Rectal polyps
Rectal polyps are masses of tissue that rise above the mucosal membrane and protrude into the GI tract. Types of polyps include common polypoid adenomas, villous adenomas, hereditary polyposis, focal polypoid hyperplasia, and juvenile polyps (hamartomas). Most rectal polyps are benign; however, villous and hereditary polyps show a marked inclination to become malignant. Indeed, a striking feature of familial polyposis is that it’s commonly associated with rectosigmoid adenocarcinoma.
Causes and incidence
Formation of polyps results from unrestrained cell growth in the upper epithelium. Predisposing factors include heredity, age, infection, and diet.
Villous adenomas are most prevalent in men older than age 55; common polypoid adenomas, in white women between ages 45 and 60. Incidence in both sexes rises after age 70. Juvenile polyps usually occur among children younger than age 10 and are characterized by rectal bleeding.
Signs and symptoms
Because rectal polyps don’t generally cause symptoms, they’re usually discovered incidentally during a digital examination or rectosigmoidoscopy. Rectal bleeding is a common sign; high rectal polyps leave a streak of blood on the stool, whereas low rectal polyps bleed freely.
Rectal polyps vary in appearance. Common polypoid adenomas are small, multiple lesions that are redder than normal mucosa. They’re commonly pedunculated (attached to rectal mucosa by a long, thin stalk) and granular, with a red, lobular, or eroded surface.
Villous adenomas are usually sessile (attached to the mucosa by a wide base) and vary in size from 0.5 to 12 cm. They are soft, friable, and finely lobulated. They may grow large and cause painful defecation; however, because adenomas are soft, they rarely cause bowel obstruction. Sometimes adenomas prolapse outside the anus, expelling parts of the adenoma with feces. These polyps may cause diarrhea, bloody stools, and subsequent fluid and electrolyte depletion, with hypotension and oliguria.
In hereditary polyposis, rectal polyps resemble benign adenomas but occur as hundreds of small (0.5 cm) lesions carpeting the entire mucosal surface. Associated signs include diarrhea, bloody stools, and secondary anemia. In patients with hereditary polyposis, changes in bowel habits with abdominal pain usually signal rectosigmoid cancer.
Juvenile polyps are large, inflammatory lesions, commonly without an epithelial covering. Mucus-filled cysts cover their usually smooth surface.
Focal polypoid hyperplasia produces small (less than 3 mm), granular, sessile lesions, similar to the colon in color, or gray or translucent. They usually occur at the rectosigmoid junction.
Diagnosis
Confirming diagnosis Firm diagnosis of rectal polyps requires identification of the polyps through proctosigmoidoscopy or colonoscopy and rectal biopsy.
Barium enema can help identify polyps that are located high in the colon. Supportive laboratory findings include occult blood in the stools, low hemoglobin level and hematocrit (with anemia) and, possibly, serum electrolyte imbalances in patients with villous adenomas.
Treatment
Treatment varies according to the type and size of the polyps and their location in the colon. Common polypoid adenomas less than 1 cm require polypectomy, usually by fulguration (destruction by high-frequency electricity) during endoscopy. For common polypoid adenomas over 4 cm and all invasive villous adenomas, treatment usually consists of abdominoperineal resection or low anterior resection.
Focal polypoid hyperplasia can be obliterated by biopsy. Depending on GI involvement, hereditary polyps necessitate total abdominoperineal resection with a permanent ileostomy, subtotal colectomy with ileoproctostomy, or ileoanal anastomosis. Juvenile polyps are prone to autoamputation; if this doesn’t occur, snare removal during colonoscopy is the treatment of choice.
Special considerations
During diagnostic evaluation:
❑ Check sodium, potassium, and chloride levels daily in the patient with fluid imbalances; adjust fluid and electrolytes, as necessary. Administer normal saline solution with potassium I.V., as ordered. Weigh the patient daily, and record the amount of diarrhea. Watch for signs of dehydration (decreased urine and increased blood urea nitrogen levels).
❑ Tell the patient to watch for and report evidence of rectal bleeding.
After biopsy and fulguration:
❑ Check for signs of perforation and hemorrhage, such as sudden hypotension, a decrease in hemoglobin level or hematocrit, shock, abdominal pain, and passage of red blood through the rectum.
❑ Have the patient walk as soon as possible after the procedure.
❑ Watch for and record the first bowel movement, which may not occur for 2 to 3 days.
❑ Provide sitz baths for 3 days.
❑ If the patient has benign polyps, stress the need for routine follow-up studies to check the polypoid growth rate.
❑ Prepare the patient with precancerous or familial lesions for abdominoperineal resection. Provide emotional support and preoperative instruction.
After ileostomy or subtotal colectomy with ileoproctostomy:
❑ Properly care for abdominal dressings, I.V. lines, and indwelling urinary catheters. Record intake and output, and check the patient’s vital signs for hypotension and surgical complications. Administer pain medication, as ordered.
❑ To prevent embolism, have the patient walk as soon as possible, and apply antiembolism stockings; encourage range-ofmotion exercises.
❑ Provide enterostomal therapy and teach the patient stoma care.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Anal symptoms
» Next page: Rectal prolapse (Professional Guide to Diseases (Eighth Edition))
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