The primary cause of death
The primary medical cause of death is defined as the disease or injury that began the sequence of events and that led directly to death.
The following are often confused with the primary cause of death and are mistakenly indicated as such: mechanism of death, occurrence, place or environment where the death occurred, contributory cause, precipitating cause, underlying cause, predisposing cause and terminal cause.
Merely supplying these particulars does not provide the necessary informa-tion about the primary medical cause of death. It is not incorrect to include this information, but if the practitioner himself has not seen the place, this must be indicated by the addition of the words ``as ascertained'' or ``as I am informed'', otherwise it is hearsay evidence. The practitioner also has to be consistent: if in some cases he indicates that someone died in a car accident, he must also indicate a fall from stairs in a house or hospital, or an injury in a garden elsewhere.
Mechanisms causing death are those physiological mechanisms or changes that ultimately cause death, such as a disturbance in the acid-base balance of the body or neurogenic stimulation of the heart. These or other loose terms such as ``cardiac arrest'' or ``respiratory arrest'' are not primary medical causes of death. It is therefore inadvisable to use them as such because they do not provide the necessary information about the cause which initiated the mechanism.
A contributory condition or cause does not in itself cause death, but rather contributes to an earlier demise. A person may, for example, suffer from a natural condition such as coronary atherosclerosis which on its own (but not necessarily at any specific moment) may cause death. The same applies to other diseases such as diabetes, where an infection following on an injury will spread far quicker than it would in the case of a healthy person. In the above-mentioned cases atherosclerosis and diabetes are the contributory causes.
Predisposing or underlying conditions or causes can trigger a certain occurrence. They are very similar to contributory conditions or causes and often cannot be separated from them. Examples are the imbibing of alcohol or epileptic seizures which may lead to an accident where injuries are sustained by the subject himself.
Precipitating conditions or causes are responsible for the immediate development of a particular illness or occurrence. They are closely related to contributory or predisposing conditions. Excitement may precipitate a cerebral haemorrhage or a myocardial ischaemia, the primary causes of which are cerebral or coronary atherosclerosis respectively.
Please note that contributory, predisposing and precipitating conditions/ causes are closely related and often interchangeable.
The terminal cause of death is usually the complication that eventually sets in. A person with a head injury (the primary medical cause) often develops bronchopneumonia (terminal cause).
The sole cause of death is the cause where no contributory or other factors have played a role. In a case where a person has suffered a single injury such as a stab wound in the aorta, that is the primary cause of death.
Having established the primary medical cause of death, the doctor must decide, to the best of her knowledge and conviction, whether the death is solely the result of natural causes.
When the cause of death has been formulated, it must always be borne in mind that the diagnosis is based solely on personal observation. Where death from natural causes is concerned, the patient's history and the results of all special investigations should be taken into consideration in order to establish the cause of death. This is not permissible in a medico-legal case because information from other sources could be considered as hearsay. Such information could however be used as a clue, so that special attention can be paid to specific aspects which may be important and which otherwise may possibly have been overlooked in a routine examination.
If a diagnosis cannot be made in a medico-legal case on the grounds of the findings of the investigation alone, this fact must be recorded on the relevant form, for example ``cause of death could not be determined by the post mortem'', or ``death could not be determined by the post-mortem examination alone''.
Only if the cause of the injury has been indisputably determined may the aetiological factors in the cause of death be mentioned. A bullet wound in the head can only be diagnosed if the bullet fragments are found in the head, or other findings make the diagnosis obvious. Furthermore, it is wrong to record ``penetrating knife-wound'' as the cause, because similar wounds can also be inflicted by other instruments such as daggers, razor blades, swords, bayonets or even long pieces of glass. The use of the term ``stab wound'' is preferable.
If further information is provided by the submission of a full investigation dossier of a case, together with all the statements to the doctor in the form of affidavits, or the furnishing of background information to the court, the doctor will be able to determine the primary medical cause of death by way of inferences based on her general medical and medico-legal knowledge and background.
In medico-legal cases where death resulted from an acute neurogenic cardiac arrest due to parasympathetic stimulation; an anoxia or other mechanism in cases of strangulation, suffocation and choking; drowning; where the dying person was under the influence of drugs; or in cases of poisoning, the primary medical cause of death is determined by the court after an evaluation of the following evidence:
This evidence relates to the following:
· the findings which indicate a specific occurrence
· the exclusion of any other possible cause of death
This evidence relates to the special investigation carried out, such as the following:
· the result of an investigation of blood from the right and left ventricles in a case of suspected drowning
· the result of a histological investigation to confirm or exclude macroscopic changes
· the result of a toxicological investigation of organs and body fluids in the case of a suspected poisoning
If the doctor feels competent to give his opinion on the result of a laboratory investigation and to testify to it, he may do so.
The evidence of others must be presented by the prosecutor, especially with regard to the following:
· the state of health of the deceased and indications whether a death was expected or not
· the course of events that led to the death