viral infections and intracellular bacterial infections
cause unknown, but likely to do w/ an immunologic response, w/ some evidence of direct invasion |
