The exact etiology of colon and rectal cancer is unknown. Both genetic and environmental factors probably play a role. Most colorectal cancers are sporadic occurrences with the patient having no family history of colorectal cancer and no predisposing disease. However some colorectal cancers are caused by known genetic disorders; some colorectal cancers seem to have strong familial tendencies; and some colorectal cancers are related to specific premalignant diseases.

Inherited colorectal cancer includes familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. Familial adenomatous polyposis (FAP) is an autosomal dominant condition that accounts for 1% of all colorectal cancers. Individuals that inherit the gene develop hundreds of adenomatous polyps throughout the colon – and develop colorectal cancer by the age of 40 if not treated surgically.

When epidermoid cysts and osteomas of bone accompany the colon polyps in FAP, the condition is known as Gardner’s Syndrome. When brain tumors are associated with FAP, the condition is known as Turcot’s Syndrome.

The abnormal gene in FAP has been identified – it is known as the APC gene or adenomatous polyposis coli gene. Also, patients are seen with FAP as a result of a spontaneous genetic mutation – no family history of FAP is present.

Children of patients with FAP should be screened for colon polyps beginning at the age of 10 and screened at yearly intervals. Ten is selected as the age to begin screening because polyps start developing in affected individuals around the time of puberty. Screening means flexible sigmoidoscopy – not colonoscopy – because the polyps always involve the rectum and sigmoid colon. Screening, when negative, should be continued at yearly intervals until the age of 40.

Gastroscopy should be included as screening – both in patients at risk and in patients with FAP – because of the increased frequency of gastric and duodenal adenomas. Gastroscopy should be done every two years.

During the course of screening, or in a patient with a spontaneous mutation, the finding of large numbers of adenomatous polyps is an indication for surgery. Subtotal colectomy with ileorectal anastomosis is the procedure of choice if the rectal mucosa is not covered with polyps. (Description) Following surgery, patients require proctoscopic examination every six months to detect and remove any new rectal polyps that develop. Drug therapy has been tried for polyps that are left in the rectum after subtotal colectomy and ileorectal anastomosis. These drugs include Sulindac, Vioxx, and Vitamin C.

If a patient has large numbers of polyps in the rectum, proctocolectomy with ileal pouch and anal anastomosis is the best surgical option. (Description)

Following surgery for FAP, the development of an intra-abdominal desmoid tumor is seen on rare occasions. Although benign, the development of a desmoid is a lethal complication – producing severe pain and small bowel obstruction. Surgical resection is not possible. Other forms for therapy have been tried with only modest success – radiation, chemotherapy, Tamoxifen, and Sulindac.

Hereditary Non-polyposis Colorectal Cancer (HNPCC) accounts for 5% of cases of colorectal cancer. This is also an autosomal dominant condition. Cancers arise from polyps, but patients do not have the large numbers of polyps that are seen in FAP.

The key to diagnosis of HNPCC is the family history. The Amsterdam criteria must be met to diagnose the condition. These criteria include all of the following: (1) Three or more family members must have had colorectal cancer and one of the three must be a first degree relative of the other two. (2) The presence of colorectal cancer must cross generations. (3) One of the affected family members must be less than 50 years of age.

Other cancers are associated with HNPCC, especially endometrial cancer, gastric cancer, and urinary tract cancers.

Genetic testing is now available, but cannot detect all affected individuals. If a genetic defect can be identified in a patient with HNPCC then that defect will be present in affected siblings and affected offspring.

In families who most likely have this genetic predisposition for cancer, screening is of utmost importance and should include screening for all associated cancers. Members of affected families should have colonoscopy every two years after the age of 20 and yearly after the age of 40. Occasionally, subtotal colectomy with ileorectal anastomosis is recommended to prevent the development of cancer. Screening for uterine cancer includes annual pelvic exam, Pap smear and vaginal ultrasound. Total abdominal hysterectomy with bilateral salpingo-oophorectomy is frequently recommended to prevent uterine and ovarian cancer. (In a family who undergoes genetic testing and a genetic defect is identified, those family members with negative results are spared the intense cancer screening procedures.)

The majority of colon cancers develop from adenomatous polyps. The development of adenomas may be due to genetic mutations. Further genetic mutations may result in the development of carcinoma in the adenoma. The factors that initiate genetic mutations are not known, but may be environmental.

Although most colorectal cancers are not inherited, there is also a familial predisposition to the development of colorectal cancer. If a person has one or more first-degree relatives with colorectal cancer there is a 3 to 9 fold increase in that individual’s risk of developing colorectal cancer.

Environmental factors may have role in the development of colon and rectal cancer. A diet high in fat may be associated with the development of colon cancer. The incidence of colon cancer in a nation or group of people tends to correlate with the percent of fat in their diet. In the United States and Europe diets tend to have an increased amount of fat and there is an increased number of cases of colon cancer. In Africa, diets tend to be low in fat and there is a decreased frequency of colon cancer.

An increase in dietary fiber has been suggested, but not proven, to be associated with a decreased risk of colon cancer.

No specific carcinogen has been associated with colon cancer, but a number have been suggested, - including bile acids, food additives, alcohol, and ionizing radiation.

There are diseases that are considered pre-malignant conditions. In both chronic ulcerative colitis and in Crohn’s colitis, there is a significant increase in the development of colon cancer.

Detection of polyps, cancer. Colon cancer is the second leading cause of cancer deaths in the United States. The detection and surgical removal of cancer in an early stage, especially in a patient without symptoms, will result in an improved cure rate. The hemoccult test for blood in the stool is useful in screening large groups of asymptomatic adults. A patient should be given a hemoccult kit and instructed to follow the directions. If a positive result is obtained, colonoscopy should be carried out. False positive results are common – due to things in the diet, due to certain medications, and due to non-neoplastic sources of bleeding. The hemoccult test should not be performed on a stool specimen obtained by digital rectal exam during a routine physical examination because of the increased risk of false positive results. False negative results occur because most benign polyps do not bleed and 25% of cancers do not bleed at the time of the hemoccult test.

Other methods that may detect polyps and cancer of the colon and rectum include digital rectal examination, rigid proctoscopy, flexible sigmoidoscopy, air contrast barium enema, video colonoscopy, and, in the future, virtual colonoscopy.

Again, screening of asymptomatic individuals will decrease the death rate due to colon and rectal cancer. Unfortunately, only about 20% of Americans over the age of 50 have had any form of screening.

The American Cancer Society recommends that Americans over the age of 50 who have no risk factors for colon and rectal cancer undergo either sigmoidoscopy every 5 years with annual hemoccult testing or undergo colonoscopy every 10 years.

Patients at increased risk for colorectal cancer include those with (1) a previous cancer or adenomatous polyp (2) a history of chronic ulcerative colitis or Crohn’s colitis (3) a family history of colon cancer, involving a first degree relative (4) a family history of FAP or HNPCC (5) a history of ovarian, uterine or breast cancer (6) a history of abdominal radiation. These patients should have colonoscopy. The age at which screening should begin and the frequency of screening depends upon the specific risk factor. For more information on screening for colon and rectal cancer, see www.clinic-for-crs.com

Polyps. A polyp refers to a growth in the colon found on endoscopy or barium enema that appears to be benign. A hyperplastic polyp is a small polyp that is frequently encountered at the time of colonoscopy. It is more common than the adenomatous polyp. The hyperplastic polyp is usually about 5 mm in size although larger ones do occur. It should be biopsied, destroyed, or removed when found. Mixed hyperplastic and adenomatous polyps do occur and should be treated as adenomatous polyps. Most "experts" consider hyperplastic polyps to have no relationship to the development of cancer.

Adenomas (adenomatous polyps) are benign polyps that are considered to be potential sites for the development of colon and rectal cancer. Adenomas are described as pedunculated if on a stalk or sessile if flat. According to the microscopic appearance adenomas may be classified as tubular adenomas (65 to 80% of adenomas), tubulovillous adenomas (10 to 20 %), or villous adenomas (5 to 10%). Tubular adenomas tend to be pedunculated and villous adenomas tend to be sessile. There is a good deal of evidence that the benign adenoma is the precursor to colorectal cancer in the majority of cases. Even at a size of 1 centimeter, an adenoma has a chance to contain malignant cells, especially if it is flat or of the villous variety.

Polyps may be discovered when screening patients or during the workup of patients with symptoms, especially rectal bleeding. At the time of colonoscopy, most pedunculated polyps can be removed entirely by the snare cautery technique. Sessile polyps can be totally removed in some cases, removed piecemeal in some cases, or destroyed with the electrocautery after adequate biopsies are taken.

Invasive cancer – cancer that invades into the submucosal layer – may be seen in polyps. Polypectomy is sufficient treatment if the polyp is pedunculated (has a stalk) and the cancer does not invade the stalk of the polyp and if the cancer does not show unfavorable features such as poor differentiation or vascular invasion. Invasive cancer in a flat polyp usually requires bowel resection to be assured of a cure.

Colorectal Cancer (CRC). In 2002, The American Cancer Society estimates that 152,000 cases of CRC will be diagnosed. CRC, thus, ranks fourth in frequency of cancer – following lung, breast, and prostate. Approximately 57,000 people will die of CRC – colorectal cancer being second to lung cancer in number of deaths.

Over 99% of colorectal cancers are adenocarcinomas, originating in the mucosa of the colon or rectum. For every 99 adenocarcinomas seen, one cancer of the anal canal will be seen. Cancers of the anal canal originate in the squamous lining or skin of the anal canal or originate at the transition zone, the dentate line, between the skin and rectal mucosa. These cancers are called by various names – squamous cell carcinoma, basaloid cancer, transitional cell cancer – and are grouped together as cancer of the anal canal. Adenocarcinoma of the colon and rectum is treated primarily by surgery whereas cancer of the anal canal is treated primarily by radiation. Cancers of the anal canal may metastasize to the inguinal lymph nodes whereas adenocarcinoma of the rectum rarely metastasizes to the inguinal lymph nodes.

Colorectal cancer has about an equal frequency in men and women. The peak incidence of CRC is between ages 60 and 70. Colorectal cancer can occur at any age, but is unusual prior to the age of 40.

The symptoms and signs of colorectal cancer are dependent upon the location of the cancer. Cancers of the right colon tend to involve only a portion of the wall of the colon and do not cause a change in bowel habit. These tumors may produce anemia, a positive hemoccult test, or dark blood in the stool. Occasionally, in advanced cases periumbilical pain or right lower quadrant pain may occur and in thin patients a right lower quadrant mass may be detected.

Cancers of the left colon tend to be circumferential and cause a change in bowel habit, cramping abdominal pain, or bright red blood in the stool.

Rectal cancer may produce bright red blood per rectum, rectal pain, or tenesmus. Tenesmus refers to increased frequency or urge to defecate.

Occasionally, a patient will initially be seen with a large bowel obstruction after only a brief period of symptoms. Such a patient will complain of obstipation, cramping abdominal pain, and abdominal distention. Unrelieved large bowel obstruction with distention of the colon can lead to ischemia, necrosis, and perforation of the cecum.

The diagnosis of large bowel obstruction can be made with a flat plate (x-ray) of the abdomen – which shows marked dilatation of the colon proximal to the point of obstruction – followed by a water-soluble enema.

Small bowel obstruction is a common problem seen in the practice of medicine. The cause of small bowel obstruction is usually different from that of large bowel obstruction. The signs, symptoms, diagnosis, and treatment are likewise different and one should read carefully the text on small bowel obstruction.

Other causes of large bowel obstruction, besides CRC, include volvulus, incarcerated hernias, intussusception, and strictures. Strictures may be due to diverticulitis, radiation treatments, or inflammatory bowel disease.

Obstruction of the colon secondary to cancer, as well as other causes, requires surgery as soon as the patient is ready. A cancer of the right colon, causing obstruction, may be treated by resection and ileocolic anastomosis – a one-stage resection. Cancer of the distal ½ of the colon is a more difficult problem and may require a two stage or three-stage resection. (Description) This is because the bowel cannot be adequately prepped for surgery in a patient with large bowel obstruction. Occasionally, an obstruction of the distal ½ of the colon can be treated by subtotal colectomy with anastomosis of the terminal ileum to the sigmoid or rectum.

A patient with colon cancer occasionally presents with a perforation of the colon. The tumor may obstruct the blood flow to that segment of the colon with the result being a perforation. Perforation into the peritoneal cavity may cause peritonitis and require urgent surgery. Perforation diminishes the opportunity for cure of the patient. Perforation may also lead to a contained intra-abdominal abscess or to a fistula into another organ. For cases of perforation with peritonitis or perforation with abscess, a two stage resection is required.

Similar to polyps, colorectal cancer may be detected by digital rectal exam, rigid proctoscopy, flexible sigmoidoscopy, air contrast barium enema or video colonoscopy. In the future virtual colonoscopy may be a tool to diagnose colon cancer.

A patient diagnosed with colon cancer should have total colonoscopy, if possible, to look for polyps or a second colon cancer. If colonoscopy is not feasible because of partial or complete obstruction by the primary lesion, total colonoscopy should be performed about 4 to 6 months after surgery.

Other testing that is commonly carried out in patients with CRC includes CEA testing, CT scanning of the abdomen and pelvis, and chest x-ray. Evaluation of any medical problems should be done. A blood transfusion may be necessary prior to surgery in patients who are anemic.

For elective surgery, bowel preparation is necessary to remove fecal material from the colon and to reduce the bacterial population. The diet is restricted to clear liquids for 24 hours prior to surgery. A polyethylene glycol solution – PEG, Colyte, Golytely – is given orally to lavage the large intestine. Intravenous antibiotics are started simultaneously with surgery and continued for 24 hours. If a patient cannot tolerate Colyte, two doses of Fleet Phoso-soda, each 1 ½ ounces, may be used for bowel preparation.

The bowel prep may be done as an outpatient. Older patients may require hospital admission for bowel preparation or for evaluation of other medical problems.

At the time of surgery for colon cancer, the section of colon containing the tumor as well as the mesentery to that part of the colon should be resected. The mesentery contains the draining veins, lymphatics, and lymph nodes. (Description) If the tumor invades an adjacent structure, it may be resected along with the tumor. Structures that can easily be resected "en-bloc" include small bowel, abdominal wall, uterus, ovary, spleen, and tail of the pancreas. Part or all of the bladder can be resected with a rectal cancer.

The rectum is the distal 15 cms of the large bowel. Cancers of the rectum are removed by anterior resection or by abdominal perineal resection. Because of the narrow confines of the pelvis, especially in men and in the obese patient, resection is more difficult than that carried out for tumors of the colon. There is also an increase in the risk of local recurrence and a decrease in the survival rate. (Description)

Abdominal perineal resection results in a permanent colostomy. (Description) An enterostomal therapist – E.T. – sees patients who may need a colostomy and marks the optimal site on the abdominal wall – a site away from scars, skin folds, and the belt line, and a site that can be seen and managed by the patient. The ideal location is ½ way between the iliac crest and the umbilicus and through the rectus abdominus muscle. Three fourths of patients irrigate the colostomy after surgery and establish very good control of their bowel function.

Complications of surgery for rectal cancer may include:

1. Anastomotic leak. The proximal bowel to be anastomosed must be healthy in appearance with an unequivocally good blood supply. There must be NO tension on the anastomosis.

2. Intra-operative hemorrhage – from pre-sacral veins.

3. Non-healing perineal wound after AP resection.

4. Impotence in men.

5. Urinary problems – urinary retention in men, especially those with BPH, and incontinence in women.

6. Stomal complications – hernia, prolapse, stenosis.

7. Small bowel obstruction, especially in patients with postoperative radiation.

It is my opinion that surgical technique has not lead to improved cure rates in the last 30 or so years. One exception may be in surgery for rectal cancer. Recent studies have shown that surgeons with a high volume practice – 20 or more resections per year – and surgeons with additional training – colon and rectal surgical residency – get better results than those who do fewer than 20 cases per year and lack additional training.

The key to survival in surgery for colon and rectal cancer is the stage of the disease. Screening and identification of early stage disease will decrease the number of deaths.

Dukes Stage - TMN Stage - 5 Year Survival

A - I - Approximately 80%

B - II - Approximately 50-60%

C - III - Approximately 30%

D - IV - Less than 5%

(A and I refer to cancer confined to the wall of the colon. B and II refer to cancer penetrating the wall of the colon. C and III refer to involvement of the lymph nodes. D and IV refer to distant metastasis.)

Several histological factors have an adverse prognostic influence – these include poor differentiation, presence of signet cells, and venous or lymphatic invasion by the tumor.

In patients with Stage III colon cancer – the lymph nodes are involved – it has been shown that chemotherapy following surgical resection improves the cure rate and is now standard treatment. Studies are underway in patients with Stage II colon cancer – the tumor is through the bowel wall but the lymph nodes are not involved – and preliminary results indicate that the cure rate is increased in young and in healthy individuals.

If a rectal cancer is found to be below the peritoneal reflection (The peritoneal reflection is about 10 cm. from the anal verge), chemotherapy plus postoperative radiation results in a better cure rate than surgery alone. However, there is a significant increase in postoperative problems when radiation is given following surgery. Another way to treat rectal cancer that may reduce the complications of radiation therapy is to stage the cancers with rectal ultrasound. In those patients who have a tumor within 10 cm of the anal verge and who are staged by ultrasound as II or III should have pre-operative radiation followed by surgical excision followed by postoperative chemotherapy. Again, there seems to be fewer complications, especially small bowel obstruction secondary to adhesive disease, when radiation is given pre-operatively.

 

After surgery for colorectal cancer, patients should be seen every 4 months for 5 years. A brief history should be taken. Examination of the abdomen and perineal wound (if present) is done. Digital rectal examination is done if the patient has had a low anastomosis. A CEA is obtained. More extensive evaluations – chest x-ray, liver studies, CT scanning – have not been shown to result in improved survival.

In patients with a low rectal anastomosis proctoscopic exam should be done yearly. Colonoscopy should be done one year after surgery or at 4-6 months if not done before surgery. After obtaining a negative colonoscopy, the procedure should be repeated every 3 years.

DIVERTICULAR DISEASE

A diverticulum is a hernia or protrusion of mucosa and submucosa through a weak area in the wall of the colon. These weak areas occur where blood vessels penetrate the wall of the colon. A diverticulum (singular) can occur anywhere in the colon, but is most common in the sigmoid colon. The presence of diverticula (plural) in the colon is known as diverticulosis. Diverticulosis is a problem associated with aging. Approximately 50% of people over the age of 50 have diverticulosis and 80% of those over 80 have the condition.

The most popular theory concerning the development of diverticulosis is a diet low in fiber. It is said that a low fiber diet produces a small caliber stool. It requires the generation of increased pressures within the colon to advance such a stool to the rectal area. This results in muscle thickening in the wall of the colon – muscle thickening being the first pathological change in the development of diverticular disease. The high pressure within the colon results in the formation of diverticula at the sites where blood vessels penetrate the wall of the colon.

Countries that tend to eat a low fiber diet – the United States and the West European countries – have a high incidence of diverticulosis. The condition is uncommon in Africa where the diet is high in fiber.

Diverticulosis may be asymptomatic, having been found on barium enema or colonoscopic examinations.

Because diverticula occur at the site of penetration of the wall of the colon by blood vessels, significant bleeding may occur. In fact, diverticulosis is the most common cause of massive bleeding from the large intestine. On the other hand, the finding of diverticulosis is not a sufficient explanation for occult blood loss or a relatively small amount of blood in the stool.

Diverticulitis refers to infection involving a segment of the colon containing diverticula. Usually a microscopic perforation of a diverticulum occurs with a minute amount of fecal extravasation. The infection is contained locally and peri-diverticulitis occurs.

A patient with acute diverticulitis presents with fever, abdominal pain – usually in the left lower quadrant – abdominal tenderness, and an elevated WBC count. If the diverticulitis is adjacent to the bladder, frequency or urgency of urination may occur. Changes in the bowel habit may or may not occur. Bleeding is usually not seen in acute diverticulitis. A patient with diverticulitis may have a left lower quadrant mass. This may indicate the presence of a phlegmon, or more likely, an abscess. Pelvic examination should be carried out in women and may reveal a pelvic mass.

X-rays that are useful in confirming the diagnosis include a water-soluble enema and a C.T. scan of the abdomen and pelvis. The water-soluble enema may show diverticulosis and an area of persistent spasm in the sigmoid colon. Extravasation of the water-soluble contrast indicates a more serious problem – perforation of the colon. Barium should never be used if acute diverticulitis is suspected. The C.T. scan may be normal in some cases, but usually shows thickening of the wall of the colon and streaks in the mesenteric fat.

Treatment of the acute diverticulitis is dietary restriction (clear liquid diet or IV fluids) and antibiotics (PO or IV). Treatment may be rendered as an outpatient or as an inpatient depending upon the severity of the attack. Metronidazole and a cephalosporin or quinolone are good choices of antibiotics. When the patient recovers from the attack of diverticulitis, he or she should have a colonoscopy, or sigmoidoscopy plus barium enema, to identify diverticulosis and to rule out other disease processes such as cancer and Crohn’s disease. Patients with a history of diverticulitis should be placed on a high fiber diet and/or psyllium.

If the patient does not seek medical attention promptly or in severe cases, a perforation of the colon may occur. A perforation with spillage of colon contents into the peritoneal cavity results in peritonitis with an acute surgical abdomen. Free air may be seen on an upright chest film or on an abdominal x-ray or a C.T. scan. These patients require surgical intervention and the conservative operation is a two-stage resection.

A perforation of the colon may occur and be contained by an adjacent structure – abdominal wall, small bowel, or omentum – with the formation of an abscess. An abscess may be detected by C.T. scanning. A patient with a diverticular abscess should be treated with I.V. antibiotics and a consult should be obtained with a radiologist for C.T. guided drainage. If percutaneous drainage is successful, colon resection with anastomosis is performed in 4-6 weeks. If surgery is required for a diverticular abscess, a two-stage resection may be necessary. (Description) This is also called a Hartman Procedure – having first been performed by the Frenchman, Henri Hartman, in 1921 for rectal cancer.

Occasionally, perforation of a diverticular abscess will occur into an adjacent organ resulting in the formation of a fistula. A colovesical fistula occurs between the sigmoid colon and the bladder and is the most common cause of pneumaturia. A colovaginal fistula may occur between the sigmoid colon and the vaginal cuff in women who have had a hysterectomy.

When a patient presents with pneumaturia, this is pathognomonic of an enterovesical fistula. The most common fistula is a colovesical fistula secondary to diverticulitis. These fistulas are more common in men because the uterus is positioned between the sigmoid colon and the bladder in women. Other causes of enterovesical fistulas include cancer, Crohn’s disease, and fistulas complicating radiation treatment. An enterovesical fistula requires surgery to prevent chronic ascending urinary tract infection and renal failure.

A colovesical fistula secondary to diverticulitis is usually detected by C.T. scan with the finding of pericolic inflammation and air around and in the bladder. Cystoscopic examination usually shows evidence of cystitis, especially at the site of the fistula. This is called a herald patch.

Surgery for a colovesical fistula secondary to diverticulitis is not an emergency as the infection is usually drained by way of the bladder. Colonoscopy should be done to rule out colon cancer and inflammatory bowel disease. Elective surgery should be performed when the patient is ready. A left hemicolectomy is carried out, the fistula is divided, and an anastomosis is performed between healthy proximal colon and the rectum. Resection of the bladder is not required as the disease is in the colon. The opening into the bladder should be closed if possible. Omentum is placed between the colon and bladder. A Foley catheter is left in place for 7 to 10 days.

Following resolution of acute diverticulitis, a stricture of the colon may result. Surgery is usually indicated because the stricture may be symptomatic and because one can never be sure that a malignancy is not present.

The indications for surgery in diverticulitis include (1) recurrent bouts of diverticulitis and (2) the development of a complication of the disease – perforation with acute peritonitis, perforation with an abscess, fistula, stricture.

In patients who have had two documented attacks of diverticulitis, elective surgery is indicated to prevent subsequent attacks, which may result in perforation of the colon with an increased morbidity and mortality and the likelihood of a temporary colostomy. In the younger patient, less than 40, surgery should be offered to them for the same reasons following a single episode of diverticulitis.

When a patient has elective surgery for a previous bout(s) of diverticulitis, a one-stage procedure is nearly always possible. All of the diverticulosis does not need to be resected – only the segment of the bowel that is found to be thickened due to previous inflammation. Usually the descending colon is anastomosed to the upper rectum.

HEMORRHOIDS

Hemorrhoids, or piles, have afflicted mankind since the beginning. A hemorrhoid is a highly vascularized cushion of tissue containing both arteries and veins as well as smooth muscle and connective tissue. Hemorrhoids are located just above the dentate line of the anal canal and just below the dentate line. There are normally three distinct hemorrhoidal columns – one in the left lateral position, one in the right anterior position, and one in the right posterior position. Each of the three hemorrhoids has an internal component, above the dentate line, covered by rectal mucosa and an external component, below the dentate line, covered by skin.

The cause of hemorrhoids is unknown. There is no common factor associated with the development of symptomatic hemorrhoids – pregnancy may be the one exception. With time hemorrhoids may increase in size and protrude through the anal verge, especially with straining. Symptoms due to hemorrhoids include rectal bleeding, protrusion with discomfort, and anorectal discharge. Hemorrhoids are only one of several causes of itching or pruritis. Rupture of a vein associated with a hemorrhoid my lead to a hematoma, commonly called a thrombosed external hemorrhoid. A thrombosed external hemorrhoid results in moderate to severe pain and a perianal mass.

Hemorrhoids are diagnosed by placing the patient in the prone jack-knife position and inspecting the perianal area and performing a digital rectal exam and anoscopic exam.

Virtually every anorectal complaint is ascribed to hemorrhoids by patients and a flexible sigmoidoscopy should be done to rule out other pathology. In patients with rectal bleeding or a change in the bowel habit a total colon study, such as colonoscopy, should be performed.

One should be very careful when evaluating patients with hemorrhoids and rectal bleeding. Although hemorrhoids may be the most common cause of rectal bleeding, patients may need flexible sigmoidoscopy and air contrast barium enema or may need colonoscopy to be accurately diagnosed.

Hemorrhoids may be classified as grade I – IV. Grade I hemorrhoids protrude with straining, but not through the anal verge. Grade II hemorrhoids protrude through the anal verge and spontaneously return to their normal positions. Grade III hemorrhoids prolapse through the anal verge and require manual reduction. Grade IV hemorrhoids are incarcerated and cannot be reduced.

Hemorrhoids are treated non-surgically with the use of fiber, with warm tub soaks, with the use of a cleansing agent such as Balneol, and with topical ointments and creams. Though popular the topical agents have never been proven to be effective. Grade II and grade III hemorrhoids may be treated by placing a rubber band on the internal component. Theoretically, the rubber band interrupts the blood flow through the hemorrhoid with some shrinkage. It may also fix the hemorrhoid in the anal canal and prevent most of the prolapse. Some grade III hemorrhoids and most grade IV hemorrhoids are treated surgically.

A very painful thrombosed external hemorrhoid can usually be excised in the office. If the patient is having little or no pain when he is seen excision is not necessary. The patient may be treated with fiber, warm tub soaks and a cleansing agent.

ANAL FISSURE

An anal fissure (fissure-in-ano) is a tear or ulceration in the perianal skin at the anal verge. It is usually located in the midline, either posteriorly or anteriorly with posteriorly being the most common. The diagnosis can usually be made by examination of the patient in the prone jack-knife position with gentle spreading of the buttocks. Digital rectal examination and anoscopic examination are usually not necessary. These examinations may even be impossible in a patient with a painful fissure.

Patient who have a fissure have been found to have increased internal anal sphincter pressures and this is the most likely cause of a fissure.

The usual symptom of a fissure is pain at the time of defecation. Rectal bleeding may also occur. Occasionally an associated abscess may develop.

Non-operative treatment of an anal fissure requires the use of fiber, hot tub soaks, a cleansing agent such as Balneol, and topical agents such as Americaine ointment, hydrocortisone cream, or nitroglycerine ointment. About one half of fissures fail to heal with medical management and require surgery because of persistent pain. The surgical procedure of choice is lateral internal sphincterotomy. (Description)

Following lateral internal sphincterotomy, 95% or more of fissures will heal. Complications include temporary incontinence (of flatus or loose stools) and wound infection. Permanent incontinence is rare.

PERIRECTAL ABSCESS AND FISTULA-IN-ANO

There are vestigial glands that empty into the anal canal – at the level of the dentate line. Bacterial infection of the glands may result in a perirectal abscess. This is known as a cryptoglandular infection. These common infections should not be confused with other forms of anorectal infection such as hidradenitis supprative, pilonidal disease, anorectal Crohn’s disease or rarer infections such as tuberculosis or actinomycosis.

The acute phase of cryptoglandular infection is an abscess. If the abscess is drained – either spontaneously or by surgical intervention – and an infected tract remains, the process enters the chronic phase, that of a fistula-in-ano. (Description)

Infection begins in the anal glands. Because these glands extend through the internal sphincter, an abscess usually develops between the internal and external sphincter. If the abscess extends downward to a location adjacent to the anus, it becomes a perianal abscess. If the abscess ruptures through the external sphincter into the ischiorectal fossa it becomes an ischiorectal abscess. The abscess may extend upward between the internal and external sphincters to form an intersphincteric abscess or a supralevator abscess. Fortunately, the supralevator abscess is not common.

Clinically, the patient with a perirectal abscess has moderate to severe anal pain. A mass may be detected on inspection of the perianal area or on digital rectal exam. Occasionally, the patient will have urinary retention, fever, or sepsis.

The treatment of a perirectal abscess is drainage as soon as the diagnosis is made. Antibiotics have no role as primary treatment of a perirectal abscess, but should be used in association with the surgery if there is extensive cellulitis, if the patient is diabetic or immunocompromised, or if the patient has an artificial heart valve. Proctosigmoidoscopy should be carried out at the time of surgery to rule out other anorectal disease.

A perianal abscess can occasionally be drained in the office under local anesthesia. Those perianal abscesses that cannot be drained in the office and ischiorectal abscesses should be drained under anesthesia. Enough skin is removed over the abscess to allow adequate drainage. An intersphincteric abscess is drained, under anesthesia, by dividing the internal anal sphincter from its lower edge to the upper extent of the abscess. A supralevator abscess can be drained by an incision in the rectal wall over the abscess.

Drainage, alone, of these abscesses results in a cure in 40 to 50% of cases. The remaining patients develop a fistula. A fistula is associated with chronic infection and the patient has persistent drainage or recurrent abscess formation. The site of origin of the fistula – usually at the dentate line – is known as the primary opening of the fistula. The site of drainage of the fistula is known as the secondary opening of the fistula.

At the time of surgery for a perirectal abscess, if the primary opening can be definitely identified, surgery in the form of a fistulotomy can be carried out. Otherwise, it is best to simply drain the abscess. If a fistula develops the patient will need a second procedure.

Following the drainage of a perirectal abscess a fistula will develop in about 50 to 60% of cases. The diagnosis of a fistula is made by inspection of the perianal area and by anoscopic exam.

There are four types of fistulas. (Diagram)

The goal of treatment of a fistula is eradication of the fistula and preservation of continence. For intersphincteric fistulas, 70% of all fistulas, and for transphincteric fistulas, 25% of all fistulas, treatment is a fistulotomy. The fistula is incised or "laid open" from its secondary opening on the perianal skin to its primary opening in the anal canal.

In the anterior fistula in a female and in a fistula that involves a large amount of sphincter muscle, fistulotomy may lead to incontinence. In these cases a fistula may be divided in two stages or may be divided with the use of a cutting seton. (Description) Also, the fistulas may be removed from the primary opening through the rectal wall and the resultant defect covered by an advancement flap of rectal wall. A newer form of treatment of fistulas is the injection of fibrin glue.

Care should be taken in treatment of the anterior fistula in women because of a paucity of sphincter muscle in the area between the rectum and vagina. This fistula as well as fistulas involving a large amount of sphincter muscle, suprasphincteric fistulas and extrasphincteric fistulas should be treated by surgeons who do a large volume of anorectal surgery.