PITTSBURGH — Renee Terney, who last month traveled to Erie, Pa., to ride the slides at Splash Lagoon, has come a long way in the 2½ years since she was struck by a form of liver disease that has quickly emerged as a public-health threat and a challenge to transplant programs.

Blood work and other tests revealed that Terney, of Sheradon, Pa., had nonalcoholic fatty liver disease — an accumulation of fat in liver cells, a condition associated with poor diet, a sedentary lifestyle and obesity. The damage to Terney’s liver was so extensive that she was near death at the time of her May 2013 transplant at Allegheny General Hospital.

Terney, now 48, lost 85 pounds during the ordeal. “My goal is not to put it back on,” she said.

Like other chronic conditions and other liver ailments, nonalcoholic fatty liver disease can be a silent killer, with some patients experiencing no symptoms for years or longer.

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Jose Oliva, medical director of Allegheny Health Network’s liver transplantation program, said it’s often discovered when routine blood work ordered by a primary-care physician reveals elevated levels of liver enzymes. He said follow-up tests, such as a CT scan or ultrasound, are used to confirm diagnosis.

If caught early, exercise and improved diet can slow or reverse the disease. “It’s behavior modification,” Oliva said.

However, there are no medications to assist with treatment, and in the most severe and advanced cases, known as nonalcoholic steatohepatitis, or NASH, the scarring of the liver is identical to the damage caused by alcoholism.

Some of these patients — who eventually experience symptoms such as belly pain, jaundice and swelling of the legs, as Terney did — must pin their hope for survival on a transplant.

But livers are in short supply. “There aren’t enough now as it is,” and a rising tide of nonalcoholic fatty liver disease will make matters worse, said Vinod Rustgi, medical director of liver transplantation for University of Pittsburgh Medical Center.

Of about 17,000 people nationwide who are on wait lists for a liver transplant, Oliva said, only about 6,500 receive transplants each year. Rustgi said 15 percent die before receiving a new liver.

According to the American Liver Foundation, nonalcoholic fatty liver disease is already “the most common liver disease in most of the Western world.” It affects 30 million Americans, and the numbers are growing.

“We are particularly concerned about the high prevalence of fatty liver disease in children. It is setting them up on a path to liver failure and puts them at significant health risk,” foundation Chairman Tom Nealon said in a statement.

Obesity is believed to be the chief culprit.

“I think it’s very, very important that people recognize that obesity can shorten life expectancy, and, conversely, longevity has been associated with thinness,” Rustgi said.

Unlike heart disease, hypertension and type 2 diabetes — long the subject of public awareness and education campaigns — nonalcoholic fatty liver disease remains little known and little understood in the U.S.

More than a year after her transplant, Terney says she feels great. She credited her partner, Nancy Burns, with supporting her, and said her five children were an inspiration.

“I wanted to keep going for them,” she said.