What are hemorrhoids?
A precise definition of hemorrhoids does not exist, but they can be described as masses or clumps (“cushions”) of tissue within the anal canal that contain blood vessels and their surrounding, supporting tissue made up of muscle and elastic fibers. The anal canal is the last four centimeters through which stool passes as it goes from the rectum to the outside world. The anus is the opening of the anal canal to the outside world.
Although most people think hemorrhoids are abnormal, they are present in everyone. It is only when the hemorrhoidal cushions enlarge that hemorrhoids can cause problems and be considered abnormal or a disease.
Prevalence of hemorrhoids
Although hemorrhoids occur in everyone, they become large and cause problems in only 4 percent of the general population. Hemorrhoids that cause problems are found equally in men and women, and their prevalence peaks between 45 and 65 years of age.
Anatomy of hemorrhoids
The arteries supplying blood to the anal canal descend into the canal from the rectum above and form a rich network of arteries that communicate with each other around the anal canal. Because of this rich network of arteries, hemorrhoidal blood vessels have a ready supply of arterial blood. This explains why bleeding from hemorrhoids is bright red (arterial blood) rather than dark red (venous blood), and why bleeding from hemorrhoids occasionally can be severe. The blood vessels that supply the hemorrhoidal vessels pass through the supporting tissue of the hemorrhoidal cushions.
The anal veins drain blood away from the anal canal and the hemorrhoids. These veins drain in two directions. The first direction is upwards into the rectum, and the second is downwards beneath the skin surrounding the anus. The dentate line is a line within the anal canal that denotes the transition from anal skin (anoderm) to the lining of the rectum.
Formation of hemorrhoids
If the hemorrhoid originates at the top (rectal side) of the anal canal, it is referred to as an internal hemorrhoid. If it originates at the lower end of the anal canal near the anus, it is referred to as an external hemorrhoid. Technically, the differentiation between internal and external hemorrhoids is made on the basis of whether the hemorrhoid originates above or below the dentate line (internal and external, respectively).
As discussed previously, hemorrhoidal cushions in the upper anal canal are made up of blood vessels and their supporting tissues. There usually are three major hemorrhoidal cushions oriented right posterior, right anterior, and left lateral. During the formation of enlarged internal hemorrhoids, the vessels of the anal cushions swell and the supporting tissues increase in size. The bulging mass of tissue and blood vessels protrudes into the anal canal where it can cause problems. Unlike with internal hemorrhoids, it is not clear how external hemorrhoids form.
What causes hemorrhoids?
It is not known why hemorrhoids enlarge. There are several theories about the cause, including inadequate intake of fiber, prolonged sitting on the toilet, and chronic straining to have a bowel movement (constipation). None of these theories has strong experimental support. Pregnancy is a clear cause of enlarged hemorrhoids though, again, the reason is not clear. Tumors in the pelvis also cause enlargement of hemorrhoids by pressing on veins draining upwards from the anal canal.
One theory proposes that it is the shearing (pulling) force of stool, particularly hard stool, passing through the anal canal that drags the hemorrhoidal cushions downward. Another theory suggests that with age or an aggravating condition, the supporting tissue that is responsible for anchoring the hemorrhoids to the underlying muscle of the anal canal deteriorates. With time, the hemorrhoidal tissue loses its mooring and slides down into the anal canal.
One physiological fact that is known about enlarged hemorrhoids that may be relevant to understanding why they form is that the pressure is elevated in the anal sphincter, the muscle that surrounds the anal canal and the hemorrhoids. The anal sphincter is the muscle that allows us to control our bowel movements. It is not known, however, if this elevated pressure precedes the development of enlarged hemorrhoids or is the result of the hemorrhoids. Perhaps during bowel movements, increased force is required to force stool through the tighter sphincter. The increased shearing force applied to the hemorrhoids by the passing stool may drag the hemorrhoids downward and enlarge them.
What are the symptoms of hemorrhoids?
There are two types of nerves in the anal canal, visceral nerves (above the dentate line) and somatic nerves (below the dentate line). The somatic (skin) nerves are like the nerves of the skin and are capable of sensing pain. The visceral nerves are like the nerves of the intestines and do not sense pain, only pressure. Therefore, internal hemorrhoids, which are above the dentate line, usually are painless.
As the anal cushion of an internal hemorrhoid continues to enlarge, it bulges into the anal canal. It may even pull down a portion of the lining of the rectum above, lose its normal anchoring, and protrude from the anus. This condition is referred to as a prolapsing internal hemorrhoid. In the anal canal, the hemorrhoid is exposed to the trauma of passing stool, particularly hard stools associated with constipation. The trauma can cause bleeding and sometimes pain when stool passes. The rectal lining that has been pulled down secretes mucus and moistens the anus and the surrounding skin. Stool also can leak onto the anal skin. The presence of stool and constant moisture can lead to anal itchiness (pruritus ani), though itchiness is not a common symptom of hemorrhoids. The prolapsing hemorrhoid usually returns into the anal canal or rectum on its own or can be pushed back inside with a finger, but it prolapses again with the next bowel movement. Less commonly, the hemorrhoid protrudes from the anus and cannot be pushed back inside, a condition referred to as incarceration of the hemorrhoid. Incarcerated hemorrhoids can have their supply of blood shut off by the squeezing pressure of the anal sphincter, and the blood vessels and cushions can die, a condition referred to as gangrene. Gangrene requires medical treatment.
For convenience in describing the severity of internal hemorrhoids, many physicians use a grading system:
- First-degree hemorrhoids: Hemorrhoids that bleed but do not prolapse.
- Second-degree hemorrhoids: Hemorrhoids that prolapse and retract on their own (with or without bleeding).
- Third-degree hemorrhoids: Hemorrhoids that prolapse but must be pushed back in by a finger.
- Fourth-degree hemorrhoids: Hemorrhoids that prolapse and cannot be pushed back in. Fourth-degree hemorrhoids also include hemorrhoids that are thrombosed (containing blood clots) or that pull much of the lining of the rectum through the anus.
In general, the symptoms of external hemorrhoids are different than the symptoms of internal hemorrhoids. External hemorrhoids can be felt as bulges at the anus, but they usually cause few of the symptoms that are typical of internal hemorrhoids. This is perhaps, because they are low in the anal canal and have little effect on the function of the anus, particularly the anal sphincter. External hemorrhoids can cause problems, however, when blood clots inside them. This is referred to as thrombosis. Thrombosis of an external hemorrhoid causes an anal lump that is very painful (because the area is supplied by somatic nerves) and often requires medical attention. The thrombosed hemorrhoid may heal with scarring and leave a tag of skin protruding from the anus. Occasionally, the tag is large, which can make anal hygiene (cleaning) difficult or irritate the anus.
How are hemorrhoids treated?
It is believed generally that constipation and straining to have bowel movements promote hemorrhoids and that hard stools can traumatize existing hemorrhoids. It is recommended, therefore, that individuals with hemorrhoids soften their stools by increasing the fiber in their diets. Fiber is found in numerous foodstuffs including fresh and dried fruits, vegetables, grains, and cereals. Generally 20-30 grams per day of fiber are recommended whereas the average American diet contains less than 15 grams of fiber. Supplemental fiber (psyllium, methylcellulose, or calcium polycarbophil) also may be used to increase the intake of fiber. Stool softeners and increased drinking of liquids also may be recommended. Nevertheless, there is no strong, scientific support for the benefits of fiber, liquids, or stool softeners.
Diarrhea is believed to aggravate the symptoms of hemorrhoids and it is recommended that diarrhea be controlled with fiber and anti-motility drugs.
Over-the-counter medications for hemorrhoids
Many over-the-counter products are sold for the treatment of hemorrhoids. These often contain the same drugs that are used for treating anal symptoms such as itching or discomfort. There are few studies showing that they do anything for hemorrhoids. They probably only reduce the symptoms of hemorrhoids. It is possible, however, that their effectiveness relates to their treatment of anal conditions other than hemorrhoids, for example, idiopathic anal itching, that often accompany hemorrhoids.
Products used for the treatment of hemorrhoids are available as ointments, creams, gels, suppositories, foams, and pads. Ointments, creams, and gels--when used around the anus--should be applied as a thin covering. When applied to the anal canal, these products should be inserted with a finger or a "pile pipe." Pile pipes are most efficient when they have holes on the sides as well as at the end. Pile pipes should be lubricated with ointment prior to insertion. Suppositories or foams do not have advantages over ointments, creams, and gels.
Most products contain more than one type of active ingredient. Almost all contain a protectant in addition to another ingredient. Only examples of brand-name products containing one ingredient in addition to the protectant are discussed below.
Local anesthetics temporarily relieve pain, burning, and itching by numbing the nerve endings. The use of these products should be limited to the perianal area and lower anal canal. Local anesthetics can cause allergic reactions with burning and itching. Therefore, if burning and itching increase with the application of anesthetics, they should be discontinued. Local anesthetics include:
- Benzocaine 5% to 20% (Americaine Hemorrhoidal, Lanacane Maximum Strength, Medicone)
- Benzyl alcohol 5% to 20%
- Dibucaine 0.25% to 1.0% (Nupercainal)
- Dyclonine 0.5% to 1.0%
- Lidocaine 2% to 5%
- Pramoxine 1.0% (Fleet Pain-Relief, Procto Foam Non-steroid, Tronothane Hydrochloride)
- Tetracaine 0.5% to 5.0%
Vasoconstrictors are chemicals that resemble epinephrine, a naturally occurring chemical. Applied to the anus, vasoconstrictors make the blood vessels become smaller, which may reduce swelling. They also may reduce pain and itching due to their mild anesthetic effect. Vasoconstrictors applied to the perianal area--unlike vasoconstrictors that are taken orally or by injection--have a low likelihood of causing serious side effects, such as high blood pressure, nervousness, tremor, sleeplessness, and aggravation of diabetes or hyperthyroidism. Vasoconstrictors include:
- Ephedrine sulfate 0.1% to 1.25%
- Epinephrine 0.005% to 0.01%
- Phenylephrine 0.25% (Medicone Suppository, Preparation H, Rectacaine)
Protectants prevent irritation of the perianal area by forming a physical barrier on the skin that prevents contact of the irritated skin with aggravating liquid or stool from the rectum. This barrier reduces irritation, itching, pain, and burning. There are many products that are themselves protectants or that contain a protectant in addition to other medications. Protectants include:
- Aluminum hydroxide gel
- Cocoa butter
- Mineral oil (Balneol)
- White petrolatum
- Zinc oxide or calamine (which contains zinc oxide) in concentrations of up to 25%
- Cod liver oil or shark liver oil if the amount of vitamin A is 10,000 USP units/day.
Astringents cause coagulation (clumping) of proteins in the cells of the perianal skin or the lining of the anal canal. This action promotes dryness of the skin, which in turn helps relieve burning, itching, and pain. Astringents include:
- Calamine 5% to 25%
- Zinc oxide 5% to 25% (Calmol 4, Nupercainal, Tronolane)
- Witch hazel 10% to 50% (Fleet Medicated, Tucks, Witch Hazel Hemorrhoidal Pads)
Antiseptics inhibit the growth of bacteria and other organisms. However, it is unclear whether antiseptics are any more effective than soap and water. Examples of antiseptics include:
- Boric acid
- Benzalkonium chloride
- Cetylpyridinium chloride
- Benzethonium chloride
Keratolytics are chemicals that cause the outer layers of skin or other tissues to disintegrate. The rationale for their use is that the disintegration allows medications that are applied to the anus and perianal area to penetrate into the deeper tissues. The two approved keratolytics used are:
- Aluminum chlorhydroxy allantoinate (alcloxa) 0.2% to 2.0%
- Resorcinol 1% to 3%
Analgesic products, like anesthetic products, relieve pain, itching, and burning by depressing receptors on pain nerves. Examples include:
- Menthol 0.1% to 1.0% (greater than 1.0% is not recommended)
- Camphor 0.1% to 3% (greater than 3% is not recommended)
- Juniper tar 1% to 5%
Corticosteroids reduce inflammation and can relieve itching, but their chronic use can cause permanent damage to the skin. They should not be used for more than short periods of a few days to two weeks. Only products with weak corticosteroid effects are available over-the-counter. Stronger corticosteroid products that are available by prescription should not be used for treating hemorrhoids.
Nonoperative procedures for internal hemorrhoids
There are several nonoperative treatments for internal hemorrhoids. All of them have the same effect. These procedures cause inflammation in the hemorrhoidal cushions, which then produces scarring. The scarring causes the cushions to shrink and attach to the underlying muscle of the anal canal. This prevents the cushions from being pulled down into the anal canal. These treatments do not require anesthesia since they do not cause pain. (The treated area contains only visceral nerves.)
Sclerotherapy is one of the oldest forms of treatment. During sclerotherapy, a liquid (phenol or quinine urea) is injected into the base of the hemorrhoid. Inflammation sets in, and ultimately scarring takes place. Pain may occur after sclerotherapy but usually subsides by the following day. Symptoms of hemorrhoids frequently return after several years and may require further treatment.
Rubber band ligation
The principle of ligation with rubber bands is to encircle the base of the hemorrhoidal anal cushion with a tight rubber band. The tissue cut off by the rubber band dies and is replaced by an ulcer that heals with scarring. It can be used with first-, second-, and third-degree hemorrhoids and may be more effective than sclerotherapy. Symptoms frequently recur several years later but usually can be treated with further ligation. The recurrence of symptoms may be less with ligation than with sclerotherapy.
The most common complication of ligation is pain, which may occur slightly more often than with sclerotherapy, but it tends to be mild. Bleeding one or two weeks after ligation occurs occasionally and can be severe. Bacterial infection may begin in the tissues surrounding the anal canal (cellulitis). Rarely, the infection spreads to the tissues within the pelvis and results in an abscess, or the infection may enter the bloodstream (sepsis). Infectious complications may be more common in patients who have defective immune systems, e.g., from AIDS, cancer, chemotherapy, or severe diabetes.
There are several treatments that use heat to kill hemorrhoidal tissue and promote inflammation and scarring, including bipolar diathermy, direct-current electrotherapy, and infrared photocoagulation. Such procedures kill the tissues in and around the hemorrhoids and cause scar tissue to form. They are used with first-, second-, and third-degree hemorrhoids. Pain is frequent, though probably less frequent than with ligation, and bleeding occasionally occurs. Sclerotherapy, ligation, and heat coagulation are all good options for the treatment of hemorrhoids.
Cryotherapy uses cold temperatures to obliterate the veins and cause inflammation and scarring. It is more time consuming, associated with more posttreatment pain, and is less effective than other treatments. Therefore, this procedure is not commonly used.
The vast majority of patients with symptom-causing hemorrhoids are able to be managed with non-surgical techniques. In the practice of a surgeon adept at managing hemorrhoids non-operatively, it is estimated that less than 10% of patients require surgery if the hemorrhoids are treated early.
Forceful dilation of the anal sphincter by stretching the anal canal has been used to weaken the anal sphincter, the assumption being that the increased sphincter pressure is responsible for the hemorrhoids. Unfortunately, the dilation frequently damages the sphincter itself and many patients become incontinent or unable to control their stool after dilation. For this reason, dilation is rarely used to treat hemorrhoids.
Recently, the use of a special, illuminated anoscope with a Doppler probe that measures blood flow has enabled doctors to identify the individual artery that fills the hemorrho/idal vessels. The doctor then can tie off (ligate) the artery. This causes the hemorrhoid to shrink. The Doppler probe is expensive and seems to offer little advantage over rubber band ligation.
Sphincterotomy. Occasionally, the internal portion of the anal sphincter is partially cut in an attempt to reduce the pressure of the sphincter within the anal canal. This procedure is rarely used alone, and there is concern about incontinence (loss of control) of stool as a potential complication.
Hemorrhoidectomy. Non-operative treatment is preferred because it is associated with less pain and fewer complications than operative treatment. Surgical removal of hemorrhoids (hemorrhoidectomy) usually is reserved for patients with third- or fourth-degree hemorrhoids.
During hemorrhoidectomy, the internal hemorrhoids and external hemorrhoids are cut out. The wounds left by the removal may be sutured (stitched) together (closed technique) or left open (open technique). The results with both techniques are similar. At times, a proctoplasty also is done. A proctoplasty extends the removal of tissue higher into the anal canal so that redundant or prolapsing anal lining also is removed.
What is new in hemorrhoids?
Stapled hemorrhoidectomy. This is the newest surgical technique for treating hemorrhoids. Stapled hemorrhoidectomy is a misnomer since the surgery does not remove the hemorrhoids but, rather, the abnormally lax and expanded hemorrhoidal supporting tissue that has allowed the hemorrhoids to prolapse downward.
For stapled hemorrhoidectomy, a circular, hollow tube is inserted into the anal canal. Through this tube, a suture (a long thread) is placed, actually woven, circumferentially within the anal canal above the internal hemorrhoids. The ends of the suture are brought out of the anus through the hollow tube. The stapler (a disposable instrument with a circular stapling device at the end) is placed through the first hollow tube and the ends of the suture are pulled. Pulling the suture pulls the expanded hemorrhoidal supporting tissue into the jaws of the stapler. The hemorrhoidal cushions are pulled back up into their normal position within the anal canal. The stapler then is fired. When it fires, the stapler cuts off the circumferential ring of expanded hemorrhoidal tissue trapped within the stapler and at the same time staples together the upper and lower edges of the cut tissue.
Internal Hemorrhoids in Anal Canal
Hollow Tube Inserted into the Anal Canal and Pushing up the Hemorrhoids
Suturing the Anal Canal through the Hollow Tube
Bringing Expanded Hemorrhoidal Supporting Tissue into the Hollow Tube by Pulling on Suture
Hemorrhoids Pulled Back Above Anal Canal after Stapling and Removal of Hemorrhoidal Supporting Tissue
During stapled hemorrhoidectomy, the arterial blood vessels that travel within the expanded hemorrhoidal tissue and feed the hemorrhoidal vessels are cut, thereby reducing the blood flow to the hemorrhoidal vessels and reducing the size of the hemorrhoids. During the healing of the cut tissues around the staples, scar tissue forms, and this scar tissue anchors the hemorrhoidal cushions in their normal position higher in the anal canal. The staples are needed only until the tissue heals. They then fall off and pass in the stool unnoticed after several weeks. Stapled hemorrhoidectomy is designed primarily to treat internal hemorrhoids, but if external hemorrhoids are present, they may be reduced as well.
Stapled hemorrhoidectomy is faster than traditional hemorrhoidectomy, taking approximately 30 minutes. It is associated with much less pain than traditional hemorrhoidectomy and patients usually return earlier to work. Patients often sense a fullness or pressure within the rectum as if they need to defecate, but this usually resolves within several days. The risks of stapled hemorrhoidectomy include bleeding, infection, anal fissuring (tearing of the lining of the anal canal), narrowing of the anal or rectal wall due to scarring, persistence of internal or external hemorrhoids, and, rarely, trauma to the rectal wall.
Stapled hemorrhoidectomy was first used in Europe in the mid 1990's and there has been increasing, worldwide usage in recent years. If results continue to be good with more experience and longer follow-up of patients, stapled hemorrhoidectomy is likely to become the mainstay of surgical therapy for symptomatic, prolapsing hemorrhoids.