On a typical day, 11-year-old Adrienne Tamayo takes classes, plays a video game that requires her to dance like Michael Jackson, crafts Shrinky Dinks or colorful picture frames, takes 12 types of medication and undergoes a three-hour-long dialysis session at the Lucile Packard Children's Hospital.

Like thousands of other children, the Reno, Nev., native came to Palo Alto for medical care. Last August, after suffering through recurring episodes of stomach pains and nausea, she was diagnosed with microscopic polyangiitis, a disease that attacked her immune system and forced her kidneys to shrink. Adrienne needs a new kidney, but her immune system is currently too weak to accommodate a transplant. Since October, she and her mom, Carmen Prieto, have been constantly shuttling between the hospital and the nearby Ronald McDonald House, a home for children with life-threatening illnesses and their families. She could be here for another year.

Adrienne takes her situation in stride. She knows her way around the Ronald McDonald House and has made many friends here. Polite and precocious, she can describe in graphic terms how the human digestive system works -- a lesson she learned earlier in the day at a hospital-run school. She cheerfully displays Disney-themed accessories in the second-story suite she shares with her mom and leads a tour through the house's playroom and computer room. The only time she breaks down is when she's asked about her friends back home, whom she misses terribly. Her classmates from Reno had recently created a poster for her that includes pictures of each student and a message urging her to feel better.

Extended stays like Adrienne's were once a rarity at the Ronald McDonald House, a peach-and-blue facility on Sand Hill Road, across the street from the Stanford Shopping Center. As recently as in 2003, the average stay at the house was six nights, said Linda Lyon, the facility's development director. But recent technical advances brought about new treatment options, which means more patients and longer stays. Last year, the average stay was 24 nights, Lyon said.

"Treatment has grown by leaps and bounds," Lyon said. "We're seeing amazing advancement, but families have to be close to the hospitals to get this done."

The new treatment options have pushed the demand at the Ronald McDonald House to new heights. When the Palo Alto house was built in 1979, becoming the fifth such facility in the nation, it featured 13 rooms. The number was expanded to 24 in 1992 and to the present level of 47 in 2003. Demand is expected to further accelerate in the coming years as the Children's Hospital embarks on a major expansion -- one that would raise the number of patient beds from 257 to 361.

To cope with the rising demand, the Ronald McDonald House is planning its most ambitious expansion yet -- a three-story, 46,000-square-foot addition that would effectively double its space and add 68 guest rooms. Stanford University is providing land, currently a vacant, grassy plot, adjacent to the current one at 520 Sand Hill Road. The two buildings would share some services, and officials expect to achieve savings through economy of scale. Bern Beecham, a former Palo Alto mayor who volunteers at the Ronald McDonald House and serves on its board of directors, said the new facility would also draw on lessons from previous expansions when it comes to room arrangements.

"Every time we do something, we learn what works for the patients and what works for the House," Beecham said.

The City Council will get its first look at the expansion plan on Feb. 13. The city would have to rezone the property to allow the project to be built.

With 15 employees and an annual budget of $3.2 million, the house greatly depends on volunteer support (despite its name, only 6 percent of its funding actually comes from McDonald's). More than 150 people volunteer here every week and scores of local restaurants, shops and professionals donate food, linens and services such as haircuts and massages. Volunteers at the front desk tend to be Palo Alto residents who can guide families to local attractions, Lyon said.

When they first arrived in Palo Alto, Prieto and her husband, Fernando Tamayo, had to share a small couch at the Children's Hospital for three weeks while Adrienne underwent treatment. They later stayed at hotels in Sunnyvale and Mountain View before getting a spot at the Ronald McDonald House. One hotel, Prieto recalled, was noisy, messy and malodorous. It had no curtains and its doors had at least three locks -- hardly a reassuring sign. People were constantly drinking outside and the atmosphere was "scary," Prieto said.

The family was relieved when they got the call from the Ronald McDonald House notifying them that a room was available. When they arrived at the facility, they encountered welcoming smiles at the front desk, Prieto said.

The facility offers its patients a generous menu of diversions, including playrooms with board games and video games, a library and several television rooms (patients' rooms don't have televisions). On a recent afternoon, a small squadron of friendly dogs pranced through the lobby and a man dressed as a clown and holding balloons walked out of the elevator. In the Maya Wing, several doors from Adrienne's suite, a group of children dressed in costumes giggled in an improvised photo studio while a photographer snapped away.

Occasionally, famous visitors stop by. The Dalai Lama visited the Ronald McDonald House, as did members of the San Francisco 49ers.

The facility tries to encourage socializing by holding activities immediately after dinner and by restricting televisions to communal rooms. Families get to know each other, and parents often ask one another about status updates of children. Prieto said the social aspect makes it easier for her to deal with an otherwise stressful situation. Knowing about what other families are going through helps put her and Adrienne's experiences in perspective.

Adrienne's positive outlook also helps, Prieto said.

"She teaches me a lot and she forces me to be strong," Prieto said. "She would say, 'Mom, I'm OK. Something is broken and I'm here to get it fixed, but I'll be fine.'"