PERIANAL, RECTAL AND PILONIDAL

Anus and rectum

The main symptom in perianal septic conditions is throbbing, anal pain with or without fever. Rule out the presence of an abscess in all cases of perianal pain. Perianal, ischiorectal, inter-sphincteric or submucous abscess are identified by location. Patients may be unable to sit. Rectal examination is often diagnostic. For female patients, perform a rectal examination followed by a vaginal examination. The discomfort may be severe and regional or general anaesthesia may be necessary to perform these examinations.

Part the buttocks to inspect the perianal region, the natal cleft and the anal margin. A tightly closed anus suggests spasm, due to a painful anal condition. Palpate any lesions in this area.

Slowly introduce a lubricated, gloved finger into the anus with the palmar surface turned posteriorly. Palpate the posterior anal wall and any anal contents against the curve of the sacrum. Rotate the finger anteriorly to detect any bulge or tenderness suggestive of a pelvic abscess (Figure 5.49). The prostate in the male, and the cervix in the female, will be palpable anteriorly (Figure 5.50). Withdraw the finger and inspect it for stool, mucus or blood. Take specimens for laboratory examination.

Figure 5.49

Figure 5.50

Patients with a perianal abscess will have tenderness on rectal examination confined to the anal margin, whereas patients with an ischiorectal abscess will have deep tenderness. If you are in doubt about the diagnosis, perform a diagnostic needle aspiration.

A perianal abscess presents as an extremely tender, inflamed, localized swelling at the anal verge (Figure 5.51). An ischiorectal abscess is indicated by tenderness with a diffuse, indurated swelling in the ischiorectal fossa. Fluctuation in these lesions is rare at an early stage and may not ever occur. Pain is a more reliable feature of perianal or rectal abscess.

Figure 5.51

Give parenteral antibiotic and administer analgesics. To drain the abscess, place the patient in the lithotomy position. Centre an incision over the most prominent part of the abscess. Take a specimen for culture and gram stain. Break down all loculi with a finger (Figure 5.52). Irrigate the cavity with saline and pack it loosely with petrolatum or saline soaked gauze, leaving it protruding slightly (Figure 5.53). Cover the wound with dry gauze and a bandage.

Figure 5.52

Figure 5.53

Instruct the patient to bathe sitting in warm saline for 15–30 minutes twice a day until the wound is healed, and to change the pack after each bath. Do not allow the wound edges to close. Give a mild laxative, such as liquid paraffin (mineral oil), daily until the bowels move and continue antibiotic treatment for 5 days. Continue analgesics for up to 72 hours.

Recurrence of the abscess is often due to inadequate drainage or to premature healing of the skin wound.

Anal fistula occur as a late complication. Patients presenting with an anal fistula should be referred for surgical correction. The reason this requires referral is that fistulotomy in a high fistula-in-ano will result in incontinence if not managed correctly; expert management is therefore required.

Pilonidal disease and abscess

Pilonidal disease results from ingrown hair causing cutaneous and subcutaneous sinus formation in the post sacral intergluteal cleft overlying the sacrum. The sinus may be single or multiple and presents with single or multiple orifices (Figure 5.54). The disease causes both acute and chronic inflammation. Patients present with pain, swelling and discharge or with an acute abscess. A pilonidal abscess will not respond to antibiotics alone. Treat initially with incision and drainage. For definitive treatment, remove all sinus and hair bearing tissue by excising an ellipse of tissue down to the presacral fascia (Figure 5.55). A field block with 1% lidocaine with epinephrine (adrenaline) gives adequate anaesthesia.

Figure 5.54

Figure 5.55