Post-mortem vitreous sodium and chloride levels – a biochemical test for salt water drowning?

Abstract

Deaths due to drowning, in both salt and fresh water, are quite frequently encountered in forensic pathology practise. A diagnosis of drowning may be made when other causes of death from trauma, drugs, natural disease, etc, have been excluded after a body is retrieved from water and examined. These types of cases can be difficult for the pathologist, especially when factors such as absence of witnesses to the event, prolonged immersion time, and/or decomposition occur. Post-mortem changes may significantly alter the integrity of the body and affect opinions relating to the cause and time of death. Eleven cases of salt water drowning are presented, where vitreous sodium and chloride levels have been tested for post-mortem. In 10 out of 11 cases, there was a statistically significant elevation of the sodium and chloride levels, in comparison with 35 case controls. It is proposed that post-mortem vitreous sodium and chloride testing could be used as an adjunct to the autopsy in the investigation of death from presumed salt water drowning. If the post-mortem vitreous sodium + chloride levels exceed 280–290 mmol/L, a cause of death from salt water drowning would appear quite likely, if circumstances surrounding the death and autopsy findings also suggest drowning as a likely cause of death.