Anorectal Abscess in Children Treatment & Management
- Author: Nelson G Rosen, MD, FACS, FAAP; Chief Editor: Robert K Minkes, MD, PhD more...
In infants younger than 1 year who present with a small perianal abscess, it is reasonable to try to attain full resolution with antibiotic therapy alone, without operative intervention or general anesthesia. Such an approach may decrease the likelihood of fistula formation.
In children younger than 1 year who present with a large, red, bulging perianal abscess and who appear to be in significant distress, more aggressive treatment is indicated. The abscess should be drained, most commonly in the office, and oral antibiotics initiated. Children who show signs of true systemic illness (eg, weakness, lethargy, or fever) secondary to the infection should be admitted for intravenous antibiotic therapy; however, such cases are exceedingly rare.
An identical approach can be followed in older children without a history of inflammatory bowel disease (IBD), with perhaps a shorter threshold to perform drainage in any patients initially deemed suitable for treatment with antibiotics alone. Older children who have complex fistulas or are in extreme pain during the examination require general anesthesia for examination and treatment.
Babies who present with a fistula after surgical or spontaneous drainage of an abscess should undergo a period of nonoperative observation and should be observed until age 18 months, provided that they remain otherwise happy and healthy. After this time, it is reasonable to consider surgical fistulotomy for resolution. Older children with fistulas secondary to Crohn disease should be referred to a pediatric surgeon with significant IBD experience or to an adult colorectal surgeon.
Treatment of both anorectal abscess and fistula-in-ano remains controversial. Antibiotics were originally believed to play a limited role in primary therapy for perianal abscesses but were frequently initiated by pediatricians before surgical referral. The concept that abscesses must be drained in order to heal is perhaps the closest thing to a universally accepted incontrovertible surgical law that one can find. It can be argued, however, that such thinking perpetuates dogma and stifles advances in care.
A 2007 study brought into question the benefit of draining perianal abscesses and suggested a potential advantage to treating with antibiotics alone. The data presented in this study support the idea that in otherwise healthy babies, not draining abscesses decreases the risk of fistula formation, and adding antibiotics further decreases the risk.
Once a fistula has formed, the optimal approach to treatment is also controversial. Historically, babies with fistula-in-ano were treated in exactly the same way as adults (see Anorectal Abscess) and underwent surgical fistulotomy; in some cases, such patients underwent seton placement. Current evidence indicates that this procedure is largely unnecessary and may be reserved for the rare cases that do not resolve after a sufficient period of nonoperative management.
Older children with no evidence of IBD can be treated with the approaches described above, with more aggressive intervention added if symptoms persist or worsen. Children in whom IBD is suspected should undergo evaluation for that condition.
It is important to note that the evolution of treatment strategies in the direction of less aggressive intervention should not be confused with the adoption of a more conservative therapeutic approach. The term conservative, with respect to therapy, should be reserved for treatments that are tried and true and that are considered almost certain to yield a positive outcome. From this viewpoint, conservative treatment of an anorectal abscess in a pediatric patient would be drainage.
When first proposed, nonoperative treatment of a small perianal abscess in an otherwise healthy baby was considered radical. Time, experience with a large number of patients, and a supporting body of evidence are required to transform a radical therapy into a conservative therapy. Thus, when properly understood, the terms radical and conservative have nothing whatsoever to do with how much physician intervention and treatment is required, be it surgical or nonsurgical.
This understanding is critical for the treatment of children with anorectal abscess and fistula. If a child of any age is ever appearing sick or toxic, treatment should revert to the most conservative approach possible. This would include the addition of antibiotics if they had been withheld thus far, the drainage of any abscesses, and the search for deep infection in the ischiorectal fossa via computed tomography (CT). Such deep infections occur in the adult population but are virtually unheard of in the pediatric population.
The use of antibiotics to treat anorectal abscesses remains controversial. Traditional teaching holds that drainage alone is sufficient for abscess treatment in otherwise healthy patients. A 2007 study by Christison-Lagay et al demonstrated that antibiotic use for perianal abscess decreased the likelihood of fistula formation.
All immunocompromised patients with infections should receive antibiotics as a component of their therapeutic plan. Patients with Crohn disease require antibiotic therapy in addition to the medical therapy used to treat their Crohn disease.
Anorectal abscesses often grow mixed flora and can be well covered by various antibiotic choices. Common oral agents administered for routine infection include cephalexin and amoxicillin-clavulanate. Methicillin-resistant Staphylococcus aureus (MRSA) is rarely implicated in perianal abscesses but should be considered as a pathogen in patients who are not responding to traditional antibiotic choices. Trimethoprim-sulfamethoxazole is available in liquid form and can cover MRSA.
When it has been determined that medical management is not sufficient, surgical treatment is indicated.
No preoperative preparation is required for simple abscess drainage in otherwise healthy children. Children undergoing general anesthesia should avoid eating solid food for at least 8 hours before the surgical procedure. Surgeons may require some form of bowel preparation to clean the anus and rectum in preparation for a fistulotomy.
Management of abscess
Surgical treatment of a perianal abscess consists of incision and drainage. Most babies can easily undergo this procedure in the office.
A dependable assistant is required to hold the child still. The procedure itself takes little time but is not possible without an experienced pediatric assistant who can firmly hold the baby motionless for the few seconds during which sharp items are being used.
The area over the abscess is swabbed with povidone-iodine or an equivalent skin preparation solution. The skin immediately overlying the abscess is anesthetized by using a tuberculin syringe and local anesthetic to raise a small wheal. Whether this step is warranted is debatable; some believe that the pain caused by the local anesthetic is comparable to the pain caused by the incision. However, the author prefers to use local anesthesia.
A No. 11 blade scalpel is used to make an incision directly into the abscess. Pus is then expressed. A simple incision is sufficient, and no packing is required. Once the pus is drained, the remaining local anesthetic in the syringe can serve as a skin wash, and dry gauze is applied. There is usually only minor bleeding, which can be controlled with just a few minutes of pressure. Once the procedure is concluded, the best analgesia is to return the infant to the arms of a parent.
Management of fistula
Surgical treatment of a superficial fistula-in-ano consists of fistulotomy (unroofing of the fistulous tract). This requires anesthesia and takes place in an operating room. Fistulectomy, in contrast, is a procedure whereby the entire fistulous tract is stripped out, either by surgical means or by the use of fistulotomy and curettage. This procedure is not required in the pediatric population.
The patient is positioned in the lithotomy position. Once the child has been fully anesthetized, the fistulous opening is identified within the anal canal, either via gentle probing of the skin opening with a lacrimal probe or through the use of anoscopy. Once the opening has been identified, a probe is passed through the entire length of the fistula from the skin side all the way into the anal lumen.
Next, the fistulous tract is then opened up completely by cutting the tissue between the anal lumen down to the probe, so that the probe is free and within the anal lumen. The cut may be made with a fine needle-tip electrocautery to aid in hemostasis. Once the probe is free and the fistulous tract therefore completely opened, the procedure is complete.
Patients with Crohn disease rarely undergo fistulotomy; instead, they usually undergo a procedure in which the fistulous tract is identified in a similar manner, and a noncutting seton (often a long soft rubber or silicone band called a vessel loop, used in vascular surgery to isolate blood vessels) is placed through the tract to facilitate drainage and help control the localized sepsis.
At one time, cutting setons were also used to treat fistulas in pediatric patients. In this technique, a thick suture (the seton) is placed through the fistulous tract and tied to itself. It is then tightened progressively over several weeks so that it slowly cuts through the tissue while allowing scar tissue to form on the other side of the cut; thus, at no point is the sphincter cut completely open.
The use of cutting setons is a painful technique that has proven essentially unnecessary in children and thus has been largely abandoned in the pediatric population. The main issue with this technique is the possibility that cutting open the fistulous tract will cut the sphincter and risk incontinence. This is a major concern for large high fistulas that track above the sphincter (referred to as suprasphincteric fistulas).
If a suprasphincteric fistula is encountered on examination under anesthesia, it can be treated initially by placing a bioprosthetic fistula plug (an absorbable device made specifically for this purpose). The plug is inserted by passing a suture through the tract, tying the suture to the plug, and pulling the plug completely into the tract. The plug is then tacked into position by suturing it at the entrance into the anal canal, as well as at the skin. A literature review of this technique in the adult population quotes a 54% closure rate.
For patients who experience a recurrence after a fistula plug insertion, a rectal advancement flap can be used to cover the fistulous opening.
After abscess drainage, acetaminophen may be useful for postoperative pain, but most patients feel better once the pus is no longer under pressure. Parents should be counseled that a drop of blood in the diaper or dressing is not unusual but that persistent bleeding is a problem calling for pressure and perhaps a return to the office.
After abscess drainage, babies should undergo a brief warm bath after every bowel movement to ensure that the area is being adequately cleaned. Older children who undergo abscess drainage or fistulotomy should take a sitz bath (to sit and dunk the bottom in a warm tub, traditionally but not necessarily with Epsom salts) after every bowel movement, a minimum of 2-3 times each day.
The opening often closes within several days and resolves completely, but many patients who undergo drainage eventually form a fistula. Dressings are required as only long as the opening is draining. Panty liners make excellent dressings and have an adhesive strip that holds them in place in the underwear.
All patients receiving antibiotics alone require close follow-up and should be seen a few days after therapy is initiated and then weekly until the infection is completely resolved.
Patients who underwent surgical drainage of an abscess should be seen weekly until the abscess is completely resolved and the skin opening healed. Thereafter, the author prefers to see these patients every 3 months until at least 6 months have passed without any evidence of the hole reopening (proof that a fistula has not formed).
Patients who underwent surgery for a fistula need acute and long-term follow-up similar to that indicated for those who underwent acute abscess drainage.
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