Case 5.5

Case Presentation by Dr. Megan Dougherty

A 43 year old female with a history of IVDU presents to the ED via EMS with a four day history of progressive left upper extremity swelling and pain with subjective fevers.  The patient had a history of a fall off a ladder while she was at work 2 days prior and was unsure of whether she injured the arm, but did not seek medical attention at that time because she thought nothing of it at the time. However, as the pain has increased, the patient sought medical attention.  When asked where she injected drugs, the patient stated that she had injected in the deltoid region of that extremity before, but never in the forearm.

ROS:  Positive for subjective fevers, pain and swelling of left upper extremity in addition to progressive erythema.

PMH: none

PSH: none

Allergies: no known drug allergies

Family History: no history of hypertension or diabetes

Social History: Uses tobacco 1/3 ppd. Uses IV drugs-heroin user for 8 years and cocaine.  Last injection was 3 days prior to presentation.

Physical Exam

Constitutional: T: 36.8, BP: 107/70, HR: 110, Respirations: 16. The patient appears well developed with thin body habitus.  The patient is lying comfortably on stretcher.

HEENT: NC/AT. EYES: Sclera clear.

CVS: RRR.  Good S1, S2.  NO S3 or S4.

Respiratory: Clear to auscultation bilaterally. No wheezes

Abdomen: Soft, non tender, non distended.

Musculoskeletal exam: LEFT UPPER EXTREMITY: 2+ radial pulse, area of fluctuance on the lateral distal part of the forearm, marked tenderness and cellulitis involving the entire left upper extremity with some crepitus, decreased active and passive ROM in the shoulder, elbow and wrist, Nikosky sign negative

Labs:

WBC: 16.8, Hgb: 14.1, Platelets: 275

Na: 128  K:3.8  CL:93  Bicarb:21  BUN:20 Creatinine: 1.0 Glucose: 110

Radiology:

Questions:

  1. Based on the patient’s x-ray and physical exam findings, what is the most likely clinical diagnosis?
    1. polymyositis
    2. gas gangrene
    3. necrotizing fasciitis type 1
    4. necrotizing fasciitis type 2
    5. myonecrosis
  1. What are cultures likely to grow?
    1. anaerobes only
    2. non group A streptococcus only
    3. group A beta hemolytic streptococci and staphylococcus aureus
    4. non group A streptococci and anaerobes
    5. staphylococcus aureus
  1. Risk factors for necrotizing fasciitis include:
      1. diabetes
      2. poor circulation
      3. immunocompromise
      4. trauma
      5. IVDA
      6. all of the above


    ANSWERS:
    1. d
    2. c
    3. f

    DISCUSSION:

    The patient presents with a history and radiographs highly suggestive of necrotizing fasciitis. Necrotizing fasciitis is infection of the fascia, subcutaneous tissue and skin that is potentially lethal. The CDC reports that there are 500-1000 new cases of necrotizing fasciitis reported yearly in the United States, however this is an underestimate as this only reports those infections caused by group A streptococcal infections.

    Necrotizing Fasciitis Classification:
    Type I infections: The most common type. On average, 4 or more organisms are isolated including non group A streptococci and anaerobes. Diabetes, obesity, PVD, CKD and alcohol abuse are commonly found in patients with this type of infection. The infections are typically found on the abdomen and perineum. Specifically named types include Fournier’s gangrene (involves perineum).

    Type II infections: Typically caused by group A B hemolytic streptococci species, but staphylococcus aureus is increasingly associated with type II infections.

    Typical presentation:
    -Initial presentation is typically pain, degree of pain is typically disproportionate to the physical findings.
    -eventually, blistering, crepitus, bullae or hemorrhagic blebs will develop.

    Diagnosis:
    Direct examination of involved tissues is usually required to make the diagnosis
    Radiographs only demonstrate gas in the soft tissues about 1/3 of the time
    CT has a sensitivity of about 80% for the presence of soft tissue gas but is not specific for necrotizing fasciitis
    MRI: low sensitivity (80-90%), low specificity (50-55%)

    Treatment:
    1. Fluid resuscitation and electrolyte/acid/base correction
    -major goal is to restore intravascular volume, which is always depleted in patients due to fluid shifts associated with response to infection
    -Crystalloid fluids are utilized as first line treatment. Lactated Ringers is preferable since there is usually an element of acidemia
    -If anemia is present, the patient should be given blood. Anemia is sometimes caused by hemolysis due to toxins produced by some of the microorganisms present in the infection
    -The most common electrolyte abnormality is hyponatremia and hypocalcemia. The hypocalcemia is caused by precipitation of calcium in necrotic subcutaneous fat.

    2. Initiation of antimicrobial therapy
    -initial broad-spectrum antibiotics should be started. Possible therapies include:
    – clindamycin + PCN
    – 2nd generation cephalosporin + ciprofloxacin

    Based on type of infection
    -Type I-start Piperacillin-tazobactam + Clindamycin + Ciprofloxacin- due to the polymicrobial nature of these infections, multiple antibiotics need to be employed. Clindamycin has been shown to suppress the toxin production by S. aureus, hemolytic streptococci and clostridia and should be included when these organisms are present or suspected and for all patients with hypotension, coagulopathy or organ system failure. If the patient happens to be allergic to clindamycin, then linezolid or vancomycin may be used, but they do not have the same toxin production suppressive properties.

    -Type II-start Clindamycin+Penicillin or Linezolid (if PCN allergy) or Vancomycin (if PCN allergy)
    -Doxycycline should be added when the infection is thought to be due to Vibrio or Aeromonas.

    3. Immediate debridement of necrotic tissues*
    -Need to have early involvement of the surgical team in patient care

    *Single most effective treatment is timely debridement of necrotic tissue
    4. Support of failing organ systems

    Long Term Outcomes:
    Mortality rate ranges from 6-76%, with cumulative mortality rate at about 35%.
    Diabetes mellitus is the most important predictor of mortality
    Other contributors to mortality include: Advanced age, two or more associated comorbidities, a delay before surgery of greater than 24 hours and presence of streptococcal toxic shock syndrome.

    References:

    Meizlin, HW and JA Guisto. “Soft Tissue Infections.” in Rosen’s Emergency Medicine Concepts and Clinical Practice 7th edition. 1845. Ed. Marx. Philadelphia: Mosby Elsevier, 2010.

    Ustin, JS and MA Malangoni. Necrotizing soft tissue infections. Critical Care Medicine. 2011; 39(956-62.):21

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: