When four-year-old Olivia Elliot woke up vomiting and complaining of a headache, her mother assumed she had caught a sickness bug. But within hours, Olivia could no longer grip her mum's hand and kept toppling onto her left side. Her mother, Rebecca, 31, rushed her to hospital, where doctors performed a barrage of tests and discovered the little girl had suffered a life-threatening stroke.Further tests revealed severe inflammation in one of the main arteries in her neck, cutting off blood supply to the brain.Specialists believe the deadly attack was triggered by the chickenpox virus she had contracted six months earlier, in December 2024. While sitting on her mother's lap at St John's Hospital in Livingston, Olivia lost movement down the left side of her body, her speech became slurred and one side of her face drooped. 'I started screaming "something's not right. Something's happening to Olivia,"' her mother recalls.'The most heart-breaking thing for me was looking at her. She didn't look like Olivia at all. Her face was so drooped and she couldn't eat or speak.' When Olivia woke up vomiting and complaining of a headache, her mother assumed she had caught a sickness bugWhile the majority of strokes affect those over 65, the number of young people suffering them is increasing. Stroke in childhood is uncommon, affecting roughly 400 UK children a year, according to the charity Brain Research UK.In Olivia's case, doctors explained that the life-threatening incident had likely occurred as a result of the chickenpox virus Olivia had suffered over Christmas - medically known as varicella-zoster virus. The infection triggered swelling in her major arteries - which supply the brain with life-giving blood and oxygen - which eventually sparked a stroke. In approximately one to two out of every 1,000 chickenpox cases the virus reaches the brain causing encephalitis, or brain swelling. Recalling the events leading up to the frightening ordeal, Rebecca said: 'I didn't think children as young as four could have strokes. 'A simple headache turned out to be something really serious. 'She had chickenpox in December, just before Christmas, she had lots of spots but she wasn't unwell really. But just hours later, her grip had gone, she was unable to sit upright and her speech became slurred A barrage of blood tests and MRI scans revealed that Olivia had suffered a stroke at just four years old 'I thought we'd had an easy case.'Rebecca, from West Lothian, Scotland, developed selective growth syndrome while carrying Olivia and her identical twin, who was lost during the pregnancy.Olivia was born nine-weeks early and subsequently diagnosed with mild cerebral palsy after brain damage was detected. But, despite her condition, Olivia was fiercely independent and made a full and speedy recovery from the chickenpox. Her parents had no reason to believe something more sinister was around the corner.When Rebecca's husband found their daughter vomiting clear liquid in the night, Rebecca decided to keep Olivia at home for a 'sick day'. The mother and daughter were playing darts when Rebecca noticed Olivia was struggling to grip the dart between her fingers. 'I put my finger into her hand and said, 'Can you grab Mummy's hand?' She couldn't do it,' she said. Her doctors believe the inflammation was caused by the chickenpox virus Olivia had contracted six months earlier In approximately one to two out of every 1,000 chickenpox cases the virus reaches the brain causing encephalitis, or brain swelling.