An imperforate anus or anal atresia is a birth defect in which the rectum is malformed. Its cause is unknown. more...
There are several forms of imperforate anus:
- A low lesion, in which the colon remains close to the skin. In this case, there may be a stenosis (narrowing) of the anus, or the anus may be missing altogether, with the rectum ending in a blind pouch.
- A high lesion, in which the colon is higher up in the pelvis and there is a fistula connecting the rectum and the bladder, urethra or the vagina.
- A cloaca (named after the analogous orifice in amphibians), where the rectum, vagina and colon are joined into a single opening.
Imperforate anus usually presents along with other birth defects—spinal problems, anal atresia, heart problems, tracheoesophageal fistula, esophageal atresia, renal anomalies, and limb anomalies.
Imperforate anus usually requires immediate surgery to open a passage for faeces. Depending on the severity of the imperforate, it is either treated with a perineal anoplasty or colostomy.
With a high lesion, many children have problems controlling bowel function and most also become constipated. With a low lesion, children generally have good bowel control, but they may still become constipated.
Imperforate anus has an estimated incidence of 1 in 5,000 live births. It is more common in boys than in girls.
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