(LONDON) -- Queen Elizabeth is waking up in a hospital bed for the first time in nearly a decade, suffering from a stomach infection that forced her to check in Sunday and cancel or postpone a week's worth of engagements.
The queen, 86, is experiencing symptoms of gastroenteritis and is expected to receive treatment at London's Kind Edward VII Hospital for two days, according to Buckingham Palace. The palace says she is in "good spirits" and all signs suggest that her illness is not serious.
She first fell ill on Friday but kept up her scheduled events through Sunday morning, after which she was driven to the hospital in a car, rather than an ambulance.
"This is a precautionary measure," read a statement from the palace. "She was not taken into hospital immediately after feeling the symptoms. This is simply to enable doctors to better assess her."
Gastroenteritis is an infection of the intestine and causes diarrhea and vomiting, according to doctors. It is usually treated with fluids, and symptoms often pass after two to three days, but the queen's age will have doctors proceeding cautiously.
"Age is a factor which makes us worry a bit more about when people have gastroenteritis, because it's more difficult for the body to maintain fluid balance. Once you get a bit older, your kidneys tend not to work as sufficiently," Dr. Anton Emmanuel, a gastroenterologist who works at Edward VII Hospital but is not treating the queen, told ABC News.
Emmanuel said that doctors would intensely watch the queen's hydration levels and would let the infection pass through her system, but would aggressively treat any side effects she suffered, including fevers and cramps.
"There will be intravenous drip saline to replace the fluids the body is losing, very careful monitoring of the hydration status which we can do by clinical testing on the blood tests, and then treating symptoms and then waiting for the infection to break, which it usually does in two, three days," he said.
Last week, the queen held nearly a dozen engagements, and she takes pains not to have her schedule interrupted. She has cancelled only a handful of engagements over the years and has only visited the hospital about half a dozen times, according to local media.
This week, she has cancelled or postponed a trip to Rome to meet the outgoing president of Italy, as well as a visit to a Royal Navy ship in London known as "The Queen's Frigate" on Tuesday, and a military celebration in Wales on Saturday.
The last time the queen visited the hospital was December 2003, when doctors operated on her knee to remove torn cartilage.
The queen's husband, Prince Phillip, will maintain his schedule, attending an event by himself on Monday, another sign that the queen's illness is not serious. Prince William, the Duchess of Cambridge and Prince Harry were travelling back from Switzerland after attending a friend's wedding.
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