A mother of a five year-old with aggressive brain cancer has told of how she confused the first warning signs of the disease with an episode of severe heat stroke. 

Holly Brown, 31, a stay-at-home mum from Clacton-on-Sea, Essex, initially thought her daughter Olivia had spent too long in the sun when she began vomiting one morning in May. 

But the sickness didn't stop for the rest of that week. What's more, it came with a paralysing exhaustion.

Eventually, in mid-June, Ms Brown took her little girl took her to A&E for further investigations.

By this point, she appeared 'wobbly on her feet', and one of her eyes looked a little 'lopsided'. 

Concerned, medics embarked on a range of investigations, including detailed scans. 

Devastatingly, the results showed she had a brain tumour — though doctors were not yet sure which type or how advanced the disease was. 

Olivia was immediately rushed in for emergency surgery to fit an external ventricular drainage system to relieve a blockage preventing her spinal fluid from draining.

And within a few days, she had undergone an eight-hour operation to remove 95 per cent of the tumour.

The remaining five per cent was too close to the brain to remove without causing damage.

A week later, doctors informed the family that Olivia had grade three medulloblastoma — a type of tumour that develops in the cerebellum in the back of the brain, which is the area responsible for balance and movement.  

These types of brain tumours are typically diagnosed within the first five years of life, according to Brain Tumour Research. The doctors also discovered that the cancer had spread to her spine.

Ms Brown said: 'I burst out crying, I was just devastated.'

She struggled to explain the situation to her three other children, who were used to having her around for support all of the time.

She said: 'I think my eldest is probably taking it the hardest, because she understands a lot more than the others, so she can be quite withdrawn, but I’ve just been trying my hardest to reassure her and let her know she can talk to me.'

Olivia's treatment planned combined chemotherapy and radiotherapy, and offered a 50 per cent survival rate, but came with the risk of future learning difficulties.

'Doctors said chemo and radiotherapy could lower her IQ and she would most likely end up with learning difficulties,' said Ms Brown.

Throughout this period, Ms Brown found it difficult to know what to say to Olivia about her condition.

'Olivia gets quite upset at times, which is understandable with everything she’s been through,.

'She does get a little bit scared when she has to do things but overall, she’s taken it quite well.

'I tell her as much as I can do, age appropriately, in a way that she’ll understand.

'I don’t go into too much detail, but I told her, she’s got cancer, and she’s got to have some treatments to make her better, and it will take quite a while, that’s all I can do, really.'

In August, Olivia underwent two five-day rounds of chemotherapy, during which she lost her hair.

'She took it quite well, really, we got given a children’s book by the hospital that explains chemotherapy, I think that helped with easing her mind.

'She was a little bit upset about what happened, but when it happened, I think probably because she’s young, she doesn’t really mind too much.

'I collected her hair, I kept it. I think maybe that helped and I’ve told her that it will grow back.'

Between the two rounds, doctors told the family that the brain tumour had shrunk, but its exact size and the status of cancer in her spine remained unclear due to fluid build up.

In September, Olivia had six weeks of proton beam therapy, a type of radiotherapy that uses high-energy protons to treat cancer, as part of a clinical trial.

After radiotherapy, Olivia suffered from sore, flaky skin, and had extreme nausea and sickness – as a result, she had to be tube fed for several weeks.

Olivia’s medical team has scheduled another scan for December 4 to reassess the tumour and will begin six to nine months of further chemotherapy on December 9.

Until then, the family are uncertain about what lies ahead.

'The hardest part is not knowing, it feels like everything is up in the air,' Ms Brown said.

Determined to make the most of Christmas, Ms Brown and her mother, Amanda, set up a GoFundMe to transform the family home into a Santa’s Grotto for December.

'We don’t really know how well she’s going to be because she’ll be having chemo in December, so it’s not a good idea to try and take her out anywhere.

'We just wanted to kind of make it the best we can at home – just fill the house with decorations, make it sort of like a Santa’s grotto. We want some precious Christmas memories.'

Looking back on the past year, she thinks her experience has made her appreciate her family even more.

'I think about things that used to upset me – now, it doesn’t matter.

'None of that mattered, the most important things are your family and health and appreciating what you’ve got.'