Imperforate anus
Encyclopedia
An imperforate anus or anal atresia is a birth defect in which the rectum
is malformed. Its cause is unknown.
Imperforate anus is usually present along with other birth defects—spinal
problems, heart
problems, tracheoesophageal fistula
, esophageal atresia
, renal
anomalies, and limb
anomalies are among the possibilities.
:
e. There are two main categories of anorectal malformations: those that require a protective colostomy
and those that do not. The decision to open a colostomy is usually taken within the first 24 hours of birth.
Sonography can be used to determine the type of imperforate anus.
to open a passage for feces
unless a fistula
can be relied on until corrective surgery takes place. Depending on the severity of the imperforate, it is treated either with a perineal anoplasty or with a colostomy
.
. With a low lesion, children generally have good bowel control, but they may still become constipated.
For children who have a poor outcome for continence and constipation from the initial surgery, further surgery to better establish the angle between the anus and the rectum may improve continence and, for those with a large rectum, surgery to remove that dilated segment may significantly improve the bowel control for the patient. An antegrade enema mechanism can be established by joining the appendix to the skin (Malone stoma); however, establishing more normal anatomy is the priority.
Imperforate anus is an occasional complication of sacrococcygeal teratoma
.
Rectum
The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
is malformed. Its cause is unknown.
Features
There are several forms of imperforate anus:- A low lesionLesionA lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
, in which the colonColon (anatomy)The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
remains close to the skin. In this case, there may be a stenosisStenosisA stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure.It is also sometimes called a stricture ....
(narrowing) of the anus, or the anus may be missing altogether, with the rectumRectumThe rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
ending in a blind pouch. - A high lesion, in which the colonColon (anatomy)The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
is higher up in the pelvisPelvisIn human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
and there is a fistulaFistulaIn medicine, a fistula is an abnormal connection or passageway between two epithelium-lined organs or vessels that normally do not connect. It is generally a disease condition, but a fistula may be surgically created for therapeutic reasons.-Locations:Fistulas can develop in various parts of the...
connecting the rectum and the bladderUrinary bladderThe urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
, urethraUrethraIn anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...
or the vaginaVaginaThe vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
. - A persistent cloacaPersistent cloacaA persistent cloaca is a complex anorectal and genitourinary malformation, in which the rectum, vagina, and urinary tract meet and fuse, creating a cloaca, a single common channel.-Diagnosis:...
(from the term cloacaCloacaIn zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
, an analogous orifice in reptileReptileReptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s and amphibians), in which the rectum, vagina and urinary tract are joined into a single channel.
Imperforate anus is usually present along with other birth defects—spinal
Vertebral column
In human anatomy, the vertebral column is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It is situated in the dorsal aspect of the torso, separated by intervertebral discs...
problems, heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
problems, tracheoesophageal fistula
Tracheoesophageal fistula
A tracheoesophageal fistula is an abnormal connection between the esophagus and the trachea...
, esophageal atresia
Esophageal atresia
Esophageal atresia is a congenital medical condition which affects the alimentary tract. It causes the esophagus to end in a blind-ended pouch rather than connecting normally to the stomach. It comprises a variety of congenital anatomic defects that are caused by an abnormal embryological...
, renal
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
anomalies, and limb
Limb (anatomy)
A limb is a jointed, or prehensile , appendage of the human or other animal body....
anomalies are among the possibilities.
Associated anomalies
Imperforate anus is associated with an increased incidence of some other specific anomalies as well, together being called the VACTERL associationVACTERL association
VATER syndrome or VACTERL association is a non-random association of birth defects. The reason it is called an association, rather than a syndrome is that while all of the birth defects are linked, it is still unknown which genes or sets of genes cause these birth defects to occur.Each child with...
:
- V - Vertebral anomalies
- A - Anal atresia
- C - Cardiovascular anomalies
- T - Tracheoesophageal fistulaTracheoesophageal fistulaA tracheoesophageal fistula is an abnormal connection between the esophagus and the trachea...
- E - Esophageal atresiaEsophageal atresiaEsophageal atresia is a congenital medical condition which affects the alimentary tract. It causes the esophagus to end in a blind-ended pouch rather than connecting normally to the stomach. It comprises a variety of congenital anatomic defects that are caused by an abnormal embryological...
- R - Renal (Kidney)KidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
and/or radialRadius (bone)The radius is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...
anomalies - L - Limb defects
Diagnosis
When an infant is born with an anorectal malformation, it is usually detected quickly as it is a very obvious defect. Doctors will then determine the type of birth defect the child was born with and whether or not there are any associated malformations. It is important to determine the presence of any associated defects during the newborn period in order to treat them early and avoid further sequelaSequela
A sequela) is a pathological condition resulting from a disease, injury, or other trauma.Chronic kidney disease, for example, is sometimes a sequela of diabetes, and neck pain is a common sequela of whiplash or other trauma to the cervical vertebrae. Post-traumatic stress disorder may be a...
e. There are two main categories of anorectal malformations: those that require a protective colostomy
Colostomy
A colostomy is a surgical procedure in which a stoma is formed by drawing the healthy end of the large intestine or colon through an incision in the anterior abdominal wall and suturing it into place. This opening, in conjunction with the attached stoma appliance, provides an alternative channel...
and those that do not. The decision to open a colostomy is usually taken within the first 24 hours of birth.
Sonography can be used to determine the type of imperforate anus.
Treatment
Imperforate anus usually requires immediate surgerySurgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
to open a passage for feces
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
unless a fistula
Fistula
In medicine, a fistula is an abnormal connection or passageway between two epithelium-lined organs or vessels that normally do not connect. It is generally a disease condition, but a fistula may be surgically created for therapeutic reasons.-Locations:Fistulas can develop in various parts of the...
can be relied on until corrective surgery takes place. Depending on the severity of the imperforate, it is treated either with a perineal anoplasty or with a colostomy
Colostomy
A colostomy is a surgical procedure in which a stoma is formed by drawing the healthy end of the large intestine or colon through an incision in the anterior abdominal wall and suturing it into place. This opening, in conjunction with the attached stoma appliance, provides an alternative channel...
.
Prognosis
With a high lesion, many children have problems controlling bowel function and most also become constipatedConstipation
Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...
. With a low lesion, children generally have good bowel control, but they may still become constipated.
For children who have a poor outcome for continence and constipation from the initial surgery, further surgery to better establish the angle between the anus and the rectum may improve continence and, for those with a large rectum, surgery to remove that dilated segment may significantly improve the bowel control for the patient. An antegrade enema mechanism can be established by joining the appendix to the skin (Malone stoma); however, establishing more normal anatomy is the priority.
Epidemiology
Imperforate anus has an estimated incidence of 1 in 5000 births. It affects boys and girls with similar frequency. However, imperforate anus will present as the low version 90% of the time in females and 50% of the time in males.Imperforate anus is an occasional complication of sacrococcygeal teratoma
Sacrococcygeal teratoma
Sacrococcygeal teratoma is a teratoma located at the base of the coccyx . It is thought to be a derivative of the primitive streak.-Natural history:...
.