More than 100,000 U.S. children visit the emergency room for a concussion each year, with many discharged without instructions to get needed follow-up care, a new study suggests.

The findings, published in the Journal of Pediatrics, appear to be the first estimate of how many children are treated for concussions in U.S. ERs annually.

They also point to an important shortcoming in care: many parents may take their children home from the hospital without knowing they should follow-up with a visit to their pediatrician.

That follow-up is important because the job of the ER doctors is essentially limited to making sure there is no emergency -- such as bleeding on the brain or other injury that requires immediate attention, explained Dr. William P. Meehan III, director of the sports concussion clinic at Children's Hospital Boston and one of the researchers on the new study.

It's only in days following the concussion that the course of the injury can be assessed, and parents can be advised on when their kids can safely return to sports or other activities.

None of that can be done in the ER, Meehan told Reuters Health in an interview.

The term concussion refers to a temporary disruption in normal brain function, usually due to a blow to the head. Symptoms include dizziness, confusion, balance problems and vision disturbances. Contrary to common belief, most concussions -- up to 90 percent -- do not involve a loss of consciousness, Meehan noted.

For the current study, Meehan and colleague Dr. Rebekah Mannix examined a national database that collects information on ER and outpatient visits to about 600 U.S. hospitals.

Based on figures for 2002 to 2006, the researchers found that concussions were diagnosed in an estimated one in every 220 patients age 19 or younger seen in U.S. ERs. On the national level, that translates to about 144,000 pediatric concussions each year.

In 28 percent of these cases, the researchers found, patients were discharged from the ER with no specific instructions to follow-up with another doctor. Meehan called the finding disappointing.

For parents of children who sustain a head injury, he said the message is this: Go to the ER, make sure there is no emergency, then follow up with your pediatrician.

If your pediatrician is not experienced in managing concussions, Meehan noted, he or she can refer you to a sports medicine specialist, neurologist or other provider who is.

The standard treatment for concussions is rest, both physical and cognitive -- which means a break from running and calculus, for example. In most cases, people with concussions recover in a few days to weeks, but some have symptoms that last weeks to months -- most commonly headaches and insomnia, Meehan said.

In this study, sports were the most common cause of concussion, accounting for about 30 percent of the total number and 41 percent of concussions among 11- to 19-year-olds.

It's important for children and teens involved in sports to get the medical OK before returning to the game, Meehan said.

Car accidents were the second-most common cause of concussions among children and teenagers, while bicycle accidents and falls together accounted for one-quarter of all cases.

The study also found that a large proportion of children with concussions -- about 69 percent -- had a head-imaging test in the ER, almost always a CT scan. Exactly why so many had head imaging is not clear, since concussions can be diagnosed based on symptoms and the circumstances of the injury.

A CT scan may be needed in some cases, Meehan said, in order to rule out structural injuries.

But the high rate seen in this study, he and Mannix write, is an area where improvement might be made.

CT scans expose the body to radiation, at much higher doses than conventional X-rays, and there have been increasing calls of late to reduce unnecessary CT use.

SOURCE: Journal of Pediatrics, online August 16, 2010.