From The Guardian:
Massive internal bleeding, which is now being blamed for Ian Tomlinson's death, can be triggered by someone being assaulted or simply falling over, according to a senior emergency medicine doctor.
Dr Charles O'Donnell, a consultant in emergency and intensive care medicine at Whipps Cross hospital in east London, said a person could have an abdominal haemorrhage as the result of suffering some kind of trauma.
"An abdominal haemorrhage is a fairly common occurrence as a result of a blunt injury, such as a road traffic accident, fall or assault," he said. "Most people who have trauma don't have [such] problems. But among people who have trauma, a small percentage will have life-threatening bleeding. It would not be common for someone to die from an abdominal haemorrhage in response to a simple fall, but it's not unknown. It can happen, but it's rare."
Consultant forensic pathologist Dr Nat Cary's new postmortem report states that, while Tomlinson's cause of death was abdominal bleeding, it was still unclear what led to that haemorrhage. O'Donnell said that the many potential reasons for it included someone having a liver that was already diseased, through heavy drinking, an infection or problem with the body's immune system. Liver disease causes problems by interfering with the person's ability to clot and stop their bleeding. "Something that wouldn't be a problem in the rest of us can be a problem in such patients," he said.
Trauma can also produce an abdominal haemorrhage - serious bleeding around organs such as the liver, spleen, intestine and bladder - by causing a large, solid organ to bleed, O'Donnell added. "That can lead to the person possibly dying or having a major haemorrhage which requires an urgent blood transfusion," he said.
The doctor who conducted the first, disputed postmortem on Tomlinson, Dr Freddy Patel, said he found that his heart and liver were diseased.