Congenital anorectal malformation
Introduction
Introduction to congenital rectal anus deformity Congenital rectal anal developmental malformations are very common, and there are many types, and the position of the rectal blind end and the fistula are different. Its incidence rate in the newborn is 1:1500 ~ 5000, accounting for the first place in the digestive tract malformation. More men than women, high malformations accounted for about 50% of men and 20% of women. The incidence of various fistulas is 90% in women and 70% in men. The incidence of other congenital malformations is about 30-50%, and often multiple deformities. Family history is rare, only 1%. There is heredity, but the genetic method is still inconclusive. basic knowledge The proportion of illness: 0.002% Susceptible people: good for newborns Mode of infection: non-infectious Complications: constipation, intestinal obstruction
Cause
Causes of congenital rectal anal malformation
Cause:
The occurrence of rectal anal malformation is the result of impaired embryonic development. Male and female are basically the same, only the anatomical difference, the result of the cloaca separation process, the urogenital sinus and the anorectal sinus communicate, forming a high position or Median malformation, various anorectal hypoplasia and fistula between the rectum and the urethra or vagina, the anal posterior movement process and the hypoplasia of the perineum, constitute a low deformity, anal skin spasm, anal vestibular fistula, anal stenosis.
Prevention
Congenital rectal anus deformity prevention
The disease is a congenital disease, no effective preventive measures, early detection and early treatment is the key to the prevention and treatment of this disease.
Complication
Congenital rectal anus malformation complications Complications constipation intestinal obstruction
Complications such as acute complete low intestinal obstruction may occur; anorectal stenosis may occur with difficulty in defecation, constipation, formation of fecal stone, secondary megacolon and other chronic obstructive symptoms.
Symptom
Congenital rectal anus deformity symptoms Common symptoms Anal malformation does not have a fetus and bowel stenosis without anal nodule anal sphincter transection
Due to the deformity of the body surface, it is easy to diagnose. In addition to the clinical examination, the distance between the blind end of the rectum and the levator ani muscle plane and the anal skin must be further determined to determine the type of deformity, the position of the fistula, and the malformation. The treatment.
(1) High malformation
About 40%, boys are more common, often have fistulas, but because of the small tube, almost all have intestinal obstruction symptoms, the innervation of the pelvic muscles are often defective, accompanied by atlas and upper urinary tract malformation, this type of case The skin of the normal anus is slightly sunken, the pigment is deep, but there is no anus. When the crying is noisy, the depression does not bulge outward. There is no impact when touched by fingers. The girl is often accompanied by vaginal fistula and opens in the posterior wall of the vagina. The external genitalia is also stunted, it is naive, and the feces often flow out from the mouth. It is easy to cause genital tract infections. Boys are often accompanied by urinary fistulas. Gases and feces are discharged from the urethra. Recurrent urethritis, penile head inflammation and upper Urinary tract infection.
(2) Middle position malformation
About 15% of the intestines are located in the urethral bulbar corpus cavernosum or near the lower part of the vagina. The puborectalis muscle surrounds the distal rectum. The fistula is open to the urethral bulb, the lower vagina or the vestibule. The appearance of the anus is similar to the high malformation. It can also be defecation from the urethra or vaginal. The probe can enter the rectum through the fistula. The tip of the probe can be touched in the perineum. The girl is more common in the rectum vestibule. Located in the vestibular vestibular fossa, also known as the scapular fossa, the pupil is larger, the baby can basically maintain normal bowel movement through the pupil in the early stage, which can cause vaginitis or ascending infection.
(3) Low position deformity
About 40%, the rectal end position is lower, more with a fistula, rarely accompanied by other deformities, and some are covered by a film at the normal anus position, faintly visible color of the fetus, the diaphragm bulges out obviously when crying, sometimes The anal membrane has been broken, but it is not complete and the bowel movement is difficult. In the boy with anal skin spasm, the tube is filled with feces and is dark blue, the mouth is located in the perineum, or more in front of the scrotum, or any part of the urethra. In the girl with an anal vestibule or skin sputum, the mouth is located in the vestibule or perineum of the vagina.
Examine
Examination of congenital rectal anus deformity
1. X-ray see
Abdominal standing flat films showed low colonic obstruction, and the typical lateral and anterior and posterior sacral sacs showed typical sacral and dilated bowel segments. The sputum function was poor. After 24 hours, there were still sputum retention, if not timely. Enema can be used to form vermiculite. In the case of enteritis, the intestinal wall of the dilated intestine is serrated. In the neonatal period, the dilatation of the intestine is more than half a month after birth. If the diagnosis is still not confirmed, the following examination is performed. .
1 inverted side position X-ray film
Known as the Wangenst-een-Rice method, it is required to take more than 12 hours after birth, waiting for the gas to reach the rectum. The poor living ability takes longer, and the sputum is applied as a marker on the skin of the perineal anal area. Inverted for 2 to 3 minutes, so that the rectal blind end of the fetus and the intestine gas exchange with each other, taking the hip joint with a 90° flexion position, so that the retention can fully display the P point (the pubic center), the C point (the appendix joint), and the I point (the ischial bone). The lowest point) is centered on the femur trochanus and is taken at the time of exhalation, inhalation and crying.
Set the I line parallel to the PC line through I point, and the distance between the PC line and the PC line is the levator muscle group. The blind end of the rectum is above the PC line, and the middle line is between the second line. Or set M point, that is, the upper 2/3 and lower 1/3 junction of the ischial tuberosity, the middle position above the M line, and the lower position below the M line.
However, it is necessary to pay attention to various influencing factors, such as insufficient intestinal inflation, too thick fetus, movement of the levator ani muscle, and deflection of the X-ray projection angle, which can affect the correctness of the position.
2 fistula angiography
The angiography requires the image of the colon at the time of contrast injection and the image of the rectal fistula when the contrast agent is discharged. The double contrast of the colorectal and urethra can show the relationship between the rectal fistula and the urethra. The vaginal angiography can show the relationship between the vagina and the rectum.
Careful observation of the perineum after birth can reveal that there is no anus in the normal anal position, especially if the fetus is not discharged 24 hours after birth, it should be checked promptly. If it can be found early, its clinical manifestations are different degrees of low intestinal obstruction. Innocent or with small fistulas, acute complete low intestinal obstruction often occurs early in life, in cases of anorectal stenosis or with large fistulas, depending on the degree of stenosis and fistula size, Weeks, months or even years later, there are difficulties in defecation, constipation, formation of fecal stones, and secondary symptoms of chronic obstruction such as megacolon.
2. Biopsy
Take a small piece of tissue from the submucosal and muscular layers of the rectal wall 4 cm above the anus, check the number of ganglion cells, and lack of ganglion cells in children with megacolon.
3. Anorectal manometry
Determination of reflex pressure changes in the rectum and anal sphincters, diagnosis of congenital megacolon and identification of constipation caused by other causes, in normal children and functional constipation, when the rectum is stimulated by swelling, the internal sphincter immediately undergoes reflex relaxation, stress Decreased, the internal sphincter of children with Hirschsprung's disease not only does not relax, but also has obvious contraction, which increases the pressure. This method can sometimes produce false positive results in newborns within 10 days.
4. Rectal mucosal histochemistry
This is based on the proliferation of submucosal and myometrial ganglion cells in the sacral segment. The hypertrophic parasympathetic ganglia fibers release a large amount of acetylcholine and choline enzymes. The chemical quantity can be used to determine the amount and activity of both. Normal children 5 to 6 times, help to diagnose the Hirschsprung's disease, and can be used in newborns.
Diagnosis
Diagnosis and diagnosis of congenital rectal anus deformity
According to the medical history, clinical manifestations and laboratory data is not difficult to make a diagnosis.
Mainly distinguished from rectal atresia, rectal atresia is a certain distance between the blind end of the rectum and the anus, due to the primordial anal dysplasia in the fetal period, the symptoms are more serious than the lock anal, and the degree of expansion around the anus is smaller than that of the lock anus. Mainly differentiated from rectal atresia.
Rectal atresia is a certain distance between the blind end of the rectum and the anus. It is caused by the primordial anal dysplasia during the fetal period. The symptoms are more serious than the lock anal. The degree of swelling around the anus is smaller than that of the lock anus.
