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Date: 2 December 2012

Case Presentation: Healthy 45-year-old man presents with a 3cm abscess under left arm. There is no surrounding cellulitis. He is not an  intravenous drug user and never had an abscess before. You make the diagnosis of an uncomplicated superficial cutaneous abscess. You know that antibiotics are probably not necessary after incision and drainage (I&D). However, the patient gets nervous after you describe the I&D process. He wants to know if you can do anything to make this procedure less painful and if packing is really necessary?

Your Inside Voice Says:

  1. Why to men have such low pain tolerance
  2. Mmmm, pus…time for lunch
  3. Suck it up butter cup
  4. Of course there is something we can do regarding oligoanalgesia
  5. To pack or not to pack, that is the question

Background: Simple cutaneous abscesses (SCA) are a very common presentation to the emergency department (ED).  In 2005 there were 3.3 million ED visits for SCA and the numbers are increasing faster than the total number of ED visits.

Question: Does buffering lidocaine make it less painful to inject?

Reference: Cepeda MS et al. Adjusting the pH of lidocaine for reducing pain on injection. Cochrane Database of Systematic Reviews 2010

  • Population: Adults and children in need of local anaesthesia for epidural catheter insertion, IV cannulation or a small surgical procedure. Total of 23 trials with 1,067 patients.
  • Intervention: Buffering lidocaine with 1ml of 8.4% sodium bicaronate in 9ml of 1% or 2% lidocaine with or without epinephrine.
  • Studies Included: 23 studies (10 parallel and 13 cross over). Eight of the 23 studies had moderate to hight risk of bias.

Results:

Note: This Cochrane Review was withdrawn from publication in 2015. The reason provided was that the review was no longer compliant with the Cochrane Commercial Sponsorship Policy. The non-conflicted authors have decided not to update the review.

Bottom Line: Patients might appreciate the extra effort of buffering the lidocaine.

BEEM Commentary: Local injection of lidocaine is common in the ED. These injections can be a painful experience for patients and it is thought that the acidic pH of the commercially available solutions (pH 3.5-7.0) is the cause of the pain. This review included 23 studies. However, eight of the 23 lacked allocation concealment making the results more prone to bias. However, buffering lidocaine is a quick and inexpensive step with no reported adverse effects or toxicity and can reduce the burning sensation experienced by some patients.

Question: Do you have to use antibiotics when treating simple cutaneous abscesses especially in the age of MRSA?

Reference: Hankin A and Everett WW. Are Antibiotics Necessary After Incision and Drainage of a Cutaneous Abscess? Annals Emerg Med 2007 50(1), 49-51.

  • Review: The authors reviewed the literature (MEDLINE, EMBASE) for English-language articles from 1966 to current, using human subjects. The initial search found 1396 articles, which were limited to five original randomized trials and one abstract dealing specifically with this question.
  • Intervention: I&D with and without antibiotics

Results: The results of three randomized trials, two prospective cohorts and one retrospective cohort study all suggest that antibiotics were not necessary after an appropriate I&D and packing. More importantly, significant proportions of the more recent studies had MRSA in the patient populations, and even these patients did not need antibiotics. No adverse events were noted in either treatment or placebo arms.

Limitations: There is very little high quality evidence surrounding this field, which is mildly surprising given the prevalence of this condition in North America ED’s. The six studies with <1000 total enrolled patients do not constitute the total body of evidence for this clinical question. BEEM’s independent search identified at least three additional randomized controlled trials of an additional 752 subjects also refuting the need for antibiotics in abscess management. No study clearly defined “abscess”. There are no comments about treatment choices when there is an overlying cellulitis.

Bottom Line: As usual with EBM the answer is “it depends”. The evidence does not suggest using antibiotics routinely in simple cutaneous abscesses even in the era of  MRSA.

BEEM Commentary: A limited body of evidence suggests that antibiotics are not needed after I&D and packing of cutaneous abscesses, even in an era of increasingly prevalent MRSA. The current review offers no guidance on treating in the presence of overlying cellulitis. The choice to treat/not treat with antibiotics may need to be balanced between guidelines from IDSA and CDC suggesting treatment when increased MRSA risk (don’t treat otherwise), versus concerns about antibiotic misuse, increasing resistance and MRSA proliferation. If choosing to treat suspected MRSA patients, the key issue to remember is to avoid cephalexin (which doesn’t treat MRSA effectively), and to use clindamycin, doxycycline or trimethoprim-sulfamethoxazole.

Individual clinicians may want to factor in specific patient comorbidities and history among other things in their decision whether or not to prescribe antibiotics. For more information about antibiotic use with I&Ds check out our 2008 publication done by a BEEM faculty member in EP Monthly. I just noticed that Dr. Richard Bukata made a similar conclusion four years later in his 2012 EP Monthly article on the same topic.

Question: Is routine packing of simple cutaneous abscesses necessary after an I&D?

Reference: O’Malley GF et al. Routine Packing of Simple Cutaneous Abscesses Is Painful and Probably Unnecessary. Acad Emerg Med. 2009; 16:470-473.

  • Population: Adult (≥ 18 y.o.) ED patients presenting with cutaneous abscesses requiring I&D
    • Exclusion criteria: Abscesses larger than 5 cm in any dimension; pregnancy; comorbid medical conditions including diabetes, HIV, or any malignancy; chronic steroid use; immunosuppressive states including but not limited to sickle cell disease and sarcoidosis; abscesses located on the face, neck, scalp, hands, feet, perianal, rectal, or genital areas; hidradenitis or pilonidal abscesses; allergy to sulfa or hypersensitivity to trimethoprim-sulfamethoxazole (TMP-SMX); need for procedural sedation or supplemental treatment (intravenous antibiotics or surgical consultation) based on physician’s discretion; or subject inability to return for 48-hour follow-up.
  • Intervention: I&D without standard packing of the abscess cavity. Control: I&D with standard packing of the abscess cavity.
  • Outcome:
    • Primary Outcome: Need for intervention at 48 hours
    • Secondary Outcomes: Pain and wound evaluation.

Results: There were 48 patients in this study. They were randomized with 23 receiving packing and 25 with no packing.Only two-thirds of the patients were evaluated at 48-hours. Twenty-one patients were from the packing group and 13 were from the no packing group. The primary end point was the need for intervention (extension of the incision, further probing, irrigation, packing of the wound, change of initial antibiotics, need for surgical evaluation, admission to hospital or need for another follow-up visit to the ED) at 48-hrs by a blinded attending physician. A total of 9 subjects needed an intervention at the follow-up visit (see below).

BEEM Commentary: This pilot study run as a single center RCT challenges surgical dogma commonly practiced in EDs everywhere. It appears that the study was well designed and implemented but there are deficiencies. Specifically: both allocation and ascertainment bias should have been minimized; there was a lack of information about prognostic factors by group and no CONSORT Statement as required by most journals. Some of the deficiencies may have more to do with the editors than the investigators. Although, as a single RCT the evidence is not sufficient to widespread change of standard Emergency Medicine practice, it is certainly enough to make many EPs reconsider their options in treating simple cutaneous abscesses. It should also serve as a catalyst for funding trials addressing the same question.

Bottom Line: Routine packing of simple cutaneous abscesses may not be necessary. For more information on packing abscesses check out the write up we did in EP Monthly.

Where is all of this heading? When we looked at the literature we found many different reviews addressing I&D. Check out the variety of treatments (+/- antibiotics, +/- packing, +/- primary closure).

A recent systematic review looking at primary closure of abscesses post I&D by Singer et al. They concluded: “Studies from 4 countries suggest that primary closure of incised and drained abscesses results in faster healing and similar low abscess recurrence rates than after secondary closure.These studies provide a foundation for which clinical trials can be conducted in the United States.”

Summary for I&D of Simple Cutaneous Abscesses:

  1. Buffer your lidocaine
  2. I&D is the solution (better out than in) and not routine antibiotics
  3. No packing required

Case Resolution: You try to address the problem of oligoanalgesia in the ED by buffering your lidocaine. You have an informed discussion about antibiotics and make the mutual decision not to subject him to the harm with limited support for benefit. You explain the incomplete data doesn’t support packing and duh? he decides to forego wound packing. You discharge him with instructions to return in 2-days for a wound re-evaluation. At the same time you wonder whether someday routine follow-up might proven not to be necessary too.

KEENER KONTEST: Last weeks winner was Lauren Westafer a fourth year medical student from Florida. According to her Twitter profile she is passionate about emergency medicine, public (and global) health and #FOAMed (Free Open Access Meducation). Lauren very quickly  identified the NNT with ondansetron to prevent further vomiting in children is 5 (my favourite number).

  • This weeks question: What is oligoanalgesia?

Email your answer to TheSGEM@gmail.com or go to the “Contact Us” link at the top of the home page. Use “Keener Kontest” in the subject line. First one to email me the correct answer will win a cool skeptical prize:)

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.

If you want to cut the KT window down to less than 1 year consider coming to SkiBEEM 2013 Feb 4-6 at SilverStar BC.  Meet some of the BEEM faculty and enjoy a great CME holiday.