Imperforate Anus: Causes, Complications, Symptoms, Treatment, Prognosis

Imperforate Anus or Anorectal Malformation is a defect spotted at birth in which the anal opening is either blocked or is entirely missing. According to researchers, this abnormality exists in 1 out of every 6000 births. This is found mostly in boys than girls. This condition usually develops in utero between the fifth and seventh weeks of pregnancy. There is no known cause for Imperforate Anus, but this condition may be associated with certain other defects of the rectum. Diagnosis of Imperforate Anus is generally made just after birth. It is a potentially serious condition and requires immediate treatment. Surgery is by far the most effective treatment for Imperforate Anus or Anorectal Malformation with excellent prognosis postsurgery.

There may be several different forms of Imperforate Anus or Anorectal Malformation:

• The rectum may end in a sort of a pouch which is not connected to the colon
• The rectum can have openings to other structures like the urethra, bladder, base of the penis in boys or vagina in girls.
• There may severe stenosis of the anus.

Imperforate Anus is a rare defect and is caused due abnormal development of fetus.

Imperforate Anus or Anorectal Malformation can result in a number of complications, some of which are illustrated below:

• If the anal opening is narrow or is not in the normal position, a child may have a difficult time passing stools resulting in chronic constipation and resultant discomfort
• In case of a membrane covering the opening, the child may not be able to have a bowel movement at all till the time the membrane covering the anal opening is removed with a surgical procedure
• In case the rectum is not joined to the anus and in the absence of any connection between the rectum and the anus it becomes impossible for the stool to move out of the intestine resulting in the child not being able to have a bowel movement causing bowel obstruction
• In cases where the rectum is not connected to anus and there is a fistula present, the stools may then pass through fistula instead of anus which may cause urinary tract infections.

Symptoms of Imperforate Anus or Anorectal Malformation Include:

• No anal opening
• Anal opening at the wrong area
• No passage of stool within the first 24 hours of life
• Passage of stool through urethra, vagina, or base of penis
• Abdominal swelling.

A physical examination of the newborn soon after birth is good enough to diagnose an Imperforate Anus or Anorectal Malformation. Apart from this, radiologic studies can be done to identify the extent of the abnormality. Some radiologic studies which may be ordered are:

• Abdominal x-rays.
• Ultrasound of the abdomen.

Once a diagnosis of Imperforate Anus is confirmed, the physician will then look for conditions that are associated with Imperforate Anus or Anorectal Malformation and perform certain other tests which include:

• Spinal x-rays to look for bone abnormalities
• Spinal ultrasound to look vertebral abnormalities
• EKG to look for cardiac abnormalities
• MRI to look for any esophageal defects.

Surgery is by far the best method to treat Imperforate Anus or Anorectal Malformation. At times, more than one surgery may be required for correcting Imperforate Anus. If required, a temporary colostomy can be used in order for the infant to grow enough to perform surgery.

The type of surgery required to correct Imperforate Anus or Anorectal Malformation depends on the defect like the length of the infant’s rectum or whether the adjacent muscles are affected. A surgical procedure called perineal anoplasty is done in which any fistulas found are closed such that the rectum is not attached to urethra or vagina anymore and an anus is created at the normal position. If the rectum is pulled down to connect to the newly created anus then this procedure is called as pull-through procedure. In order to prevent the anus from getting stenosed, it is imperative that periodic anal dilatation is performed.

• After some time postsurgery, the parents of the affected child are instructed on how to perform regular anal dilatations so that there is no stenosis of the anus postsurgery and the child is able to pass stools easily.
• Another surgical procedure is performed a few weeks later to close out the colostomy. A few days postsurgery, the child will start passing stools through the anal opening. For a few days postsurgery, the bowel movements may be loose and their frequency will be more which will improve over time
• With time, the frequency of the bowel movements come down and the stool also become more solid. It is imperative to continue regular anal dilatations for several weeks or even months postsurgery.
• In some cases, the child may get constipated. Hence, high fiber diet is suggested. In some cases, laxatives are also used.
• In cases where a child complains of acute constipation, the physician may formulate a bowel management program which will be made according to the requirements of the affected child, which may include educating the parent and child about the use of laxatives, stool softeners, enemas, and other bowel training techniques.

Postsurgery the parents are instructed on how to perform periodic anal dilatations, so that the newly created anus does not get stenosed and stool can pass easily through it. There may be some instances of constipation in some children for which stool softeners and enemas may be used, although in majority of cases, the prognosis for imperforate anus with surgery is excellent and most children lead a normal healthy life after surgery for Imperforate Anus or Anorectal Malformation.

Toilet training in cases of Imperforate Anus or Anorectal Malformation is usually started at the normal age that is when the child is around 3 years old. Children with this condition usually learn bowel control more slowly than others and depending on the surgical procedure the child has undergone the child may not be able to get adequate bowel control. This condition varies on a case to case basis and is adequately determined by the treating physician.