The word polyp refers to any overgrowth of tissue from the surface of mucousmembranes. Polyps come in a variety of shapes--round, droplet, and irregularbeing the most common; and they affect various parts of the body--the intestines, the nasal passages, the rectum, and the vocal cords.
Polyps are one of many forms of tissue overproduction that can occur in the body. Cells in many body tissues sometimes keep growing beyond their usual limits. Medical scientists call this process neoplasia, which means simply "new growth." An individual overgrowth is called a neoplasm. In most casesthese growths are limited, and the result is a benign swelling or mass of cells called a tumor. If the new growth occurs on the surface of the tissue instead of inside an organ it is often called a polyp. Cancer is another type ofneoplasm marked by unlimited tissue growth. The essential feature that distinguishes cancer from nonmalignant neoplasms is that it does not stop growing.
Intestinal polyps are a common form of neoplasm. All intestinal polyps arisefrom the inner lining of the intestinal wall. This layer of mucosal tissue does the work of digestion. About 30% of the general population will develop intestinal polyps at some point in life, with the likelihood increasing with age. Most of these polyps are never noticed during a person's lifetime becausethey cause no problems. They are often discovered accidentally at autopsy. The primary importance of intestinal polyps is that 1% of them become cancerous. Because the polyps that eventually turn malignant cannot be identified in advance, they are all suspect.
Nasal polyps tend to occur in people with respiratory allergies. Hay fever (allergic rhinitis) is an irritation of the membranes of the nose by airborne particles or chemicals. These membranes make mucus. When irritated, they can also grow polyps. The nose is not only a passageway for air to reach the lungs; it also provides the connection between the sinuses and the outside world.Sinuses are lined with mucus membranes, just like the nose. Polyps can easilyobstruct the drainage of mucus from the sinuses. When any fluid in the bodyis trapped so it cannot flow freely, it becomes infected. The result, sinusitis, is a common complication of allergic rhinitis.
Rectal polyps are tissue growths that arise from the wall of the rectum and protrude into it. They may be either benign or malignant (cancerous). The rectum is the last segment of the large intestine, ending in the anus, the opening to the exterior of the body. Rectal polyps are quite common. They occur in7-50% of all people, and in two thirds of people over age 60.
Vocal cord nodules and polyps are noncancerous growths on the vocal cords that affect the voice.
The vocal cords, located in the voice box in the middle of the neck, are twotough, fibrous bands that vibrate to produce sound. They are covered with a layer of tissue that is similar to skin. With use, this layer thickens. With heavy use, the thickening may localize, producing a nodule. Unlike skin, heavyusage over a short time may also produce polyps. A polyp is a soft, smooth lump containing mostly blood and blood vessels. A nodule is similar to a polyp, but tends to be firmer.
The chances of a polyp's becoming cancerous depend to some extent on its location within the digestive tract. 95 percent of all intestinal polyps developinside the large bowel.
The stomach's lining is host to polyps of a similar appearance, but there isno agreement as to their potential for becoming stomach cancer.
Polyps in the small bowel do not seem to have malignant potential. Instead they can produce obstruction in either of two ways. A large polyp can obstructthe bowel by its sheer size. Smaller polyps can be picked up by the rhythmiccontractions (peristalsis) of the intestines and pull the part of the bowel to which they are attached into the adjoining section. The result is a telescoping of one section of bowel into another, called intussusception.
Population studies of colon cancer suggest that diet plays an important rolein the disease, and by implication in the formation of colon polyps. The mostconsistent interpretation of these data is that animal fats--though not vegetable fats--are the single most important dietary factor. Lack of fiber in the diet may also contribute to polyp formation. Other types of polyps are toorare to produce enough data for evaluation.
Most polyps cause no symptoms. Large ones eventually cause intestinal obstruction, which produces cramping abdominal pain with nausea and vomiting. As colon polyps evolve into cancers, they begin to produce symptoms that include bleeding and altered bowel habits.
Some people who are allergic to aspirin develop both asthma and nasal polyps.
Nasal polyps often plug the nose, usually one side at a time. People with allergic rhinitis are so used to having a stopped up nose they may not notice the difference when a polyp develops. Other polyps may be closer to a sinus opening, so airflow is not obstructed, but mucus becomes trapped in the sinus. In this case, there is a feeling of fullness in the head, no sense of smell, and perhaps a headache. The trapped mucus will eventually get infected, addingpain, fever, and perhaps bloody discharge from the nose.
The cause of most rectal polyps is unknown, however a diet high in animal fatand red meat, and low in fiber, is thought to encourage polyp formation. Some types of polyps are hereditary. In an inherited disease called familial polyposis, hundreds of small, malignant and pre-malignant polyps are produced before the age of 40. Also, inflammatory bowel disease may cause growth of polyps and pseudo-polyps. Juvenile polyps (polyps in children) are usually benignand often outgrow their blood supply and disappear at puberty.
Most rectal polyps produce no symptoms and are discovered on routine digitalor endoscopic examination of the rectum. Rectal bleeding is the most common complaint when symptoms do occur. Abdominal cramps, pain, or obstruction of the intestine occur with some large polyps. Certain types of polyps cause mucous-filled or watery diarrhea.
Chronic infections caused by allergies and inhalation of irritants, such as cigarette smoke, may produce vocal nodules and polyps, but extensive use of the voice is their most common cause. Nodules and polyps are more common in male children, female adolescents, and female adults. This may be due in part tothe faster speed at which the cords vibrate to produce higher-pitched voices.
Voice alterations are most apparent in singers, who may notice the higher registers are the first to change. Hoarseness causes others to seek medical attention.
Routine screening for bowel cancer is recommended for everyone over the age of 40. Screening may be as simple as testing the stool for blood or as elaborate as colonoscopy. Colonoscopy is a procedure in which the doctor threads aninstrument called a colonoscope up through the entire large bowel. Most polyps are in the lower segment of the colon, called the sigmoid colon. These polyps can be seen with a shorter scope called a sigmoidoscope. X ray imaging canalso used to look for polyps. For x rays, the colon is first filled with barium, which is a white substance that shows up as a shadowed area on the film.The colon can also be filled with barium and air, which is called a double contrast study.
Because polyps take about five years to turn into cancers, routine examinations are recommended every three years.
The head and neck surgeon (otorhinolaryngologist) is equipped to diagnose nasal polyps. In order to perform the exam, medicine must be applied to decongest the membranes. Cotton balls soaked with one of these agents and left in thenostrils for a few minutes provide adequate shrinkage.
Rectal polyps are commonly found by sigmoidoscopy (visual inspection with aninstrument consisting of a tube and a light) or colonoscopy. If polyps are found in the rectum, a complete examination of the large intestine is done, asmultiple polyps are common. Polyps do not show up on regular x rays, but theydo appear on barium enema x rays.
The otorhinolaryngologist must see the vocal cords to diagnose vocal nodulesand polyps. It is also important to confirm that there are not other problemsinstead of or in addition to these benign lumps. Other causes of hoarsenessinclude throat cancers, vocal cord paralysis, and simple laryngitis. The cords can usually be seen using a mirror placed at the back of the tongue. More elaborate scopes, including a videostroboscope, allow better views while the cords are producing sounds.
A biopsy of a nodule or polyp will ensure they are not cancerous.
All intestinal polyps should be removed as preventive care. Most of them canbe taken out through a colonoscope. Complications like obstruction and intussusception are surgical emergencies.
Most nasal polyps can be removed by the head and neck surgeon as an office procedure called a nasal polypectomy. Bleeding, the only complication, is usually easy to control. Nose and sinus infections can be treated with antibioticsand decongestants, but if airflow is restricted, the infection will recur.
Before the operation to remove rectal polyps, a colonoscopy (examination of the intestine with an endoscope) is performed, and standard pre-operative blood and urine studies are done. The patient is also given medicated enemas to cleanse the bowel.
The patient is given a sedative and a narcotic pain killer. A colonoscope isinserted into the rectum. The polyps are located and removed with a wire snare, ultrasound, or laser beam. After they are removed, the polyps are examinedto determine if they are malignant or benign. When polyps are malignant, itmay be necessary to remove a portion of the rectum or colon to completely remove cancerous tissue.
Voice rest is the first choice treatment for polyps. Polyps that appeared suddenly will resolve with a few days of complete silence. Nodules do not disappear with rest. Lesions that have been there longer may be slower to disappearand require voice training by a speech therapist.
Nodules and polyps may be surgically removed, using either conventional techniques or lasers.
Patients with hereditary disorders associated with polyps must undergo totalcolectomy early in adult life. All children of parents with these disorders should be screened early in adulthood, because half of them will have the samedisease. For the bulk of the population, increased dietary fiber and decreased animal fat are the best preventives known at present. For the occasional intestinal polyp that arises in spite of good dietary habits, routine screening should prevent it from becoming cancerous.
Since most nasal polyps are the result of allergic rhinitis, they can be prevented by treating this condition. New treatments have greatly improved control of hay fever. There are now several spray medicines that are quite effective. Spray cortisone-like drugs are the most popular. Over-the-counter nasal decongestants have an irritating effect similar to the allergy they are supposed to be treating. Continued use can bring more trouble than relief and resultin an addiction to nose sprays. The resulting disease, rhinitis medicamentosa, is more difficult to treat than allergic rhinitis.
Allergists and ENT surgeons both treat allergic rhinitis with a procedure called desensitization. After identifying suspect allergens using one of severalmethods, they will give the patient increasing doses of those allergens in order to produce blocking antibodies that will impede the allergic reaction. This is effective in a number of patients, but the treatment may take a periodof months to years.
Eating a diet low in red meat and animal fat, and high in fiber, is thought to help prevent rectal polyps.
Careful use of the voice will prevent most vocal cord nodules and polyps. Avoiding inhaled irritants, may also prevent nodules and polyps from forming.