European Journal of Cardiovascular Medicine

Drowning is defined as the process of experiencing respiratory impairment as a result of submersion or immersion in a liquid medium [1]. Despite advances in forensic science, establishing drowning as the cause of death continues to pose considerable diagnostic difficulty, especially in decomposed bodies or cases lacking eyewitness accounts. Unlike many traumatic deaths, drowning often leaves behind subtle and inconsistent autopsy findings, making it a diagnosis that relies heavily on a constellation of features rather than a single definitive marker [2].

Classical autopsy findings described in drowning include fine frothy fluid at the mouth and nostrils, waterlogged lungs (emphysema aquosum), overdistension of the alveoli, and presence of water in the stomach and duodenum. However, these findings may be absent, altered by decomposition, or encountered in non-drowning deaths, thereby limiting their diagnostic reliability. Consequently, forensic pathologists continue to explore additional indicators that may improve diagnostic confidence [3].

One such proposed indicator is the presence of fluid within the paranasal sinuses. During the act of drowning, vigorous inspiratory efforts occur as the victim struggles for air. This negative intrathoracic pressure facilitates aspiration of water into the respiratory tract and, potentially, retrograde flow into the paranasal sinuses through natural ostia [4]. The anatomical continuity between the nasal cavity and the paranasal sinuses provides a plausible pathway for fluid entry during active respiration [4].

Paranasal sinuses—namely the maxillary, frontal, ethmoid, and sphenoid sinuses—are air-filled cavities within the facial and cranial bones. Under physiological conditions, these sinuses are devoid of fluid. The detection of fluid at autopsy raises the possibility of antemortem aspiration or pathological processes. In the context of drowning, sinus fluid is believed to reflect active inhalation of water rather than passive postmortem seepage [5].

Earlier forensic studies have suggested that paranasal sinus fluid is encountered more frequently in drowning victims than in other causes of death. Some studies have reported high sensitivity but variable specificity, while others have questioned its reliability due to occasional presence in non-drowning asphyxial deaths or advanced decomposition. Additionally, environmental factors such as water pressure, body position, and duration of submersion may influence sinus involvement [6].

Asphyxial deaths other than drowning—including hanging, strangulation, and smothering—share a common endpoint of hypoxia but differ fundamentally in the mechanism of airway involvement. In these deaths, aspiration of external fluid is typically absent, and any sinus fluid is more likely to result from congestion, transudation, or postmortem changes [7]. Comparing drowning with other asphyxial deaths therefore offers an appropriate framework to evaluate the diagnostic relevance of sinus fluid.

Despite its potential value, systematic comparative studies focusing on paranasal sinus fluid across different asphyxial deaths remain limited, particularly in the Indian forensic context. Given the high incidence of water-related deaths in India due to occupational exposure, accidental falls, and seasonal flooding, identifying reliable supportive markers is of practical importance.

The present study was undertaken to compare the presence, distribution, and pattern of paranasal sinus fluid in confirmed drowning cases and other asphyxial deaths, with the objective of assessing its forensic utility as a supportive autopsy finding.

Study Setting: This autopsy-based comparative observational study was conducted in the Department of Forensic Medicine at a Government Medical College in Tamil Nadu. The department caters to a large urban and rural population and routinely performs medicolegal autopsies referred by law enforcement authorities from multiple districts. The study was carried out over a period of 18 months from January 2024 to June 2025, during which all eligible medicolegal autopsies were screened for inclusion. The institution follows standardized autopsy protocols in accordance with national medicolegal guidelines, ensuring uniformity in examination techniques and documentation. Study Participants: The study population comprised deceased individuals subjected to complete medicolegal autopsy during the study period, where the cause of death was certified as either drowning or other forms of asphyxia. A total of 150 cases fulfilling the eligibility criteria were included in the final analysis. These cases were divided into two equal groups for comparative evaluation: • Drowning group: 75 cases in which death was attributed to drowning. • Non-drowning asphyxial group: 75 cases in which death resulted from other asphyxial mechanisms, including hanging, ligature strangulation, manual strangulation, and smothering. Classification into the respective groups was based on a combination of police inquest reports, circumstantial evidence, scene findings, and comprehensive autopsy examination. Only cases where the cause of death was clearly established after complete autopsy were included, thereby minimizing diagnostic ambiguity. Selection Criteria: Inclusion criteria for the drowning group consisted of cases where death occurred following submersion in a liquid medium, supported by circumstantial evidence such as recovery from water bodies, witness statements when available, and autopsy findings consistent with drowning. For the non-drowning asphyxial group, cases included deaths due to mechanical interference with respiration such as hanging, strangulation, or smothering, as certified after autopsy. In both groups, only cases in which the autopsy was performed within 72 hours of death were included. This criterion was applied to reduce the influence of postmortem decomposition on sinonasal findings and to ensure accurate assessment of fluid presence within the paranasal sinuses. Exclusion criteria were applied stringently to avoid confounding factors. Bodies showing advanced decomposition with putrefactive changes affecting the facial structures were excluded. Cases with severe craniofacial trauma involving the paranasal sinuses, fractures of facial bones, or surgical interventions affecting the sinonasal region were not considered. Individuals with documented pre-existing sinus pathology such as chronic sinusitis, mucoceles, neoplasms, or recent nasal surgery were excluded to prevent misinterpretation of sinus fluid. Sample Size and Sampling Technique: A sample size of 150 cases was selected using a purposive sampling technique, ensuring equal representation of drowning and non-drowning asphyxial deaths. Equal allocation between groups was adopted to facilitate direct comparison and reduce sampling bias. Study Tools: Data collection was carried out using a structured and pre-tested proforma specifically designed for the study. The proforma captured detailed demographic variables such as age, sex, and place of residence, along with circumstantial information obtained from police inquest reports. Autopsy findings relevant to asphyxia and drowning were systematically recorded. For sinus examination, standard autopsy instruments including bone saws, chisels, forceps, and suction devices were utilized. Digital photographic documentation was employed wherever feasible to support visual confirmation and maintain record accuracy. All observations were recorded contemporaneously during autopsy to minimize recall bias. Study Methodology: All autopsies were performed following standard forensic protocols. After completion of external examination and opening of the cranial cavity, the brain was carefully removed. Subsequently, attention was directed towards systematic exposure of the paranasal sinuses. The anterior cranial fossa and facial bones were approached using standard craniofacial dissection techniques. Each paranasal sinus—maxillary, sphenoid, ethmoid, and frontal—was exposed individually. Care was taken to avoid artificial introduction or loss of fluid during dissection. The presence or absence of fluid within each sinus was noted meticulously. When fluid was present, the following parameters were documented: • Sinus involved (maxillary, sphenoid, ethmoid, frontal) • Laterality (unilateral or bilateral) • Number of sinuses involved (single versus multiple) • Estimated volume of fluid, categorized as minimal, moderate, or copious • Nature of fluid, classified as clear, blood-tinged, or frothy Where possible, the fluid was visually inspected for clarity and consistency. The findings were correlated with other autopsy features of asphyxia and drowning to maintain interpretative coherence. Photographic documentation was undertaken in selected cases to enhance objectivity and allow peer verification. Ethical Issues: The study protocol was reviewed and approved by the Institutional Ethics Committee prior to initiation. As the research involved deceased individuals undergoing medicolegal autopsy, informed consent from relatives was not required. However, ethical principles concerning respect for the deceased and confidentiality were strictly adhered to. All case records were anonymized, and identifying information was excluded from data analysis and reporting. The study was conducted in compliance with ethical norms governing forensic research and biomedical investigations involving human material. Statistical Analysis: Collected data were entered into Microsoft Excel and subsequently analyzed using Statistical Package for the Social Sciences (SPSS) version 26. Categorical variables such as presence of sinus fluid, sinus involvement patterns, laterality, and nature of fluid were expressed as frequencies and percentages. Descriptive statistics were used to summarize demographic variables. Inferential analysis was performed using the Chi-square test to assess the association between cause of death and paranasal sinus findings. Variables such as presence of sinus fluid, multiple sinus involvement, bilateral distribution, and individual sinus involvement were tested for statistical significance. A p value less than 0.05 was considered statistically significant for all analyses.

A total of 150 medicolegal autopsy cases were included in the present study. Based on the certified cause of death and circumstantial evidence, cases were categorized into two groups: deaths due to drowning (n = 75) and deaths due to other forms of asphyxia (n = 75), which included hanging, ligature strangulation, manual strangulation, and smothering.

The demographic profile of the study population is summarized in Table 1. The mean age of the overall study population was 35.8 ± 13.2 years. Both groups were comparable with respect to age distribution, sex, and place of residence, indicating demographic homogeneity.

Table 1: Demographic Characteristics of the Study Population (N = 150)

The overall prevalence and anatomical distribution of paranasal sinus fluid across the study groups are detailed in Table 2. Sinus fluid was identified in a substantially higher proportion of drowning cases compared to other asphyxial deaths. Among drowning cases, the maxillary sinus was the most frequently involved, followed by sphenoid, ethmoid, and frontal sinuses.

Table 2: Presence and Sinus-wise Distribution of Paranasal Sinus Fluid.

Table 3 describes additional qualitative characteristics of sinus fluid, including laterality, number of sinuses involved, and nature of the fluid. Multiple sinus involvement and bilateral distribution were more frequently observed in drowning deaths.

Table 3: Qualitative Characteristics of Paranasal Sinus Fluid.

The association between the presence of paranasal sinus fluid and the cause of death was assessed using the chi-square test. As shown in Table 4, the presence of sinus fluid demonstrated a statistically significant association with deaths due to drowning.

Table 4: Association Between Presence of Paranasal Sinus Fluid and Cause of Death.

Further analysis evaluating specific patterns of sinus involvement revealed that multiple sinus involvement and bilateral distribution were strongly predictive of drowning. The inferential comparisons are presented in Table 5.

Table 5: Association of Sinus Involvement Pattern With Drowning.

Establishing drowning as a cause of death remains a persistent challenge in forensic practice, particularly when classical external signs are absent or altered by postmortem changes. The findings of this study provide compelling evidence that paranasal sinus fluid, especially when present bilaterally and involving multiple sinuses, is significantly associated with deaths due to drowning and may serve as a valuable supportive indicator in forensic diagnosis.

The demographic profile of the study population revealed no statistically meaningful differences between the drowning and non-drowning asphyxial groups with respect to age, sex, or place of residence. The mean age of approximately 36 years and the predominance of males in both groups are consistent with the demographic patterns commonly reported in medicolegal autopsy series [8].

One of the most notable findings of the present study is the markedly higher prevalence of paranasal sinus fluid in drowning cases compared to other asphyxial deaths. Sinus fluid was detected in more than four-fifths of drowning victims, whereas fewer than one-third of non-drowning asphyxial deaths demonstrated similar findings. This statistically significant association reinforces the concept that sinus fluid accumulation is closely linked to the pathophysiological events occurring during drowning [9].

During active drowning, forceful inspiratory efforts against a liquid medium generate negative pressure within the upper airway, facilitating the ingress of water into the nasal cavity and subsequently into the paranasal sinuses through their natural ostia. In contrast, other forms of asphyxia primarily involve external airway obstruction or compression of the neck structures, without active aspiration of environmental fluid, explaining the lower prevalence of sinus fluid in these cases [9, 10].

The sinus-wise distribution observed in the present study further supports this mechanism. The maxillary sinus was the most frequently involved sinus in drowning deaths, followed by the sphenoid, ethmoid, and frontal sinuses. This pattern has anatomical and physiological plausibility. The maxillary sinuses are the largest paranasal sinuses and are situated in a relatively dependent position, making them more susceptible to fluid entry and retention. Additionally, the patency and orientation of the maxillary ostia favor the accumulation of aspirated fluid during forceful breathing. The progressively lower involvement of sphenoid, ethmoid, and frontal sinuses may reflect differences in sinus anatomy, ostial size, and drainage pathways [11].

Bilateral sinus fluid distribution was strongly associated with drowning. These findings are particularly valuable from a forensic perspective, as they suggest that not merely the presence, but the pattern of sinus fluid involvement enhances its diagnostic significance. Bilateral and multi-sinus involvement likely reflect sustained and vigorous respiratory efforts during drowning, allowing fluid to reach multiple sinus cavities. In contrast, isolated or unilateral sinus fluid may occur sporadically in non-drowning deaths and should be interpreted with caution [12].

The nature of the sinus fluid also demonstrated notable differences between the two groups. Clear fluid was the predominant finding in drowning cases, consistent with aspirated water from the environment. Blood-tinged and frothy fluid were also observed, likely reflecting mucosal trauma, vascular congestion, or admixture with airway secretions during the drowning process. In non-drowning asphyxial deaths, sinus fluid was less frequent and more often blood-tinged, possibly related to congestion or terminal hypoxia-induced capillary leakage rather than aspiration [13].

The present study shows a highly significant association between drowning and the presence of sinus fluid, multiple sinus involvement, bilateral distribution, and specific sinus involvement indicate that these findings are unlikely to be due to chance. Among individual sinuses, maxillary and sphenoid sinus involvement showed particularly strong associations with drowning. The sphenoid sinus, due to its deeper location and relatively narrow ostium, is less likely to contain fluid unless there has been forceful aspiration, making its involvement a potentially more specific indicator of drowning [14].

From a practical forensic standpoint, these findings have important implications. In many medicolegal cases, especially those involving recovery of bodies from water, the diagnosis of drowning may be questioned due to the absence of classical features or the presence of confounding injuries [15]. In such scenarios, systematic examination of the paranasal sinuses and careful documentation of fluid presence and distribution can provide valuable supportive evidence. The present study suggests that the identification of bilateral, multi-sinus fluid—particularly involving the maxillary and sphenoid sinuses—should raise strong suspicion of drowning when correlated with circumstantial findings [15].

By employing a relatively large sample size and a balanced comparative design, this study adds robustness to the existing evidence base. The inclusion of multiple qualitative and quantitative variables related to sinus involvement further enhances the interpretative value of the findings.

Despite its strengths, the study has certain limitations that merit consideration. Being an autopsy-based observational study, it is inherently dependent on the accuracy of circumstantial and investigative data provided by law enforcement agencies. Additionally, biochemical or microscopic analysis of sinus fluid was not performed, which might have provided further insights into its origin. Future studies incorporating fluid analysis, radiological correlation, or multicentric data could help refine the diagnostic utility of sinus findings.

The present study demonstrates that paranasal sinus fluid is significantly more prevalent in drowning deaths than in other asphyxial deaths, particularly when bilateral and involving multiple sinuses. These findings reinforce the value of detailed sinus examination during autopsy and support its role as an important ancillary tool in the forensic diagnosis of drowning. When interpreted judiciously within the broader medicolegal context, paranasal sinus fluid can enhance diagnostic confidence and contribute meaningfully to cause-of-death determination.

1.             Beck B, Smith K, Mercier E, Bernard S, Jones C, Meadley B, et al. Potentially preventable trauma deaths: A retrospective review. Injury. 2019 May;50(5):1009-1016.

2.             Coulthard MG, Varghese V, Harvey LP, Gillen TC, Kimble RM, Ware RS. A review of children with severe trauma admitted to pediatric intensive care in Queensland, Australia. PLoS One. 2019;14(2):e0211530.

3.             Nathanson A. Sailing Injuries: A Review of the Literature. R I Med J (2013). 2019 Feb 01;102(1):23-27.

4.             Leth PM. Homicide by drowning. Forensic Sci Med Pathol. 2019 Jun;15(2):233-238.

5.             Peden AE, Taylor DH, Franklin RC. Pre-Existing Medical Conditions: A Systematic Literature Review of a Silent Contributor to Adult Drowning. Int J Environ Res Public Health. 2022 Jul 21;19(14):24-30.

6.             Cimpoesu D, Corlade-Andrei M, Popa TO, Grigorasi G, Bouros C, Rotaru L, Nedelea PL. Cardiac Arrest in Special Circumstances-Recent Advances in Resuscitation. Am J Ther. 2019 Mar/Apr;26(2):e276-e283.

7.             Parenteau M, Stockinger Z, Hughes S, Hickey B, Mucciarone J, Manganello C, Beeghly A. Drowning Management. Mil Med. 2018 Sep 01;183(suppl_2):172-179.

8.             M RS, V HS. Socio-demographic profile of drowning deaths in a rural region - An autopsy based study. Indian J Forensic Community Med. 2021;8(2):80-83.

9.             Mendes LF, Lago LP, Egger C, Schmid J. Characterization of fluid in facial sinuses on post-mortem CT in case of death by drowning. Int J Legal Med. 2025 Sep;139(5):2233-2240.

10.          Heo JH, Yoon Y, Seo IS, Im SB, Ko YS, Lee S, Jang SJ. The significance of evaluating sphenoid sinus fluid by postmortem computed tomography in cases of drowning. J Forensic Leg Med. 2023 Jul;97:102551.

11.          Mendes LF, Lago LP, Egger C, Schmid J. Characterization of fluid in facial sinuses on post-mortem CT in case of death by drowning. Int J Legal Med. 2025 Sep;139(5):2233-2240.

12.          Scholing M, Saltzherr TP, Fung Kon Jin PH, Ponsen KJ, Reitsma JB, Lameris JS, Goslings JC. The value of postmortem computed tomography as an alternative for autopsy in trauma victims: a systematic review. Eur Radiol. 2009 Oct;19(10):2333-41.

13.          Jalalzadeh H, Giannakopoulos GF, Berger FH, Fronczek J, van de Goot FRW, Reijnders UJ, Zuidema WP. Post-mortem imaging compared with autopsy in trauma victims--A systematic review. Forensic Sci Int. 2015 Dec;257:29-48.

14.          Ebert LC, Franckenberg S, Sieberth T, Schweitzer W, Thali M, Ford J, Decker S. A review of visualization techniques of post-mortem computed tomography data for forensic death investigations. Int J Legal Med. 2021 Sep;135(5):1855-1867.

15.          Modzelewski W, Janica J. The role of computed tomography in post-mortem examinations. Arch Med Sadowej Kryminol. 2024;74(2):124-133.