Necrotizing fasciitis

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Necrotising fasciitis refers to a rapidly progressive and often fatal infection of soft-tissue fascia deep to the skin but superficial to the muscles 3.

Epidemiology

Necrotising fasciitis is relatively rare, although its prevalence is thought to be rising due an increase in the number of immunocompromised patients with HIV infection, diabetes mellitus, cancer, alcoholism, vascular insufficiency, and organ transplants. It can also occur after trauma or around foreign bodies in surgical wounds 7.

Pathology

There are at least two recognised forms:

  • the most common type is a polymicrobial infection with both aerobic and anaerobic organisms such as Clostridium, Proteus, Escherichia coli, Bacteroides, and Enterobacteriaceae: this form is often seeded from underlying infections such as diverticulitis
  • the second form of the disease is caused by a single organism - most commonly group A streptococci, the “flesh-eating bacteria,” and is seen in approximately 10-15% of cases 3-4: toxic shock syndrome may complicate this latter form.
Location

While it can affect any part of the body, the extremities, the perineum, and the truncal areas are the most commonly involved 4.

Sub types

Radiographic features

Plain film

The common plain radiographic findings non specific an often similar to those of cellulitis, with increased soft-tissue thickness and opacity. Radiographs can be normal until the advanced stages of infection and necrosis. The characteristic finding of gas in the soft tissues is seen in only a minority of cases.

CT

CT classically tends to show soft-tissue gas associated with fluid collections within the deep fascia, although this finding is inconstant. 

Other non specific findings include:

  • asymmetrical fascial thickening associated with fat stranding
  • edema extending into the inter-muscular septa and the muscle
  • thickening of one or both of the superficial and deep fascial layers

Although fascial fluid collections are typically non-focal, abscesses may be seen. 

Post contrast CT 

Some authors describe diffuse enhancement of fascia with contrast 3,8. If there is no enhancement of the fascia, this can be a finding that can help differentiate from a non-necrotising fasciitis 7.

Ultrasound

Ultrasound may be more useful in children3-4 (with a rising incidence after primary varicella infection 11). Sonographic findings include distorted and thickened fascial planes with turbid fluid accumulation in the fascial layers and subcutaneous oedema. Sonographic assessment may however be limited by soft-tissue gas, although if identified, this finding may be of diagnostic benefit.

MRI
  • T1: - usually has subtle abnormality with loss of muscle texture and may show high signal intensity compatible with intramuscular haemorrhage.10
  • T2: - usually shows subcutaneous and intramuscular oedema in a reticulated pattern as well as subfascial and interfascial crescentic fluid collections.10

Treatment and prognosis

Mortality rates can range between 25-75% 5. Treatment is usually with a prompt surgical fasciotomy with debridement of the necrotic tissue.

Differential diagnosis

For gas within soft tissues consider

EtymologyHostory and etymology

It was first described by Joseph Jones, an American army surgeon during the American civil war 3.

See also

  • -<p><strong>Necrotising fasciitis</strong> refers to a rapidly progressive and often fatal infection of soft-tissue fascia deep to the skin but superficial to the muscles <sup>3</sup>.</p><h4>Epidemiology</h4><p>Necrotising fasciitis is relatively rare, although its prevalence is thought to be rising due an increase in the number of immunocompromised patients with HIV infection, diabetes mellitus, cancer, alcoholism, vascular insufficiency, and organ transplants. It can also occur after trauma or around foreign bodies in surgical wounds <sup>7</sup>.</p><h4>Pathology</h4><p>There are at least two recognised forms</p><ul>
  • -<li>the most common type is a <strong>polymicrobial infection</strong> with both aerobic and anaerobic organisms such as <em style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-style: none; font-style: italic; font-size: inherit; font-family: inherit; line-height: inherit; vertical-align: baseline; ">Clostridium</em>, <em style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-style: none; font-style: italic; font-size: inherit; font-family: inherit; line-height: inherit; vertical-align: baseline; ">Proteus</em>, <em style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-style: none; font-style: italic; font-size: inherit; font-family: inherit; line-height: inherit; vertical-align: baseline; ">Escherichia coli</em>,<em style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-style: none; font-style: italic; font-size: inherit; font-family: inherit; line-height: inherit; vertical-align: baseline; ">Bacteroides</em>, and <em style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-style: none; font-style: italic; font-size: inherit; font-family: inherit; line-height: inherit; vertical-align: baseline; ">Enterobacteriaceae -</em> this form is often seeded from underlying infections such as diverticulitis</li>
  • -<li>the second form of the disease is caused by a <strong>single organism</strong> - most commonly group A streptococci, the “flesh-eating bacteria,” and is seen in approximately 10-15 % of cases <sup>3-4</sup> : toxic shock syndrome may complicate this latter form.</li>
  • -</ul><div>
  • -<h5>Location</h5>
  • -<p>While it can affect any part of the body, the extremities, the perineum, and the truncal areas are the most commonly involved <sup>4</sup>.</p>
  • -<h5>Sub types</h5>
  • -<ul><li>
  • -<a href="/articles/fournier-gangrene" title="Fournier gangrene">Fournier gangrene</a> :  is a necrotising fasciitis of the perineum</li></ul>
  • -<h4>Radiographic features</h4>
  • -<h5>Plain film</h5>
  • -<p>The common plain radiographic findings non specific an often similar to those of <a href="/articles/cellulitis" title="Cellulitis">cellulitis</a>, with increased soft-tissue thickness and opacity. Radiographs can be normal until the advanced stages of infection and necrosis. The characteristic finding of <a href="/articles/gas-in-the-soft-tissues" title="gas in the soft tissues">gas in the soft tissues</a> is seen in only a minority of cases.</p>
  • -<h5>CT</h5>
  • -<p>CT classically tends to show <a href="/articles/soft-tissue-gas" title="soft-tissue gas">soft-tissue gas</a> associated with fluid collections within the deep fascia, although this finding is inconstant. </p>
  • -<p>Other non specific findings include</p>
  • -<ul>
  • -<li>asymmetrical fascial thickening associated with fat stranding</li>
  • -<li>edema extending into the inter-muscular septa and the muscle</li>
  • -<li>thickening of one or both of the superficial and deep fascial layers</li>
  • -</ul>
  • -<p>Although fascial fluid collections are typically non-focal, abscesses may be seen. </p>
  • -<h6>Post contrast CT </h6>
  • -<p>Some authors describe diffuse enhancement of fascia with contrast <sup>3,8</sup>. If there is no enhancement of the fascia, this can be a finding that can help differentiate from a non-necrotising fasciitis <sup>7</sup>.</p>
  • -<h5>Ultrasound</h5>
  • -<p>Ultrasound may be more useful in children<sup>3-4</sup> (with a rising incidence after primary varicella infection <sup>11</sup>). Sonographic findings include distorted and thickened fascial planes with turbid fluid accumulation in the fascial layers and subcutaneous oedema. Sonographic assessment may however be limited by soft-tissue gas, although if identified, this finding may be of diagnostic benefit.</p>
  • -<h5>MRI</h5>
  • -<ul>
  • -<li>
  • -<strong>T1</strong> - usually has subtle abnormality with loss of muscle texture and may show high signal intensity compatible with intramuscular haemorrhage.<sup>10</sup>
  • -</li>
  • -<li>
  • -<strong>T2</strong> - usually shows subcutaneous and intramuscular oedema in a reticulated pattern as well as subfascial and interfascial crescentic fluid collections.<sup>10</sup>
  • -</li>
  • -</ul>
  • -<h4>Treatment and prognosis</h4>
  • -<p>Mortality rates can range between 25-75% <sup>5</sup>. Treatment is usually with a prompt surgical fasciotomy with debridement of the necrotic tissue.</p>
  • -<h4>Differential diagnosis</h4>
  • -<p>For gas within soft tissues consider</p>
  • -<ul><li>
  • -<a href="/articles/subcutaneous-emphysema" title="Subcutaneous emphysema">subcutaneous emphysema</a> from a non infective cause : has an entirely different clinical presentation</li></ul>
  • -<h4>Etymology</h4>
  • -<p>It was first described by <strong>Joseph Jones</strong>, an American army surgeon during the American civil war <sup>3</sup>.</p>
  • -<h4>See also</h4>
  • -<ul><li><a href="/articles/soft-tissue-abscess" title="soft tissue abscess">soft tissue abscess</a></li></ul>
  • -</div>
  • +<p><strong>Necrotising fasciitis</strong> refers to a rapidly progressive and often fatal infection of soft-tissue fascia deep to the skin but superficial to the muscles <sup>3</sup>.</p><h4>Epidemiology</h4><p>Necrotising fasciitis is relatively rare, although its prevalence is thought to be rising due an increase in the number of immunocompromised patients with HIV infection, diabetes mellitus, cancer, alcoholism, vascular insufficiency, and organ transplants. It can also occur after trauma or around foreign bodies in surgical wounds <sup>7</sup>.</p><h4>Pathology</h4><p>There are at least two recognised forms:</p><ul>
  • +<li>the most common type is a <strong>polymicrobial infection</strong> with both aerobic and anaerobic organisms such as <em>Clostridium</em>, <em>Proteus</em>, <em>Escherichia coli</em>,<em> Bacteroides</em>, and <em>Enterobacteriaceae:</em> this form is often seeded from underlying infections such as diverticulitis</li>
  • +<li>the second form of the disease is caused by a <strong>single organism</strong> - most commonly group A streptococci, the “flesh-eating bacteria,” and is seen in approximately 10-15% of cases <sup>3-4</sup>: toxic shock syndrome may complicate this latter form.</li>
  • +</ul><h5>Location</h5><p>While it can affect any part of the body, the extremities, the perineum, and the truncal areas are the most commonly involved <sup>4</sup>.</p><h5>Sub types</h5><ul><li>
  • +<a href="/articles/fournier-gangrene">Fournier gangrene</a>:  is a necrotising fasciitis of the perineum</li></ul><h4>Radiographic features</h4><h5>Plain film</h5><p>The common plain radiographic findings non specific an often similar to those of <a href="/articles/cellulitis">cellulitis</a>, with increased soft-tissue thickness and opacity. Radiographs can be normal until the advanced stages of infection and necrosis. The characteristic finding of <a href="/articles/gas-in-the-soft-tissues">gas in the soft tissues</a> is seen in only a minority of cases.</p><h5>CT</h5><p>CT classically tends to show <a href="/articles/soft-tissue-gas">soft-tissue gas</a> associated with fluid collections within the deep fascia, although this finding is inconstant. </p><p>Other non specific findings include:</p><ul>
  • +<li>asymmetrical fascial thickening associated with fat stranding</li>
  • +<li>edema extending into the inter-muscular septa and the muscle</li>
  • +<li>thickening of one or both of the superficial and deep fascial layers</li>
  • +</ul><p>Although fascial fluid collections are typically non-focal, abscesses may be seen. </p><h6>Post contrast CT </h6><p>Some authors describe diffuse enhancement of fascia with contrast <sup>3,8</sup>. If there is no enhancement of the fascia, this can be a finding that can help differentiate from a non-necrotising fasciitis <sup>7</sup>.</p><h5>Ultrasound</h5><p>Ultrasound may be more useful in children <sup>3-4</sup> (with a rising incidence after primary varicella infection <sup>11</sup>). Sonographic findings include distorted and thickened fascial planes with turbid fluid accumulation in the fascial layers and subcutaneous oedema. Sonographic assessment may however be limited by soft-tissue gas, although if identified, this finding may be of diagnostic benefit.</p><h5>MRI</h5><ul>
  • +<li>
  • +<strong>T1:</strong> usually has subtle abnormality with loss of muscle texture and may show high signal intensity compatible with intramuscular haemorrhage.<sup>10</sup>
  • +</li>
  • +<li>
  • +<strong>T2:</strong> usually shows subcutaneous and intramuscular oedema in a reticulated pattern as well as subfascial and interfascial crescentic fluid collections.<sup>10</sup>
  • +</li>
  • +</ul><h4>Treatment and prognosis</h4><p>Mortality rates can range between 25-75% <sup>5</sup>. Treatment is usually with a prompt surgical fasciotomy with debridement of the necrotic tissue.</p><h4>Differential diagnosis</h4><p>For gas within soft tissues consider</p><ul><li>
  • +<a href="/articles/subcutaneous-emphysema">subcutaneous emphysema</a> from a non infective cause: has an entirely different clinical presentation</li></ul><h4>Hostory and etymology</h4><p>It was first described by <strong>Joseph Jones</strong>, an American army surgeon during the American civil war <sup>3</sup>.</p><h4>See also</h4><ul><li><a href="/articles/soft-tissue-abscess">soft tissue abscess</a></li></ul>

References changed:

  • 10. Fugitt J, Puckett M, Quigley M, Kerr S. Necrotizing Fasciitis. Radiographics. 2004;24(5):1472-6. <a href="https://doi.org/10.1148/rg.245035169">doi:10.1148/rg.245035169</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/15371620">Pubmed</a>
  • 10. J. Brett Fugitt, MD, Michael L. Puckett, MD, Michael M. Quigley, MD, PhD and Stewart M. Kerr, MD. Necrotizing Fasciitis, September 2004 RadioGraphics, 24, 1472-1476. http://radiographics.highwire.org/content/24/5/1472.full
Images Changes:

Image 4 CT (C+ portal venous phase) ( update )

Caption was changed:
Case 3 -: Fournier gangrene

Image 6 CT (non-contrast) ( update )

Caption was changed:
Case 5 -: Fournier gangrene

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