A grieving family spent Mother's Day saying goodbye to their only child after she unexpectedly suffered a rare and catastrophic brain bleed.

Nine-year-old Hannah Teklic was 'perfect' as she danced in the kitchen and proudly posed with her school certificate for track and field age champion shortly before she went to bed as usual on May 6.

Hours later, she woke up complaining of a headache and neck pain.

'She said the pain was really bad and wanted to go to hospital because she thought she was going to die,' her mother Wasima Lamrani told the Daily Mail.

Ms Lamrani gave her daughter painkillers, thinking the pain could be from dancing and doing cartwheels several days earlier.

A short time later, Hannah began vomiting, fell out of bed and suffered a seizure.

She stopped breathing in the ambulance on the way to Sydney's St George Hospital, where she underwent emergency surgery to remove excess fluid and relieve pressure from her brain before being transferred to Sydney Children's Hospital. 

Two days later, doctors told her parents Wasima and Ivan that Hannah had been declared brain dead and very unlikely to recover.

'There was nothing more they could do,' Mr Teklic said.

'We did not have the heart to turn off her life support on Mother's Day, so we stayed with her until Monday.

'She was totally fine on Wednesday night. It makes no sense.' 

It is understood that Hannah suffered an arteriovenous malformation, a tangle of blood vessels that creates irregular connections between arteries and veins, which disrupts blood flow and prevents tissue from receiving oxygen.

AVMs, which occur in roughly three in 10,000 people, usually form during development or shortly after birth, according to the Brain Foundation.

'It literally came out of nowhere,' Mr Teklic said. 

'It can't be detected on scans and many patients don't show symptoms until it ruptures.

'Doctors told us that there was nothing that we could have done, even if we had called earlier for an ambulance.'

Hannah's parents hope that sharing her story will raise awareness of the symptoms, which include sudden and severe headache, vomiting, double or blurred vision, seizures, muscle weakness, neck stiffness, lethargy, disorientation and irritability. 

The heartbroken couple are also hopeful that AVMs can one day be detected earlier as they struggle to process the loss of their only child. 

'Nothing matters anymore,' Mr Teklic said. 

'She was everything to us and she's not here anymore. We won't see her start high school, grow up, get married or have kids.

'I'm angry that she got ripped off.' 

The couple have remembered their 'best buddy' as a free spirit who was talented, kind, creative and caring.

'Hannah loved everything and everyone,' Mr Teklic said. 

'She wouldn't hurt a fly or walk on ants. Even when she lost something, she would be sad. Her energy was so huge.' 

Hannah's death has sparked an outpouring of tributes, led by her school, St Pius’ Catholic Primary School in Enmore, in Sydney's inner-west. 

'What has been most evident over these past days is the strength, compassion, and unity of our community,' the school shared in a statement online. 

'I know that Ivan and Wasima feel this support, and it brings them comfort during an incredibly painful time.'

Marrickville FC also paid tribute.

'Hannah loved playing football with her friends and had been part of Marrickville FC for three years,' the club wrote online. 

Friends have rallied around Hannah's parents and set up a fundraiser to ease the financial burden, which has already raised more than $65,000.

Hannah's body will be repatriated to her mother's homeland, Ireland, where she will be buried next to her great-grandparents.

'She is a bright, beautiful soul who brought so much love, laughter and happiness to her mum, dad and everyone around her,' the organiser wrote. 

'This unimaginable sudden loss has deeply affected her family in Australia, Ireland, Spain and Morocco. It has also impacted Hannah's friends, classmates, teachers and all who knew and loved her (of which there are so many).

'We pray for strength for Hannah's family, comfort for all who loved her, and peace as our community comes together to support one another through a devastating loss.'

Hannah's parents are grateful for the overwhelming support.

'We are immensely grateful; many of those who have donated we don't even know,' Mr Teklic said.