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Three Part Question

In [patients with soft tissue infection of a limb] does [bedside ultrasound] improve [the diagnostic accuracy of necrotizing fasciitis]?

Clinical Scenario

A 54-year-old man attends the emergency department complaining of a rapidly progressive pain and swelling in his right arm. He is mildly tachypnoeic and tachycardic. His arm is very tender and painful even at rest but is only slightly erythematous. He can move his hand, wrist and elbow with complete range of motion. You suspect a necrotising fasciitis. You wonder whether an ultrasound of the soft tissue night help to differentiate between cellulitis and a necrotising fasciitis.

Search Strategy

No bestbet was found on this topic.
MEDLINE, EMBASE and Cochrane library were searched for relevant articles.


Embase using NHS evidence 10 May 2014

((Exp ultrasound/ OR ultrasound ti,ab, OR exp echography/ OR echography ti,ab) AND (exp necrotizing fasciitis/ OR ‘necrotizing fasciitis’ ti,ab OR ‘necrotising fasciitis’) LIMIT to humans and English language.
Medline using NHS evidence 10 May 2014

((Exp ultrasonography/ OR ultrasound ti,ab, OT exp echography/ OR echography ti,ab) AND (exp necrotizing fasciitis/ OR ‘necrotizing fasciitis’ ti,ab OR ‘necrotising fasciitis’) LIMIT to humans and English language.
The Cochrane Library issue 5 of 12 May 2014

MeSH descriptor: [Fasciitis, Necrotizing] explode all trees; 3 results 0 relevant.

Search Outcome

Thirteen articles were found with Medline and 185 with Embase. No relevant papers were identified using the Cochrane Library. No articles were found by scanning the references of relevant papers. One paper which presented the best evidence to answer the clinical question is summarised in the table

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Yen ZS, et al. 2002 Taiwan	Patients with clinically suspected necrotizing fasciitis of a limb. Total: 62 patients with limb infection including 17 with a confirmed necrotizing fasciitis	Prospective observational study	Diagnostic accuracy of ultrasound for necrotizing fasciitis	Sensitivity : 88.2 %; Specificity : 93.3%; Positive predictive value : 83.3%; Negative predictive value : 95.4%.	Small single center observational study; Only one doctor performed all of the ultrasound; No validated diagnostic criteria for necrotizing fasciitis.

Comment(s)

Early diagnosis of necrotising fasciitis is of utmost importance. Bedside ultrasound is a non-invasive diagnostic tool and scanning can be quickly performed. Only one study that evaluated the value of ultrasound in differentiating between limb cellulitis and necrotising fasciitis was found. This is a small single-centre study in which the same doctor performed all the ultrasound examinations. A few case reports of bedside ultrasound which has helped in making the diagnosis of necrotising fasciitis were also found. Recently, evaluation of subcutaneous thickening, air and fascial fluid (the STAFF examination) (Castleberg et al, 2014) was proposed but the diagnostic value of this examination has never been examined by a cohort study. Therefore, the real diagnostic value of beside ultrasound remains unknown. A multicentre prospective trial is required to determine the ability of bedside ultrasound to establish the diagnosis of necrotising fasciitis and to help the clinical decision-making for this potentially catastrophic infection.

Clinical Bottom Line

There is limited evidence supporting the use of bedside ultrasound as an adjunctive diagnostic tool to adequately differentiate cellulitis from necrotising fasciitis in a patient with a limb infection.

References

1. Yen ZS, Wang HP, Ma HM et al. Ultrasonographic screening of clinically-suspected necrotizing fasciitis. Acad emerg med 2002;9:1448–51.
2. Castleberg E, Jenson N, Dinh VA. Diagnosis of necrotising fasciitis with bedside ultrasound: the STAFF exam. Western J Emerg Med 2014;15:111–13.