Anal conditions

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Anal conditions
ANORECTAL DISEASES

Surgical anatomy of the anal canal

Terminal part of G.I.T.3-4 cm in length.The anal canal commences at the level where the rectum passes through the pelvic diaphragm and ends at the anal verge.The muscular junction between the rectum and anal canal can be felt clearly with the finger as a thickened ridge the anorectal bundle or ‘ring’ especially on its posterior and lateral aspects.

Division of the anorectal ring results in permanent incontinence of faeces like in case of surgery for high anal fistula.

The anal canal continues downwards and backwards surrounded by three concentric cylinders of muscles, these are the internal and external sphincters, with the thin longitudinal muscle layer between them.

On either side of the anal canal there is the fat filled space named the ischiorectal fossa.

The Dentate lineimportant landmark surgically it separates: 

Above • columnar epithelium;•autonomic nerves (insensitive);•portal venous system; Below •from squamous epithelium;•from spinal nerves (very sensitive);•from systemic venous system.

Arterial supply:- Superior haemorrhoidal A.from inferior mesenteric A. Middle haemorrhoidal a. from int. iliac A. Inferior haemorrhoidal a. from int. iliac A.


Venous drainage:- The superior and middle haemorrhoidal veins drains the upper half of the anal canal & they drain via the inferior mesenteric vein into the portal system. The inferior haemorrhoidal veins drain the lower half of the anal canal and the subcutaneous perianal veins: they eventually join the external iliac vein on each side.

Lymphatic drainage:- Above dentate line to para aortic lymph nodes. Below dentate line to inguinal lymph node.

The Anal Glands Found in the submucosa and intersphincteric space,number up to10 . Their function is unknown although they secrete mucin which perhaps lubricates the anal canal to ease defecation. The importance of intersphincteric anal glands is that they are widely considered to be the potential source of anal sepsis, either acute, presenting as perianal, ischiorectal or pelvic sepsis, or chronic, presenting as a cryptoglandular (non-specific) anal fistula.

Examination of the anus

The examining couch should be of sufficient height to allow easy inspection and access for any necessary maneuvers. A good light is mandatory. The Sims (left lateral) or the lithotomy position is satisfactory, the lithotomy is less convenient for an elderly patient and can cause social embarrassment to young women.

A protective glove should be worn. The patient should be relaxed and able to cooperate. A few quiet words from the doctor can prevent many loudones from the patient.

Inspection

With the buttocks opened, the anus is inspected.The patient is asked to strain down before inspection is concluded.inspect any lesions, e.g. inflammatory skin changes, haemorrhoids, fissure(‘sentinel pile’) or fistula.

Digital Examination With Index Finger

The examination check normal, and abnormal, structures as follows:
Intraluminal:— normal: faeces.— abnormal: polyp or carcinoma. Intramural:— normal: sphincter muscles and anorectal angle.— abnormal: carcinoma .Extramural:— normal: perianal structures.— abnormal: abscess.


Before withdrawing the finger, the patients asked again to strain down, and a note is made regarding the prostate in a male patient and the cervix, uterus and pouch of Douglas in a female. Discharge After withdrawal, the finger is examined for mucus, pus, blood and abnormal fecal material.

Proctoscopy

This examination is of great importance. Either the Sims position with the buttocks elevated on a small cushion, or the knee-elbow position may be used. The lower third of the rectum, the anorectal junction and the anal canal can be inspected as the instrument is withdrawn slowly.

Minor procedures can be carried out through this instrument, e.g. treatment of haemorrhoids by injection or banding and biopsy.

Sigmoidoscopy

This examination of the rectum and lower sigmoid colon, should be carried out even when an anal lesion has been confirmed. Rectal pathology, e.g. colitis or carcinoma, is frequently the cause of an anal lesion, e.g. fissure or hemorrhoids. Not infrequently, rectal pathology is found that is independent of the anal lesion and which requires treatment.

Special Investigation

Congenital Abnormalities
Imperforate anus Sacrococcygeal Teratoma Post anal Dermoid Post-anal Dimple

PILONIDAL SINUS (PNS)

Pilonidal means "nest of hairs". It is an infected tract under the skin, usually between the buttocks, in the natal cleft. Consisting of one or more, usually non infected, midline openings, which communicate with a fibrous track lined by granulation tissue and containing hair lying loosely within the lume and possibly can be oozing pus.

Anyone can develop a pilonidal sinus. However it mainly affects people between the age of 16 and 30, common minor condition of skin overlying the sacrum. A sinus developed after an abscess is cleared (by itself or by medical treatment), then one of more of the small openings (tracts) join the cavity to the skin surface. Some people can develop a pilonidal sinus without ever having a pilonidal abscess.


Aetiology:-Affect young adult males with dense, dark, strong hair.Females also affected but less than male.Rare below 30 years.A common affliction amongst the military, it has been referred to as ‘jeep disease’. The exact cause is not clear, there are various theories.

Congenital Theory: - The problem may develop from a minor congenital or hereditary abnormality in the skin of the natal cleft. This may explain why the condition tends to run in some families. Part of the abnormality in this part of the skin may be that the hairs grow into the skin rather than outwards.

Acquired theory :- Is more acceptable , hair from the head and back pentrate to the skin over the sacrum and coccyx. In the presence of pressure from sitting , a rolling movement of the buttocks , sweat, and poor hygiene , the hairs are drawn through the skin to accumulate in the subcutaneous tissue with debris and M.O .

The following facts support this theory :- P.N.S may occur in umbilicus, webs of fingers of barbers. Microscopic examination show loose hairs in the cavity but no hair follicles. The tip of hair is always directed inward. Liability for recurrences.

Pathology:- Originally there is a cavity that contains loose hairs, lined by granulation tissue and lined in the subcutaneous space overlying the lower sacrum. The cavity opens on the skin in the midline by one or more openings, their tracks being partially epithelized.

Intermittently aerobes and anaerobes proliferate causing an abscess which empty through the midline opening or point and open laterally and inferiorly producing secondary sinuses. abscess formation has tendency to recurrence.

Clinical Features:-

Patient may be Asymptomatic. patient present with Local Discomfort. Discharge. Acute Abscess formation. P.N.S disease tends to Reoccur if not properly treated. Differential Diagnosis:- Perianal abscess. Anal fissure.

Treatment:-

Conservative treatment In those whose symptoms are relatively minor: simple cleaning out of the tracks. Removal of all hair, Regular shaving of the area Strict hygiene recommended.

Pilonidal abscess:- Incision and drainage of pus, hairs are removed and the wound is left open, packed and is allowed to heal by granulation tissue formation. If a sinus recurs it is formally treated by exesion of the sinus.



Recurrent pilonidal sinusThree possibilities account for this disappointment:• Part of the sinus complex has been overlooked at the primary operation.• New hairs enter the skin or the scar.• There is persistence of a midline wound caused by shearing forces and scarring.

In this situation, revisional surgery may include re-excision followed by wound closure and obliteration of the natal cleft either by myocutaneous rotational buttock flap or cleft closure.

ANAL FISSURE (synonym: fissure-in-ano)

An anal fissure is a longitudinal split (ulcer) in the distal anal canal which extends from the anal verge proximally towards, but not beyond, the dentate line always in the midline . In 90 % of cases it lies in the midline posteriorly , while in the remaining 10 % the fissure is anterior .

Aetiology: -

The cause of an anal fissure, and particularly the reason why the posterior midline is so frequently affected, is not completely understood. Constipation: - hard faecal material cause injury of the posterior wall below dentate line. Repeated passage of Diarrhoea. Anterior fissure occur more in female due to weakness in the perineum may arise following vaginal delivery.

Rarely fissure due to Crhon’s disease.Complication of haemorrhoids operation in which too much skin is removed. This results in anal stenosis and tearing when a hard motion is passed.sexually transmitted diseases.

Pathology:-

Acute fissure: - superficial tear in the lower half of the anal canal in the mid line usually posteriorly, pain lead to spasm of internal sphincter muscle which prevents its healing.

Clinical Features:- 

Although most sufferers are young adults, the condition can affect any age, from infants to the elderly. Men and women are affected equally. Pain: sharp start during defecation and continue then relieved after few hours, remission for few days or weeks then pain recurs. Bleeding: streaks of blood around the stool. Constipation: - due to pain patient postpone defecation.

Chronic fissure:- Indurations of the edge. Anal papilla or a sentinel pile may be present. Examination done using anesthetic gel.

DDx:-

A fissure sited elsewhere around the anal circumference or with atypical features should raise the suspicion of a specific aetiology, and failure of adequate examination in the clinic should prompt early examination under anaesthesia,Early carcinoma of the anus.Fissures due to Crohn’s disease, multiple, not indurated, not very tender.T.B ulcers have undermined, cyanotic edges.Anal chancre present as painful ulcer.In any atypical presentation histopathology of the excised specimen should be performed.

Treatment:-

Chronic fissure:- 1- If not very chronic, a lateral internal sphinctrotomy operation is very successful. 2- If the fissure is heavily fibrosed with a sentinel pile, the best procedure Fissurectomy with posterior internal sphinctrotomy.

3- Anal flap

excision of the edges of the fissure and, if necessary, its base overlying the internal sphincter, an inverted house-shaped flap of perianal skin is carefully mobilised with its blood supply and advanced without tension to cover the fissure, and then sutured with interrupted absorbable sutures. The patient is maintained on stool softeners and bulking agents postoperatively, and usually also on topical sphincter relaxants; minor breakdown of one anastomotic edge does not mean failure

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HAEMORRHOIDS [PILES]

In Greek Haima means blood Rhoos means flowing In latin pila means a ball (pile)

Hemorrhoids

Cushions of tissue and dilated varicose veins occurring in relation to the anal canal, usually swollen and inflamed. Precipitating factors: Constipation. Diarrhea. Pregnancy. Straining. Aging.


Over 2/3 of healthy people report having hemorrhoids. Hemorrhoids tend to become worse over the years, never better, unless intervention.

Normally the terminal branches of the superior haemorrhoidal vessels form a vascular plexus beneath the epithelial lining of the anal canal called the anal cushions, these cushions are usually arranged at 3, 7, 11 o'clock with the patient in the lithotomy positions around the anal canal.

Pathology:-

Any process impairs venous return will promote stasis. Which can be produced by either: 1. systemic or by portal venous hypertension (CHF or cirrhosis). 2.Increase Intra-abdominal pressure also impairs venous return (ascites, pregnancy, straining, and tumors).


Haemorrhoids may be external or internal, to the anal orifice. The external is covered by skin, while the internal lies beneath the anal mucous membrane. When the two varieties are associated, they are known as interoexternal haemorrhoids.

Each principal haemorrhoid divided into three parts: The pedicle is situated at the anorectal ring. seen by a proctoscope, covered with pale pink mucosa. The internal haemorrhoid, which commences just below the anorectal ring. It is bright red or purple, covered by mucous membrane. The external haemorrhoid lies between the dentate line and the anal margin. It is covered by skin, through which blue veins can be seen, unless fibrosis occurred.

Hemorrhoids

In between these three primary hemorrhoids there may be smaller secondary hemorrhoids. Straining causes these cushions to slide downwards and internal hemorrhoids develop in the prolapsing tissues. Congestion, enlargement, and prolapse of the cushions constitute hemorrhoids.

Etiology:- Primary, no definite cause. Secondary, there is definite cause.

Primary: - Genetic factors. (Hereditary) The condition frequently seen in members of the same family that there must be a predisposing factor, such as a congenital weakness of the vein walls. Anatomical factors Due to loss of elastic fibers in the anal cushions.


Secondary hemorrhoids may occur with: Pregnancy due to increase intra-abdominal pressure and the relaxing effect of progesterone on the smooth muscle in the walls of the veins, plus an increased pelvic circulating volume. Pelvic tumor [ Ca rectum ]. Chronic straining at defecation ( chronic constipation) or Straining at micturation consequent upon a stricture of the urethra or an enlarged prostate.

Clinical Picture:-

Bright red painless bleeding per rectum occurs with straining, at the end of defecation, fresh bright red, jet or drops that are separate from stools. Prolepses pile enlarge and descend down.

Anal discharge (pruritus) Itching due to mucous discharge . Pain and discomfort usually piles painless, pain due to complication or associated fissure. Reflex symptoms are commonly present pain along thighs.

3rd Degree Prolapse

4th Degree Prolapse

Examination:-

Early cases no abnormality can be seen on examination of anal verge. Proctoscopy there may be internal haemorrhoid . In late cases prolapsing piles can be seen in 3, 7, 11 position there are mother piles, there may be daughter piles between the main three ones. Uncomplicated piles are impalpable on PR but important to do it to exclude malignancy. Sigmoidoscopy to exclude cancer.

Complications:-

Profuse haemorrhage. Anaemia. Strangulation when internal piles prolapse and become gripped by the external sphincter this will interfere with venous return and become very tender, swollen and very painful. Thrombosis after strangulation, thrombosis occur and the piles look dark purple or black.

Fibrosis may occur after thrombosis. Ulceration may follow strangulation and thrombosis. Gangrene if strangulation tight it lead to gangrene of piles and sloughing. Suppuration due to infection after thrombosis. Portal pyaemia is rare.


Perianal Edema

Management Of Haemmorriods

Exclusion of other causes of rectal bleeding, especially colorectal malignancy, is the first priority. In the absence of a specific cause, important measures: Normalizing bowel and defaecatory habits (only evacuating when the natural desire to do so arises). Adopting a defaecatory position to minimise straining.

Addition of stool softeners and bulking agents to ease the defaecatory act in constipated patients. Various creams can be inserted into the rectum from a collapsible tube fitted with a nozzle, at night and before defaecation. Suppositories are also useful.

Primary haemorrhoids; In those with first or second degree piles whose symptoms are not improved by conservative measures, injection sclerotherapy ,rubber band ligation , and photocoagulation are successful . For third and forth degree haemorroids surgery is recommended. Secondary haemorrhoids : Treatment is directed to the cause .

Complications:- Severe pain . Necrosis of mucosa. Allergic manifestations. Submucous abscess formation.

Rubber band ligation:- For 2nd and early third degree piles, place rubber band around the pedicle of the pile with ischemic necrosis.


CryosurgeryThe application of liquid nitrogen , The extreme cold (-196’C) of the application causes coagulation necrosis of the piles, which subsequently separate and drop off.the technique often caused mucus discharge and pain, and has now been abandoned.

Transanal Haemorrhoidal Dearterialisation

(THD) is used for the treatment of 2nd and 3rd-degree haemorrhoids. Some have recently advocated transanal Doppler-guided ligation of those vessels feeding the haemorrhoidal masses (ultriod), to which others have added suture ‘mucopexy’ to deal with any prolapse.Longterm outcomes are unknown, but recurrence rates for fourth degree haemorrhoids are high.



Cases unsuitable for injection or banding treatment are:. •Third & 4th degree haemorrhoids. • Failure of nonoperative treatments of 2nd-degree haem. • Fibrosed haemorrhoids. • Intero-external haem, when the external haem, is well defined. Indications Of Surgical Treatment:-


Some preoperative treatment is necessary: The anal region is shaved. On the morning of the operation the rectum is evacuated with the aid of a disposable enema.

Haemorrhoidectomy can be performed using an open or a closed technique. The open The technique is most commonly used , and is known as the Milligan-Morgan operation named after the surgeons who described it. The closed Both involve ligation and excision of the haemorrhoid, but in the open technique the anal mucosa and skin are left open to heal by secondary intention, and in the closed technique, the wound is sutured.

Haemorrhoidectomy:-

Postoperative care:

The patient is discharged from hospital within a day or two of the operation and usually performed on a day care basis. The patient is instructed to take two warm baths a day. Given a bulk laxative to take twice daily. Appropriate analgesia. The patient is seen again 3-4 weeks after discharge and a rectal examination is performed. If there is evidence of stenosis, the patient is encouraged to use a dilator.

Management of Complications 

Hemorrhage : Reactionary -- pressure or surgery with analgesia. Secondary – antibiotic with pressure and surgery.Retention of urine: conservative if fails catheterization.Anal stricture: post-operative anal dilatationI.

Recurrence: revsion surgery. Incontenance : uncommon, serious problem that is difficult to treat. Fissure: conservative treatment or sphinctorotomy.

Treatment of prolapsed strangulated, thrombosis and gangrene :-

surgery: promote portal pyaemia, but if adequate antibiotic cover is given from the start early excision can be done .The other risk if surgery is performed at this stage, is that of postoperative stenosis, results .An anal dilatation technique: has in the past been used as an alternative treatment to surgery for painful ‘strangulated’ haemorrhoids. However, because of the risk of incontinence this is no longer advised.

Thrombosed External Hemorrhoids (Acute Perianal Haematoma)

Pathogenesis: - Acute and very painful problem that develops rapidly due to rupture in one of the subcutaneous or submucosal dilated anal vein secondary to straining on defecation, coughing or lifting heavy object, it lead to haemorrhage & clot formation usually in lateral position.

Anal conditions

ANORECTAL DISEASES

Anorectal Absces:-

Infection of these glands by gram –ve bacilli lead to formation of an intersphincteric abscess which may spread:- Downwards ---perianal abscess.Outwards --- ischiorectal abscess.Inward ------- submucous abscess.


In the majority of these abscesses, there is an inner opening in the anal canal and drainage of the abscess is usually followed by fistula.Infection of apocrine glands or hair follicles of the perianal skin [15 – 25%] of cases, in such cases the causative M.O are staph. and there is no communication with anal canal .


Secondary anorectal abscess:-Inflammatory bowel disease as in Crohn’s and ulcerative colitis.Specific infection T .B.Anorectal carcinoma.Infection of perianal haematoma , thrombosed pile, fissure abscess.

2- Ischiorectal abscess 30% :- Lateral extension of an intersphincteric abscess, fever with large indurated Swelling in the ischiorectal space, throbbing pain with pitting edema . If not drained it will spread to other side forming horse shoe abscess, this need Urgent drainage.

3- Submucous abscess 5%:- The abscess in the sub mucous space above the dentate line, the patient has Severe pain, fever, but nothing in the anal verge. Digital examination of the rectum reveals tender boggy swelling.

ANAL FISTULA:-

Aetiology:-
Most fistulas begin as an anorectal abscess which burst spontaneously or was opened inadequately.Anal fistulae may be found in association with specific conditions, such as Crohn’s disease, tuberculosis, rectal duplication, and malignancy (which may also very rarely arise within a longstanding fistula). The majority are termed non-specific, idiopathic or crypto glandular.

A probe must be passed between the opening of the skin’s surface and the interior opening

The fistula continues to discharge and, because of constant reinfection from the anal canal or rectum, seldom, if ever, closes permanently without surgical aid.

Classification:-

These are divided into two groups, according to weather their internal opening is below or above the anorectal ring. Low-level fistulae open into the anal canal below the anorectal ring. High-level fistulae open into the anal canal at or above the anorectal ring.


The importance of deciding a fistula is a low or a high-level type is that: A low-level fistula can be open without fear of permanent incontinence (from damage to the anorectal bundle), while a high-level fistula treated only by ‘staged’ operations, with the use of a protective colostomy to prevent septic complications and to shorten healing time between the stages.

In probing a high fistulous track, great care must be taken not to create an internal opening into the rectum where none existed previously. Such a disaster could convert a relatively straightforward ‘intersphinctenic’ track into a high ‘pelvirectal’ fistula that might prove very difficult to cure.

Clinical Picture:-

Give history of previous perianal abscess which drain spontaneously, followed by intermittent or persistent discharge. the principal symptom is a persistent seropurulent discharge that irritates the skin in the neighborhood and causes discomfort. Often the history dates back for years. And as far as the opening is large enough for the pus to escape, pain is not a symptom, but if the orifice is occluded pain increases until the discharge erupts.


Attacks of perianal pain occur as recurrent abscesses build up .Frequently, there is a solitary external opening, usually situated within 3.5—4 cm of the anus, presenting as a small elevation with granulation tissue pouting from the mouth of the opening.Local soreness and pruritus ani .

Sometimes superficial healing occurs, pus accumulates and an abscess reforms and discharges through the same opening or a new opening. Thus there may be two or more external openings, usually grouped together on the right or left of the midline but, occasionally, when both ischiorectal fossas are involved, an opening is seen on each side, in which case there is often intercommunication between them .

Goodsall’s rule:-Fistulae with an external opening in relation to the anterior half of the anus tend to be of the direct type. Those with an external opening or openings in relation to the posterior half of the anus, which are much more common, usually have curving tracks, and may be of the horseshoe variety. Note that posteriorly situated fistulae may have multiple external openings which always connect to a solitary internal orifice, usually midline

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Examination:-

Single or multiple external openings next to anal orifices.Active fistula granulation tissue with pus.Perianal skin show indurations .By PR internal opening may be felt.Proctoscopy may show the internal opening at the level of dentate line.Investigations by colonoscopy, Ba enema if Crhon’s is suspected.

Treatment:-

High type (through the sphincter). Fistulotomy or fistulectomy take care of the sphincter, divide internal sphincter, sometime part of external. High type above the sphincter, treat the cause, multiple stage excision and colostomy.

Pruritis Ani

This is intractable itching around the anus. Usually the skin is reddened hyperkeratotic and may become cracked and moist. The causes are numerous: ‘pus, polypus, parasites, piles, psyche’.

Lack of clean lines, excessive sweating, and wearing rough or woolen underclothing are common causes. An anal or perianal discharge which renders the anus moist. The causative lesions include an anal fissure, fistula in ano, prolapsed internal or external haemorrhoids, genital warts and excessive ingestion of liquid paraffin. A mucous discharge is an intense pruritic agent and a polyp can be the cause. A vaginal discharge, especially due to the Trichomonas vaginalis.

Parasitic causes: Threadworms in Children should wear gloves at night, less they scratch the perianal region and are reinfested. Scabies and pediculosis pubis may infest the anal region. Allergy is sometimes the cause, in which case there is likely to be a history of other allergic manifestations, such as urticaria, asthma or hay fever. Antibiotic therapy may be the precipitating factor.

Skin diseases localised to the perianal skin : psoriasis, lichen planus and contact dermatitis. Bacterial infection. Intertrigo due to a mixed bacterial infection. A psychoneurosis. neurotic individuals become so immersed in their complaint that a pain pleasure complex develops, the pleasure being the scratching. Diabetes can sometimes present with pruritus ani and the urine should be tested in all patients.

Treatment

The cause is treated. Other methods include the following. Hygienic measures. Cotton wool should be substituted for toilet paper. Soap is avoided . If there is much anal hair trapping the moisture and discharge, shaving can be very helpful. Hydrocortisone. in cases with dermatitis, and only in cases with dermatitis, prednisolone, applied topically.


Hypertrophied Anal Papilla Anal papillae present at the dentate line. As these papillae are present in 60 per cent of patients examined proctologically, they should be regarded as normal structures. Anal papillae can become elongated, as they frequently do in the presence of an anal fissure.

Occasionally, an elongated anal papilla may be the cause of pruritus. An elongated anal papilla associated with pain and/or bleeding at defecation is sometimes encountered in infancy. Haemorrhage into a hypertrophied anal papilla can cause sudden rectal pain. Treatment. Using a proctoscope, elongated papillae without haemorrhoids should be crushed and excised after injecting the base with local anaesthetic.

Proctalgia Fugax

This disease is characterised by attacks of severe pain arising in the rectum, recurring at irregular intervals and apparently unrelated to organic disease. The pain is described as cramp-like, often occurs when the patient is in bed at night, usually lasts only for a few minutes and disappears spontaneously. It may follow straining at stool, sudden explosive bowel action or ejaculation. It seems to occur more commonly in patients suffering from anxiety or undue stress, and also it is said to afflict young doctors. The pain may be unbearable. It is unpleasant, incurable, but fortunately harmless and gradually subsides.


Non Malignant Strictures 
Congenital Patients who have had an operation for imperforate anus in infancy may require periodic anorectal dilatation.

Spasmodic

• An anal fissure causes spasm of the internal sphincter.•Rarely, a spasmodic stricture accompanies secondary megacolon , possibly due to chronic use of laxatives.

Organic

Postoperative stricture sometimes follows haemorrhoidectomy performed incorrectly, low coloanal anastomoses, especially if a stapling gun is used, can narrow down postoperatively. Irradiation stricture. Senile anal stenosis a condition of chronic internal sphincter contraction is sometimes seen in the aged. Increasing constipation is present with pronounced straining at stool.

Inflammatory bowel diseaseStricture of the anorectum also complicates ulcerative proctocolitis and most commonly large bowel Crohn’s disease, A carcinoma should be suspected if a stricture is found, until a biopsy is obtained.Endometriosis of the rectovaginal septum may present as a stricture. There is usually a history of frequent menstrual periods with the appearance of severe pain during the first 2 days of the menstrual flow Neoplastic.

Clinical features Increasing difficulty in defecation is the leading symptom. The patient finds that increasingly large doses of aperients are required, and if the stools are formed, they are ‘pipe-stem’ in shape.In cases of inflammatory stricture, tenesmus, bleeding and the passage of mucopus are superadded. Sometimes the patient comes under observation only when subacute or acute intestinal obstruction has supervened.

Rectal examination. The finger encounters a sharply defined shelf-like interruption of the lumen. A biopsy of the stricture must be taken.

Anoplasty This technique is particularly useful for postoperative strictures.

Colostomy Colostomy must be undertaken when a stricture is causing intestinal obstruction, and in advanced cases of stricture complicated by flstulae in ano. Rectal excision and coloanal anastomosis When the strictures are at or just above the anorectal junction, and with a normal anal canal, but irreversible changes necessitate removal of the area., Eg. post irradiation.

Malignant lesions of the anus and anal canal

Pathological types Squamous cell carcinoma Basaloid carcinoma Mucoepidermal carcinoma Basal cell carcinoma Malignant melanoma Anal intraepithelial neoplasia (AIN)

Squamous cell carcinoma Because of its superficial situation, the presence of this lesion is frequently recognized by the patient, who often presents early.

The following malignant tumours of the anal canal are also found, but they are rare.Basaloid carcinomais a form of nonkeratinising squamous carcinoma. It can metastasise to lymph nodes and can be highly malignant. It is not very sensitive to irradiation. Mucoepidermoid carcinoma This tumour arises near the squamocolumnar cell junction and is of average malignancy. It is radiosensitive.Basal cell carcinoma These are ‘skin tumors' and behave accordingly.

Melanoma Melanoma of the anus presents as a bluish-black soft mass that is confused with a thrombotic pile, and therefore unfortunately incised, Such trauma, followed by the trauma of defecation, incites the tumour to rapid metastasis. Left undisturbed, it ulcerates and the colour of the tumour changes from blue to black. The inguinal lymph nodes are soon involved. Unless a melanoma is excised at an early stage, it disseminates by the bloodstream. The tumour is radioresistant and has a very poor prognosis

Lymphoma This may rarely affect the anal region and may be part of a more widespread lymphomatous condition.

Clinical features Anal cancer can occur at almost any age, but is usually found in the 6th and 7th decades. It is a rare condition, accounting for approximately 2 per cent of all colorectal cancers. Symptoms include rectal bleeding, mucus discharge, tenesmus, the sensation of a lump in the anus and a change in bowel habit.

Occasionally, a patient may present with a mass in the inguinal region due to metastatic lymph nodes. Rectal examination may reveal an ulcerating, hard, tender, bleeding mass in the anal canal or at the anal verge. The lesion may fungate through the anal canal and appear on the anal skin, or present through a chronic anal fistula.

Predisposing conditionsThere appears to be a relationship between anal condylomata caused by the human papilloma virus, particularly type 16, and anal cancer. The disease is more prevalent in patients infected with the human immunodeficiency virus .Higher incidence of anal cancer in patients with Crohn’s disease.

Treatment:-

Carcinoma of Anal Canal: - 
One of two lines:- Abdominoperineal resection: Resection of anal canal and rectum with terminal colostomy. Chemo-radation: A coarse of combination of chemotherapy followed by raddation , residual tumour after 4-6 weeks A-P resection done .