US woman, 27, on honeymoon in Japan was 'left fighting for her life’ after major health decline

A woman enjoying her honeymoon in Japan had her life turned upside down after suddenly suffering a 'life-threatening health decline'.

Sarah Danh and her husband Luke Gradl's newlywed vacation took a dramatic turn less than a day after the American couple landed in Tokyo on 8 April.

They'd tied the knot during their 'dream wedding' the month prior, with Dahn, 27, showing no tangible indication of poor health.

On the second day, she began 'suffering' from a number of strange symptoms, including jaundice, vomiting, fever and body aches.

According to Gradl, 28, who has kept PEOPLE constantly in the loop, his bride was also presenting signs of 'extreme' hepatic encephalopathy - a decline in brain function caused by liver disease.

It occurs when the liver struggles to filter toxic chemicals from the blood, which build up, wreaking havoc on the brain.

The couple tied the knot last month (GoFundMe)

Most patients become unresponsive or go into a temporary coma. In the most severe cases, the condition can cause death.

After being rushed to the hospital, doctors determined that, on top of her acute liver failure, Danh's kidneys were also failing, and that she was experiencing increased intracranial pressure.

Her mother, Le Le, flew out to Japan from America to provide 'moral support'.

Gradl also made sure Danh's brother Rob, a cardiologist, was fully aware of the situation.

"[Rob] has been in this fight with us since the beginning. I have informed him of all blood work, treatments, medications [and] dosing," the groom told PEOPLE.

"He has been working tirelessly, being on all status calls that we have with the doctors here in Japan, so that he is up to date on anything and everything. Without him, we would be lost on the medical side of things.

"Due to the time difference, he is usually up until 2 or 3 in the morning, making sure he is receiving all updates, on top of having to spend time with the family and performing his normal duties as a cardiologist."

Danh's mother flew over to provide 'moral support' (GoFundMe)

Danh, a labour and delivery nurse, was treated in Japan with '24/7 CRRT (continuous renal replacement therapy), dialysis, blood transfusions, and plasma exchanges', her husband explained.

Thankfully, medics ruled last week that Danh was stable enough to return home to the US.

Despite her boarding an emergency medical evacuation flight yesterday (21 April), doctors are still mystified by the horror that unfolded, unaware of what caused her sudden decline.

She's scheduled to receive further medical testing and evaluations at home in San Antonio, Texas.

As part of their latest update, the couple told PEOPLE: "Thank you to HCA Healthcare and Methodist Hospital for providing the medical flight home. That generosity means more to us than we can put into words.

Doctors still aren't sure what caused her sudden illness (GoFundMe)

"A huge thank you to the medical team in Japan — the doctors and nurses who worked nonstop to keep Sarah stable up until evacuation. We'll never forget your care and dedication. To the AirMed team, thank you for moving so quickly and making everything come together when it mattered most."

They added: "You made a real difference for us. We're also so thankful to the team in San Antonio for being ready and waiting for Sarah.

"Knowing she was going into such good hands brought us peace during a very uncertain time."

Danh and Gradl added that they're 'beyond grateful' to anyone who donated to a GoFundMe page that was set up while she was receiving treatment, which currently stands at $175,274.

"Whether we know you personally or you reached out from somewhere far away, your kindness, prayers, and support helped carry us through one of the hardest times in our lives," they continued.

"You gave us comfort, strength, and hope when we needed it most."

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