Early Diagnosis of Anorectal Malformations / Imperforate Anus
Early diagnosis and prompt treatment can help change the outcome for children born with anorectal malformations / imperforate anus.
An emerging area of interest is the prenatal diagnosis of anorectal malformations. Much is being learned in this area as technology improves, and perinatologists are learning to recognize certain clues of the prenatal ultrasound.
Immediate Postnatal Diagnosis
Certainly the vast majority of anorectal malformations diagnoses are made in the delivery room on examination of the infant after birth or in the newborn nursery when the nurse attempts to take a rectal temperature and no anus is visible.
Inspection of the perineum, the area surrounding the external genitals and where the anus would normally be located, should be performed on all newborns and may result in an immediate postnatal diagnosis of an anorectal malformation / imperforate anus.
An infant who is diagnosed with an anorectal malformation / imperforate anus requires a more comprehensive examination that may include evaluation of the following conditions:
- Does the abdomen appear distended (enlarged or stretched out)?
- Is the infant vomiting?
- Does the infant display a voiding (urination) pattern that would indicate involvement of the urinary tract?
- Is meconium present in the perineum of a male infant or in the genitalia of a female infant? Meconium, a greenish mass of cells that accumulate in the bowel of the fetus, is usually discharged after birth.
- Is meconium present in the urine of a male baby? Meconium can be detected by filtering the urine through a gauze pad placed at the tip of the penis or by laboratory examination of the urine (urinalysis).
Infant Care Following Anorectal Malformation / Imperforate Anus Diagnosis
Once the infant has been diagnosed with an anorectal malformation / imperforate anus, the goals of care are:
- Determining whether the infant needs a temporary colostomy (explained below) or whether the defect can be treated primarily without a colostomy
- Evaluating other defects or medical problems that require immediate attention
- Providing information and emotional support to the parents and other family members
- Providing general medical support to the child
Decision to Perform a Colostomy Versus an Anoplasty
Some anorectal malformations / imperforate anus can be treated with a one-stage surgical repair. In infants with more extensive defects, however, a colostomy is needed to surgically create an alternate route for feces to exit the infant's body while the infant awaits more extensive surgery to correct the anorectal malformation.
A colostomy decompresses the bowel, diverting feces outside the body. It also helps prevent infection during the reconstructive surgery to correct the anorectal malformation / imperforate anus. The decision to perform a colostomy is generally made after 24 hours of observation.
Associated Defects Requiring Immediate Attention
The most frequently associated defects of anorectal malformations / imperforate anus that require immediate attention are those of the urinary tract.
Infants with anorectal malformations require an ultrasound examination of the abdomen to detect a urinary obstruction. If the ultrasound examination is abnormal, a more detailed urologic evaluation is indicated.
Associated defects of the digestive tract include an obstruction of the esophagus (tube that carries food and liquids from the throat to the stomach).
Known as esophageal atresia, this condition can also cause leakage from the digestive tract into the lungs, and requires surgical correction so the child can eat.
Children born with anorectal malformations / imperforate anus may also have abnormalities in the bones, particularly the sacrum bone and the lumbosacral spine, and heart.
All infants diagnosed with an anorectal malformation should have a thorough cardiac evaluation with an echocardiogram before undergoing surgery.
An ultrasound of the spine will help to rule out the presence of a condition called tethered cord, which includes the final outcome.
Care of the Infant Awaiting Treatment
Once an infant has been diagnosed with an anorectal malformations and is being evaluated for treatment, several steps are recommended:
- Intravenous nourishment while taking nothing by mouth (NPO)
- Inserting a nasogastric (NG) tube to avoid vomiting and risk of aspiration
- Intravenous fluids
- Antibiotics
- Vitamin K to correct clotting deficiencies of a newborn prior to surgery
- Strict monitoring of intake and output
We believe that it is now possible to establish an accurate early diagnosis, which allows us to tell the parents what the future of their child is going to be in terms of bowel control.
Rev. 2/06
For more information or to request an appointment, please contact the Colorectal Center at Cincinnati Children's.
