The cheer of a musical birthday card could turn into a medical nightmare if a child swallows the coin-sized battery inside the card.

Authorities say more children are showing up in emergency rooms after ingesting those small batteries found in toys, watches, remote controls and now greeting cards.

The Georgia Poison Center has received more calls about the batteries than in previous years, according to Gaylord Lopez, executive director. Lopez said the Poison Center receives an average of 70 to 80 calls about the batteries each year. This year, the center has already received 48 calls.

Georgia Poison Center records show that since 2006 the center has assisted on 526 such cases, he said.

A recent study by the Research Institute at Nationwide Children's Hospital shows that over the past 20 years, the number of children under 18 treated at emergency rooms for battery-related incidents has doubled and that 84 percent of them are directly related to button batteries. Lopez said most of those calls -- 70 percent - come from parents of children under 6.

"We need to educate everyone to see how these batteries are really dangerous," Lopez said. "Kids are attracted because they are so shiny, and small like candies. Even some doctors are not really aware of how dangerous are those batteries."

For the Research Institute study, experts sampled about 100 U.S. hospitals. From 1990 to 2009, more than 65,000 children visited emergency rooms for a battery-related issue.

"Parents and other caregivers often don't realize that coin-sized button batteries are included in devices they buy," said Terri Miller of Safe Kids Georgia. "Car keys with electronic fobs, for example, are often shared with children for their amusement. The batteries inside, if swallowed, can get stuck in a child's throat and cause serious injury and even death."

Lopez from the Georgia Poison Center said parents and doctors should first make sure the battery is not blocking any airways and will need medical intervention. If not, he said, children who ingest a battery should not take any medications while waiting for the battery to find its way out. "We ask the parents to keep the children's regular diet, in some cases we recommend them to drink more liquids and eat things that will make them evacuate, but nothing abrasive."

Gary Smith, director of the Center for Injury Research and Policy in Columbus, Ohio, told USA Today that in most cases an ingested battery will be eliminated in the stool. But under some circumstances it can cause alkaline burns and perforations of the esophagus.

"Often there are no symptoms early on, so it's important that an X-ray be taken as soon as possible if ingestion is suspected," he said.

In Georgia no deaths have been reported, but nationally eight children have died since 2006 after swallowing the batteries.