(CNN) A doctor at Le Bonheur Children's Hospital in Memphis, Tennessee, says he admitted two young patients -- a toddler and a preschooler -- because the specialty formula they need is out of stock and they haven't been able to tolerate any replacements.
The toddler, who had been in the hospital for about a week, was discharged Tuesday. The preschooler, who was admitted in April, remains in the hospital, according to a hospital spokesperson.
"It's been a crisis since February of shifting and trying to sift through and figure something else to work," Dr. Mark Corkins, a pediatric gastroenterologist at the hospital who is treating the patients, told CNN in a telephone interview.
The US Food and Drug Administration said Monday that it is making it easier to import certain infant formulas as it works to address a nationwide formula shortage.
Both of the children hospitalized in Memphis have short bowel syndrome and can't absorb full-size proteins. The condition is rare, affecting about 25 out of every 100,000 infants. They rely on a formula made of amino acids, the building blocks of proteins. These broken-down proteins don't have to be digested; they can just be absorbed by the gut.
Formula maker Abbott produced about 80% of the specialty formula they need, a brand called EleCare. When its Sturgis, Michigan, production plant shut down in February, patients on that formula were switched to those made by smaller suppliers, and now those stocks have run out too, Corkins said.
He said they tried to use other kinds of formulas, made with chopped-up proteins, but it didn't work. The kids couldn't tolerate them and became dehydrated.
"In the hospital, we give them IV fluids, and the other thing we give them is IV nutrition. That's not ideal," he said. The doctors want to feed these children by mouth so they can use their gut. The more they use their gut, the more it develops.
Corkins says both children could have stayed home, if it weren't for their special nutritional needs, but they were hospitalized so they could be fed.