"Mono" linked to chronic fatigue syndrome in teens

By Michelle Rizzo

NEW YORK (Reuters Health) - Teens who develop "mono," otherwise known as infectious mononucleosis, may be at risk for chronic fatigue syndrome, according to a study in Pediatrics.

Previous studies suggested that about one in ten adults with acute infectious mononucleosis go on to develop chronic fatigue syndrome, Dr. Ben Z. Katz, of Northwestern University Feinberg School of Medicine, Chicago, and colleagues write. However, what happens to teens with mononucleosis is less well-studied.

The researchers monitored 301 adolescents with the infection. Six months after the mononucleosis diagnosis, 70 patients (24 percent) had not made a full recovery.

Thirty-nine of these subjects were diagnosed with chronic fatigue syndrome, reflecting 13 percent of the original group of 301.

Six months later, at a 12-month follow-up visit, 7 percent had chronic fatigue syndrome, and at 24 months, chronic fatigue syndrome persisted in 4 percent. That is about 20 times higher than in the general teenage population.

All 13 patients who still had chronic fatigue syndrome at 24 months were female and, on average, they reported worse fatigue at 12 months.

Treatment with steroids for the infectious mononucleosis at the time of its diagnosis did not affect the risk of developing chronic fatigue syndrome.

"As part of our study, we also followed a group of adolescents who completely recovered from their mononucleosis," Dr. Katz told Reuters Health.

"We are now in the process of trying to figure out what differentiates adolescents who recover from those who don't," he said.

SOURCE: Pediatrics, July 2009.