A Fistula is a permanent abnormal passageway between two organs in the body or between an organ and the exterior of the body.
Fistulas can arise in any part of the body, but they are most common in the digestive tract. They can also develop between blood vessels and in the urinary, reproductive, and lymphatic systems. Fistulas can occur at any age or can be present at birth (congenital). Some are life-threatening, others cause discomfort, while still others are benign and go undetected or cause few symptoms. Diabetics, individuals with compromised immune systems (AIDS
, cancer) and individuals with certain gastrointestinal diseases (Crohn's disease, inflammatory bowel disease) are at increased risk of developing fistulas.
Fistulas are categorized by the number of openings they have and whether they connect two internal organs or open through the skin. There are four common types:
- Blind fistulas are open on one end only.
- Complete fistulas have one internal opening and one opening on the skin.
- Horseshoe fistulas are complex fistulas with more than one opening on the exterior of the body.
- Incomplete fistulas are tubes of skin that are open on the outside but closed on the inside and do not connect to any internal structure.
Fistulas of the digestive tract
Anal and rectal fistulas develop in the wall of the anus or rectum. They connect the interior of the body to one or several openings in the skin. Anal and rectal fistulas almost always begin as an inflammation in an anal gland. The inflammation then moves into muscle tissue and develops into an abscess
. In about half of all cases, the abscess develops into a fistula, degrading the muscle until an opening in the skin is created. About 9 people of every 100,000 develop anal fistulas, with men almost twice more likely to develop the condition than women. Although they may develop at any age, the average age for the development of anal fistulas is 38.
Intestinal fistulas can develop in both the large and small intestine. They are commonly associated with diseases such as inflammatory bowel disease(IBD) and Crohn's disease.
Tracheoesophageal fistulas (TEF) are usually birth defects
. The windpipe, or trachea, is abnormally connected to the esophagus. This allows air to enter the digestive system and makes it possible to breathe food into the lungs (aspiration). In many cases, the esophagus is also incomplete, causing immediate feeding problems. There are several types of TEFs categorized by where the fistula is located and how the esophagus and trachea are connected, but all are life-threatening and require prompt surgery to repair. TEFs occur in about one of every 1,500-3,000 births.
Fistulas of the urinary and reproductive tract
The most common type of fistula involving these systems is a vesicovaginal fistula, in which the woman's vagina is connected to the urinary bladder. This causes leakage of urine from the vagina and results in frequent vaginal and bladder infections. Fistulas may also develop between the vagina and the large intestine (a enterovaginal fistula) so that feces leaks from the vagina. Although both these types of fistulas are uncommon in the developed world, they are common in poor developing countries and result from long, difficult labor and childbirth
, especially in very young girls. As a result, they are sometimes referred to as obstetric fistulas.
Some experts suggest that in parts of Africa, as many as 3-4 women develop these fistulas out of every 1,000 births. Others estimate that as many as 2 million women worldwide are living with unrepaired obstetric fistulas. If left unrepaired, obstetric fistulas cause women to constantly leak urine and feces. As a result, they become social outcasts, causing them extreme hardship and psychological trauma.
Fistulas of the circulatory system
Arteriovenous fistulas (AVF) can develop between an artery and a vein in any part of the body. These fistulas vary in size, length, and frequency. Arteries contain blood carrying oxygen to all parts of the body, while veins carry blood that has given up its oxygen back to the lungs. Connections between arteries and veins cause changes in blood pressure that result in abnormal development of the walls of the arteries and abnormal blood flow. Arteriovenous fistulas that are present at birth are sometimes referred to as arteriovenous malformations
(AVMs). Many arteriovenous fistulas are present, but not evident at birth, and become obvious only after trauma. AVFs can also be acquired from penetrating trauma.
Causes and symptoms
The causes and symptoms of fistulas vary depending on their location. Anal and rectal fistulas are usually caused by an abscess. Symptoms include constant throbbing pain
and swelling in the rectal area. Pus is sometimes visible draining from the fistula opening on the skin. Many individuals have a fever
resulting from the infection causing the abscess.
Vaginal fistulas are caused by infection and trauma to the tissue during childbirth. They are easily detected, because the woman smells unpleasant and leaks urine or feces through her vagina. Rarely these fistulas may develop as a complication of hysterectomy
Tracheoesophageal fistulas are the result of errors in the development of the fetus. They are evident at birth, because the infant is unable to swallow or eat normally and are considered a medical emergency that requires surgery if the infant is to survive.
Arteriovenous fistulas are most often congenital defects. Symptoms vary depending on the size and location of the fistula. Often the skin is bright pink or dark red in the area of the fistula. Individuals may complain of pain. The pain is a result of some tissues not receiving enough oxygen because of abnormal blood flow.
Tests use to determine the presence of a fistula vary with the location of the fistula. When there is an opening to the outside, the physician may be able to see the fistula and probe it. Various imaging studies such as x rays, CT scans, barium enemas
, endoscopy, and ultrasonography are used to locate less visible fistulas.
Anal and rectal fistulas are treated by draining the pus the infected area. The individual also is usually given antibiotics
to help prevent recurrence of the abscess. If this fails to heal the fistula, surgery may be necessary.
Intestinal fistulas are treated first by reducing the inflammation in the intestine and then, if necessary with surgery. Treatment varies considerably depending on the degree of severity of symptoms the fistula causes. TEFs are always treated with surgery. Obstetric fistulas must also be repaired with surgery. The treatment of arteriovenous fistulas depends on the size and location of the fistula and usually includes surgery.
No effective alternative treatments for fistulas are known.
The outcome of fistulas depends on the type and cause of the condition. Surgical repair of obstetric fistulas is almost always successful. Unfortunately, many women in developing countries do not have access to this type of surgery. Treatment of anal and rectal fistulas is almost always successful, although fistulas may recur in up to 18% of individuals. The outcome of surgery on TEFs is highly variable, especially since infants born with this condition often have other developmental abnormalities that may affect the outcome of fistula repair. The degree of successful repair of arteriovenous fistulas depends on their size and location. Uncontrolled bleeding is the most common complication of surgery to repair AVFs.
Obstetric fistulas are the only preventable fistulas. These can be prevented with good prenatal and childbirth care and by avoiding pregnancy
in very young girls. Although anal and rectal fistulas are not preventable, their damage can be minimized by prompt drainage and treatment.
— A collection of pus surrounded by inflamed, infected tissue.
— The part of the circulatory system that carries lymph, a clear fluid that is involved in immune system response.
American Society of Colon and Rectal Surgeons. 85 W. Algonquin Road, Suite 550, Arlington Heights, IL 60005. 847-290-9184. http://www.facrs.org.
Legall, Ingrid. Anal Fistulas and Fissures, 11 June 2004 [cited 16 February 2005]. http://www.emedicine.com/emerg/topic495.htm.
"Fistula." Medline Plus Medical Encyclopedia 29 October 2003 [cited 16 February 2005]. http://www.nlm.nih.gov/medlineplus/ency/article/002365.htm.
Morasch, Mark D. and Dipen Maun. Arteriovenous Fistulas, 24 October 2003 [cited 16 February 2005]. http://www.emedicine.com/med/topic169.htm.
Zagrodnik, Dennis II. Fistula-in-Ano, ii June 2004 [cited 3 March 2005]. http://www.emedicine.com/med/topic2710.htm.
fistula [fis´tu-lah] (pl. fistulas, fis´tulae) (L.)
any abnormal tubelike passage within body tissue, usually between two internal organs or leading from an internal organ to the body surface. Some fistulas are created surgically for diagnostic or therapeutic purposes; others occur as result of injury or as congenital abnormalities. Among the many kinds of fistulas, the anal type (fistula in ano
) is one of the most common. It generally develops as a result of a break or fissure in the wall of the anal canal or rectum, or an abscess there. Treatment is by surgery.
In women, difficult labor in childbirth may result in formation of a vesicovaginal fistula
between the bladder and the vagina with resulting leakage of urine into the vagina. In a vesicointestinal fistula
, there is leakage of urine from the bladder into the intestine. In a rectovaginal fistula
, feces escape through the wall of the anal canal or rectum into the vagina. This condition, formerly a serious hazard of childbirth, is now rare; like other kinds of fistula, it can be corrected by surgery.
With the types of fistulas described here, typical symptoms are pain in the affected region and an abnormal discharge through the skin near the anus or through the vagina. Fistulas at different places of the body may be caused by tuberculosis
(a fungus infection), the presence of diverticula
, or certain other serious diseases, and the fistula itself may be a site of infection and discomfort.
abdominal fistula one between a hollow abdominal organ and the surface of the abdomen.
anal fistula (fistula in a´no) one opening on the cutaneous surface near the anus, which may or may not communicate with the rectum.
one between an artery and a vein, either pathologic (such as a varicose aneurysm
) or surgically created to ensure an access site for hemodialysis
. The site must be allowed 6 to 8 weeks to mature before it can be cannulated. Such a fistula may be the anastomosis of a natural artery and vein, a bovine graft, or a synthetic polytetrafluoroethylene (PTFE) graft. The bovine graft is taken from the bovine carotid artery and anastomosed to the vein and artery of the patient. In a PTFE graft, fibers are woven into a mesh called Gore-Tex and made into a sleeve and flange; this is available in a variety of sizes.
Precautions necessary to insure patient safety when caring for an individual with an arteriovenous fistula include frequent assessments for adequate circulation in the fistula and the distal extremity. A bruit or thrill can be heard over the access site. Blood pressure measurements, withdrawal of blood, injections, and administration of intravenous fluids should not be done on the extremity with such a fistula.
Internal arteriovenous fistulas.
blind fistula one open at one end only, opening on the skin (external blind fistula) or on an internal surface (internal blind fistula).
bronchopleural fistula one between a bronchus and the pleural cavity, causing an air leak into the pleural cavity; sometimes seen as a complication of empyema, fibrosis, or pneumonia.
cerebrospinal fluid fistula
one between the subarachnoid space and a body cavity, such as from head trauma or bone erosion, with leakage of cerebrospinal fluid, usually in the form of rhinorrhea
complete fistula one extending from the skin to an internal body cavity.
craniosinus fistula one between the cerebral space and a paranasal sinus, permitting escape of cerebrospinal fluid into the nose.
Eck's fistula an artificial communication made between the portal vein and the vena cava.
one connecting some part of the intestine with the urinary bladder; called also vesicoenteric f.
fecal fistula one between the colon and the external surface of the body, discharging feces.
1. one communicating between the stomach and some other body part.
2. a passage created artificially through the abdominal wall into the stomach.
horseshoe fistula one near the anus, having a semicircular tract with both openings on the skin.
rupture of the round window
with leakage of perilymph
into the inner ear, so that changes in middle ear pressure directly affect the inner ear, causing sensorineural deafness
as well as dizziness, vertigo, nausea, and vomiting. Head trauma and dramatic changes in atmospheric pressure are the most common causes. The usual treatment is restriction in activity (sometimes with complete bed rest), so that the fistula can heal. Surgical repair may be necessary, consisting of placement of a graft over the defect.
pulmonary arteriovenous fistula a congenital fistula between the pulmonary arterial and venous systems, allowing unoxygenated blood to enter the systemic circulation.
rectovaginal fistula one between the rectum and vagina.
rectovesical fistula one between the rectum and urinary bladder.
salivary fistula one between a salivary duct or gland and the cutaneous surface, or into the mouth through an abnormal pathway.
thoracic fistula one communicating with the thoracic cavity.
umbilical fistula one communicating with the intestine or urachus at the umbilicus.
urinary fistula any fistula communicating between the urinary tract and another organ or the surface of the body.
vesicovaginal fistula one from the bladder to the vagina.