An Antibiotic Backfires

A common antibiotic used to treat whooping cough in newborns caused a severe stomach disorder in seven babies at a Tennessee hospital, the government said yesterday in a report that stunned pediatricians.

Doctors said the report from the Centers for Disease Control and Prevention marks the first time that erythromycin has been strongly linked to pyloric stenosis, an illness among newborns that blocks digestion and causes projectile vomiting. The illness must be treated with surgery.

The CDC said physicians and parents need to be aware of the potentially serious side effect of the antibiotic. But the agency said that doesn't mean doctors should stop prescribing it for whooping cough, which puts most infected babies in the hospital and can be fatal.

A 1994-96 study found an average of about 1,900 cases of whooping cough a year among infants in the United States.

A hospital in Knoxville, Tenn., prescribed erythromycin to 200 babies born there in February after they were exposed to whooping cough by a hospital worker, the CDC said. Seven of the newborns became ill with pyloric stenosis, in which a muscle at the bottom of the stomach enlarges, blocking food from passing to the small intestine. The babies recovered.

It is rare for a large number of infants to be prescribed erythromycin at the same place and time, but that enabled the CDC to make the connection with pyloric stenosis. The side effect is apparently too rare for doctors to see the link in isolated cases.

Signature for ADHD

Brain scans have revealed measurable biochemical differences in people with attention-deficit/hyperactivity disorder (ADHD), a discovery that could reduce the number of children mistakenly diagnosed and put on drug treatment, researchers say.

The diagnosis of ADHD, usually made in school-age children, is commonly based on observed behavior and some experts believe it is highly subjective. Some say the condition is being overdiagnosed in the United States, exposing children unnecessarily to medication; others argue it is not treated often enough.

Earlier studies have shown scans can detect structural differences in ADHD sufferers' brains, as well as abnormalities in brain activity, and scientists suspect that defects in genes relating to the brain chemical dopamine probably are involved.

The latest study, conducted at Massachusetts General Hospital in Boston and published in this week's issue of the Lancet medical journal, is the first to show a measurable biochemical abnormality in people with the disorder.

Dopamine is associated with movement, thought, motivation and pleasure. One brain cell signals another by squirting dopamine. Then the first cell mops up the released chemical with a structure called a dopamine transporter.

The researchers scanned the brains of six adults diagnosed with ADHD and 30 healthy people of the same age after injecting both groups with a chemical agent that attaches to the dopamine transporter.

The ADHD sufferers had 70 percent more dopamine transporters than their healthy counterparts.

The scientists could not tell, however, whether that was a cause or an effect of the disorder.