Annals of the Royal College of Surgeons of England (1990) vol. 72, 160-162

The management

of

acute anorectal sepsis

R H Grace FRCS Consultant Surgeon The Royal Hospital, Wolverhampton

Key words: Anorectal abscess; Fistula-in-ano; Microbiology; BacteroiPes

Anorectal sepsis is a common surgical emergency. Classified as a minor procedure, patients are generally treated by junior surgeons with an ill-understanding of the basic anatomy of the anal canal and aetiology of the abscess. Subsequent results of surgery are poor and the associated discomfort, the time off work and the incidence of recurrent sepsis are far from minor problems to the patient. There are few good follow-up studies relating to the incidence of recurrence of abscess or fistula after drainage of an acute anorectal abscess, but Vasilevsky and Gordon (I) reported a recurrence rate of 48% after simple incision and drainage, with 37% of the patients presenting with a fistula and 11% with a further abscess. Charbot et al. (2) identified inadequate surgery and spontaneous drainage as factors responsible for subsequent recurrence. Buchan and Grace (3) reported an incidence of 25% in a retrospective study from Cardiff. This alleged high incidence of recurrent sepsis is supported by studies showing that in any group of patients presenting with anorectal sepsis there is a high incidence of previous episodes of sepsis (3-6) with an increased incidence of subsequent fistula in those presenting with multiple previous abscesses (3). In our latest study from Wolverhampton, as yet unpublished, we have found a 29% incidence of previous sepsis with three-quarters of these patients having their recurrent abscess at the same site as the previous episode, and with 63% of these patients having a fistula subsequently demonstrated at operation.

Aetiology It is accepted that anorectal sepsis is more common in men than in women with the highest incidence in the third and fourth decade; it is uncommon in children.

Correspondence to: Mr R H Grace, Consultant Surgeon, The Royal Hospital, Cleveland Road, Wolverhampton, West Midlands

Although anorectal sepsis is relatively common in inflammatory bowel disease, particularly large bowel Crohn's disease, the overall incidence of associated disease is low. The possibility of malignant disease presenting with an abscess makes examination under anaesthetic and sigmoidoscopy an obligatory part of the management of any abscess (6-8). Diabetes, tuberculosis and Aids should be excluded in any at-risk population. There is no data concerning the incidence of anorectal sepsis in differing racial populations, but in a further recent study from Wolverhampton we have found that there is a significantly higher incidence of anorectal sepsis and fistula-inano in the Indian population than in the native Caucasian population (unpublished). An understanding of the microbiology of anorectal sepsis is all-important to the correct management of the acute abscess. The so-called intersphincteric or intermuscular abscess (9-13) presenting clinically as a perianal, ischiorectal or submucous abscess is associated with the culture of intestinal flora in the pus and the presence of a fistula. The culture of a skin organism, eg Staphylococcus aureus is not associated with the presence of a fistula (4). This original study was later confirmed by elegant microbiological studies from St Thomas' Hospital, combined with further surgery from Wolverhampton (5). This second study also defined the role ofBacteroides: the culture of bowel-derived Bacteroides was associated with the finding of a fistula, whereas no fistula was found when skin-derived Bacteroides were cultured from the pus. There is therefore a separate population of patients from those with an intermuscular abscess; this separate population has an anorectal boil and no fistula. Subsequent independent evidence from Henrichsen and Christiansen (14) has further supported this concept.

Management Surgery should aim to relieve symptoms, minimise the time off work, be associated with as low an incidence of recurrence as possible, and identify any underlying disease.

Management of acute anorectal sepsis

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Historical management has included: 1 Incision and drainage which relieves the symptoms and is associated with minimal time off work. 2 Incision and primary suture under antibiotic cover, which relieves the symptoms and is associated with minimal time off work. 3 Incision and saucerisation, which relieves the symptoms but is associated with a large wound and a significant time off work. None of these procedures excludes the possibility of underlying disease, however, nor do they deal with the underlying aetiology. It is suggested that: 1 A careful history will establish data relating to past history, to inflammatory bowel disease and to any recent change of bowel habit. 2 Examination under anaesthetic defines the extent of the abscess in relation to the anatomy of the anal canal, that is, whether it is perianal or whether it involves the ischiorectal fossa on one or both sides. External pressure on the abscess, with a speculum in the anal canal, may demonstrate pus discharging into the anal canal and thereby demonstrate the internal opening of a fistula. Sigmoidoscopy will exclude inflammatory bowel or malignant disease. 3 The abscess is drained through a linear incision and the pus is sent for culture in a sterile bottle rather than on a pus swab. The incision should be radial if it is felt there may be a low fistula running directly into the anal canal, or circum-anal if there is the possibility of a fistula opening posteriorly; bilateral sepsis requires bilateral incisions. If no fistula is obvious nothing further is necessary; management of any demonstrated fistula is discussed below. 4 If no fistula has been demonstrated, further management depends upon microbiology; the culture of a bowel-derived organism demands a second EUA, by an experienced surgeon, 7 to 10 days later, seeking a fistula. Skin-derived sepsis needs no further examination for there will be no associated fistula.

a joint study from three Birmingham teaching hospitals found an incidence of only 5.1% in patients with perianal sepsis and 0.9% of patients with ischiorectal sepsis (6), perhaps a reflection of inexperience with surgery performed by junior surgeons. The surgical management of a fistula associated with acute anorectal sepsis should be carried out with great care for unnecessary damage to the sphincter is unacceptable; uneducated probing of the anal canal when the tissues are friable and oedematous is dangerous and the principles of cold fistula surgery should still hold good during an acute episode. At the initial procedure, pus discharging into the anal canal demonstrates the internal opening, the 'external' opening being the cavity of the abscess. A curved 2700 Lockhart-Mummery probe placed carefully in the internal opening will often be visible in the abscess cavity and a low fistula can easily be laid open. When the tissues are oedematous and friable, confident assessment of the relationship of the probe to the external sphincter, especially anterior, may be difficult and, if so, a seton placed in the fistula track is the safe management. A second examination under anaesthetic when the oedema and sepsis have settled makes for much easier definition. The track can then be laid open or the practice of routine seton management can be applied. If positive microbiology necessitates a second examination under anaesthetic when no fistula has been demonstrated at the first procedure, the granulation tissue along the track is a clear marker and there is no place for methylene blue. The granulation tissue in the abscess cavity should be curetted but it is not possible to curette the small nubbin of granulation tissue which marks the track as it leaves the abscess cavity. Further careful probing with a Lockhart-Mummery probe will demonstrate the track, which can be laid open or a seton inserted. Good surgery in anorectal sepsis depends upon exactly the same principles as for other surgical infections, that is a sound understanding of the anatomy and microbiology and careful operative technique designed to cure the symptoms, prevent recurrence and inflict no damage.

Fistula management in acute anorectal sepsis

This contribution is based on an article which was published in Current Practice in Surgery 1989;1: 102-5, and I am grateful to the Editor of that publication for permission to use some of the material from the article.

There is considerable controversy about fistula management in acute anorectal sepsis. McElwain et al. (15) supported primary management and they have been strongly supported by Hanley (16) and by Abcarian (17,18), but several authors have argued against primarv management (19-22), and recently Vasilevsky and Gordon (1) have advocated secondary management for persistent sepsis. Data relating to the incidence of fistula in acute anorectal sepsis are scarce, but in the first Wolverhampton study (4) and the combined Wolverhampton/St Thomas' study (5), 37% and 66% of the patients had a fistula demonstrated, the higher figure perhaps a reflection of increased experience. In contrast,

References 1 Vasilevsky C-A, Gordon PH. The incidence of recurrent abscesses or fistula-in-ano following anorectal suppuration. Dis Colon Rectum 1984;27:126-30. 2 Charbot CM, Prasad ML, Abcarian H. Recurrent anorectal abscess. Dis Colon Rectum 1983;26: 105-8. 3 Buchan R, Grace RH. Anorectal suppuration: the results of treatment and the factors influencing the recurrence rate. BrJr Surg 1973;60:537-40.

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4 Grace RH, Harper IA, Thompson RG. Anorectal sepsis: microbiology in relation to fistula-in-ano. Br J Surg 1982;69:401-3. S Eykyn SJ, Grace RH. The relevance of microbiology in the management of anorectal sepsis. Ann R Coll Surg Engl 1986;68:237-9. 6 Winslett MC, Allan A, Ambrose NS. Anorectal sepsis as a presentation of occult rectal and systemic disease. Dis Colon Rectum 1988;31:597-600. 7 Dukes CE, Galvin C. Colloid carcinoma arising within fistulae in the ano-rectal region. Ann R Coll Surg Engl 1956;18:246-61. 8 Nelson RL, Prasad ML, Abcarian H. Anal carcinoma presenting as a perirectal abscess or fistula. Arch Surg 1985;120:632-5. 9 Nesselrod JP. Anal canal and rectum. In: Christopher F ed. A Textbook of Surgery, 5th Ed. Philadelphia: Saunders, 1949:1092. 10 Eisenhammer S. The internal anal sphincter and the anorectal abscess. Surg Gynecol Obstet 1956;103:501-6. 11 Eisenhammer S. A new approach to the anorectal fistulous abscess based on the high intermuscular lesion. Surg Gynecol Obstet 1958;106:595-9. 12 Eisenhammer S. The anorectal and anovulval fistulous abscess. Surg Gynecol Obstet 1961 ;113:519-20. 13 Parks AG. Pathogenesis and treatment of fistula-in-ano. Br

MedJ7 1961;1:463-9.

14 Henrichsen S, Christiansen J. Incidence of fistula-in-ano complicating anorectal sepsis: a prospective study. Br 7 Surg 1986;73:371-2. 15 McElwain JW, Maclean D, Alexander RM, Hoexster B, Guthrie JF. Anorectal problems: experience with primary fistulotomy for anorectal abscess, a report of 1000 cases. Dis Colon Rectum 1975;18:646-9. 16 Hanley PH. Anorectal abscess fistula. Surg Clin North Am 1978;58:487-503. 17 Abcarian H. Acute suppurations of the anorectum. In: Nyhus LM ed. Surgery Annual. New York: Appleton Century Crofts, 1976;8:305. 18 Abcarian H. Surgical management of recurrent ano-rectal abscesses. Contemp Surg 1982;21:85-91. 19 Goldberg SM, Gordon PH, Nivatvongs S. Essentials of Anorectal Surgery. Philadelphia: JB Lippincott, 1980;8: 100. 20 Goldberg SM, Parks AG, Goligher JC, Alexander-Williams J, Hanley PH. Symposium: fistula-in-ano. Dis Colon Rectum 1976;19:487-528. 21 Lockhart-Mummery HE. Symposium: anorectal problems: treatment of abscess. Dis Colon Rectum 1975;18: 650-1. 22 Scoma JA, Salvati EP, Rubin RJ. Incidence of fistulas subsequent to anal abscesses. Dis Colon Rectum 1974; 17:357-9.

The management of acute anorectal sepsis.

Annals of the Royal College of Surgeons of England (1990) vol. 72, 160-162 The management of acute anorectal sepsis R H Grace FRCS Consultant Surg...
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