Updated: 6/19/2019

Necrotizing Fasciitis

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Questions
5
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100%
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Evidence
3
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Topic
Snapshot
  • A 45-year-old woman presents to the emergency department for severe pain of her left foot. She states that this has never happened before. Her symptom is accompanied by fever and generalized myalgias. Medical history is significant for type II diabetes mellitus. On physical exam, there is exquisite tenderness to palpation, erythema, palpable crepitus, and tense bullae. Surgery is immediately consulted.
Introduction
  • Clinical definition
    • infection of the superficial fascia that is life-threatening
  • Epidemiology
    • risk factors
      • diabetes mellitus
      • chronic corticosteroid use
      • alcohol abuse
      • injection drug use
  • Etiology
    • polymicrobial infection
      • most common (70-80%)
      • contains aerobic and anaerobic organisms
        • aerobes
          • Streptococcus spp. (most common)
        • anaerobes
          • Bacteroides spp.
          • Peptostreptococcus spp. 
    • monomicrobial infection
      • most commonly caused by group A Streptococcus
  • Pathogenesis
    • inciting infection at tissue site can be accomplished via
      • hematogenous spread
      • direct inoculation
    • the infection rapidly spreads leading to
      • vascular occlusion → ischemia and necrosis
      • crepitus in cases of gas forming organisms (e.g., Clostridium) and anaerobic organisms
  • Prognosis
    • increased mortality and risk of amputation
Presentation
  • Symptoms
    • severe pain
      • out of proportion of superficial findings of the affected area
    • fever
  • Physical exam
    • tenderness to palpation
    • palpable crepitus
      • secondary to methane and CO2 production
    • erythema
    • bullae, blisters, or ulcers
    • cutaneous necrosis
    • progression of disease despite antibiotic treatment
Imaging
  • Magnetic resonance imaging (MRI)
    • indication
      • can be helpful to determine the extent of the infection
        • however, it must not delay antibiotics and surgical debridement
Studies
  • Labs
    • ↑↑ C-reactive protein
    • ↑ creatine kinase
    • ↑ white blood cell count (WBC) and blood urea nitrogen (BUN)
  • Intraoperative studies
    • Gram stain and culture
    • biopsy
  • Diagnostic criteria
    • based on clinical suspicion and confirmed intraoperatively with surgical debridement
      • labs or imaging do not override clinical judgement
Differential 
  • Cellulitis
  • Staphylococcus scalded skin syndrome
  • Gas gangrene
Treatment
  • Management approach
    • prompt surgical debridement is the mainstay of treatment along with antibiotic treatment 
  • Medical
    • intravenous empiric antibiotics
      • indication
        • a treatment component of necrotizing fasciitis directed against likely organisms
          • e.g., antibiotics that target group A Streptococcus, gram-negative organisms, anaerobes, and methicillin-resistant Staphylococcus aureus (MRSA)
      • drugs
        • meropenem or piperacillin-tazobactam and vancomycin or linezolid
          • meropenem or piperacillin-tazobactam covers
            • group A Streptococcus
            • gram-negative organisms
            • anaerobes
          • vancomycin or linezolid covers
            • MRSA
        • penicillin and clindamycin
          • treatment of choice for known group A Streptococcus necrotizing fasciitis
  • Operative
    • surgical debridement 
      • indication
        • a necessary component of treatment that also confirms the diagnosis
Complications
  • Streptococcal toxic shock syndrome
  • Compartment syndrome
  • Myositis
  • Muscle necrosis

Please rate topic.

Average 4.6 of 5 Ratings

Questions (5)

(M3.DM.16.69) A 32-year-old man presents to the emergency department complaining of excruciating pain of his left calf. He states that he was bitten by a spider three days ago; however, yesterday his calf became swollen, red, and extremely painful. His vital signs are: T 102.8 F, HR 112 bpm, and BP 134/76. On exam, his distal left leg is swollen, extremely tender to palpation, and appears purples and dusky. You note crepitus is present. A biopsy is performed and the results are shown in Figure A. What is the most likely diagnosis?

QID: 103360
FIGURES:
1

Deep venous thrombosis

0%

(0/8)

2

Thrombophlebitis

0%

(0/8)

3

Venous insufficiency

12%

(1/8)

4

Necrotizing fasciitis

75%

(6/8)

5

Osteomyelitis

0%

(0/8)

M 10 B

Select Answer to see Preferred Response

(M3.DM.16.36) A 40-year-old woman with a history of alcoholism presents to the emergency department complaining of extreme pain in her left leg for the past four days after falling while drunk. Vital signs are T 103.1 F, HR 115 bpm, and BP 108/74. An image of the leg is shown in Figure A. Apart from the findings on Figure A, exam is positive for severe tenderness of the left thigh and crepitus. Apart from IV fluids, what other treatment should this patient receive?

QID: 102977
FIGURES:
1

Culture the wound and await the results before initiating directed antibiotic treatment

0%

(0/11)

2

Aggressive fluid resuscitation and serial renal function studies

0%

(0/11)

3

Systemic prednisone treatment

0%

(0/11)

4

IV penicillin and clindamycin

0%

(0/11)

5

IV penicillin and clindamycin and surgical debridement

100%

(11/11)

M 11 B

Select Answer to see Preferred Response

(M3.DM.16.34) A 53-year-old man with type 2 diabetes mellitus presents to the emergency department complaining of the worst pain he has ever experienced in his right leg. He states that two days ago he cut his calf while working on the lawn. This morning he noticed a slight discoloration of his right calf. He says that although his leg does not look that bad, the pain is excruciating. Vital signs are as follows: T 102.5 F, HR 102 bpm, and BP 124/82. Physical exam reveals a slightly erythematous and swollen distal right calf that is extremely tender to palpation. A photo of the leg is shown in Figure A. What is the most common causative agent for this condition?

QID: 102975
FIGURES:
1

Bacteroides fragilis

0%

(0/0)

2

Vibrio vulnificus

0%

(0/0)

3

Group A streptococcus

0%

(0/0)

4

Methicillin-resistant Staphylococcus aureus

0%

(0/0)

5

Clostridium perfringens

0%

(0/0)

M 10 B

Select Answer to see Preferred Response

(M2.DM.15.73) A 47-year-old female presents to the emergency department in distress with a wound on her right lower leg. The patient describes intense pain over the site yesterday that has since dissipated; she is now insensate and not in pain. She also states that the area has been changing colors from first red to now purple/black. She reports having been stung by a bee near that spot 2 days ago. Her medical history is significant for type II diabetes, which is controlled with glipizide, and chronic headaches, for which she regularly takes naproxen. Her vital signs are as follows: T 38.9 C, HR 109, BP 80/57, RR 22, and SpO2 96%. Physical examination shows a 5cm x 12cm wound over the anterior right lower leg that is discolored purple and black towards the center of the wound with expanding edema and erythema towards the edges (Figure A). The area is insensate to light touch and pin-prick. No crepitus is noted on palpation of the wound. Which of the following is the most likely causative organism in this patient's presentation?

QID: 106591
FIGURES:
1

Staphylococcus aureus

21%

(5/24)

2

Streptococcus pyogenes

42%

(10/24)

3

Pseudomonas aeuroginosa

21%

(5/24)

4

Escherichia coli

0%

(0/24)

5

Clostridium botulinum

12%

(3/24)

M 7 B

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(M2.DM.13.5) A 57-year-old man comes to the emergency department complaining of a rash and pain in his left calf. He has a past medical history notable for diabetes and does not take his medications as prescribed. He says he cleaned the wound himself and bandaged it; however, he has been having worsening pain. This morning, the wound was hardly noticeable; however, it has now become quite large over the past several hours. His temperature is 103°F (39.4°C), blood pressure is 129/74 mmHg, pulse is 103/min, respirations are 12/min, and oxygen saturation is 98% on room air. The patient's leg is seen in Figure A. Notably, there is warmth over the leg, no crepitus, and a bedside ultrasound does not reveal a discrete fluid collection or loculations. Which of the following is the most appropriate next step in management?

QID: 104216
FIGURES:
1

Ceftriaxone

0%

(0/104)

2

Vancomycin and ceftriaxone

8%

(8/104)

3

Vancomycin, cefepime, clindamycin, and surgical debridement

8%

(8/104)

4

Vancomycin, cefepime, piperacillin-tazobactam, and surgical debridement

79%

(82/104)

5

Vancomycin, piperacillin-tazobactam, clindamycin, and surgical debridement

2%

(2/104)

M 7 E

Select Answer to see Preferred Response

Evidence (3)
EXPERT COMMENTS (4)
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