Peculiar and Unusual Drowning in Waste Oil from Motor Vehicles: Case Report

Drowning is one of the most frequent causes of accidental or suicidal death, and more rarely it is associated with a homicide. Cases of drowning in water or in the sea are common. The authors report an unusual and peculiar case of drowning, that of a woman who accidentally fell inside a collection tank of waste oil of motor vehicles.


Introduction
In Italy 800 drowning cases per year have been appraised, 45% of which are fatal [1]. Generally, drowning means a form of mechanical asphyxia subsequent to the occlusion of the respiratory tract by a fluid. Usually water represents the most common means by which drowning and asphyxia occurs, in these cases the body can be found totally or partially submersed.
If we consider alternative fluids to the water, it is more common that their penetration in the respiratory tract is subsequent to inhalation, which is followed by lung pathologies more than by a real asphyctic syndrome [2][3][4][5][6][7][8]. Other fluid that in rare occurrences have been mentioned in the literature as a means of drowning asphyxia are represented by wax, paraffin, beer, bitumen, and gas oil [9][10][11][12][13][14]. Therefore, due to its uniqueness, the authors present a case of drowning in waste oil from motor vehicles.

Case Report
The case concerns a 64-year-old woman, who had been missing for six days, and then was found dead in a collection tank for motor oil waste. The judiciary ordered the implementation of the autopsy aimed at clarifying the cause of death and if it was due to a homicide, a suicide or an accident.
The external examination showed an advanced stage of decomposition of the body, at evident gas stage. The facial traits were altered due to the swelling of integuments caused by putrefaction gases. The putrefaction epidermolysis was widespread. On the head and trunk there was some stratified blackish oily fluid. No traumatic lesion was detected. The body dissection showed the presence of the blackish oily fluid inside the mouth, in the upper digestive tract to the stomach and in the respiratory tree ( Figure 1). In particular the lungs were solids and heavy, even if they were found expanded and emphysematous; the dissection revealed the presence of the blackish fluid inside the main bronchi and into their intraparenchymal ramifications which in some cases were completely obstructed ( Figure  2).  The histological examination showed some structural changes on the laryngeal and tracheal wall, in which the mucosa was found completely without epithelium and its tunic was covered by a blackish amorphous granular substance.
In the lung sections there were some areas of emphysema, visibly empty and alternated with other areas covered by the blackish matter ( Figure 3). The lumen of many bronchus ramifications showed blackish substance on the mucosa (Figure 4) while others were totally obstructed.
Another noteworthy aspect was given by the evidence that came out by the kidneys examination that showed a widespread fibrosis, several cystic formations, a marked thickening of capillary loops, glomerulus transformed into connective and tubular epithelium reduced to an amorphous granular substance without nuclei.

Discussion
The results of the autopsy and of the histological examination enabled us to ascribe the death due to acute asphyxia caused by drowning in mineral oil waste used for motor vehicles contained in a collecting well. The drowning fluid, in fact, has been found up to the smallest ramifications of the respiratory tree and it has been partially swallowed. This coincides with what usually happens during drowning in water and confirms that the woman at that moment was alive.
The causes that brought about the drowning could be attributed to an accidental event, since there are no forensic elements allowing us to formulate the hypothesis of suicide or homicide.
In fact, the external examination of the body did not show any sign of traumatism referable to the possible intervention of other subjects; and the woman, according to what the relatives said, had never manifested suicidal thoughts nor suffered from psychiatric pathologies.
Furthermore, considering the severe grade of nephrosclerosis with cystic transformation of the kidney parenchyma and the severe nephrotic component that appeared during the histological examination, we have considered as a reliable hypothesis to be evidence of kidney failure at uremic stage with possible clinical signs such as the state of mental confusion. This could have facilitated the fall of the woman in the well and the subsequent drowning. This hypothesis has been supported by her relatives' statements who said that the woman, in that period, was submitted to dialysis three times a week.
The analysed case represents the unique of drowning in waste motor oil and the authors reported it to document the macroscopic and microscopic characteristic evidences.