An inquest is the proper place to tease out differences between Prof John Harbison and Dr Marie Cassidy over the death of Brian Murphy, writes Muiris Houston, Medical Correspondent
Yesterday's intervention by consultant chemical pathologist Dr Bill Tormey into the debate over what exactly caused Brian Murphy's death has added further uncertainty to the case. It must be very difficult for the Murphy family to listen to the finer points of their son's postmortem being teased out on the airwaves and in print.
Doctors are trained to record their findings in detail and to form an opinion based on these findings as well as on their experience and knowledge. Medical opinions differ as often as they concur; it should not come as a surprise that the current and former State pathologists have reached different conclusions in this case.
In her statement of April 21st, the current State Pathologist, Dr Marie Cassidy, actually spells out the most clearcut scenario following severe head injury: "Death following a head injury most commonly results from severe trauma to the brain or related complications, usually bleeding inside the skull cavity which compresses the brain and its vital centres."
Because the brain is confined within the closed space of the skull, any bruising or bleeding following injury has nowhere to escape to. As a blood clot builds up inside the skull, it squeezes the brain against the skull on the opposite side. The pressure inside the cranium increases steadily, causing damage to the brain tissue itself.
One of the most vital parts of the brain is called the brain stem. It is situated at the base of the brain, close to the spinal cord. The brain stem controls many automatic body functions, including those of the lungs and the heart. A mass of blood can directly injure specific areas of the brain stem, such as the respiratory centre, leading to the cessation of breathing and death. Or downward pressure on the brain stem shears off its blood supply, again leading to death.
However, we know that in Brian Murphy's case this typical result of a severe assault to the head did not occur, meaning that both the former State pathologist who carried out the postmortem, Prof Harbison, and Dr Cassidy had to look to other explanations for his death.
Prof Harbison, in his report, concluded that Mr Murphy died from swelling of the brain due to severe facial injuries he received as a result of an assault. A part of the victim's brain has been flattened and was bleeding, the former State pathologist said.
Dr Cassidy, who it must be remembered did not have the opportunity to examine Brian Murphy's body, but relied instead on clinical photographs, formed a different opinion.
"Internal photographs of the head and neck showed bruising around the right eye socket and on the chin. The skull was not fractured and there was no evidence of bleeding into the skull cavity.
"In my opinion, these injuries were relatively minor. . . [ and] would not normally be expected to cause or even contribute to death," the State Pathologist said.
While the two pathologists disagree about the presence of bleeding, Dr Cassidy makes no reference to a photograph of brain tissue in her statement. If she did not see postmortem photographs of Mr Murphy's brain, then Dr Cassidy is at a considerable disadvantage; neither examining the victim's brain at postmortem in 2000 nor being able to examine photographs of the brain when asked for her opinion last month.
What else may happen to the brain following head injury? Blood pressure may drop and the brain may be starved of oxygen. This in turn is associated with brain swelling.
What about the role of alcohol? It depresses brain function, usually in direct proportion to the amount of alcohol in the bloodstream. Dr Cassidy links head trauma and alcohol.
In considering four possible causes for Brian Murphy's death (apart from brain compression), Dr Cassidy's final opinion is to bring together two of these causes when she concludes: "It is most likely that his head injury was complicated by alcohol-induced apnoea [stopping of breathing] and acute brain swelling, resulting in hypoxia, [lack of oxygen] ischaemic brain injury and death".
It is unhelpful to adjudicate conflicting sets of medical evidence in the media. However, an inquest has yet to be heard into Mr Murphy's death. It will provide an opportunity to question Dr Cassidy on her conclusions. She is likely to be asked to account for her final opinion and to provide evidence from medical research for that opinion.
Further public judgment is best left until the conclusion of all legal elements of this tragic case.