Sudden infant death syndrome

A medical mystery of early infancy, sudden infant death syndrome (SIDS)—commonly called crib death—kills apparently healthy infants, usually between ages 1 month and 1 year, for reasons that remain unexplained, even after an autopsy. Typically, parents put the infant to bed and later find him dead, often with no indications of a struggle or distress of any kind.

Some infants may have had signs of a cold, but such symptoms are usually absent. SIDS has occurred throughout history, all over the world, and in all climates.

Causes
SIDS is one of the leading causes of infant death. Most of these deaths occur during the winter, in poor families, and among underweight babies and those born to mothers younger than age 20.
Although infants who die from SIDS often appear healthy, research suggests that many may have had undetected abnormalities, such as an immature respiratory system and respiratory dysfunction. In fact, the current thinking is that SIDS may result from an abnormality in the control of ventilation, which causes prolonged apneic periods with profound hypoxemia and serious cardiac arrhythmias.

Risk factors for the infant include 

sleeping on the stomach (up to age 4 months), 

soft bedding in the crib (up to age 1 year), 

premature birth, 

having a history of a sibling who had SIDS, and

being born into poverty. 

Maternal risk factors include 

multiple births, 

smoking or illicit drug use, 

teenage motherhood, 

short intervals between pregnancies, and 

late prenatal care.

Clinical Presentation
Although parents find some victims wedged in crib corners or with blankets wrapped around their heads, autopsies rule out suffocation as the cause of death. Even when frothy, blood-tinged sputum is found around the infant’s mouth or on the crib sheets, an autopsy shows a patent airway, so aspiration of vomitus isn’t the cause of death.
Typically, SIDS babies don’t cry out and show no signs of having been disturbed in their sleep, although their positions or tangled blankets may suggest movement just before death, perhaps from terminal spasm.
Depending on how long the infant has been dead, a SIDS baby may have a mottled complexion, with extreme cyanosis of the lips and fingertips, or pooling of blood in the legs and feet that may be mistaken for bruises. Pulse and respirations are absent, and the infant’s diaper is wet and full of stools.

Diagnosis
An autopsy rules out other causes of death. Characteristic histologic findings on autopsy include small or normal adrenal glands and petechiae over the visceral surfaces of the pleura, within the thymus (which is enlarged), and in the epicardium.
An autopsy also reveals extremely well-preserved lymphoid structures and certain pathologic characteristics that suggest chronic hypoxemia, such as increased pulmonary artery smooth muscle. Examination also shows edematous, congestive lungs fully expanded in the pleural cavities, liquid (not clotted) blood in the heart, and curd from the stomach inside the trachea.

Management
If the parents bring the infant to the emergency department, the physician will decide whether to try to resuscitate him. An “aborted SIDS” is an infant who is found apneic and is successfully resuscitated. Such an infant, or any infant who had a sibling stricken by SIDS, should be tested for infantile apnea. If tests are positive, a home apnea monitor may be recommended.

Because most infants can’t be resuscitated, however, treatment focuses on emotional support for the family