The doctors eventually agreed with Susanna and her husband, Joe, that this was a case of horrific neglect - that Katie, along with more than a dozen other disabled children at the orphanage, was simply a victim of long-term starvation.
What Katie needed, in careful doses, was healthy food. Once she left the orphanage for her trip back to Pennsylvania, however, the hollow-faced child had other ideas.
Finally in the arms of parents who had waited months to hold her fragile body, Katie suddenly refused to eat.
It began, as so much else does these days, with the Internet.
Joe and Susanna Musser had a large, happy bunch of kids in their cozy, gray-shingled house, at the end of a gravel driveway in Lancaster County. Joe, a former pastor, earned a living as a carpenter, while Susanna taught their nine children at home.
Then came Verity. The Mussers' 10th child, whose name means truth, was born with Down syndrome. Though they knew almost nothing about children with disabilities, they saw her as a blessing from God.
So when Susanna started a blog, she named it "The Blessing of Verity," and it quickly drew an avid group of followers.
One of them e-mailed Susanna to ask about adopting children with Down syndrome, so Susanna did some research. She came across a Today show video from 2007, with wrenching images of emaciated children, confined to cribs in a Serbian mental institution. Some, like Verity, had Down syndrome.
Devout Christians, Susanna and Joe couldn't imagine that someone like their daughter would be discarded that way.
They looked at each other and realized that they, too, wanted to adopt.
The world of international adoption is changing. The number of foreign-born children adopted by U.S. families dropped to 9,300 last year, down from 23,000 in 2004.
Some of the decline came after allegations of child-trafficking, or because officials in other countries felt that children were better off in their native lands.
No matter the country, certain children have always been available to a family that wants them - those with special needs.
Exact numbers are unavailable, but now, most children adopted from other countries either have some sort of disability or are older children that have suffered psychological neglect, said Adam Pertman, executive director of the Evan B. Donaldson Adoption Institute in New York.
That's where programs such as the one at Children's Hospital come in.
Doctors review the health records of foreign children awaiting adoption, to prepare parents for what might lie ahead. The records can be scanty, inaccurate, or both. But the doctors have an idea of what to expect, depending on the country: parasites, fetal alcohol syndrome, missed vaccinations.
Many of the problems are minor by U.S. standards. Yet for kids with severe needs, program medical director Susan Friedman knows it can be a lot to handle. She does not want parents to adopt out of pity. And if they decide not to adopt, she tells them it is OK.
When Susanna and Joe went to the hospital last year, their minds already were made up.
The girl they had chosen to adopt lived in an orphanage in the city of Pleven, in northern Bulgaria. The couple had found Katie's picture on an adoption-agency website and knew at once.
"It was like paging through a yearbook full of faces of strangers and suddenly coming across the face of my own child," Susanna said later.
Friedman warned them that Katie's medical problems were likely to be daunting. She had never seen a case of malnutrition this bad.
"This is quite remarkable what you're doing," the doctor told the parents.
"I don't want to sound disrespectful," Susanna responded, polite but firm. "There's nothing remarkable about this. I'm a mother. I'm just saving my child's life like any mother would."
Legally, the brown-eyed waif was not yet their child, but Susanna and Joe didn't see it that way.
They know some people, like Friedman, are in awe of the couple's efforts. Others, Susanna knows, will just think she and Joe are crazy.
On her blog, after she and Joe successfully went through one of their pre-adoption evaluations for parental fitness, Susanna wrote this:
For any of you who held this in doubt, the psychiatrist considers us to be in good mental health, and we have the papers to prove it! Haha!
Susanna says there is nothing crazy or extraordinary about the whole thing, that it just requires love, hard work, and a bit of help.
And there has been help. The Mussers are not well-off and have no health insurance, but they belong to Samaritan Ministries International, a Christian health-care cost-sharing program, whose members would cover Katie's medical bills. Readers of the blog, meanwhile, prayed for them and donated money to cover most of the roughly $28,000 in adoption costs.
And out of the blue, the Mussers got an offer from someone who understood their story in a way few could. His name was Adam Boroughs, a nurse at the Hospital of the University of Pennsylvania. After his wife, Amy, saw the blog, he volunteered to go to Bulgaria with the Mussers to get Katie.
Adam and Amy also have 10 children, seven of them adopted. Of the seven, four had something in common with Verity and Katie. They have Down syndrome.
Susanna first went to Bulgaria by herself in August to visit the orphanage and meet Toni Vladimirova, the local attorney handling the adoption. Susanna assumed that the orphanage, like many in Eastern Europe, was doing the best it could with limited resources.
It was not. Katie lived on the top floor with children that orphanage officials referred to as "malformations," Vladimirova later wrote in a report to the national Ministry of Justice.
The top-floor children were bone-thin, their bodies stunted. They spent most of their time in cribs, and the air stank of urine and vomit, the attorney wrote.
The official explanation from the orphanage was that the children were not malnourished, that they were unable to gain weight because of their disabilities.
Susanna and her attorney felt otherwise. The children were given nothing to eat but a thin, whitish liquid in a bottle, they said. Susanna thinks it was watered-down yogurt, mixed with a broth or fruit puree; Vladimirova said it seemed like flour and water.
The attorney, who had been handling special-needs adoptions since 1996, had never seen anything like it.
She and Susanna were determined to do something. After months of effort, they prompted government officials to remove the orphanage director and launch investigations. Some readers of Susanna's blog would start the process of adopting more children from Katie's floor, while others donated money for their medical care.
But before all that, the first order of business was getting Katie home.
Susanna and Joe were in a panic.
They had gone to Bulgaria in November to pick up their newest family member, but the little girl who desperately needed food would not eat. At their hotel in Sofia, Katie had finished some of the leftover gruel from the orphanage, but that was it. She was rapidly becoming dehydrated.
In the middle of the night, the couple took her to a hospital. Adam, the nurse from Penn, arrived that afternoon and met them there.
Katie was stabilized with IV fluids, and she got nutrients through a tube that went in one nostril and down past her esophagus.
Back in Philadelphia, Friedman was worried about something called refeeding syndrome - known to the medical community from treating war prisoners and Holocaust survivors. If a starving person eats too much too soon, it sets off a dangerous metabolic cascade that can lead to seizures, heart failure, and even death.
Susanna, who was still providing breast milk for Verity, asked if Katie could have that through her tube. Friedman thought it would be OK, in moderation, despite Katie's age.
Once Katie was stable, she spent two days at the hotel, but Adam still worried. Periodically, he took samples of her blood back to the hospital for tests, giving the results to Friedman by Skype.
After the first leg of the journey home, a flight to Frankfurt, Germany, Adam called Friedman at 3 a.m. Philadelphia time, warning that Katie's oxygen levels had dropped somewhat.
An anxious Friedman got to the Philadelphia airport 90 minutes early, ready to take Katie to intensive care.
"I really had no idea whether she was going to arrive alive," the physician said.
When Susanna, Joe, and Adam finally walked off the plane with their frail travel companion, Katie was indeed alive.
She was home.
At the house in Lancaster County, in the town of New Providence, everyone pitches in, from 18-year-old Joseph to 3-year-old Stephen. The kids handle breakfast, lunch, laundry, and yard work. And they dote on Katie.
Before her arrival, Joe and Susanna had met with the older children to see if they'd be OK with adding to the family. They were, and now that Katie is here, they feel no different.
"I would've thought it would be more difficult than it is," said Daniel, 16. "I would say it's only gotten better."
By any measure, Katie seems like a different child. Her weight has nearly tripled, to 27 pounds, and she is 34 inches tall. The median for a girl with Down syndrome at that age is about 66 pounds and 47 inches.
The years in the orphanage were devastating for her development, on top of the delays associated with Down syndrome. She suffered from anemia, scurvy, and compression fractures of the spine. Her metabolism had shifted into ultralow gear, Friedman said.
"It defies understanding how she could've survived for nine years like this," the doctor said, "but she did."
One reason she got so little to eat in Bulgaria may be that as infants, people with Down syndrome can have trouble coordinating the muscles for swallowing, she said. Katie, Friedman figures, never got the chance to learn how.
Now she has. Her feeding tube is gone, and she has learned to eat from a spoon.
Susanna carries Katie much of the time, but a therapist has predicted she could learn to walk in about a year.
One day recently, Susanna helped Katie scoot forward in a wheeled walker device.
"Good gii-rrlll!" Susanna said, in the singsong voice parents use to talk to a baby.
Then Susanna stopped, a bit self-conscious, acknowledging that she was, after all, talking to a girl who turned 10 in March. But it seems as good a way as any for her to learn words.
Katie says "ma-ma-ma" and "ba-ba-ba," and she mouths the word up when being picked up. She uses sign language to say "all done!" and "all clean!"
She likes music. Sitting in father Joe's lap as the family sings "Guide Me O Thou Great Jehovah" in rich four-part harmony, Katie slapped her palm excitedly on the table. When brother Joseph plays Mozart on the piano, she beams.
"If we would write down all the issues that Katie has on a piece of paper, and you didn't see Katie, didn't see her face, just read her list of diagnoses, it would look scary on paper," Susanna said. "But that's not Katie."
Who can say how much progress she will make?
For Susanna and Joe and Katie's 10 brothers and sisters, the fact that she is here is enough.
See videos about Katie's adoption and the care she received at Children's Hospital at www.philly.com/katie and www.philly.com/katiedoc
Contact Tom Avril at 215-854-2430
or firstname.lastname@example.org .