Cause of death

Cause of death

As the cause of death poses such a serious problem in the medico-legal investigation, it is necessary to focus one's attention (through the eyes of the forensic pathologist) on so-called ``natural'' and ``non-natural or unnatural'' deaths, particularly with regard not only to identifying them as such but also to the formulation of the cause of death.

The importance of accurately identifying the cause of death is not only relevant to criminal matters, but may also be of considerable importance for the family of the deceased. In a specific case, the deceased's family was issued with a death certificate in which it was stated that ``death was solely and exclusively due to natural causes'', to wit tetanus. The deceased had taken out substantial insurance against accidental death. It was the insurers who, when presented with a copy of this certificate, identified the fact that tetanus had been the direct consequence of an injury sustained by the deceased some six weeks earlier. By the time tetanus had developed the initial injury had already healed. (Tetanus has a variable incubation period which may vary in length from days to a few months.)

The inquest often constitutes an essential element of the medico-legalinvestigation, and by the very nature of the provisions of the Inquests Act 58 of 1959, forms an effective audit of medical practice, especially where medical treatment, or lack of it is identified in the course of the inquiry.

Natural or non-natural (unnatural) death

The medical practitioner who completes a death certificate must decide whether the death was solely and exclusively due to natural causes or whether it should be reported to the magistrate.

The decision may be difficult because not all cases which appear to be the result of natural causes are in fact natural deaths; similarly, a death which initially appears to be the result of non-natural causes may eventually turn out to have been caused by natural disease.

Where the cause of death is obvious there is no problem in designating it ``non-natural'' or ``natural'', for example deaths following stab wounds, multiple injuries sustained during an accident, and exposure to fire or deaths due to myocardial infarction (necrosis of the heart muscle). Problems may arise, however, if a diagnosis has to be made based on symptoms suggesting gastro-enteritis, as they can also be caused by a poison. It is incorrect to record the complication, terminal event or underlying condition as the primary cause of death. Stating, for example, that the cause of death of a patient with a head injury was bronchopneumonia (the terminal complication), implies that this was a natural death.

The medical practitioner who is required to make a decision about what constitutes a non-natural or natural death receives little guidance from legislation in this respect. His dilemma can be illustrated by the death of a newborn infant following meconium aspiration due to foetal distress. This may be a natural complication. On the other hand, it may be the result of an omission on the part of a midwife or medical practitioner. In the former case there is no question of negligence, whereas in the latter there is.

Pneumoconiosis (a chronic condition resulting from dust inhalation) and certain lung tumours are caused by the inhalation of foreign material; yet death as a result of these conditions is traditionally considered to be natural but compensatable. Death due to acute or chronic arsenic poisoning and death due to acute alcohol intoxication are unnatural, whereas the chronic ingestion of alcohol which eventually causes death as a result of liver failure is considered natural! The general attitude of the legislature is that the medical practitioner is required to exercise his professional discretion and, for purposes of completing the death certificate, must decide on grounds of available information or circumstances whether death is due to natural or unnatural causes.

Non-natural (unnatural death)

Unnatural death can be classified as follows:

Death due to violence to the body

physical (stab wounds, gunshot wounds), microbiological (biological warfare) and chemical (poisoning)trauma due to nature related events, including dog bites, lightning, snake bites and anaphylaxis after a bee stingconditions like tetanus and gas gangrene as complications of trauma

Death classified as unnatural by section 56 of the Health Professions Act

Any death whilst under the influence of a general or local anaesthetic agent, or where the administration of such a drug played a role in the death of an individual, is not regarded as natural.

Death due to an omission or commission

Meconium is the faecal content that a foetus sometimes passes in utero if it experiences stress, especially a lack of oxygen (intra-uterine foetal distress). The primary aim of the management of the birth process is to prevent intra-uterine oxygen deficiency or hypoxia. If hypoxia does occur, it is expected that the medical practitioner or midwife will either perform (or refer the patient for) a Caesarian section to prevent hypoxic injury to the foetus. If the labour process is already well advanced, all attempts must be made to hasten the delivery of the baby. In addition, immediately after the delivery of the head, the airways of the baby must be cleaned by suction to prevent any aspiration of meconium-stained amniotic fluid. If aspiration does occur, respiratory distress, lung infection and death will often occur. If a baby aspirates meconium, and subsequently dies due to lung complications, the circumstances of birth must be assessed. If a baby dies due to meconium aspiration and this is a result of poor management of the mother in the maternity ward, it must be regarded as a non-natural death. However, it may be regarded as a natural death if the delivery occurred in the absence of proper medical care, for instance in a remote village.

Sudden and unexpected death

Sudden and unexpected death occurs in two situations, namely so-called sudden infant death syndrome or cot death, or where a young person suddenly and unexpectedly dies, for instance while exercising:

·              In the case of cot death no obvious cause of death can be found. It is not possible to exclude unnatural causes like trauma or poisoning, before a post- mortem examination has been performed and excluded any possible unnatural causes. After exclusion of an unnatural cause with a post-mortem examination, the death will then be classified and regarded as natural.

·              The same applies where a young athlete suddenly and unexpectedly dies due to a previous undiagnosed heart condition. It is also important to remember that the findings at the post-mortem examination are not only of help in formulating the cause of death, but also benefit the family if a possible hereditary and treatable condition is diagnosed. The other siblings can then receive precautionary treatment.

Unnatural deaths are dealt with in terms of the Inquests Act 58 of 1959. This Act determines action to be taken after someone has died due to non-natural causes. We shall now discuss unnatural deaths and give some examples.

By and large unnatural deaths are deaths which follow injury. Death may follow only weeks or months after the injury as a result of complications (eg a patient with a spinal cord injury may survive for months). The length of time between the original injury and death in no way influences the decision.

Death due to infection following an injury caused by an animal with rabies, for example, or an injury resulting in tetanus (including tetanus neonatorum), cannot be regarded as natural. Similar considerations apply to snake and spider bites, bee and scorpion stings. In contrast, fatal malaria infection transmitted by a mosquito bite is usually considered a natural cause of death. Yet if death is the consequence of an infected blood transfusion, it is considered non-natural.

A further category of non-natural deaths is that of deaths caused by the effect of physical agents or of chemical or biological substances. Physical agents include lightning, electricity (causing electrocution), fire, steam, hot fluid (causing burns), suffocation (causing obstruction of the respiratory passages), natural heat or cold (causing hyperthermia or hypothermia), and submersion in water or other fluids (causing drowning). Chemical substances may be administered accidentally or deliberately (for therapeutic reasons or in cases of suicide or murder). Biological substances that may play a role include sera and micro-organisms, which may cause food poisoning.

In the course of medical practice acts or omissions may also cause death, for example omitting to test sensitivity where indicated, or omitting to perform a routine examination or prescribe routine treatment.

The fact that the medical practitioner cannot make a definite or satisfactory diagnosis when her patient dies is no reason to label the case an unnatural death. She may so decide if she is convinced that the death was not solely and exclusively due to natural causes, that is, she must have a reasonable doubt that the death was not due to natural causes and if so requested, must be prepared to substantiate her decision.

Sudden unexpected death poses an additional problem. It may be due to either natural or unnatural causes, and in the absence of any background information or personal knowledge of the deceased (as in cot deaths) the medical practitioner will be unable to certify that to the best of her knowledge and belief the death was due solely and exclusively to natural causes.