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A congenital disorder (also known as birth defect or congenital abnormality) is am abnormality in body structure or function that is present at birth. While most structural (physical) congenital disorders can be recognised at birth, unfortunately some internal abnormalities (e.g. of the heart) or functions (e.g. haemophilia, single gene defects and other metabolic disorders) can sometimes only be diagnosed weeks or months after birth. About 3% of all infants have a congenital disorder. These may be minor and not important, or serious enough to make the infant appear abnormal or to be the cause of the infant’s death.
About 3% of infants have a congenital disorder.
There are many different causes of congenital disorders. The main causes are:
Factors that may alter the intra-uterine environment, such as infections, teratogens and maternal diabetes, have a far greater chance of causing structural congenital disorders if they are present during the first trimester when the fetal organs are still forming.
Unfortunately the cause of many congenital disorders is not known.
All infants should be carefully examined after delivery for congenital disorders.
Many pregnant women are now being screened for major structural congenital disorders by having an ultrasound examination of the fetus and screening blood tests at 12–20 weeks.
It is not uncommon for an infant to be born with extra fingers (or toes). Extra fingers are usually attached to the side of the hand with a narrow thread of skin. Often the mother or father also had extra fingers at birth. After getting the parents’ consent, these extra fingers can be tied off with a piece of cotton or surgical silk. An assistant must gently pull the finger away from the hand so that you can tie the thread as close to the skin as possible.
Less commonly the extra finger or toe contains bone or cartilage. This is often associated with other major congenital abnormalities. These fingers or toes cannot be simply tied off and the infant must be referred to a level 2 or 3 hospital for further investigation. The fingers or toes will later be removed surgically.
Many infants have feet that are slightly twisted inward due to the position the fetus lies in during pregnancy. These feet are not abnormal as they can easily be turned into a normal position by gentle pressure.
Some infants have one or both feet which are twisted inward and cannot be turned into a normal position. These are clubbed feet. The cause may be familial or due to oligohydramnios (pressure on feet during pregnancy). Often the cause is unknown. These infants must be referred to an orthopaedic clinic within a few days of delivery, as early treatment with serial plaster of Paris casts can correct the abnormality. They may also need a minor operation later. The result of treatment is good and these children can walk normally. Without correct treatment, clubbed feet result in permanent deformity and crippling.
At birth the upper end of an infant’s femur (the femoral head) is normally in the hip joint and cannot be pushed out (dislocated). However, occasionally one or both hips are dislocated or are dislocatable. If they are dislocated, the femoral head is not in the hip joint. If the hip is dislocatable then the femoral head can easily be moved out of the joint. The hips of all infants should be examined at birth (Barlow’s test) to detect either a dislocated or dislocatable joint. If the early diagnosis is missed, the infant may start to walk late and will have an abnormal waddling gait. The surgical results are poor with late treatment.
If a hip is dislocated, then the infant must be referred to an orthopaedic clinic at a level 2 or 3 hospital for treatment within a few days of delivery. Once the clinical diagnosis is confirmed with an X-ray or by ultrasonography, the infant’s legs should be placed in a plaster of Paris splint. With the correct, early treatment most children with a dislocated hip will walk normally although arthritis in adult life is common.
If the hip is only dislocatable, the infant should be examined again after 2 weeks. If the hip remains dislocatable, the infant must be referred as above. However, most dislocatable hips return to normal within 2 weeks and need no further treatment.
The hips of all infants should be examined after birth.
By term, both testes should have descended normally into the scrotum. If a testis is not in the scrotum and cannot be gently pushed into the scrotum, then it is undescended. Many undescended testes will move into the scrotum spontaneously during the first 3 months. Thereafter, surgery is usually needed to bring down the undescended testis. The operation is usually done at about 1 year. With bilateral undescended testes, an earlier operation is important to reduce the risk of infertility. All undescended testes have an increased risk of malignancy in adulthood even if they were corrected in infancy.
Normally the urethral opening in a male infant is at the end of the penis. If the opening is on the underside of the penis or at the base of the scrotum, then the infant has hypospadias. These infants also have a curved rather than a straight penis and at birth appear to have been partially circumcised.
It is important to refer these infants to a urological clinic within a few weeks of birth. The hypospadias can be corrected surgically when the infant is a few months old. These infants must not be circumcised as the foreskin may be needed to correct the urethra. It is important to reassure the parents that the abnormality can be corrected and that the infant’s sexual function will be normal when he grows up.
Ambiguous genitalia means that the external sex organs are not typically male or female. It is, therefore, difficult to decide on the sex of the infant. There are many causes of ambiguous genitalia. Some of these infants are male and others female. They should all be referred urgently to a level 3 hospital for investigation, as one of the common causes of ambiguous genitalia results in a lack of important adrenal hormones that may cause hypoglycaemia and dangerous changes in the serum sodium and potassium concentrations. This can be fatal in the first few days of life if not correctly treated. It is also important to determine the correct sex of the infant and to tell the parents as soon as possible whether the infant should be brought up as a boy or girl. This may be a very difficult decision and may take some time. These infants will need corrective surgery later during childhood.
Normally the inguinal canal closes after the testes have descended into the scrotum at about 36 weeks of gestation. However, if the canal does not close normally, bowel will push (herniated) into the scrotum resulting in an inguinal hernia. This presents as an oval-shaped mass in one or both sides of the scrotum. The mass may be firm or soft, often changes in size as the bowel moves in and out of the scrotum, and usually becomes bigger when the infant cries. Peristalsis may be felt in the hernia. The hernia does not transilluminate. Inguinal hernias are very common in infants who were born preterm.
The danger of an inguinal hernia is that the bowel may become trapped (incarcerated) in the scrotum. This will cut off the blood supply to that portion of the gut resulting in bowel obstruction, death of the bowel wall (gangrene) and perforation. A trapped hernia presents as a hard, red, tender and tense mass in the scrotum. The abdomen may also become distended and the infant may vomit repeatedly. This is a surgical emergency and requires urgent referral.
To prevent this complication, inguinal hernias should be repaired when the infant is well enough to have a general anaesthetic and weighs more than 2500 g. Usually inguinal hernias are repaired before the infant is discharged home.
This is an inguinal hernia where the opening from the abdominal cavity into the scrotum is only big enough to allow through fluid but not bowel (hydrocoeles). Like an inguinal hernia, it also presents as a one-sided or bilateral scrotal swelling. However, the scrotum transilluminates very well (the scrotum lights up if a torch is held against it). This sign is used to differentiate between typical inguinal and fluid hernias.
Most fluid hernias disappear after a few months and need no treatment. However, some fluid hernias, especially if they are very big, do not disappear and require surgical correction at about 3 months.
A birth mark (a naevus) is a mark on the skin at or soon after birth caused by increased pigment or an abnormal collection of blood vessels. There are 3 important types of birth mark:
Yes. Most infants have 2 umbilical arteries and 1 umbilical vein. If the infant has a single umbilical artery, there is a much higher than normal chance that the infant also has other structural congenital disorders. These infants, therefore, must be carefully examined after delivery.
If you find one structural congenital disorder, always look for another.
A cleft lip may occur alone or together with a cleft palate. Infants with a cleft lip look very abnormal and therefore the parents must be reassured that the cleft can be repaired. They must be referred to a plastic surgery clinic at a level 2 or 3 hospital. The lip is usually repaired at about 3 months. These infants usually feed and gain weight well. It is very helpful to show the parents a photo of a child with a repaired cleft lip.
This may be on one or both sides of the mouth and is usually seen together with a cleft lip. These infants have difficulty sucking. They must be referred within a day or 2 to a plastic surgery clinic at a level 3 hospital. Sometimes a plastic plate is fitted against the palate to help correct the position of the gums and the sides of the palate. A plate also makes feeding easier. Some infants with a cleft palate breastfeed well. Otherwise cup feeding or bottle feeding with a large hole in the teat helps. The cleft lip is usually repaired at 3 months but the cleft palate is repaired later, possibly after a few years. Speech and hearing problems are common. A multidisciplinary team at a combined assessment clinic is needed for the best results (plastic surgeon, dentist, audiologist and paediatrician).
Oesophageal atresia is an obstruction of the oesophagus due to a section of the oesophagus which is missing. It is usually associated with a connection (fistula) between the lower oesophagus and the bronchi of the lungs. Polyhydramnios is almost always present during pregnancy as the fetus cannot swallow. After birth these infants also cannot swallow as the oesophagus ends in a blind pouch. They dribble saliva. Feeds cause choking, cyanosis and collapse as the feed, which cannot be swallowed, is inhaled into the lungs. Gastric acid passes from the stomach into the bronchi, via a fistula, especially when the infants lie down. Both inhaled feeds and the reflux of gastric acid result in respiratory distress.
Do not feed any infant that you suspect of having an oesophageal atresia. The diagnosis is confirmed by the inability to pass a nasogastric tube. Any aspirate will test alkaline with litmus paper as the tube is not in the stomach. Whenever polyhydramnios is diagnosed, a nasogastric tube must be passed at birth to exclude oesophageal atresia before the first feed is given.
Infants with oesophageal atresia must be nursed head up to prevent acid reflux, they must not be fed and the mouth should be repeatedly suctioned. They must be urgently referred to a level 3 hospital and this emergency treatment should be continued during the transfer. As the infant is kept nil per mouth, an intravenous infusion of maintenance fluid (e.g. Neonatalyte) may be needed.
Polyhydramnios always suggests oesophageal atresia.
Duodenal atresia is an obstruction of the duodenum. Polyhydramnios may have been present and the amniotic fluid may also be bile stained due to the fetus vomiting. The infant may have Down syndrome. Soon after delivery the infant starts vomiting. The vomitus is often bile stained. The diagnosis is easily confirmed by an abdominal X-ray that shows 2 bubbles of air only in the bowel. These infants must be kept nil per mouth, the stomach should be emptied via a nasogastric tube, and they should be referred urgently to a level 3 hospital for surgery.
Other forms of small bowel obstruction may present in a similar way.
It is important to examine all newborn infants to make sure that an anus is present. The anus may simply be covered with skin or the absent anus may indicate a major abnormality of the large bowel. Some of these infants can pass meconium via a fistula into the vagina or bladder, but soon they develop abdominal distension due to bowel obstruction. They should be kept nil per mouth and referred urgently to a level 3 hospital for investigation. A covered anus can be corrected with a simple operation. Major defects of the large bowel require a colostomy followed later by complicated surgical correction.
An infant with exomphalos (omphalocoele) has no abdominal wall muscle around the base of the umbilical cord. The normal abdominal wall is replaced by a thin membrane through which the bowel may be seen. In a large exomphalos the bowel bulges into the umbilical cord. The covering membrane may burst at delivery. After birth the cord should be clamped well away from the exomphalos. The abnormality should be covered with sterile gauze or plastic wrapping. Whether the exomphalos is big or small, all these infants must be transferred urgently to a level 2 or 3 hospital for management. Infants with exomphalos often have other major abnormalities. An exomphalos is not the same as an umbilical hernia which is covered with skin and does not need to be treated.
There are many different types of congenital heart abnormality. Any infant with any of the above signs should be urgently referred to a level 2 or 3 hospital for further investigation.
In these infants the top of the skull is absent, exposing a poorly formed brain. They all die in a few hours or days. These infants should be kept warm and comfortable in the nursery until they die. They can be fed if necessary.
A meningomyelocoele is a major abnormality of the spine, usually in the lumbar area. A flat area of the spinal cord is exposed on the skin. Sometimes a thin-walled sac is also present and this may rupture with delivery. The legs are usually paralysed and hydrocephalus is common. The infants also dribble urine due to a paralysed bladder. Polyhydramnios is common with anencephaly or meningomyelocoele.
The meningomyelocoele should be covered with a piece of sterile gauze or plastic wrapping and the infant referred urgently to a level 3 hospital for possible closure of the area. Many of these infants die and most of the survivors have major orthopaedic and urological problems. They often also have other major abnormalities.
Most cases of anencephaly and meningomyelocoele (also called neural tube defects) can be prevented if the mother takes 0.5 mg folic acid daily for a few weeks before and after falling pregnant. Maize meal and wheat flour should be fortified with folic acid. This is very important in women who have previously had a child with either anencephaly or meningomyelocoele as both these congenital disorders are more common in some families.
Folic acid supplements reduce the risk of major neural defects.
Hydrocephalus is an excessive amount of cerebrospinal fluid in the ventricles of the brain. Hydrocephalus may be mild or severe and has many causes. The prognosis depends on the cause rather than the severity. Marked hydrocephalus should be operated on (shunted) to relieve the pressure in the brain. All infants with hydrocephalus must be referred to a level 3 hospital for further investigation.
Ultrasonography during pregnancy can diagnose hydrocephalus, anencephaly and meningomyelocoele.
This is a collection of abnormalities that form a clinical pattern which can be recognised. Therefore all children with the same syndrome look alike. Most experienced doctors and nurses can recognise an infant with Down syndrome or fetal alcohol syndrome soon after birth.
Down syndrome is caused by an extra number 21 chromosome (trisomy 21) and presents at birth with a number of recognisable signs:
Infants with Down syndrome often have major abnormalities, especially heart defects and duodenal atresia. They are all mentally retarded and, therefore, develop slowly.
The diagnosis must always be confirmed by a genetics laboratory where the extra chromosome 21 in white cells, obtained from a sample of blood, can be identified.
The risk of Down syndrome in the general population is about 1 in 600. However, the risk increases to about 1 in 200 for mothers at 35 years and 1 in 100 at 40 years. The older the mother the higher is the risk. Ideally all pregnant women, especially women of 35 years or more, should be screened. An amniocentesis at 16 weeks of pregnancy should be offered to women who are identified at high risk with the screening tests. Chromosome analysis on the cells of the amniotic fluid will diagnose Down syndrome. A termination of pregnancy can then be offered to the parents. Ultrasonography and a blood test early in pregnancy can identify most women at high risk of having a fetus with Down syndrome.
It is important to make the diagnosis and tell the parents as soon as possible after birth. The parents should be told what it means to have Down syndrome. These infants must be carefully examined for signs of major congenital abnormalities, especially heart abnormalities and duodenal atresia. If these are present, they must be referred to a level 3 hospital for further investigation. Infants with Down syndrome must be followed up to monitor their development. If possible the parents should be put in contact with other families with a Down syndrome infant. The Down Syndrome Association or other groups of parents of Down syndrome infants are very helpful. With a caring, stimulating home many children with Down syndrome are progressing far better than before.
Infants with this syndrome have been damaged by excessive alcohol intake by the mother during pregnancy. They have typical faces with a long, smooth upper lip. The eyes appear small due to a narrow palpebral fissure (opening between the eyelids). In addition, they are growth retarded with small heads and are often born preterm. Many also have abnormalities of the heart or limbs. They remain small for their age after birth and are mentally retarded. All pregnant women should be advised not to drink alcohol at all. Unfortunately fetal alcohol syndrome is common in South Africa.
Pregnant women should not drink alcohol.
When telling parents that their infant has a congenital disorder, there are a number of important points to remember:
These infants usually have a complex metabolic abnormality caused by a singe gene defects. Often there is a family history of the same disorder. If you suspect a functional congenital disorder the infant should be referred urgently to a tertiary centre for investigation and management. Most functional disorders such as haemophilia need lifelong management. Many metabolic abnormalities such as phenylketonuria are very difficult to treat.
A patient delivers an infant at term after a pregnancy complicated by polyhydramnios. The infant appears normal but dribbles a lot of saliva.
The infant may have a congenital disorder, especially oesophageal atresia, anencephaly or meningomyelocoele.
Oesophageal atresia. These infants cannot swallow because the oesophagus ends in a blind pouch.
Attempt to pass a nasogastric tube. Usually the tube will curl back into the mouth if oesophageal atresia is present. The aspirate will be alkaline when tested with litmus paper as the nasogastric tube is not in the stomach. A chest X-ray will usually show the air-filled, blind oesophageal pouch containing the coiled-up feeding tube.
Keep the infant’s head raised to prevent gastric acid refluxing up the fistula into the lungs, do not feed the infant by mouth, keep the mouth well suctioned to prevent the saliva being inhaled into the lungs.
The infant must be transferred to a level 3 hospital for surgical correction of the abnormality. The emergency treatment must be continued while the infant is being transported. As the infant is kept nil per mouth, an intravenous infusion may be needed. Speak to the parents and obtain consent for operation.
An unbooked patient of 42 years old delivers an unusual looking infant which is very floppy. The hands and feet appear wider than usual. The infant’s tongue appears large and cyanosed. After the second feed the infant vomits green fluid.
Down syndrome. These infants typically have an abnormal looking face, broad hands and feet, and hypotonia.
Phone the nearest genetics laboratory and arrange for a sample of blood to be sent to them for chromosome analysis.
An extra chromosome 21.
Because she is 42 years old (older than 34). She should have booked early and been offered screening.
A congenital heart abnormality, as suggested by the central cyanosis, and duodenal atresia, as suggested by the bile-stained vomit. Both these abnormalities are common in infants with Down syndrome.
They should be referred to the Down Syndrome Association or similar group in your area.
An infant is born preterm with an abnormal foot that is twisted inward and cannot be turned back into a normal position. On careful examination it is noticed that the infant also has a swelling in the left side of the scrotum.
The infant has a clubbed foot. A foot that is simply twisted inward, due to the position before delivery, is easily turned back into a normal position.
The infant should be referred as soon as possible to an orthopaedic clinic where the foot will be placed in serial plaster of Paris casts until it is straight.
Inguinal hernia and fluid hernia (hydrocoele).
A fluid hernia transilluminates very well as it contains clear fluid while an inguinal hernia does not transilluminate because it contains bowel.
It should be surgically corrected within the first few days if the infant is well. A delay in surgery may result in the bowel becoming trapped with resultant gangrene.