Understanding cause of death

Cause of death. How is it determined? Can it be determined with certainty? There’s no single sentence definition or guidance to answer the first question I posed. How do you determine the cause of death? We’ll, leave aside those cases where the findings are incompatible with life. For example, decapitation. I use this obviously unpleasant and dramatic example because, the number of deaths where findings are totally not compatible with life are relatively unusual. In my experience, about five to 10 per cent of deaths at most. It may be more in some other settings.

This is a surprise to many people who think of an autopsy as an exercise where, if the pathologist is good enough and looks hard enough, she’ll find the cause of death. The cause of death is just lurking somewhere in the body, and all you’ve got to do is find it. In the majority of deaths this is absolutely not the case. Take, for example, the commonest cause of death in the world and causing, by the way, about 20 per cent of death between the ages of 25 and 69 in India, coronary artery disease or more technically coronary atherosclerosis. The common form of heart disease in the community, accelerated in development by smoking.

So let’s take this specific example of a 50 year old man walking along the street and he’s seen to clasp or grab the front of his chest collapsing to the ground. The body was rushed to the hospital, but he was unable to be resuscitated. His family doctor was contacted and asked about the medical history, and she said that the deceased was quite a heavy smoker, complained of a few niggling chest pains and while his cholesterol level was a bit high, the doctor thought the pains were probably related to smoking related chronic bronchitis. And on other occasions she thought he might have had a degree of gastritis. But he was otherwise apparently quite fit and well.

The doctor was not prepared to sign a death certificate, so the deceased underwent an autopsy at the forensic facility attached to the hospital and narrowing of the coronary arteries, coronary atherosclerosis, considered sufficient to account for sudden unexpected death, is discovered by the forensic pathologists. There are no other findings. The pathologist says, ‘well this degree of coronary artery disease is sufficient to cause sudden death. The 50 year old man was heard to say and a passer-by saw that he obviously had had chest pain on this occasion, severe central chest pain, and he was witnessed to collapse suddenly and then he died. He wasn’t assaulted and he was fit and well, walking along the street. Then he was dead.

In my opinion, says the forensic pathologist, this man died of coronary atherosclerosis, a common form of heart disease in the community.’ And personally, I’d agree. There’s little doubt that that is indeed what that man died off. In general terms, what the forensic pathologist has done in concluding the cause of death in this particular case is, she has found “a” cause of death, that is a finding capable of causing death at autopsy, which accords with the medical history, the circumstances of the death, and she’s elevated that to “the” cause of death. This formulation immediately deals with the second question, can it be determined with certainty?

Within the general formulation of how the pathologist concluded the cause of death, there are at least two subjective elements. First, that the finding coronary atherosclerosis is capable of causing death. Now, if there’s any doubt about this, having followed the concept of what is it? Reviewability. We have discussed a number of times, if she followed the concept of reviewability, the pathologist would have taken good quality photographs of the cross-sections of the coronary arteries to demonstrate the degree of narrowing. And if she’s lucky enough to have access to a histology laboratory, she also took some sections to look at under the microscope. These sections also serve as a great record of the finding.

So it is a subjective finding, but in a well-functioning system, the pathologist will be supported by others of her colleagues in coming to that conclusion because they can review the findings. The second subjective element is that the finding she discovered, is capable of causing death and we talked about that, is consistent with the medical history and the circumstances of the death. Again, there’s no real disagreement that they do fit in this particular case, but actually making that judgment has subjective elements .

And while we will all agree with the conclusion the pathologist came to, we can also agree that it’s quite different to a standard medical diagnosis where we take a history from the patient, do a physical examination, order special tests and trials some treatments. The assessment in the post-mortem case is all retrospective and not testable. In clinical practice, when you’ve made a diagnosis, you can often test prospectively, whether you’re right. And in other cases, ordering the right treatment will solve the problem, therefore confirming the diagnosis. You can’t do this in the autopsy situation, obviously.

But these limitations on autopsy diagnosis simply make it even more important to discover all the pathological processes, including injuries present on and in the deceased before considering them in relation to the medical history and the circumstances of the death in coming to the formal conclusion of the cause of death.

A corollary of this is that, if there is nothing discovered which is capable of causing the deceased’s death, the cause of death will be completely dependent upon an interpretation of the medical history and an interpretation of the circumstances of death. There are a number of classical situations where there are difficulties with causation and where concluding the cause of death is approached in different ways by different pathologists.