Study of the diagnostic value of strontium, chloride, haemoglobin and diatoms in immersion cases

The Diagnostic Value of the Changes in the Renal Glomerulus in the Postmortem Diagnosis of Freshwater Drownings

Drowning is one of the major causes of unintentional injury death worldwide. As there are no pathomorphological findings specific to the diagnosis of drowning, definitive postmortem diagnosis of drowning continues to be a significant problem in forensic medicine. This study aims to present an additional diagnostic sign in cases of freshwater drowning by investigating the histopathological changes of renal tissue in the postmortem diagnosis of freshwater drowning. For this purpose, 103 cases were investigated in which the causes of death were freshwater drowning (n = 45), traffic accidents (n = 33) and acute myocardial infarction (n = 25). Renal corpuscular structures of selected cases were examined stereologically and histopathologically. Renal corpuscle diameter, renal corpuscle surface area, glomerular tuft surface area, and Bowman space were calculated by stereological method. When compared with the glomeruli of the control group, renal corpuscle diameter, renal corpuscle surface area, glomerular tuft surface area, and Bowman space values of kidney tissues of all freshwater drowning cases were found to be decreased (P < 0.001). These changes may be considered as an essential histopathological finding in postmortem diagnosis of freshwater drowning cases.

Development of 18S rRNA gene arrays for forensic detection of diatoms

Diatom test is the most commonly used method to diagnose drowning in forensic laboratories. However, microscopic examination and identification of diatom frustules is time-consuming and requires taxonomic expertise. At present, the identification of drowning is still a challenge in forensic casework. In this study, we developed a novel diatom microarray based on the detection of specific 18S rRNA gene fragments of diatom species. The array covers 169 diatom species which were documented as commonly found in a wide range of fresh waters in China. Diatom arrays were prepared from species specific oligonucleotide probes targeting to variable regions of the 18S rRNA gene. We also developed an auxiliary sample preparation method for isolation of diatom DNA from tissues, which enabled detection of diatom species in real forensic samples as well as environmental waters. We applied the diatom arrays to analyze six drowned cases and eight environmental samples. The diatom arrays showed much better sensitivity and more consistent results than those of the conventional SEM methods. We discovered major discrepancies between results generated by the diatom arrays and the routinely used SEM based diatom tests. We verified the results of our diatom arrays by species specific PCR and Sanger sequencing and found that the currently used SEM diatom test method has a serious deficiency in sensitivity due to high loss rate of frustules in the sample preparation procedure. We anticipate that the application of diatom arrays will transform current forensic practice of diagnosing drowning deaths.

Haematic silicon in drowning

The aim of this paper was to evaluate silicon (Si) concentration in human whole ventricular blood as a further potential chemical marker in the diagnosis of drowning. We employed an acidic digestion for the extraction of soluble Si, and an alkaline digestion for the determination of total Si, including particulate matter, both arising from drowning medium. 29 suspected drowning situations, 24 in fresh water (Fw) and 5 in seawater (Sw), were examined. The difference in Si concentration between the left and right ventricular blood (Si ΔL-R) was measured and alkaline Si ΔL-R seems, indeed, a potentially significant complementary tool in the diagnosis of Fw drowning, because insoluble silicon fraction does not undergo hemo-dilution or hemo-concentration, and the ΔL-R is not affected by exogenous factors. In spite of the limited number of cases investigated, a good correlation was observed between the analytical results and the macro-microscopic autoptic findings.

The Forensic Pathology of Drowning and Pulmonary Overexpansion Injury

Drowning deaths are commonly seen in most forensic pathology practices. Experienced forensic pathologists perform autopsies and assign a cause and manner of death in such cases as a matter of routine. Deaths due to pulmonary overexpansion injury and subsequent air embolism are far less common and typically involve individuals who have been breathing compressed gas at depth, generally SCUBA (self-contained underwater breathing apparatus) divers. This review outlines the pathophysiological basis of these two forensic pulmonary issues and recommends an approach to performing and interpreting the results of a forensic autopsy when faced with such cases.

Postmortem chemistry update part I

Postmortem chemistry is becoming increasingly essential in the forensic pathology routine and considerable progress has been made over the past years. Biochemical analyses of vitreous humor, cerebrospinal fluid, blood and urine may provide significant information in determining the cause of death or in elucidating forensic cases. Postmortem chemistry may essentially contribute in the determination of the cause of death when the pathophysiological changes involved in the death process cannot be detected by morphological methods (e.g. diabetes mellitus, alcoholic ketoacidosis and electrolytic disorders). It can also provide significant information and useful support in other forensic situations, including anaphylaxis, hypothermia, sepsis and hormonal disturbances. In this article, we present a review of the literature that covers this vast topic and we report the results of our observations. We have focused our attention on glucose metabolism, renal function and electrolytic disorders.

Serum biochemical markers in drowning: diagnostic efficacy of Strontium and other trace elements

The aim of our study was to analyse several serum biochemical markers in order to evaluate the discriminant capacity of trace elements individually and jointly in drowning (seawater drowning and freshwater drowning) and their correlation with age, sex, postmortem interval, time in water and concentrations of the trace elements in the drowning medium. Sixty-seven cases of drowning (53 seawater drownings (SWD); 14 freshwater drownings (FWD) and 73 control cases (other asphyxias, n=44, and other causes of death, n=29) were selected according to the scene, cause and circumstances of death, together with autopsy findings. Serum strontium (Sr), magnesium (Mg), sodium (Na), chloride (Cl), calcium (Ca), iron (Fe), urea, creatinine (Cr) and cardiac Troponine T (cTn-T) were measured in the left ventricle (Lv), right ventricle (Rv) and peripheral blood. Lv-Rv differences for each marker and Sr, Mg, Na, Cl, Ca and Fe concentrations in the drowning medium were determinated. Mean concentrations of Sr, Cl and Mg in both ventricles and peripheral serum and Lv-Rv differences and Ca Lv and Na Rv were significantly higher in cases of drowning than for other causes of death. In SWD, Sr, Mg, Ca, Na and Cl were significantly higher in Lv than in Rv as a result of aspirating water. In contrast, haemodilution is evident from the significantly higher levels of Fe and urea in Rv than in Lv in cases of SWD, and from the higher Mg and Cr levels in Rv in FWD. In the case of SWD, serum levels of Sr are confirmed as the best parameter for diagnosis, although other trace elements may also be useful, such as the serum concentrations of Mg and Cl. In the case of FWD, the joint determination of Sr and other biochemical markers, especially Fe, may increase correct diagnosis.

Forensic investigation of submersion deaths

CONTEXT

The diagnosis of the cause and the establishment of the manner of death in submersion cases are routine challenge for forensic pathologists as it presents considerable diagnostic difficulties.

OBJECTIVE

To concisely review the main questions during a submersion death investigation and to give the respective documented answers.

DATA SOURCES

The search strategy included a literature search of PubMed, Medline and Google Scholar databases, as well as a review of the cited references by the identified studies and a hand search of relevant textbooks and reference works.

CONCLUSIONS

A complete autopsy, histopathological examination and full toxicological screening are important to determine whether death indeed followed submersion in the water, or to see whether any natural disease or substance use have contributed or caused death. In ambiguous situations, the co-estimation of circumstantial evidence may be of invaluable importance toward the conclusion concerning the cause and the manner of death. The thorough forensic investigation of the submersion deaths not only serves the justice administration, but it also presents considerable benefits for the public health.

Strontium levels in different causes of death: diagnostic efficacy in drowning

Trace element determination can be applied in forensic medicine to diagnose the cause of death. Drowning is the second leading cause of death from unintentional injury. Despite the many diagnostic methods used, the post-mortem diagnosis of drowning continues to be one of the most difficult in forensic pathology. Strontium is a highly sensitive marker of water aspiration in a liquid medium rich in this metal. The aims of this study were to confirm the diagnostic value of strontium in cases of drowning compared with other causes of death, to analyse factors that could affect its concentration and to ascertain the sensitivity and specificity of strontium in right and left ventricles and peripheral serum for the post-mortem diagnosis of drowning. We studied 120 cadavers selected from medico-legal autopsies with different causes of death. Strontium (Sr) levels were measured in the serum (left and right ventricles and peripheral vein) of all cadavers and, in the case of drowning, in the water medium itself, by using Zeeman AAS. Our results confirm the usefulness of blood Sr levels for diagnosing seawater and freshwater drowning, although great care should be exercised in the latter case.

Evaluation of four digestive methods for extracting diatoms

OBJECTIVE

To compare the merit of four digestive methods (nitric acid plus hydrogen peroxide, proteinase K, nitric acid in Disorganization Can and Soluene-350) for extracting diatoms in order to choose the best digestive method for the diagnosis of drowning.

METHODS

Liver, kidney and bone marrow of rabbits were minced and then digested by four digestive methods separately with the following indices compared: (1) time demanded for complete digestion; (2) degree of digestion for different tissues; (3) the reclaiming ratio of diatoms; (4) the degree of digestive destruction to diatoms.

RESULTS

For sufficiently digesting the same tissue, the demanded times for the different methods ranked from the longest to the shortest were as follows: Soluene-350, proteinase K, nitric acid plus hydrogen peroxide, nitric acid in Disorganization Can. Nitric acid in Disorganization Can method and nitric acid plus hydrogen peroxide method digested the tissues more thoroughly than proteinase K, than Soluene-350 methods. For Cyclotella and Cybella, proteinase K method reclaimed most diatoms and nitric acid plus hydrogen peroxide method reclaimed less, while nitric acid in Disorganization Can and Soluene-350 methods reclaimed the least. For Navicula, the majority of diatoms could be extracted using proteinase K method, but only a few diatoms with other three methods. Under scanning electron microscopy (SEM), the structure of diatoms remained almost perfect after digestion with proteinase K, but destroyed to some extent with other three methods.

CONCLUSION

This study demonstrated that different diatoms (in fresh or sea water) have different resistance to different digestive reagents. As far as the reliability and applicability of the diatom test is concerned, proteinase K method is of the best choice, nitric acid plus hydrogen peroxide can be its substitute. Soluene-350 cannot be used for extracting sea water diatoms.

Virtual Autopsy: Two- and Three-dimensional Multidetector CT Findings in Drowning with Autopsy Comparison1

PURPOSE

To retrospectively determine the multidetector computed tomographic (CT) virtual autopsy findings of death by drowning in comparison with autopsy findings.

MATERIALS AND METHODS

The institutional review board of the Armed Forces Institute of Pathology approved this HIPAA-compliant study and did not require informed consent by the next of kin. Total-body multidetector CT was performed, immediately prior to routine autopsy, in 28 consecutive male subjects (mean age, 24.2 years) who died of drowning and a control group of 12 consecutive male subjects (mean age, 50.8 years) who died of sudden death from atherosclerotic coronary artery disease. Images were evaluated for the presence of fluid and sediment in the paranasal sinuses and airways, mastoid air cell fluid, frothy fluid in the airways, pulmonary opacity (ground-glass opacity or airspace consolidation), interlobular septal thickening, and gastric distention and contents (fluid or sediment). Image findings were compared with findings from autopsy reports and photographs.

RESULTS

All drowning subjects had fluid in the paranasal sinuses and mastoid air cells and had ground-glass opacity within the lungs. Twenty-six subjects (93%) had fluid in the subglottic trachea and main bronchi. Fourteen subjects (50%) had high-attenuation sediment in the subglottic airways. Frothy fluid in the airways was present in six subjects (21%). Twenty-five (89%) of the drowning subjects had pulmonary ground-glass opacity with septal lines, which was mild with apical and perihilar distribution in 12 subjects, severe and diffuse in nine, posterior and basilar in three, and limited to the apices in one (not assessed in three of 28 subjects because of decomposition). Control subjects showed mastoid cell fluid (25%), sinus fluid (83%), subglottic airway fluid (92%), and pulmonary ground-glass opacity (100%) but did not have evidence of frothy airway fluid or high-attenuation sediment in the airways.

CONCLUSION

The multidetector CT finding of frothy airway fluid or high-attenuation airway sediment is highly suggestive of drowning; multidetector CT findings of pan sinus fluid, mastoid cell fluid, subglottic tracheal and bronchial fluid, and ground-glass opacity within the lung at multidetector CT are supportive of drowning in the appropriate scenario.

Factors affecting strontium absorption in drownings

This study examines the effects of age, gender, a cold water medium versus warm water medium, and salinity on strontium levels determined in left ventricular blood in drownings. Significant differences in the amount of strontium absorbed into the bloodstream (p<0.001) were detected between individuals who drowned in fresh water versus those drowning in seawater, and between those drowning in cold water versus warm water (p=0.030). However, no significant differences were noted in the strontium concentrations of left ventricular blood according to gender or age.

Study of the diagnostic value of iron in fresh water drowning

The aim of our study was to test the diagnostic value of iron (Fe) in fresh water drowning by investigating the postmortem levels of hemodilution in drowning cases compared to control cases. Twenty-six typical fresh water drowning cases were selected from 128 immersion cases autopsied in our Department of Forensic Pathology between 1998 and 2004. The exclusion criteria were a long postmortem interval and other causes of death than drowning. For all selected cases, the diagnosis of drowning was based on the presence of autopsy findings and positive diatom test. A control population of 12 cases was also selected. For each drowning and control case, iron blood levels were measured in the left ventricle (LV) and right ventricle (RV) of the heart. The mean difference of iron concentration (RVFe-LVFe) between the drowning group and the control group was statistically compared. Furthermore, iron measurements were performed in 19 drowning cases showing advanced putrefaction. The mean difference of iron concentration was significantly higher in the drowning cases compared with controls (P<0.001). All drowning cases showed hemodilution. No overlap was found in the RVFe-LVFe levels between the two groups. Resuscitation attempts seemed to have no effect on the results. In cases of drowning showing advanced putrefaction, the iron test was not reliable because biochemical iron measurement was often prevented by no sufficient blood in the heart or postmortem clots. In conclusion, according to our results, iron seems to be a good biochemical marker in fresh water drowning with a short postmortem interval.

Drowning: still a difficult autopsy diagnosis

Investigation of bodies recovered out of water comprises an important proportion of the medico-legal requests. However, the key question whether the victim died due to "true" drowning can frequently not easily be solved. In addition, the diagnosis of hydrocution is even more difficult. In this manuscript, a review of reported diagnostic methods is discussed in order to provide guidelines, which can be used in current forensic practice. In particular, the (dis)advantages of various biological and thanato-chemical methods, described in literature during the last 20 years, will be confronted with the classical techniques such as the detection of diatoms and algae. Indeed, the diatom test is still considered as the "golden standard". In conclusion, the ideal diagnostic test as definite proof for drowning still needs to be established. At present, the combination of the autopsy findings and the diatom test is a good compromise in arriving at a conclusion. Additional biochemical and technical methods could be useful. Unfortunately, the cost-benefit analysis in current practice could be hard to defend. However, the importance of this subject asks for further scientific approaches and research.

Gastric mucosa lesions in drowning: its usefulness in forensic pathology

In a retrospective study of 52 autopsy cases of drowning fatalities, death circumstances, macroscopical and histological findings of the stomach mucosa were carefully studied. Results were compared with a control group, composed by 80 cases of different kinds of asphyxia (hanging, chocking and suffocation), skull injuries, sudden cardiac death and poisonings. The spectrum of gastric lesions observed during autopsy in drowning group, are presented. Stomach mucosa tears were found in 21.1% of the cases of drowning, preferably on fundus (54.5%). The control group does not show similar lesions. The physiopathological mechanism of its production, are also discussed. On sight of these results, it is concluded that the macro and microscopical examination of the stomach could be useful as an adjunct procedure for drowning diagnosis. The presence of gastric mucosa lesions has an intravital significance and could be correlated with other anatomical or histological signs of drowning for the diagnosis. In every case, necropsic examination must be carried out as soon as possible in order to avoid putrefactive artifacts.

An unusual case of post-mortem redistribution of ethanol

We report an unusual case of post-mortem redistribution of ethanol in a woman diver who died by drowning in seawater. The ethanol concentrations were right heart blood 0.60 g/l, left heart blood 2.08 g/l, femoral venous blood 0.63 g/l, gastric contents 5.87 g/l, bile 0.83 g/l. The mechanisms of post-mortem redistribution of ethanol described in the literature, that is, early redistribution from the stomach or the lung parenchyma in the case of inhalation of gastric contents, are inadequate to account for the degree of variation observed between the measurements. We believe that this difference in concentration is explained by the presence of seawater in the pulmonary alveoli at the time of death.

Electrolyte analysis in pleural effusion as an indicator of the drowning medium

In medico-legal autopsies for drowned bodies, the location of drowning needs to be determined. To investigate the usefulness of electrolyte analysis in pleural effusion as an indicator of the location where the deceased has drowned, we determined the concentrations of electrolytes in the pleural effusion of rats drowned in four kinds of water. The concentrations of sodium and chloride ions in the pleural effusion of rats that drowned in seawater were significantly greater than those of rats that drowned in freshwater at both 1 day and 3 days after drowning. The concentration of potassium ions in pleural effusion 1 day after drowning showed no difference between each group, although it then increased from 1 to 3 days after seawater drowning, whereas it decreased from 1 to 3 days after freshwater drowning. The concentration of total protein in pleural effusion increased from 1 to 3 days after drowning, however, there was no significant difference in the concentration of total protein in pleural effusion between each group at either 1 day or 3 days after drowning. These results suggest that analysis of electrolytes in pleural effusion may be useful for determining whether drowning has occurred in seawater or in freshwater.

Diagnosing death by drowning in fresh water using blood strontium as an indicator

The interpretation of the level of strontium (Sr) in blood has been demonstrated to be useful in the diagnosis of death by drowning occurred in sea water, but its use in fresh water drownings is not so evident because of the low Sr concentration present in most of fresh water media. In this paper, we show a survey of the results obtained in the casework analysis of Sr in ventricular blood used in the diagnosis of drowning in 144 bodies found immersed in fresh water over a period of 10 years. Thirty-two percent of the immersion cases examined could be diagnosed as drownings with a reasonable degree of confidence. It is thought that this percentage of positive diagnoses could be largely improved in the case of blood samples taken a few hours after death.

Postmortem lung weight in drownings: a comparison with acute asphyxiation and cardiac death

There are several controversial findings and arguments about the lung weight as a marker of drowning. The aim of the present study was to examine the difference in the lung weight and the amount of pleural effusion between freshwater and saltwater drownings (n=70 and n=75, respectively), in comparison with asphyxiation (n=85) and acute cardiac death (n=82), for the diagnosis of drowning. In drowning cases, a gradual postmortem time-dependent decrease in the lung weight and a reciprocal increase in the pleural effusion suggested postmortem transudation from the lungs. The decrease in the total value of the combined lung weight and the amount of pleural effusion was marked in saltwater immersion after 3 days postmortem, suggesting a leakage of the effusion out of the thoracic cavity under an osmotic effect of the immersion medium. In cases within 3 days postmortem, when the combined lung weight and amount of pleural effusion were added to estimate possible combined lung weight at the time of death, there was a gross difference among the causes of death: the value was the largest in saltwater drowning, followed by freshwater drowning, acute cardiac death and asphyxiation. However, the value depended on the gender and age of the subjects, suggesting a relation to the individual physical constitution and survival time or vital activity. These factors should be taken into consideration in evaluation of the lung weight in the diagnosis of drownings.

Blood strontium concentration related to the length of the agonal period in seawater drowning cases

The levels of ventricular blood strontium (Sr) from 70 seawater drowning victims were compared with their diagnosis of drowning based mainly on certain criteria selected from their autopsy report. From this comparison, intervals of either the difference of Sr concentration between the left and the right ventricle blood (LVSr-RVSr) or the Sr concentration in the left ventricle blood (LVSr), appear to be related to different time-lapses of the agonal period of drowning. In the aim to diagnose drownings, intervals of both LVSr-RVSr and LVSr were proposed to characterize three different agonal periods in seawater drowning cases: instantaneous death (ID), fast vital-submersion drowning (FVSD) and common vital-submersion drowning (CVSD).

Diatom test with Soluene-350 to diagnose drowning in sea water

The authors tested the Soluene-350 method to detect diatoms in three cases of sea water drowning. The negative results obtained in all three cases prompted us to re-test the method on samples of fresh water and sea water microalgae. The experiment showed that the siliceous frustule of sea water diatoms is solubilized by Soluene-350 while that of fresh water diatoms is resistant to the treatment. The method, which is effective in cases of drowning in fresh water, should therefore be used with caution in sea water drowning.