(ABC News) -- Former first lady Barbara Bush was hospitalized today for early signs of pneumonia, but the family said she was "in great spirits."
"Former First Lady Barbara Bush was admitted to Methodist Hospital in Houston's Texas Medical Center yesterday for treatment on a respiratory related issue," family spokesman Jim McGrath said. "She is in great spirits, has already received visits from her husband and family, and is receiving fantastic care."
Houston Methodist Hospital spokesman George Kovacik said she was being treated there.
Bush, 88, whose husband George H.W. Bush was president from 1989 to 1993, used her prominence as first lady to champion numerous civic and charitable causes, primarily as an advocate for global literacy.
In 1989, she formed the Barbara Bush Foundation for Family Literacy, which encourages parents to read to their children.
Famous during her tenure as first lady for her white hair and matronly manner, Bush embodied what many believed to be the traditionally dutiful political wife: silent on most issues, but enthusiastically supportive of her husband and family.
While serving as first lady in 1989, Bush revealed that she suffered from Graves' Disease, an autoimmune disorder that affects the thyroid. She reportedly lost 18 pounds in three months because of the effects.
As bad luck would have it, President Bush and the Bush's family dog, Millie, also came down with the disease around the same time. Because of the bizarre coincidence, the Secret Service conducted water tests at locations which the first family frequented -- including the White House, the Bush home in Maine, Camp David and the vice president's mansion. Bush later began taking medications for the disease and received radiation as part of her treatment.
After experiencing abdominal pains, Bush was hospitalized at Methodist Hospital in November of 2008. She underwent laparoscopic surgery to close a hole in her small intestine which had been caused by an ulcer.
Four months later, Bush underwent precautionary open-heart surgery at the same hospital to replace her aortic valve. Hospital officials reported that the procedure was a success.