NEW YORK (Reuters Health) - In infants with urinary tract infections, early antibiotic treatment reduces the risk of kidney involvement, but does not prevent scarring if a kidney infection develops, according to study findings published in the current issue of Pediatrics.

Kidney scarring is a serious condition in infants and children, causing and include rains effects such as a higher risk of kidney stones, reduction in kidney size; decline in organ function and high blood pressure.

Delaying treatment has been singled out as the most important factor that is likely to effect the development of scarring after acute kidney infection, Dr. Dimitrios Doganis and colleagues from "P & A Kyriakou" Children's Hospital, Athens, note. However, no studies have been conducted that support this.

In a 5-year study, the researchers looked at the time between the start of kidney infection and therapy, and the development of tissue changes caused by inflammation that leads to scaring. The study included 278 infants, between the ages of 0.5 and 12 months, who developed their first urinary tract infection.

Kidney imaging tests were performed within 1 to 18 days of hospital admission and a second scan was performed in infants with tissue abnormalities after 5 to 26 months.

The average time between the onset of infection and the start of treatment was 2 days. Of the 278 children, 158 (57 percent) had initial inflammatory changes in the kidney.

Fifty-one percent of infants with an abnormal scan in early stages of infection developed kidney scarring, according to the authors, but there was no statistically significant difference in the frequency of scarring in infants treated early compared with those treated later.

This suggests that once a kidney infection begins, the scarring that develops is independent of the timing of therapy, Doganis and colleagues surmise.

Early and appropriate treatment of urinary tract infection, especially during the first 24 hours after the onset of symptoms, reduces the likelihood of kidney involvement during the initial phase of infection, but can't prevent scarring, the researchers conclude.