Distinction between saltwater drowning and freshwater drowning by assessment of sinus fluid on post-mortem computed tomography

Diagnosing fatal drownings: A review of the postmortem findings

The lack of drowning-specific pathological findings postmortem complicates medico-legal investigations when bodies are recovered in water. This review provides an in-depth analysis of macroscopic and microscopic findings, as well as biochemical and molecular approaches typically used to diagnose drownings. To ensure that only studies fulfilling established scientific criteria were selected to form conclusions in this review, existing literature was systematically assessed using SPICOT for evaluation of scientific evidence and risk of bias. Analysis of selected studies indicates that several pathophysiological findings following suspected drowning lack scientific evidence, while others are supported by the literature. However, the shortage of suitable controls in drowning research, specifically addressing non-drowned immersed bodies significantly limits investigations on postmortem drowning pathology, and further research is warranted.

Postmortem CT analysis of paranasal sinuses using an experimental model of drowning

Fluid-filled paranasal sinuses are suggested to be a valuable tool to distinguish between drowning and non-drowning postmortem, yet the mechanisms governing fluid entry remains unknown. We investigate if fluid-filled paranasal sinuses are caused by a passive influx from submersion or an active aspiration mechanism during drowning. The ovine nasal cavity and maxillary sinuses are remarkably similar anatomically to humans, and have been used for endoscopic surgical training in recent decades. We submerged 15 decapitated ovine heads from agricultural waste at a depth of 2 m in flowing water for 1, 8, and 24 h and 7 days. Paranasal sinuses were CT imaged and compared pre- and post-submersion to non-submerged controls. Furthermore, we examined the paranasal sinuses of a single homicide case of a non-drowned submerged subject. Results demonstrate that fluid passively enters the maxillary sinus postmortem in the non-drowned ovine heads following 1 h of submersion. Fluid volume was independent of submersion time and influenced by time out of water as well as handling, since volume was reduced between consecutive CT scans. In contrast to our hypothesis, the filling of the paranasal sinuses is due to passive influx of fluid from submersion rather than an active aspiration during drowning. The observation that paranasal sinuses were fluid-filled in a single medico-legal case of postmortem submersion supports the finding of passive influx. Consequently, careful interpretation of fluid-filled paranasal sinuses is required when bodies are found in water, as the finding cannot distinguish between postmortem submersion and drowning.

Assessment of maxillary sinus fluid volume for postmortem diagnosis of drowning

INTRODUCTION

Drowning is a comprehensive and exclusive diagnosis at autopsy. Autopsy findings such as pleural effusion and waterlogged lungs contribute to the diagnosis. Herein, we aim to reveal the practical usefulness and postmortem changes of the maxillary sinus fluid volume to diagnose drowning.

METHODS

We evaluated 52 drowning and 59 nondrowning cases. The maxillary sinus fluid volume was measured using a computed tomography (CT) scan, and pleural effusion volume and lung weight were manually measured at autopsy. The utility of these three indices for diagnosing drowning and its postmortem changes was evaluated.

RESULTS

The maxillary sinus fluid volume was significantly higher in drowning cases than in other external causes and cardiovascular death cases. Receiver operating characteristic curve analysis revealed that a total maxillary sinus fluid volume >1.04 mL more usefully indicated drowning (odds ratio, 8.19) than a total pleural effusion volume >175 mL (odds ratio, 7.23) and a total lung weight >829 g (odds ratio, 2.29). The combination of maxillary sinus fluid volume and pleural effusion volume more effectively predicted drowning than one index alone. Moreover, the maxillary sinus fluid volume was less influenced by the postmortem interval than the other two indices up to a week after death.

CONCLUSION

Maxillary sinus fluid volume can be more useful than pleural effusion volume and lung weight with higher sensitivity and odds ratio for diagnosing drowning.

IMPLICATIONS FOR PRACTICE

Fluid accumulation in both the maxillary sinuses strongly predicts drowning in the postmortem imaging.

Differences in volume, density, electrolyte concentration, and total proteins in the fluid of the paranasal sinuses of freshwater and saltwater drowning victims: a systematic review and meta-analysis

This study summarized the available evidence on the differences in volume, density, electrolyte concentration, and total proteins in paranasal sinus fluid between freshwater and saltwater drowning victims. A systematic search was conducted in electronic databases and gray literature, resulting in the inclusion of five studies with 234 drowning victims (92 saltwater incidents and 142 freshwater incidents). Meta-analyses using the inverse-of-variance method and a random-effects model were performed, reporting effect sizes as standardized mean differences (SMD) with 95% confidence intervals (CI). The findings showed a significantly higher sinus density in saltwater drowning cases compared to freshwater drowning cases (SMD 0.91, 95% CI 0.50 to 1.32). However, no significant differences were observed in sinus fluid volume. Saltwater drowning victims exhibited higher electrolyte concentrations (sodium: SMD 3.77, 95% CI 3.07 to 4.48; potassium: SMD 0.78, 95% CI 0.07 to 1.49; chloride: SMD 3.48, 95% CI 2.65 to 4.31; magnesium: SMD 4.01, 95% CI 3.00 to 5.03) and lower total protein concentrations (SMD - 1.20, 95% CI - 1.82 to - 0.58) in sinus fluid compared to freshwater drowning victims. This meta-analysis highlights the importance of analyzing the characteristics and composition of sinus fluid in forensic investigations of drowning cases. While no differences were found in sinus fluid volume, saltwater drowning victims exhibited higher sinus density, elevated electrolyte concentrations, and lower total protein concentrations compared to freshwater drowning victims.

The role of paranasal sinus fluid in determining drowning as the cause of death: A systematic review and meta-analysis

Drowning is a significant global cause of unintentional injury fatalities, and accurate forensic diagnosis of drowning remains a challenge due to the nonspecific nature of post-mortem findings obtained through classical autopsy methods. Our manuscript addresses this issue by focusing on the emerging use of paranasal sinus fluid as a valuable tool in determining the cause of death, specifically in distinguishing drowning from non-drowning cases. The study provided a comprehensive summary of available evidence from observational studies that compared findings in the paranasal sinuses between drowning and non-drowning victims, analyzing parameters such as the presence of fluid, fluid volume, and density. The study encompassed a total of 14 selected studies involving 1044 subjects and utilized rigorous risk of bias assessment and data synthesis techniques. The meta-analysis demonstrated a strong association between the presence of fluid in the paranasal sinuses and drowning (OR = 17.1; 95% CI 7.2 to 40.5; p < 0.001). In addition, drowning victims had a significantly greater volume of fluid (SMD = 0.8; 95% CI 0.5 to 1.2; p < 0.001) and lower fluid density (SMD = -1.4; 95% -2.5 to -0.4; p = 0.008) compared to non-drowning cases. The results support the utility of paranasal sinus fluid analysis as a valuable diagnostic method in cases where drowning is suspected but cannot be definitively confirmed through traditional approaches.

Postmortem computed tomographic features in the diagnosis of drowning: a comparison of fresh water and salt water drowning cases

PURPOSE

To investigate the effectiveness of postmortem computed tomography in the diagnosis of drowning, focusing on the comparison of fresh water and salt water cases using three-dimensionally (3D) reconstructed data.

MATERIALS AND METHODS

We examined features of drowning in 25 fresh water drowning cases (FWDCs; 13 men, 12 women; mean age 73.1 years; range 43-95 years), and compared these with 12 salt water drowning cases (SWDCs; 5 men, 7 women; mean age 66.0 years; range 55-77 years). Pulmonary opacities, volume and density (CT number) of accumulated fluid in the paranasal sinuses and central airways, volume of the stomach/stomach contents, and cardiac blood density were examined.

RESULTS

In SWDCs, pulmonary ground-glass opacities with wholly thickened interstitium was frequently identified (P = 0.0274). Whereas in FWDCs, a significantly larger volume and lower density of fluid in the paranasal sinuses (P = 0.0195 and P = 0.0104, respectively), lower density of fluid in the central airways (P = 0.0077), lower stomach content density (P = 0.0216), lower density in the left atrium (P = 0.0029), and a difference of density between the atria (P = 0.0247) were observed.

CONCLUSIONS

A lower density in the left atrium was observed in FWDCs compared to SWDCs. This finding may be helpful in differentiating between FWDCs and SWDCs.

Layering of stomach contents in drowning cases in post-mortem computed tomography compared to forensic autopsy

BACKGROUND

In forensic autopsy, the analysis of stomach contents is important when investigating drowning cases. Three-layering of stomach contents may be interpreted as a diagnostic hint to drowning due to swallowing of larger amounts of water or other drowning media. The authors experienced frequent discrepancies of numbers of stomach content layering in drowning cases between post-mortem computed tomography (PMCT) and autopsy in forensic casework. Therefore, the goal of this study was to compare layering of stomach contents in drowning cases between PMCT and forensic autopsy.

METHODS

Drowning cases (n = 55; 40 male, 15 female, mean age 45.3 years; mean amount of stomach content 223 ml) that received PMCT prior to forensic autopsy were retrospectively analyzed by a forensic pathologist and a radiologist. Number of layers of stomach content in PMCT were compared to number of layers at forensic autopsy.

RESULTS

In 28 of the 55 evaluated drowning cases, a discrepancy between layering of stomach contents at autopsy compared to PMCT was observed: 1 layer at autopsy (n = 28): 50% discrepancy to PMCT, 2 layers (n = 20): 45% discrepancy, and 3 layers (n = 7): 71.4% discrepancy. Sensitivity of correctly determining layering (as observed at forensic autopsy) in PMCT was 52% (positive predictive value 44.8%). Specificity was 46.6% (negative predictive value 53.8%). In a control group (n = 35) of non-drowning cases, three-layering of stomach contents was not observed.

CONCLUSION

Discrepancies of observed numbers of stomach content layers between PMCT and forensic autopsy are a frequent finding possibly due to stomach content sampling technique at autopsy and movement of the corpse prior to PMCT and autopsy. Three-layering in PMCT, if indeed present, may be interpreted as a hint to drowning.

Diagnosis of drowning by summation of sodium, potassium, and chloride ion levels in sphenoidal sinus fluid: Differentiating between freshwater and seawater drowning and its application to brackish water and bathtub deaths

Analysis of ions in sphenoidal fluid can be a useful index for the diagnosis of drowning. We evaluated the reference ranges of non-drowning cases using statistical methods and three indices: sodium ion (Na⁺), summation of sodium and potassium ions (SUM_Na+K), and summation of sodium, potassium and chloride ions (SUM_Na+K+Cl). The reference ranges were 96≤Na⁺<152, 139≤SUM_Na+K<179, 243≤SUM_Na+K+Cl<311(mEq/L), respectively. Victim indices outside of the reference ranges indicate that the victim probably inspired water with higher or lower ion concentrations than those of body fluid in sphenoidal sinuses. Compared to the SUM_Na+K+Cl index, the Na⁺ and SUM_Na+K indices could distinguish among seawater drowning, freshwater drowning, and non-drowning. In drowning cases, sphenoidal fluid volume and time since death were not correlated, which suggests that water does not enter the sphenoidal sinuses after death and there is a different process for water accumulation in drowning and non-drowning cases. In bathtub cases, this method was not valid for the estimation of inspired water. Although it is necessary to observe the classical signs of drowning, this method is suitable for the estimation of drowning, especially in cases where pleural fluid or diatom tests are not available.

Diagnosis of drowning: Electrolytes and total protein in sphenoid sinus liquid

In this study, electrolyte (sodium (Na), chlorine (Cl), and magnesium (Mg)) and total protein (TP) concentrations and volume of liquid in the sphenoid sinus were examined to determine their usefulness to elucidate whether drowning occurred in freshwater or seawater. We examined 68 cases (seawater drowning group: 27 cases, freshwater drowning group: 21 cases, non-drowning group: 20 cases). There was a significant difference in Na, Cl, Mg, and TP concentrations of liquid in the sphenoid sinus among the three groups (seawater drowning, freshwater drowning, and non-drowning groups). To distinguish freshwater drowning from seawater drowning, Na, Cl, and Mg concentrations of liquid in the sphenoid sinus might serve as useful indicators.

Post-mortem computed tomography coaxial cutting needle biopsy to facilitate the detection of bacterioplankton using PCR probes as a diagnostic indicator for drowning

We report for the first time the use of coaxial cutting needle biopsy, guided by post-mortem computed tomography (PMCT), to sample internal body tissues for bacterioplankton PCR analysis to investigate drowning. This technical report describes the biopsy technique, the comparison of the needle biopsy and the invasive autopsy sampling results, as well as the PMCT and autopsy findings. By using this new biopsy sampling approach for bacterioplankton PCR, we have developed on previous papers describing the minimally invasive PMCT approach for the diagnosis of drowning. When such a system is used, the operator must take all precautions to avoid contamination of the core biopsy samples due to the sensitivity of PCR-based analytic systems.