Sudden Infant Death Syndrome (SIDS) is a sudden death of apparently healthy child aged up to 1 year as a result of cessation of breathing and heart failure, the cause of which cannot be established at the mortem expertise. Sometimes the syndrome is called as “death at the crib” or death for no reason. However, there are causes or risk factors for the development of this poorly studied phenomenon, and the parents, eliminating them from their life, can save the life and health of the child.
SIDS is not a disease; it is a posthumous diagnosis that is exhibited when neither results of the autopsy, nor the analysis of the child's medical card make it possible to establish the cause of the death. Such diagnosis is not presented in the case of detection of previously undiagnosed malformation or death caused by an accident.
Cases of sudden death among infants are known for a long time, but they cannot be explained up to now despite the fact that scientists around the world are working on this problem. By unknown causes SIDS is not typical for the children of Asian families. Sudden death of a child occurs in families of people of the white race twice more often than among African Americans and Indians (Mayo Clinic, 2014).
In most cases SIDS occurs when the child is sleeping without evidence of any symptoms on the eve. SIDS cases are registered among 5-6 children out of thousands of their peers. A study of infant deaths for no reason identified some patterns of this sinister and mysterious phenomenon:
• SIDS in 90% of cases occurs before 6 month age of the baby (usually from 2 to 4 months)
• Some time ago, cases of death in the cold season dominated (the highest mortality rate in January)
• Currently the probability of death does not depend on the season
• In 60% of cases boys die
• SIDS is impossible to predict and prevent
• SIDS is not connected with carrying out preventive vaccinations
Risk Factors of SIDS
During the study of SIDS cases a number of factors that contribute to its occurrence (risk factors) were identified:
• Position on the stomach while sleeping
• The use of soft baby bedding: mattress, pillow, blanket
• Overheating the baby (for example, excessive heating in the room)
• Premature birth (the less is the gestational age of the baby, the greater is the risk of SIDS)
• Insufficient weight at birth
• Multiple pregnancy
• A large number of pregnancies of a mother and short intervals between them
• SIDS cases or stillbirth of earlier born children of these parents
• A late start or absence of medical supervision during pregnancy
• Anemia or fetal hypoxia
• Recent illnesses of a child
• Maternal age younger than 17 years
• Smoking, use of drugs or alcohol by the mother
• Poor economic and social conditions in the family (overcrowding in the apartment, the absence of regular ventilation, smoking by family members, unemployed parents, lack of knowledge about the care of the baby)
• Birth of a child among single mothers
• Depression of the mother during the postpartum period
I would like to separately indicate the risk of SIDS in connection with smoking parents. Studies have proven that if pregnant women did not smoke, the number of SIDS would decrease by 40%. Both active and passive smoking during pregnancy and after childbirth is dangerous. Smoking in the next room with an open window or with a fan is also harmful (Floyd R. Livingston, 2014).
Possible Causes of SIDS
SIDS has not been fully studied yet. But still some mechanisms that take place when it occurs are described. There are several theories that explain the mechanism of occurrence of SIDS.
Violation of Respiratory Function
During sleep periodic violation of respiratory function normally occurs and breathing stops for a short time. As a result of the stop of the respiratory activity the insufficient amount of oxygen is formed in the blood (hypoxemia), which normally awakes the breathing. If breathing recovery does not occur, the child dies.
Cardiac Abnormalities
Some scientists believe that the leading factor of SIDS is not apnea, but the cardiac dysrhythmia or cardiac arrest. These scientists name such risk factors as rhythm disturbance of the heart according to the type extrasystoles and blockades on the electrocardiogram, decrease of heart rate below 70 in per minute, often changing heart rate.
Violation of the heart rate up to the short-term cessation of heartbeat can be observed in healthy children. But if such stops are noticed in an infant, it is necessary to consult a doctor immediately and perform medical examination of the child.
Changes in the Brain Stem
Both breathing center and vasomotor center which is responsible for the functioning of the heart are located in the medulla oblongata. Studies have revealed the violation of the synthesis of enzymes, the formation of acetylcholine receptors in medulla cells under the influence of tobacco smoke or its components in some cases. These changes contribute to the emergence SIDS. In some children, the victims of SIDS, structural changes and destruction of cells in the brain stem caused during fetal development due to hypoxia were identified.
Ultrasonography which was conducted to the children who were rescued after the cessation of breathing allowed identifying the pathology of the arteries that provide blood flow to the brain stem in 50% of cases. This may indicate a violation of cerebral circulation which is the cause of SIDS in some children.
Circulatory disturbance arises in connection with clamping the artery at a certain position of the infant’s head. As the neck muscles are not sufficiently developed yet, the child cannot turn his head himself. Only after the child reaches four months he reflexively turns it into a safe position. The blood supply of the brain deteriorates when laying the baby to sleep on the side, but the blood flow to the brain reduces even more in a child's position on the stomach. During studies of such situations, a weak pulse was observed and respiration slowed sharply.
Stress
As a confirmation that SIDS is caused by severe stress for the body of the child serves a whole set of pathological changes found in all absolutely healthy syndrome victims.
These changes include small hemorrhages in the thymus, lungs, sometimes in the outer shell of the heart, traces ulceration of the digestive tract, lymphoid shrunken formations and reduction of blood viscosity. All these phenomena are non-specific symptoms of stress syndrome.
The clinical manifestations of this syndrome are such symptoms as runny nose, discharge from the eyes, enlarged tonsils, liver and spleen, rash, weight loss. These symptoms are observed within 2-3 weeks before the SIDS in 90% of children. But many researchers do not consider them relevant for the subsequent death. Perhaps the stress in combination with any disorders in the child's development leads to tragic consequences.
The Immune Theory and Infection Mechanism of Occurrence of SIDS
Most of the children, who died suddenly, during the week before that or on the last day of life, had symptoms any kind of infection. Children were examined by a doctor, some of them received antibiotics.
Supporters of this theory believe that the microorganisms produce toxins or cytokines that cause violation of security mechanisms in the body. As a result, the presence of risk factors with the occurrence of infections is compounded. Toxins of microorganisms (most often Staphylococcus aureus) provoke and amplify the inflammatory reaction. But a baby's body is not able to regulate its own defensive reactions yet.
Other researchers compared the types of antibodies to the microbes in children who have died doth from other causes and from SIDS. It revealed that a significant number of children, who died in the cradle, had IgA antibodies to the toxins of enterobacteria and clostridia. Healthy children also have antibodies to these organisms, but other classes (IgM and IgG), which indicate the immune protection of the organism from this toxin.
The obtained data enabled the researchers to conclude that such toxins affect all children, but the risk factors (excessive heat, influence of tobacco smoke and other components) lead to the disturbance of protection mechanisms. As a result, a combination of infection and the risk factors lead to death.
Recently there have been reports about the discovery of the gene SIDS in the study of the DNA of healthy children and babies who died from SIDS. It turned out that the risk of sudden infant death increases by three times in children having a mutant (defective) gene which is responsible for the development of the immune system. However, scientists believe that the presence of this gene leads to the death at the presence of other factors, i.e. only in conjunction with them.
Several studies indicate that the cause of SIDS may be the causative agent of peptic ulcer (Helicobacter pylori). This conclusion is based on the fact that this microorganism is much more often released in the tissues of the stomach and respiratory tract in children who died of SIDS compared with the dead babies because of other causes. These microbes can cause ammonia synthesis, which becomes a cause of respiratory disorders and SIDS. It is believed that if while regurgitation a child inhales a certain amount of bacteria contained in the vomit, the ammonia is absorbed into the blood and causes respiratory arrest (Patrick L. Carolan).
Child’s Bed & Sleeping
The best place for a crib is in the mother's room, but not near a radiator, fireplace or heater in order to avoid overheating of the child. The mattress should be hard and smooth. Firstly, an oilcloth can be laid on the mattress, and then - a well straightened sheet. The pillow is better not to use at all. The bed should be so hard that the baby's head did not leave a dent.
The blanket in the cold season should be woolen, not feather or cotton. Also do not use the thermal blanket. To cover the baby by the blanket is necessary not higher than the shoulders in order the baby not accidentally covered his head. A child should rest against the lower rim of the crib by his legs.
When using a sleeping bag, it should be selected strictly by the baby’s size so that the child could not get down inside it. The temperature in the baby's room should not exceed 20°C. During overheating of the baby, the brain control over the respiratory center operation deteriorates.
The baby should sleep only on his back. To prevent regurgitation and subsequent aspiration of vomit in the supine position, the baby should be held for 10-15 minutes before going to bed in an upright position. This will help to withdraw air from the stomach which was swallowed with food.
In the position on stomach the risk of SIDS increases because of several reasons:
• A sleep is deeper (because of increased awakening threshold)
• Impaired lung ventilation. This is especially important for infants 3 months of age, when the reflexes contributing to the ventilation are weakened
• Violation of the balance between the sympathetic and parasympathetic nervous systems is possible
• Physiological control over the work of the heart, lungs and vegetative functions weakens
Especially dangerous is the position on the stomach for the children who tend to sleep on the back and accidentally turn over during sleeping on the stomach. Children who like to sleep on the stomach should be put on the back after they fall asleep. The position on the side is also less secure than on the back. Soft toys should not be in the crib.
In the second half of the year the baby's life, when he can roll over in bed, it is affordable to allow him occupying a comfortable posture during sleep. But putting him to bed is still needed on the back. If the child turned around, it is better to turn him on his back.
Despite the fact that cases of sudden deaths occur more often during the night and early morning, you should not leave the child unattended in the daytime sleep. A portable crib is convenient because the mother can do housework and be at the same time in the same room with the sleeping baby (Amita Shroff, 2015).
The Most Threatened Age for SIDS
The sudden death of an infant younger than one month is not typical. Most often it happens from the second to the fourth month of life (most often on the 13th week). 90% of deaths occur in bed at the age up to six months. Once the child reaches the age of 1 year, SIDS cases are extremely rare, although cases of sudden death can occur with healthy adolescents (for example, when running on physical education class) (Baby Centre, 2012).
Conclusion
Unfortunately, to exclude the likelihood of sudden death of a baby completely is impossible because the reasons for its occurrence are not fully understood. But to minimize the risk of “death in bed” is possible and necessary.
A significant degree of risk of sudden death of a child lays the mother during pregnancy. Bad habits (smoking, drug and alcohol abuse) and neglecting medical supervision during pregnancy lead to the changes in the fetus, which can cause SIDS.
Carelessness and negligence in matters of child care is a major and important cause of death of a baby in the cradle.
Socially disadvantaged families affected by the low level of education, lack of knowledge and lack of performance of the basic rules for the care of babies. Parents should be aware of SIDS and make every effort to reduce the risk of its occurrence.
Bibliography
Amita Shroff. (2015). 10 Steps to Help Prevent SIDS. Retrieved from http://www.webmd.com/parenting/baby/sleep-naps-12/sids-prevention?page=3
Baby Centre. (2012). Sudden infant death syndrome (SIDS). Retrieved from http://www.babycentre.co.uk/a419/sudden-infant-death-syndrome-sids
Floyd R. Livingston. (2014). Sudden infant death syndrome (SIDS). Retrieved from http://kidshealth.org/en/parents/sids.html#
Mayo Clinic. (2014). Sudden infant death syndrome (SIDS). Retrieved from http://www.mayoclinic.org/diseases-conditions/sudden-infant-death-syndrome/basics/definition/con-20020269
Patrick L. Carolan. (N.d). Sudden Infant Death Syndrome (SIDS). Retrieved from http://www.medicinenet.com/sids/page2.htm
