Traditional incision and drainage of a simple cutaneous abscess is a clinical dinosaur that could be banished to the tar pits of antiquity. Erudite clinicians should try the loop drainage technique as an alternative, explained in last month's column. (See FastLinks.) Instead of using the rather barbaric wide skin incision, manually removing pus, and packing open the abscess cavity until it heals by itself, the rather fascinating loop drainage treatment is very effective and clearly less invasive. I strongly urge all clinicians to give it a try. Your patients will be eternally grateful, your outcomes will be positive, and you will look like a truly gifted, if not cutting-edge, renaissance clinician.
Questioning the value of I&D may sound like medical heresy, but other sacred cows of abscess treatment, such as the ritual irrigation of the cavity and compulsive packing, may also be put out to pasture. Their value, or lack thereof, of these exalted, time-honored, and omnipresent interventions, while seemingly reasonable, are hardly evidence-based.
Routine Packing of Simple Cutaneous Abscesses is Painful and Probably Unnecessary
O'Malley JF, Dominici P, et al
Acad Emerg Med
This title says it all. These authors question the indications or necessity for routinely packing a cutaneous abscess post-I&D. A paucity of literature supports this reflex intervention, even though it is ingrained as routine practice and universally accepted. However intuitive, abscess packing is not evidence-based; it has simply survived via the see-one-do-one-teach-one tradition and the it-seems-like-a-good-idea-to-me philosophy. Theoretically, packing an abscess is necessary to prevent collapse of the cavity with infected material trapped inside and to assist developing an epithelial lining of the cavity. Abscess packing is, of course, painful, and it usually leads to repeat ED visits for packing manipulations with concomitant patient annoyance, clinician downtime, and increased expense.
This randomized trial compared the complication rate and pain perception of a small number of patients (48 individuals) treated in the ED for a simple cutaneous abscess less than 5 cm in diameter. The abscesses were located on the trunk, extremities, or buttocks, but the trial excluded pilonidal abscesses and hidradenitis suppurativa. Patients were randomized to either packing or no packing after traditional incision. A visual analog pain scale was recorded, and all patients received MRSA-effective antibiotics (trimethoprim/sulfamethoxazole), analgesics, and a repeat visit in 48 hours. The authors claim that this was the first prospective study to investigate the necessity of abscess packing.
Packing consisted of filling the abscess cavity with gauze, but the actual technique was left to physician's discretion. Wound cultures were also obtained, the cavity was irrigated with saline, and loculations were broken up with a cotton tip applicator. The volume of irrigation and probing specifics were also left to physician discretion. The packing was removed at the first 48-hour visit, and a physician, who had not seen the patient primarily, evaluated the wound for various parameters. The immediate and ensuing 48-hour pain scale was also evaluated. The primary outcome was the need for additional intervention as determined by the blinded clinician at the 48-hour visit. Additional interventions were defined as an extension of the incision, further probing, packing alterations, admission, or the need for another follow-up visit. The other endpoints were the patient's rendition of procedure pain and the amount of pain medication used.
No significant difference was found in the need for additional intervention between the packed and nonpacked subjects. Ten of the subjects in the nonpacking group did not return for ED follow-up because they reported on telephone contact that they did not think that the abscess needed to be re-evaluated. About 60 percent of the cultures were positive for MRSA.
No significant difference was detected in the pre-procedure pain scale either, but those who received packing recorded a higher pain scale immediately post-procedure and at 48 hours. Those receiving packing used statistically more analgesics.
This was a relatively small study and some abscesses were excluded, but the authors conclude that eliminating post-incision packing of a small uncomplicated cutaneous abscess did not result in increased morbidity. Those that were spared the packing reported less pain and used fewer pain medications compared with patients who received packing.
Comment: This was a small study and the abscesses were relatively minor and uncomplicated, but the results are certainly intriguing. Many would have intuited the outcome, but not many have adopted this less-invasive approach. Packing an abscess may be primarily an American tradition. Packing is often forgone in other countries, often because the facility and equipment for packing and repeat visits are not available.
This study suggests that the traditional approach to a simple abscess in the ED appears to be flawed, markedly overaggressive, unnecessarily stressful and painful to the patient, clogs up the ED waiting room, and wastes clinician time with repeat visits for packing changes.
One wonders if any abscess needs to be packed. It is instructive to note that primary suturing of an abscess cavity after initial I&D is a concept that has been extant for decades. One study used a systematic literature review to evaluate seven randomized controlled trials of about 1,000 patients who were randomized to either primary or secondary abscess suture closure. (Am J Emerg Med 2011;29:361.) Data were gathered from countries other than the United States.
Many of these abscesses were located in the anogenital region, and most were drained by surgeons in the OR. The technique used deep mattress sutures to obliterate the abscess cavity. Presumably these were clinically respectable abscesses, not just minor boils. One might think that abscesses in this area would be much more prone to complications because of the local unsterile conditions, but the time to healing after primary closure (about eight days) was significantly shorter than after secondary closure (about 15 days). The incidence of recurrence was not increased after primary closure of the grossly infected abscess cavity. This analysis concluded that primary suture closure of an abscess that has been incised and drained results in faster healing and a lower recurrence rate. This calls into the question the concept and validity of packing or allowing the abscess to heal fully by itself.
Many clinicians eschew packing in relatively small abscesses, but more than a few eyebrows will be raised if a clinician in this country drains an abscess and then immediately sutures it closed. That's exactly what has been done for many years in other countries, giving results that are somewhat counterintuitive to our thinking and certainly contrary to what I learned as a resident. It also appears that the abscesses in the controls were eventually also sutured closed rather than left open to skin healing, another intervention foreign to our EDs. Most of the studies in this review were performed before the proliferation of MRSA infections, and antibiotic use was not investigated.
Interestingly, these were not just small cutaneous abscesses but rather large ones that were often treated under general anesthesia in the OR. An abscess of the perianal region would give many clinicians hesitation for primary closing. It appears, however, that if you have your perirectal abscess drained in Nigeria or India, you will have it sutured closed immediately after drainage. Not only does primary closure not result in significant complications, it provides faster healing and a similar abscess recurrent rate with secondary closure. To be fair, however, others have reported failure of this intervention, perhaps one reason why it has not been universally adopted. (Br J Surg 1977;64:264.)
The next axioms that should be investigated are the need for irrigation and breaking up loculations. Many clinicians will meticulously irrigate an abscess cavity with saline, but this technique also has not been standardized or studied. I personally rarely irrigate an abscess cavity, but will evacuate necrotic or purulent tissue with dry 4 × 4 gauze. If pus is copious, I will initially pack and replace the packing with new gauze 10 to 15 minutes prior to discharge, hopefully before the anesthetic has worn off.
Most patients cannot deal with their own packing removal or packing changes at home, but I have occasionally instructed patients to remove the packing in 48 hours, clean out the cavity with a cotton tip containing peroxide, and to hold the skin open in the shower to clean the abscess cavity further, negating a repeat ED visit. When to stop packing or ideal packing intervals are also variable interventions. Traditionally packing is every two or three days and halted on the first visit that contains a relatively dry pack.
Irrigating an abscess cavity is relatively easy, likely impresses the patient (the show business of emergency medicine), and other than perhaps being a bit messy, it seems reasonable. Packing material is not standardized. I pack a large abscess with a few 4 × 4s or plain gauze strips. Iodinated gauze packing gives that comforting antiseptic smell and may sting a bit, but it has no proven advantage. I also presoak the packing in saline or betadine prior to packing because it is easier to place when wet.
If one is going to break up loculations, an easy way is to wrap some gauze around the hemostat and swirl it around the base of the abscess. Traditionally, surgeons have used their finger, and that's not a bad idea as long as you are sure there are no sharp objects that could cut you. Using your finger does give you an idea of the depth of the cavity, and the tactile sensation allows you to get into every nook and cranny (but it really hurts!).
UpToDate.com recommends probing the abscess cavity with a hemostat to “ensure proper drainage” and to irrigate the abscess cavity copiously with isotonic saline until all visible pus is removed. UpToDate also suggests packing abscesses greater than 5 cm in diameter, pilonidal cysts, or those in immunocompromised or diabetic patients. This is the only source I have come across that has a special recommendation for packing in immunocompromised or diabetic patients. I am certain no study supports this recommendation, and I will wager that packing has no special curative properties for this subset of patients.
Evidence-Based Approach to Abscess Management
Korownyk C, Allan GM
Can Fam Physician
The authors in this rather ambitious attempt to analyze evidence-based treatment of cutaneous abscesses searched PubMed, the Cochrane Library, and Google for the past 50 years, looking for the scientific basis for treatments of cutaneous/soft tissue infections. A lack of randomized controlled trials and little evidence-based data emerged.
The authors could find no scientific basis evaluating optimal pain control for I&D. Some patients described abscess drainage as one of the most painful procedures in the ED, despite the use of local anesthetics. Local anesthesia certainly helps, but it does not make the procedure totally pain-free. Of course, the effectiveness of any local anesthetic depends on the skill and expertise of the clinician, and one should be initially generous and repeat the local anesthesia if needed. No evidence exists for simply using vapocoolant sprays in managing abscesses.
It would be heinous not to provide local anesthesia for the skin incision. Many will stop here, but more can be done. A frequently forgotten technique is to inject through the cut edge of the opened abscess and into the soft tissue prior to further manipulation. The local skin incision should probably be painless, but abscess manipulation hurts unless one provides either a field block or anesthesia deeper into the abscess itself.
I am continually amazed by the neophyte clinician who believes that 1 mg Dilaudid IM about 20 minutes before I&D defines analgesia. Adjunct parenteral analgesics are fine, but are usually only helpful if they are given IV and in generous doses. Only a novice clinician believes that an IM dose of an analgesic is worth the time and effort prior to incising an abscess. Conscious sedation is probably the best way to go for larger cases (my favorite is ketofol), but most clinicians don't take the time or effort to do this.
Ideally, a large abscess should be drained under general anesthesia, but the surgical staff is always reluctant. If I am calling a surgeon for help with an abscess, the patient needs to be admitted or drained in the OR, not simply sliced open by a consultant who is totally uninterested in this mundane case or has just been sprung from an interesting case in the OR to aid the struggling emergency physician.
These authors conclude that no evidence beyond expert opinion and tradition support any of the currently performed rituals for I&D or post-operative care. Despite no real evidence, these authors and most clinicians continue to recommend irrigation, breaking loculations, and packing following I&D. These authors do not recommend primary closure; apparently they were not trained in Europe. This article seems to incorporate most of our current clinical practice, unproven bias, and the overall that's-the-way-we-do-it mentality under the guise of “evidence-based.”
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Dear Dr. Roberts: I have questions for you regarding your articles on gonorrhea and chlamydia. (“Neisseria Gonorrhoeae: The New Superbug,” EMN 2012;34:10; 2012;34:12; 2012;34:10.) Why do you think the accuracy or sensitivity for GC urine testing is different between men and women? What is the difference in sensitivity between the sexes? How does one justify treating for GC and chlamydia without testing or symptoms unless the prevalence of these diseases is very high? Indiscriminate use of antibiotics, I thought, was inappropriate because of the increase risk of resistance. Thank you. — Marcus Ma, MD, Temperance, MI
Dr. Roberts responds: To review, a urethral swab performs well for testing for suspected GC/Chlamydia urethritis in men, but nucleic acid amplification testing of urine is the preferred method if a noninvasive test is desired. Nucleic acid amplification testing of a vaginal swab specimen has the best overall sensitivity and specificity for women with suspected cervicitis or urethritis. The test will likely pick it up equally, regardless of gender, if the bug is in the urine.
One likely reason the vaginal swab is preferred is that the cervix, not the urethra, can be the primary infected site, and therefore the urethral urine may not be subject to organism inoculation. If it's in the urine, likely it's in the cervix, but not the other way around.
For isolated urethritis, the urine test is likely adequate for women, but it's best to test the reservoir site. Regarding treatment without testing or symptoms, I assume you are referring to treating contacts empirically. That has always been the recommendation to avoid further spread, but it's often difficult and certainly does have the potential to increase resistance, and maybe it has. Resistance vs. curing asymptomatic infection is a tradeoff; you can be the judge of the risks and benefits. The prevalence of the infection in a sexual contact is by definition, however, high, hence empiric treatment is justified by at least the CDC.