Thursday, November 02, 2006

Brain stem explanation for SIDS

Michael Conlon reports for Reuters:
An abnormality in part of the brain that controls breathing, arousal and other reflexes may be what causes sudden infant death syndrome, a finding that could lead to a preventive treatment, a study says.

The discovery could explain why babies lying face down are more likely to die of SIDS.

In that position an infant's reflexes, including head turning and arousal, are harder to trigger when breathing is challenged, says the report from Children's Hospital Boston and Harvard Medical School.

The study, published in this week's Journal of the American Medical Association, was based on autopsy data from 31 infants who had died from SIDS and 10 who had died from other causes between 1997 and 2005 in California.

In the SIDS infants, a look at the lowest part of the brainstem, the medulla oblongata, found abnormalities in nerve cells that make and use serotonin, one of the chemicals in the brain that transmit messages between nerve cells.

Serotonin and how it is processed in the brainstem may help coordinate breathing, blood pressure, sensitivity to carbon dioxide and temperature, the report says.

When babies sleep face down or have their faces covered by bedding, they are thought to breathe exhaled carbon dioxide back in, depriving them of oxygen.

When that happens the carbon dioxide increase would normally trigger nerve cells in the brainstem, which in turn stimulate respiratory and arousal centres in the brain.
Meanwhile, the American Academy of Pediatrics has been promoting a policy of using forensic pathologists to investigate infanticide whenever SIDS is reported. I don't think that they should be accusing parents of crimes in SIDS cases, unless they can at least figure out what causes AIDS.

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