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Utility of the speed bump sign in diagnosis of acute appendicitis

Three Part Question

[In adult patients] is [reported pain whilst travelling over speed bumps] indicative of
[acute appendicitis?]

Clinical Scenario

You are working in A&E and have just reviewed a patient with symptoms and clinical signs consistent with suspected acute appendicitis; you wonder whether there are any further clinical signs which may help your diagnosis and a referral to general surgery.
You recall hearing of the speed bump sign from a colleague and wonder how useful this sign is in the diagnosis of acute appendicitis.

Search Strategy

Medline 1946 – February 2017 using the Ovid interface
Search terms: (appendicitis and (speed bump* OR bump*)).mp

Search Outcome

3 search results.
One of which was a news article referring to one of the other two results so was excluded.
Of the remaining two, one paper directly referred to speed bumps, the other referred to bumps in the road which they termed the ‘cat’s eye sign’. Both were focused on the use of these in the diagnosis of acute appendicitis.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Ashdown et al
2012
United Kingdom
64 patients aged 16 and over who recalled travelling over speed bumps on the way to hospital and had been referred to the acute surgical team as possible acute appendicitisProspective diagnostic accuracy studyPain when travelling over speed bumps o n the way to hospital. Histological diagnosis confirming acute appendicitis.A positive speed bump sign had sensitivity of 97% (CI 85%-100%) and specificity of 30% (CI 15% - 49%) in the diagnosis of acute appendicitis. Relied on patients recalling travelling over speed bumps, possible recall bias as more likely to recall travelling if experienced pain. Large confidence intervals for sensitivity and specificity.
Golledge et al
1996
United Kingdom
100 patients aged 4 – 81 years referred to surgery with right iliac fossa pain and a possible diagnosis of acute appendicitis.Prospective diagnostic accuracy studyPain when travelling over bumps in the road on the way to hospital. Histological diagnosis confirming acute appendicitis.A positive cat’s eye sign had sensitivity of 80% and specificity of 0.52% in the diagnosis of acute appendicitisRelied on patients volunteering that they had experienced pain over bumps in the road. No confidence intervals given. Large age range of patients, included paediatric patients who may be more prone to forms of recall bias.

Comment(s)

The speed bump sign (and the similar 'cat’s eye sign') offer an interesting adjunct to more traditional clinical signs to help a clinician predict the likelihood of acute appendicitis. Perhaps unsurprisingly there is a paucity of literature on the diagnostic accuracy of this sign, with only two studies on the topic and a degree of heterogeneity between the two. Ashdown et al selected patients 16 and over and asked specifically about pain when travelling over speed bumps, Golledge et al had an age range of 4 – 81 years and relied on the patient volunteering pain over bumps when asked if anything exacerbated their pain on the way to hospital. The only study with direct relevance to the three part question, Ashdown et al, shows a positive speed bump sign has good sensitivity and poor specificity for a confirmed diagnosis of acute appendicitis. As this study was carried out by the acute general surgical team on referred patients, it must be remembered that this test was applied to patients who had been assessed as suspected acute appendicitis and as such already had a higher pre-test probability for acute appendicitis. This does limit the use of the speed bump sign in as yet undifferentiated abdominal pain in A&E. In A&E the speed bump sign is perhaps best used as an adjunct once appendicitis is suspected until further research is available to support wider use.

Editor Comment

CF

Clinical Bottom Line

In a patient presenting with suspected acute appendicitis, a history of abdominal pain when travelling over speed bumps or bumps on the way to hospital has good sensitivity but poor specificity with regards to a diagnosis of acute appendicitis.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

  1. Ashdown et al Pain over speed bumps in diagnosis of acute appendicitis: diagnostic accuracy study BMJ 2012; 345
  2. Golledge et al Assessment of peritonism in appendicitis Annals of the Royal College of Surgeons of England 1996 Jan; 78(1): 11–14