There is something going on in the inner ear, he said.
Explore This IssueApril 2008
Pathogenesis of SIDS
Although rare, SIDS remains the number-one cause of death in infancy. A better understanding of its pathogenesis is needed; this is impeded by the relatively low incidence of the syndrome and the difficulty in conducting studies large enough to identify the underlying cause. The search for the cause of SIDS has been under way for decades, and currently there is a common belief that a disturbance in respiratory control predisposes infants for SIDS.
SIDS is thought to involve an abnormal response to increasing carbon dioxide, which is the normal trigger for taking the next breath, said Scott Manning, MD, of the Department of Pediatric Otolaryngology-Head and Neck Surgery at Children’s Hospital and Regional Medical Center in Seattle, adding that the Back to Sleep Campaign, which, among other things, recommended laying infants on their backs when sleeping, had a tremendous public health impact on reducing SIDS presumably by decreasing any excessive carbon dioxide buildup that might result from a face-down position.
Launched first in Europe and later, in the early 1990s, in the United States, the institution of the Back to Sleep Campaign temporally paralleled a decrease in the rate of SIDS from 1.2 per 1,000 to 0.57 per 1,000 live births, said Nancy Bauman, MD, of the Division of Otolaryngology at Children’s National Medical Center in Washington, DC. She added that this finding suggests a direct association between sleeping position and the risk of SIDS.
Besides sleeping position, many other risk factors for SIDS have been identified, including tobacco exposure, bed sharing, maternal substance abuse, lack of pacifier use, genetic predisposition, and arrhythmias, particularly prolonged QT syndrome, she said. The cause of SIDS is clearly multifactorial. The lack of an appropriate arousal response to an internal stimulus is likely a common contributor among the different mechanisms. As such, these infants fail to arouse when they should, and the lack of arousal in some situations may be fatal.
But beyond a clear understanding of this main mechanism that leads to SIDS, the cause of SIDS remains a mystery.
For Dr. Rubens, who said that as a pediatric anesthesiologist he probably watches babies sleep more than anyone else, the mystery points to something that was being missed.
I looked at the literature and looked at various studies and had the strong feeling that we’ve missed something, he said. My theory is that the piece that is missing is related to the inner ear playing a role in the control of breathing.