Chapter 36: Anorectal disorders

Anorectal problems are common in family practice and tend to cause anxiety in the patient that is often related to the fear of cancer. This fear may be well founded for many instances of rectal bleeding and lumps. It is important to keep in mind the association between haemorrhoids and large bowel cancer.

Anorectal problems include:

• pain

• lumps

• discharge

• bleeding

• pruritus

Common anorectal conditions are illustrated in FIGURE 36.1.

The patient may complain that defecation is painful or almost impossible because of anorectal pain.

Causes

Pain without swelling:

• anal fissure

• anal herpes

• ulcerative proctitis

• proctalgia fugax

• solitary rectal ulcer

• tenesmus

Painful swelling:

• perianal haematoma

• strangulated internal haemorrhoids

• abscess: perianal, ischiorectal

• pilonidal sinus

• fistula-in-ano (intermittent)

• anal carcinoma

Anal fissure

Anal fissures cause pain on defecation and usually develop after a period of constipation (may be a brief period) and tenesmus. Other associations are childbirth and opioid analgesics.¹ Sometimes the pain can be excruciating, persisting for hours and radiating down the back of both legs. Anal fissures, especially if chronic, can cause minor anorectal bleeding (bright blood) noted as spotting on the toilet paper.

Examination

On inspection the anal fissure is usually seen in the anal margin, situated in the midline posteriorly (6 o’clock)—90% of fissures. The fissure appears as an elliptical ulcer involving the lower third of the anus from the dentate line to the anal verge (see FIG. 36.2).¹

Digital examination and sigmoidoscopy are difficult because of painful anal sphincter spasm. If there are multiple fissures, Crohn disease should be suspected. These fissures look different, being indurated, oedematous and bluish in colour.

In chronic anal fissures a sentinel pile is common and in long-standing cases, a subcutaneous fistula is seen at the anal margin, with fibrosis and anal stenosis.¹

Treatment

The aim is to disrupt the cycle of anal sphincter spasm, allowing improved blood flow to assist healing. Management is conservative, with avoidance of hard stools and warm salt (sitz) baths after bowel movements. A high-residue diet and avoidance of constipation (aim for soft bulky stools) may lead to resolution and long-term prevention. A combined local anaesthetic and corticosteroid ointment applied to the fissure can provide relief but may not promote healing. Topical local anaesthetic applied before passing a stool may relieve pain but does not promote healing. Hot baths relax the internal anal sphincter. An acute anal fissure will usually heal spontaneously or within a few weeks of a treatment involving a high-fibre diet, sitz baths or laxatives.² A conservative treatment is the application of diluted glyceryl trinitrate ointment (e.g. Rectogesic 2% three times daily for 6 weeks to the lower anal canal) with a gloved finger gently inserted into the anal canal. It achieves healing rates of about 50%.^3,4 Transient headache is the main adverse effect. An alternative is 2% diltiazem cream applied twice daily for 6–8 weeks.

Lateral internal sphincterotomy is indicated in patients with a recurrent fissure and a chronic fissure with a degree of fibrosis and anal stenosis.⁵ This surgical procedure is the gold-standard surgical procedure. An alternative ‘chemical’ sphincterotomy, which is as effective as surgical treatment, is injection of botulinum toxin into the sphincter.

Proctalgia fugax (levator ani spasm)

Clinical features

• Episodic fleeting rectal pain

• Varies from mild discomfort to severe spasm

• Last 3–30 minutes

• Often wakes patient from sound sleep

• Can occur any time of day

• A functional bowel disorder of unknown aetiology

• Affects adults, being more common in women

Management⁶

• Explanation and reassurance re self-healing

• An immediate drink (preferably hot) and local warmth with firm flannel pressure to the perineum

• Salbutamol inhaler (2 puffs statim) worth a trial but anecdotal evidence only

Alternatives include glyceryl trinitrate spray for the symptom or possibly antispasmodics, calcium channel blockers and clonidine.

Solitary rectal ulcer syndrome

These ulcers occur in young adults; they can present with pain but usually present as the sensation of a rectal lump causing obstructed defecation and bleeding with mucus. The ulcer, which is usually seen on sigmoidoscopy about 10 cm from the anal margin on the anterior rectal wall, can resemble cancer. Management is difficult and a chronic course is common. Treatment includes a high-residue diet and the avoidance of constipation.

Tenesmus

Tenesmus is an unpleasant sensation of incomplete evacuation of the rectum. It causes the patient to attempt defecation at frequent intervals. The most common cause is irritable bowel syndrome. Another common cause is an abnormal mass in the rectum or anal canal, such as cancer (e.g. prostate, anorectal), haemorrhoids or a hard faecal mass. In some cases, despite intensive investigation, no cause is found and it appears to be a functional problem.

Perianal haematoma

A perianal haematoma (thrombosed external haemorrhoid) is a purple tender swelling at the anal margin caused by rupture of an external haemorrhoidal vein following straining at toilet or some other effort involving a Valsalva manoeuvre. The degree of pain varies from a minor discomfort to severe pain. It has been described as the ‘five day, painful, self-curing pile’, which may lead to a skin tag. Spontaneous rupture with relief of symptoms can occur.

Management

Surgical intervention is recommended, especially in the presence of severe discomfort. The treatment depends on the time of presentation after the appearance of the haematoma.

1. Within 24 hours of onset. Perform simple aspiration without local anaesthetic using a 19 gauge needle while the haematoma is still fluid.

2. From 24 hours to 5 days of onset. The blood has clotted and a simple incision under local anaesthetic over the haematoma with deroofing with scissors (like taking the top off a boiled egg) to remove the thrombosis by squeezing is recommended. Removal of the haematoma reduces the chances of the development of a skin tag, which can be a source of anal irritation.

3. Day 6 onwards. The haematoma is best left alone unless it is very painful or (rarely) infected. Resolution is evidenced by the appearance of wrinkles in the previously stretched skin.

Follow-up

The patient should be reviewed in 4 weeks for rectal examination and proctoscopy, to examine for any underlying internal haemorrhoid that may predispose to further recurrence. Prevention includes an increased intake of dietary fibre and avoidance of straining at stool.

Strangulated haemorrhoids

A marked oedematous circumferential swelling will appear if all the haemorrhoids are involved. If only one haemorrhoid is strangulated, proctoscopy will help to distinguish it from a perianal haematoma. Initial treatment is with rest and ice packs and then haemorrhoidectomy at the earliest possible time. It is best to refer for urgent surgery.

Perianal cellulitis⁶

This occurs mainly in pre-school and school-aged children. It is usually caused by Streptococcus pyogenes. Check for a fissure.

Perianal anorectal abscess

This is caused by infection by polymicrobial organisms of one of the anal glands that drain the anal canal.

Clinical features

• Severe, constant, throbbing pain

• Fever and toxicity

• Hot, red, tender swelling adjacent to anal margin

• Non-fluctuant swelling

Careful examination is essential to make the diagnosis. Look for evidence of a fistula, Crohn disease and anorectal cancer.

Treatment

Drain via a cruciate incision, which may need to be deep (with trimming of the corners) over the point of maximal induration. A drain tube can be inserted for 7–10 days. Packing is not necessary.

Antibiotics

If a perianal or perirectal abscess is recalcitrant or spreading with cellulitis, use:

• metronidazole 400 mg (o) 12 hourly for 5–7 days plus

• cephalexin 500 mg (o) 6 hourly for 5–7 days⁷

Ischiorectal abscess

An ischiorectal abscess presents as a larger, more diffuse, tender, dusky red swelling in the buttock. The presence of an abscess is usually very obvious but the precise focus is not always obvious on inspection. Antibiotics are of little help and surgical incision and drainage as soon as possible is necessary. A deep general anaesthetic is necessary.

Pilonidal sinus and abscess

Recurrent abscesses and discharge in the sacral region (at the upper end of the natal cleft about 6 cm from the anus) can be caused by a midline pilonidal sinus, which often presents as a painful abscess. Once the infection has settled it is important to excise the pits, allow free drainage of the midline cavity and lateral tracks and remove all ingrown hair. Antibiotics, which should be guided by culture (e.g. cephalexin and metronidazole), are given to complement surgical drainage only if there is severe surrounding cellulitis. Pilonidal means ‘a nest of hairs’ and the problem is particularly common in hirsute young men (see FIG. 36.3). Refer for excision of the sinus network if necessary, possibly marsupialisation.

Fistula-in-ano⁵

An anal fistula is a tract that communicates between the perianal skin (visible opening) and the anal canal, usually at the level of the dentate line. It usually arises from chronic perianal infection, especially following discharge of an abscess. It is common in patients with Crohn disease. Symptoms include recurrent abscesses, discharge of blood, pus or serous fluid, swelling and anal pain. A surgical opinion is necessary to determine the appropriate surgical procedures, which may be complex if it traverses sphincter musculature.

Anorectal lumps are relatively common and patients are often concerned because of the fear of cancer. A lump arising from the anal canal or rectum, such as an internal haemorrhoid, tends to appear intermittently upon defecation, and reduce afterwards.¹ Common prolapsing lesions include second- and third-degree haemorrhoids, hypertrophied anal papilla, polyps and rectal prolapse. Common presenting lumps include skin tags, fourth-degree piles and perianal warts (see TABLE 36.1).

Skin tags

The skin tag is usually the legacy of an untreated perianal haematoma. It may require excision for aesthetic reasons, for hygiene or because it is a source of pruritus ani or irritation. A tag may be associated with a chronic fissure.

Treatment (method of excision)

A simple elliptical excision at the base of the skin tag is made under local anaesthetic. Suturing of the defect is usually not necessary.

Perianal warts

It is important to distinguish the common viral warts from the condylomata lata of secondary syphilis. Local therapy includes the application of podophyllin every 2 or 3 days by the practitioner or imiquimod.

Rectal prolapse

This is protrusion from the anus to a variable degree of the rectal mucosa (partial) or the full thickness of the rectal wall. It appears to be associated with constipation and chronic straining, leading to a lax sphincter. Features can include mucus discharge, bleeding, tenesmus, a solitary rectal ulcer and faecal incontinence (75%).

Visualisation of the prolapse is an important part of the diagnosis. Surgery such as rectopexy (fixing the rectum to the sacrum) is the only effective treatment for a complete prolapse.⁵

Temporary shrinking of a visible prolapse in an emergency situation can be achieved by a liberal sprinkling of fine crystalline sugar.

Internal haemorrhoids

Haemorrhoids or piles are common and tend to develop between the ages of 20 and 50 years. Roughly one out of two Westerners suffers from them by the time they reach the age of 50.³ Internal haemorrhoids are a complex of dilated arteries, branches of the superior haemorrhoidal artery and veins of the internal haemorrhoidal venous plexus (see FIG. 36.4). The commonest cause is chronic constipation related to a lack of dietary fibre and inappropriate habit.

Anatomically there are three classical sites, namely 3, 7 and 11 o’clock (see FIG. 36.5).

Clinical stages and pathology³

• Stage 1: First-degree internal haemorrhoids: three bulges form above the dentate line. Bright bleeding is common.

• Stage 2: Second-degree internal haemorrhoids: the bulges increase in size and slide downwards so that the patient is aware of lumps when straining at stool, but they disappear upon relaxing. Bleeding is a feature.

• Stage 3: Third-degree internal haemorrhoids: the pile continues to enlarge and slide downwards, requiring manual replacement to alleviate discomfort. Bleeding is also a feature.

• Stage 4: Fourth-degree internal haemorrhoids: prolapse has occurred and replacement of the prolapsed pile into the anal canal is impossible.

Symptoms

Bleeding is the main and, in many people, the only symptom. The word ‘haemorrhoid’ means flow of blood. Other symptoms include prolapse, mucoid discharge, irritation/itching, tenesmus, incomplete bowel evacuation and pain (see FIG. 36.6).

Treatment

Invasive treatment of haemorrhoids is based on three main procedures: rubber band ligation, cryotherapy and sphincterotomy. Injection is now not so favoured, while a meta-analysis concluded that rubber band ligation was the most effective non-surgical therapy.⁸ Surgery is generally reserved for large strangulated piles. The best treatment, however, is prevention, and softish bulky faeces that pass easily prevent haemorrhoids. People should be advised to have an adequate intake of non-caffeinated fluids and a diet with enough fibre by eating plenty of fresh fruit, vegetables, wholegrain cereals or bran. They should respond to the urge to defecate and avoid straining at stool, complete their bowel action within a few minutes and avoid using laxatives.

Anal discharge refers to the involuntary escape of fluid from or near the anus. The causes may be considered as follows.⁵

1. Continent

   • Anal fistula

   • Pilonidal sinus

   • STIs: anal warts, gonococcal ulcers, genital herpes

   • Solitary rectal ulcer syndrome

   • Cancer of anal margin

2. Incontinent

   • Minor incontinence—weakness of internal sphincter

   • Severe incontinence—weakness of levator ani and puborectalis

3. Partially continent

   • Faecal impaction

   • Rectal prolapse

Studies have revealed that up to 1 in 10 people suffer some degree of faecal incontinence, which is a common reason for institutionalisation of the elderly.⁹ Patients may be reluctant to seek medical advice and doctors often do not ask specifically about the condition. The problem is as common in men as in women.

Apart from ageing, risk factors include perianal injury, such as childbirth injury, anal surgery, irritable bowel syndrome and neurological disorders.

If there are symptoms of anal incontinence postnatally, early referral to a physiotherapist, continence nurse adviser or colorectal surgeon is advisable.¹⁰

Among the various possible treatments there are surgical possibilities, which vary from direct sphincter repair, directed injections such as collagen and silicone into the anal sphincter, and an artificial anal sphincter (e.g. Acticon Neosphincter). A colostomy may be the last resort. It is worth keeping in mind asking patients about the possibility of this problem and knowing ‘to whom to refer’.

Patients present with any degree of bleeding from a smear on the toilet tissue to severe haemorrhage. Various causes are presented in FIGURE 36.7. Common causes are polyps, colon and rectal cancer, ischaemic colitis, diverticular disease and haemorrhoids.

Local causes of bleeding include excoriated skin, anal fissure, a burst perianal haematoma and anal cancer. A characteristic pattern of bright bleeding is found with haemorrhoids. It is usually small non-prolapsing haemorrhoids that bleed.

The nature of the blood (e.g. bright red, dark red or black) and the nature of the bleeding (e.g. smear, streaked on stool, mixed with stool, massive) gives an indication of the source of the bleeding (see TABLE 36.2). Black tarry (melaena) stool indicates bleeding from the upper gastrointestinal tract and is rare distal to the lower ileum. Patients with melaena should be admitted to hospital.

Frequent passage of blood and mucus indicates a rectal tumour or proctitis, whereas more proximal tumours or extensive colitis present different patterns.

Substantial haemorrhage, which is rare, can be caused by diverticular disorder, angiodysplasia or more proximal lesions such as Meckel diverticulum and even duodenal ulcers. Angiodysplasias are 5 mm collections of dilated mucosal capillaries and thick-walled submucosal veins, found usually in the ascending colon of elderly patients who have no other bowel symptoms. The bleeding is persistent and recurrent. The site is identified by technetium-labelled red cell scan or colonoscopy.

The history should also include an analysis of any associated symptoms such as pain, diarrhoea or constipation, presence of lumps and a sensation of urgency or unsatisfied defecation. The latter symptoms point to a rectal cause. Associated change of bowel habit suggests a diagnosis of cancer of the rectum or left colon. Bleeding from right colon cancer is often occult, presenting as anaemia.

The examination includes a general assessment, anal inspection, digital rectal examination and proctosigmoidoscopy. Even if there is an anal lesion, proximal bleeding must be excluded in all cases by sigmoidoscopy³ and by colonoscopy if there are any bowel symptoms or no obvious anal cause or a doubt about a lesion causing the symptoms.

Pruritus ani, which is itching of the anus, can be a distressing symptom that is worse at night, during hot weather and during exercise. It is seen typically in adult males with considerable inner drive, often at times of stress and in hot weather when sweating is excessive. In children, threadworm infestation should be suspected. It may be part of general itching, such as with a skin disorder, or localised whereby various anorectal disorders have to be excluded. Seborrhoeic dermatitis is a particularly common underlying factor. Consider also the more uncomfortable lichen sclerosus with its ivory white sclerotic plaques, which may also be present in the genital region.

Signs

The skin changes can vary from minimal signs to marked pathology that can show linear ulceration, maceration or lichenification (see FIG. 36.8). Superficial skin changes can be moist and macerated or dry and scaly. Full anorectal examination is necessary.

Causes and aggravating factors

• Psychological factors:

  • – stress and anxiety

  • – fear of cancer

• Generalised systemic or skin disorders:

  • – seborrhoeic dermatitis

  • – eczema

  • – lichen sclerosus

  • – diabetes mellitus

  • – candidiasis

  • – psoriasis (look for fissures in natal cleft)

  • – antibiotic treatment

  • – worms: pinworm (threadworm)

  • – diarrhoea causing excoriation

  • – Crohn disease

• Local anorectal conditions:

  • – haemorrhoids, skin tags

  • – fissures/fistula

  • – faecal incontinence

  • – warts

• Zealous hygiene to lack of hygiene

• Contact dermatitis:

  • – dyed or perfumed toilet tissue, soap, powder

  • – clothing

• Excessive sweating (e.g. tight pantyhose in summer)

Diagnosis

• Urinalysis (? diabetes)

• Anorectal examination

• Scrapings and microscopy to detect organisms

• Stool examination for intestinal parasites

Treatment

• Treat the cause (if known) and break the scratch cycle.

• Avoid local anaesthetics, antiseptics.

• Advise aqueous cream or a soap substitute to wash anus (instead of soap).

• Most effective preparations (for short¹² courses):

  methylprednisolone aceponate 0.1% in a fatty ointment; once daily until symptoms settle (up to 4 weeks)

  or

  hydrocortisone 1% cream/ointment

  or

  hydrocortisone 1% cream with clioquinol 3% or clotrimazole 1% (especially if dermatosis and Candida suspected)

If an isolated area and resistant, infiltrate 0.5 mL of triamcinolone intradermally. Fractionated X-ray therapy can be used if very severe. For a lichenified perianal area, use a potent corticosteroid ointment, e.g. betamethasone dipropionate 0.05% daily until clear.

Patient education about anal hygiene is essential.

Hand-out sheets from Murtagh’s Patient Education 7th edition:

• Anal fissure

• Haemorrhoids

• Pruritus ani