Cloacal exstrophy is a condition where some internal organs that are normally in the lower abdomen are exposed externally. In addition, some of these organs may not have developed correctly and the lower parts of the reproductive, urinary, and intestinal tracts may not be completely formed. The cloaca is a structure that forms early in development and divides to make the lower intestine and anus, the urinary bladder and reproductive tract. Normally, the cloaca divides as development progresses. Rarely, this division does not proceed in the usual way and the cloaca remains and may be enclosed within the lower abdomen or it may be outside the abdominal wall. In the latter case, it is called a cloacal exstrophy. Structures that may also be affected include the pelvic bones, and the spinal column and spinal cord. It is a complex birth defect and requires a coordinated care plan developed with input from several specialists to assure the best outcomes.
Cloacal exstrophy is at the most severe end of a spectrum of malformations called the Exstrophy- Epispadias Complex. Other related conditions on this spectrum include epispadias (rare, but most often seen in boys, a congenital defect in which the urethra opens on the upper surface of the penis) and classic bladder exstrophy (a congenital malformation where the bladder is flattened and exposed on the abdominal wall). Most, if not all, of the conditions on Exstrophy-Epispadias Complex spectrum require one or more surgeries to repair.
In the United States, the prevalence (how common it is) is:
- Classic bladder exstrophy in 3.3 per 100,000 births
- Male epispadias occurs in 1 in 117,000 births
- Female epispadias occurs in 1 in 484,000 births
- Cloacal exstrophy occurs in 1 in 200,000-400,000 births.
In other parts of the world, the prevalence is the same as it is in the United States.
All the conditions in the Exstrophy-Epispadias Complex can be diagnosed at birth. For classic bladder exstrophy, the male-to-female ratio is 2.3 males born with the conditions for every 1 female and can be as high as 6 males to 1 female in some series. These conditions seem to be more common in whites than in other races.
Because it is so rare, the underlying causes are not well understood. Both genetic and non-genetic causes are suspected. The medical literature has reported rare recurrences in subsequent pregnancies and cases of monozygotic (identical) twins who have both been born with cloacal exstrophy. However, there have also been reports of cases of twins where one twin was affected, but the other twin was not. Both genetic and environmental factors are likely involved as causes.
Recent work from a multinational group of researchers is being done to better understand the role of genetics in cloacal exstrophy and related conditions. Although a few families have been reported where a single gene may be responsible (i.e., resulting in Mendelian inheritance patterns), much of the accumulating evidence appears to be more consistent with a multifactorial pattern of inheritance in most cases. Mendelian patterns of inheritance follow the classic recessive, dominant or X-linked patterns that were first described by Gregor Mendel in the 1800's. Multifactorial inheritance is characterized by a genetic predisposition that requires other genetic or non-genetic factors to trigger the development of the trait.
Common Associated Conditions
Cloacal exstrophy may be accompanied by additional birth defects, including:
- Omphalocele: a type of abdominal wall defect in which the intestines, liver, and occasionally other organs remain outside of the abdomen (stomach area) in a sac because of a defect in the development of the muscles of the abdominal wall.
- Imperforate anus: a defect that is present from birth (congenital) where the opening to the anus is missing or blocked. The anus is the opening to the rectum through which stools leave the body.
- Spina bifida: a congenital defect of the spine in which part of the spinal cord and the surrounding membranes (meninges) are exposed through a gap in the backbone.
- Tethered cord: a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column, resulting in abnormal stretching of the spinal cord.
This set of related features is also known as OEIS (Omphalocele, Exstrophy, Imperforate anus, Spina bifida) Complex after the first letter of each of the typical features that are seen in this condition.
Short-Term Treatment and Outcomes
To repair the organs of the lower abdomen and allow more normal function, a series of surgical procedures (multiple surgeries) will be required over a period of several years. Surgery might be performed shortly after birth to do a main repair of several of the structural malformations and to place the organs back into the abdomen.
Long-Term Treatment and Outcomes
With treatment and management, people born with cloacal exstrophy should live a normal number of years. Although there may be lifelong functional issues due to the original structural birth defects, the quality of life tends to be good.
Over time, there may be one or more additional surgeries to continue the repair of the structural malformations. The major goals of this continued reconstruction are to attain bladder, bowel, sexual and, ultimately, reproductive function. As patients grow and reach puberty, additional issues may arise and the chances of these surgeries being necessary are related to the extent of the original cloacal exstrophy and any associated birth defects. To work toward these goals, one or more surgeries over a span of years may be recommended to continue the repair of the various involved structures. Since each child's situation is different, the long-term treatment planning will involve many different professionals and the family. This team approach is associated with the best possible outcomes. Although a major goal is to arrive at a point that limits urinary and fecal incontinence, not all patients will ultimately reach this goal. Much depends on the extent of the original structural birth defect(s).
- Kidney problems: chronic renal failure (when the kidneys lose the ability to remove waste and balance fluids). In individuals with cloacal exstrophy, the chances of kidney failure and urological problems may be present at birth or may increase over time.
- Reproductive issues: In adults who were born with cloacal exstrophy, the organs needed for sexual functioning and reproduction are involved. In many of these patients, establishing and carrying a pregnancy successfully may be impacted. If a female patient desires to get pregnant, she and her partner may benefit from seeking care from an obstetrician/gynecologist who has experience dealing this these types of issues to determine the best plan for the patient's situation. In males, sexual function may also be affected. Seeking care from an urologist that has experience with managing cloacal exstrophy in males may help to determine the best plan for a patient's particular situation.