Deep tissue infections

Question 1

Necrotizing fascitis?

Answer 1

extensive tissue destruction
thrombosis of blood vessels
abundant bacteria spreading through fascial plains
in early stages relatively few acute inflammatory cells

Question 2

necrotizing fascitis from simple cellulitis?

Answer 2

pain out of proportion to the clinical appearance of affected skin
identify those at increased risk(diabetes, abnormal peripheral circulation, trauma wounds, surgical incisions)
high fever
toxic appearance

Question 3

Type 1 necrotizing fascitis?

Answer 3

diabtes mellitus, abdominal surgery, perineal infections

mixed infection

Question 4

Type 2 necrotizing fascitis?

Answer 4

Grp A streptococcus (flesh eating strain)

-Aeromonas hydrophilia and Vibrio vulnificus

Question 5

Type 1 necrotizing fasciitis?

Answer 5

clinically resembles gas gangrene
significant gas formation
copiuos seropurulent exudate occurs 3-4 days afer injury
unpleasant sour odor
if muscles involved, react to stimulation

Question 6

diagnose type 1?

Answer 6

gram stain- numerous strep, pleomorphic gram neg rods with many polys
culture usually mixed

Question 7

mixed culture in type 1?

Answer 7

anaerobic strep
group A strep or S. aureues
often enteric bacteria and bacteroides

Question 8

diagnostic criteria of NF?

Answer 8

leukocytosis with a left shift (increase in the numer of immature white blood cells)
elevated sedimentation rate
elevated creatinine phosphokinase
hypocalcemia
hypoalbuminemia

Question 9

Therapy of NF?

Answer 9

meticulous debridement

large does of antibiotics (penicillin and aminoglycoside)

Question 10

Type 2 necrotizing fascitis etiology?

Answer 10

Grp A streptococcus (flesh eating strain due to high amt of lipase enzyme, secrete superantigens)
rapid progression
resembles clostridial gas gangrene but not gas formation

Question 11

Diagnosis type 2 NF?

Answer 11

gram stain and culture of infected tissue
lab tests: lecuocytosis, ESR, creatinine phosphotase, electrolyte imbalance
Xray or MRI ck for gas (no gas with S. pyogenes NF)
Histo: incisional or fascial biopsy

Question 12

Treat type 2?

Answer 12

surgical debridement with prompt antimicrobial therapy (penicllin G)

Question 13

Aeromonas hydrophilia myonecrosis?

Answer 13

motile gram neg rods, fresh water, oxidase pos
rapid progression
resembles clostridial gas gangrene
bacteremia is frequently present

Question 14

Treatment Aeromonas hydrophilia myonecrosis?

Answer 14

surgical debriedement and prompt anitmicrobial therapy (fluoroquinolone, amioglucosides, or trimeth/sulfa)

Question 15

Gas gangrene (clostridial myonecrosis)?

Answer 15

rapidly progressive, life threatening, toxemic infection of subcutaneous tissue and skeletal due to clostridia
usually due to traumatic injury

Question 16

Patholophysiology Gas gangrene (clostridial myonecrosis)?

Answer 16

most often caused by Clostridium perfringens, others include C. novyi, C. septicum, C. hitslyticum
infections have very low level host inflammation (purulence is often absent, due to effect of the toxins)
most damage due to alpha and theta toxins

Question 17

Predisposing factors Gas gangrene (clostridial myonecrosis)?

Answer 17

accidental trauma injury with compound fracture
penetrating war wounds
surgical wounds
artery insufficiency in an extremity

Question 18

clinical findings Gas gangrene (clostridial myonecrosis)?

Answer 18

incubation period usually 2-3 days but may be as short as 6-8 hours
excruciating pain with rapid increasing intensity
patient appears ill with a rapid pulse and falling BP, shock and renal failure may follow
process is rapid and often fatal

Question 19

appearance Gas gangrene (clostridial myonecrosis)?

Answer 19

wound has peculiar foul odor
gas bubbles may be visible in the discharge, crepitus is usually present
skin around wound is usually swollen and white, yellowish discolor
blebs contain sero-sanguineous fluid develop in overlying skin and areas of green black cutaneous necrosis appear
involved m undergoes rapid disintegration and fails to contact upon stimulation
fulminant cases occur rapidly

Question 20

Diagnose Gas gangrene (clostridial myonecrosis)?

Answer 20

gram stain of exudate or aspiration of bled reveal large gram pos rods but few polymorpholeukocytes
Clostridium perfringens isolated

Question 21

Therapy Gas gangrene (clostridial myonecrosis)?

Answer 21

emergency surgery to carry out appropriate debridement
DOC: peniciilin G and clindamycin
Hyperbaric oxygen

Question 22

Spontaneous, non traumatic gas gangrene?

Answer 22

Clostridium septicum

assoc with colon cancer, diverticulitis, and GI surgery

Question 23

Clinical presentation Spontaneous, non traumatic gas gangrene?

Answer 23

bacteremia, pain, fever

Question 24

Treatment Spontaneous, non traumatic gas gangrene?

Answer 24

similar to traumatic gas gangrene

Question 25

Myalgias?

Answer 25

prominant features of a variety of viral infections and intracellular bacterial infection
actual cause is unknown but is likely do to an immunological response- some evidence of direct invasion

Question 26

Muscle degeration assoc with infection at another site?

Answer 26

catabolism of the skeletal m, weakness and muscle wasting
acute phase response to sepsis and trauma
central role played by IL-1 and TNF which leads to increased synthesis in muscle cell lysosomes

Macrophages- IL-1 and TNF- prostaglandin E2- muscle protease