Anal and Perianal Disorders

Question 1

Anal and perianal disorders

Answer 1

Common anal symptoms:

• Anal bleeding
• Anal itching and discomfort
• Pain on defaecation
• Perianal itching and irritation
• ‘Something coming down’
• Perianal discharge

Question 2

Anatomy of the anal canal

Answer 2

• The anal sphincter mechanism has three constituents: the internal sphincter, the external sphincter and the puborectalis muscle.
• The internal sphincter represents a downward but thickened continuation of the rectal wall musculature. The encircling external sphincter and the puborectalis sling (part of levator ani) arise from the pelvic floor.
• Continence is maintained principally by the anal sphincters squeezing the three anal cushions together to occlude the lumen.
• Continence is assisted by the rectum forming a compliant reservoir to accumulate faeces.

Question 3

Haemorrhoids

Answer 3

The common chronic or intermittent symptoms of haemorrhoids are:

• Perianal irritation and itching (pruritus ani) caused by mucus leakage. Scratching exacerbates the problem
• Rectal bleeding (fresh blood, on the paper or separate from stool)
• Mucus leakage due to imperfect closure of the anal cushions
• Mild incontinence of flatus also due to imperfect closure of the anal cushions
• Haemorrhoidal prolapse

Question 4

Surgical treatments for haemorrhoids (1)

Answer 4

Injection of sclerosants or banding:

• First degree haemorrhoids which do not regress with dietary change and avoiding straining, and most second degree haemorrhoids, can be treated on an outpatient basis by sclerosant injections or banding.
  *

Question 5

Surgical treatments for haemorrhoids (2)

Answer 5

Banding:

• A cone of mucosa just above the haemorrhoidal neck is drawn into a banding instrument, often by suction, and tight elastic bands released around the base of the cone, constricting the haemorrhoidal vessels
• The result of banding is that the haemorrhoid gradually shrinks. The bands separate with time and are passed.

Haemorrhoidectomy:

• Haemorrhoidal excision is indicated for third degree haemorrhoids and for lesser degrees when other treatments have failed.
• The most common operation is that described by Milligan and Morgan in which the haemorrhoidal masses are excised with overlying mucosa and some skin
• Stapled haemorrhoidectomy enjoyed some popularity for large haemorrhoids, particularly when mucosal prolapse is a feature.

Question 6

Anal fissure

• An anal fissure is a longitudinal tear in the mucosa and
• skin of the anal canal, sometimes caused by passing a large, constipated stool. The tear is nearly always in the posterior midline of the anal margin.
• On inspection, the fissure is concealed by the anal spasm but a small skin tag (sentinel pile) may be seen at the superficial end of the fissure.
• Rectal examination is extremely painful and rarely possible unless the fissure has become chronic.

Answer 6

Management of anal fissure:

• Anal fissure can be managed conservatively or operatively.
• Modern conservative treatment involves the use of topical glyceryl trinitrate (GTN) ointment 0.2–0.4%, applied three times a day for a month.
• This relaxes the sphincter spasm and increases blood supply to the fissure, allowing healing.
• Patients need to be warned that it may cause headaches.
• This treatment can cure most anal fissures. For the rest, diltiazem ointment, a calcium channel blocker, may be successful.
• Injection of botulinum toxin into the sphincter complex is another way to cause a temporary ‘chemical sphincterotomy’.

Question 7

Anorectal abscesses

• Anorectal abscesses begin as acute purulent infections of anal glands.
• These lie in the intersphincteric space between the internal and external sphincters and drain into tiny pits, the anal crypts near the dentate line. T
• he ducts are very narrow and duct obstruction may be what initiates the infection.

Answer 7

Treatment of anorectal abscesses:

• Antibiotics are used by general practitioners, coupled with early referral, reduces number and severity of cases reaching the surgeon
• However, once an abscess is diagnosed, surgical drainage
• A swab of the pus is sent for microbiological diagnosis to differentiate infection by skin pathogens (e.g. Staphylococcus) which occur spontaneously, from infections of bowel origin (e.g. E. coli) which suggest an underlying fistula.

Question 8

Anorectal abscesses

Differential diagnosis

Answer 8

• *Crohn’s disease**—may cause multiple abscesses and complex fistulae (see Ch. 28) and must be excluded
• *Hidradenitis suppurativa**—originates in perianal apocrine glands in the skin; it is easily distinguished from deeper perianal abscesses by careful inspection and palpation. There may be multiple infected glands in the natal cleft, groins and sometimes axillae
• *Pilonidal abscess**—occurs in the skin of the natal cleft but may mimic a true perianal abscess if near the anal margin; careful examination shows no communication with the anal canal and often the presence of embedded hairs. Treatment is by incision and drainage but further procedures may be required to treat the associated pilonidal sinus

Tuberculous abscess and fistula very rare

Question 9

Pilonidal sinus and abscess

• Arise from the skin of the natal cleft rather than the anus.
• As the name implies, pilonidal sinuses, cysts and abscesses contain ‘a nest of hairs’
• Sinuses also occur between the hairdresser’s fingers from implantation of their clients’ hair

Answer 9

Treatment of pilonidal sinus:

• favoured surgical treatment is the Bascom ‘cleft lift’ procedure which may have the secondary advantage of flattening the cleft to minimise recurrence
• Recurrence may also be reduced by careful attention to hygiene. Daily baths and regular shaving of the area are recommended

Question 10

Rectal prolapse

• Rectal prolapse is a herniation of the rectum through the pelvic floor, so the mucosa and muscle wall effectively intussuscept through the anal canal.
• It is mainly seen in young children and the elderly.

Answer 10

Management of rectal prolapse(Abdominal):

• Suture fixation rectopexy, where the rectum is mobilised and the mesorectum sutured to the sacral promontory and presacral fascia
• Resection rectopexy, where the rectum is mobilised and sutured in the same way, but a sigmoid colectomy is also performed to try to prevent the constipation that often accompanies suture fixation alone

Perineal procedure:

• Delorme’s operation, which is appropriate for most elderly patients because of its low morbidity and mortality. It involves excising redundant rectal mucosa, plicating the rectal wall and replacing the prolapsed rectum

Question 11

Faecal incontinence

• Incontinence presents in varying degrees: first for flatus, then for fluid and finally for solids as control is progressively lost.
• Declining mobility may also be a factor: mild incontinence that would otherwise be manageable may become a problem where debility and immobility impair the patient’s ability to move to the toilet when required.

Answer 11

Anorectal incontinence:

• Main functional abnormality in anorectal incontinence is weakness of the external anal sphincter and pelvic floor muscles
• due to direct injury from trauma or surgery but most cases were labelled idiopathic
• most important cause of sphincter dysfunction in women is obstetric injury
• mechanism is probably via traumatic pudendal neuropathy leading to atrophy of sphincteric and pelvic floor muscles
• If sphincters have been physically damaged, surgical sphincter repair may be undertaken but results are not always predictable or long-lasting
• Continuous sacral nerve stimulation, where an implanted ‘pacemaker’ promotes increased sphincter tone, can be attempted.

Question 12

Anal warts (condylomata accuminata)

• Warts in the perianal region (see Fig. 30.14) have a viral aetiology (human papilloma-virus (HPV) types 6 and 11) and are generally transmitted by sexual activity. J
• Just as cervical cancer is linked to specific strains of HPV infection, anal warts indicate an increased risk of anal canal carcinoma by virtue of their common aetiology.
• I**mmune suppression, for example in patients with organ transplants or with HIV infection, can lead to rapidly developing anal warts and progression to malignant change.

Answer 12

• Anal warts can be treated by topical applications of podophyllin.
• When large numbers are present, surgical excision under general anaesthetic is the only practical option.
• This involves meticulous excision of each individual wart by electrocautery.
• The normal skin between the warts is carefully preserved to avoid delayed healing or the disastrous complication of anal stenosis.
• Carefully mapped biopsies can also be undertaken to monitor for dysplastic change.
• In the future, prevention will come from human papilloma virus (HPV) vaccines in both sexes, shown to prevent papillomavirus-induced cervical cancer, genital warts, and some oral cancers.