Otto Warmbier on trial in North Korea in February 2016. Photo/AP
Otto Warmbier on trial in North Korea in February 2016. Photo/AP
The mysterious death of Otto Warmbier has medical experts searching for an explanation on how it could have happened.
The 22-year-old student died just days after he was medically evacuated from North Korea, where he was held as a prisoner for 17 months.
Although officials from the isolated state claim Warmbier had botulism and a sleeping pill put him into a coma, American doctors disagree with that diagnosis.
Cincinnati experts said Warmbier was returned with severe brain damage and suffered "extensive loss of brain tissue in all regions of his brain" consistent with oxygen deprivation for a prolonged period.
Neurologists suggest a blood clot, an infection or pneumonia could be the reason behind Warmbier's sudden death after his return, but most agree he was past the point of survival when he came home.
Warmbier was sentenced to 15 years in prison, convicted of subversion after he confessed he had tried to steal a North Korean propaganda banner last January.
Pyongyang said Warmbier was released last week on "humanitarian grounds", and refused to say his treatment during his imprisonment was a factor in his shockingly deteriorated state.
North Korea claims Warmbier contracted botulism shortly after he was sentenced and said a sleeping pill put him into a coma from which he never awoke.
Doctors found no evidence of the rare form of food poisoning and a sleeping pill would not be indicated in the case of that illness, which is treatable with an antitoxin.
A team of Cincinnati doctors (pictured) said Warmbier had brain damage that looked like it was caused when the brain is deprived of oxygen for a period of time, such as cardiac arrest. Photo/AP
Instead, doctors said his "neurological condition can be best described as a state of unresponsive wakefulness".
They added the brain damage looked like it was caused when the brain is deprived of oxygen for a period of time, such as cardiac arrest.
A cardiac arrest is when the heart malfunctions and suddenly stops beating unexpectedly.
A person will lose consciousness and will stop breathing normally.
Unless immediately treated by CPR or other life-saving techniques, the person will die in minutes.
Even still, survival statistics are bleak: approximately 50 percent of people who arrest are revived and only about 10 percent of these people leave the hospital.
Of those who do survive, around half suffer some level of brain impairment from the brain not getting enough oxygen.
When the brain does not receive blood or oxygen it results in damage. The longer it goes without, the greater the chance for permanent brain injury or death.
Warmbier's state indicates that his brain had no conscious function, but could still keep him breathing and sleeping.
Dr. Lori Shutter, of the University of Pittsburgh Medical Center, said to NBC News: "If they are in that state from a lack of oxygen to the brain ... and it has been more than three months ... the chance of anyone having a meaningful recovery - I don't know if any of us have ever seen it happen."
Otto Warmbier before his fateful trip to North Korea. Photo/Facebook
Dr Shutter said the prompt death of Warmbier indicated that he was not in a good state when he was returned home.
She speculated his family could have focused on quality of life instead of keeping him in a coma.
There is a very low chance of survival for people who have been in a coma for extended periods of time, due to the extensive brain damage.
Dr Shutter added: "If this young man was in this state for an extended time period, once the family heard everything, they may have started to focus on quality of life.
"They may have felt that this quality of life would not be of the type that they would feel Otto would have wanted. They may have 'let's make him comfortable'."
The doctor suggested Warmbier could have had pneumonia, which can happen when a person in a coma breathes saliva into the lungs and leads to an infection.
Dr. Daniel Laskowitz, a neurology professor at Duke University, added to the news outlet that other causes of death could be from an infection or blood clot.
He said: "If you are in a persistent vegetative state and you are just immobile for a prolonged period of time, you have a propensity to form a clot."
Warmbier's death has brought fresh scrutiny to the regime's brutal torture camps under leader Kim Jong Un.
Otto Warmbier pictured as he was taken in to custody in Pyongyang last January. Photo/AP
The Warmbiers entirely blamed their son's death on the North Korean leader and his government.
"The awful torturous mistreatment our son received at the hands of North Koreans ensured that no other outcome was possible beyond the sad one we experienced today," Fred and Cindy Warmbier said in a statement.
Donald Trump also took aim at Kim Jong Un after offering his 'deepest condolences to the Warmbier family.
"Melania and I offer our deepest condolences to the family of Otto Warmbier on his untimely passing," a statement from the White House read.
"There is nothing more tragic for a parent than to lose a child in the prime of life. Our thoughts and prayers are with Otto's family and friends, and all who loved him."
"Otto's fate deepens my Administration's determination to prevent such tragedies from befalling innocent people at the hands of regimes that do not respect the rule of law or basic human decency.
"The United States once again condemns the brutality of the North Korean regime as we mourn its latest victim."
The White House statement was released just hours after the 22-year-old's family confirmed his death.
