[Post-traumatic pulmonary and systemic fat embolism in forensic practice. Prospective histological study].

INTRODUCTION: The more or less subclinical presence of fat emboli in the lungs and other vital organs, without ischaemic changes in them, whose presence could be postmortem established only by microscopic examination, is termed in forensic medicine systemic fat embolism. On the other hand, Fat Embolism Syndrome (FES) is a clinical manifestation of the presence and influence of fat emboli in organs, with clearly defined neurological, respiratory and cutaneous signs and various symptoms, grouped in the so called major and minor signs [8-11].

PURPOSE: The purpose of this paper is to establish the frequency of post-traumatic occurrence of fat emboli in capillaries of the lungs and other organs in cases where the cause of death was not related to pulmonary or systemic fat embolism, but where the typical fat depot injury was established.

MATERIAL AND METHOD: A prospective autopsy histological study was carried out. The sample included 56 cases. The clinical and autopsy data were analyzed and compared in order to establish the value of injury Severity Score--ISS. Histological samples of all vital organs were stained by special technique (Sudan III) and the findings in the lungs and kidneys were graded according to Sevitt's criteria [12]. All data were statistically analyzed (chi 2 test, ANOVA).

RESULTS AND DISCUSSION: The sample included 38 males (average age 53.10 years) and 18 females (average age 54.84 years). The older (ANOVA; p = 0.0017) males (chi 2 = 7.14; p < 0.01), injured as pedestrians (ANOVA, p-->0) were statistically significantly more represented. The most common determined causes of death were: cerebral contusions (30), exsanguination (22), respiratory disorders (9), combustion (6), spinal cord contusions (1), and others (complication of injuries, such as inflammations or sepsis--4). These causes were singular or competitive plural. The average value of ISS was 34.59 (SD = 13.16) and that of outliving period 3.70 days (SD = 5.88). The distribution of outliving period was log-normal. Pulmonary fat embolism was established in all cases: in 14 cases pulmonary fat embolism of the first degree; in 16 of the second grade and in 26 of the third degree. Pulmonary fat embolism of the third degree could be the precipitate singular or concurrent cause of death. The presence of fat emboli in glomeruli was established in 39 cases: in 30 cases the kidney fat embolism of the first degree was established, in 6 of the second degree and in 3 cases of the third degree. In 11 cases the presence of fat globules in brain capillaries was established and in 3 cases in the capillaries of other organs (heart, liver, spleen). By analyzing the clinical and autopsy data, as well as microscopic findings, we concluded that in four cases the cause of death was associated with systemic fat embolism, what previously had been missed.

CONCLUSION: In all our sample cases pulmonary fat embolism was verified, and in a great number of them systemic fat embolism. According to medicolegal principles, pulmonary and systemic fat embolism that develop a few hours after trauma can be considered as a consequence of typical body fat depot injury. The later developed FES could be considered as the complication of such an injury. Pulmonary and systemic fat embolism could complicate the basic trauma, e.g. craniocerebral, abdominal or thoracic, and could be considered as the precipitating cause of death. Because of non-specific and non-characteristic macroscopic autopsy findings, pulmonary and systemic fat embolism could be missed as the cause of death.