The research, conducted at the Department of Forensic Medicine in Hradec Králové in the Czech Republic, is the first systematic, statistically validated investigation of reactive splenic contraction in human hypothermia deaths. The finding itself is not new to physiology. The spleen acts as a rapidly mobilizable blood reservoir, capable of sequestering up to 200 to 250 milliliters of densely packed erythrocytes. When the sympathetic nervous system fires—during exercise, hypoxia, hemorrhage, or severe stress—the splenic capsule and vessels contract, squeezing stored red blood cells into the circulation and boosting oxygen-carrying capacity within moments. What had never been done before was to rigorously test whether this dramatic physiological response leaves a recognizable and diagnostically reliable footprint at autopsy in people who died of hypothermia.

The study team, led by Lenka Zátopková and Štěpánka Pohlová Kučerová together with senior author Petr Hejna, examined 54 fatalities attributed to accidental hypothermia and compared them against 170 randomly selected control cases representing both natural and non-natural deaths, including heart failure, cardiopulmonary failure, hanging, and suffocation. The researchers defined reactive splenic contraction by a strict macroscopic triad: an apparent reduction in splenic volume or weight relative to the decedent’s body size, wrinkling of the splenic capsule, and anemization of the red pulp on the cut surface, typically accompanied by increased firmness of the tissue. All three components had to be present simultaneously, a deliberately conservative requirement designed to maximize specificity and prevent misclassification based on isolated, nonspecific splenic changes.

The results were unambiguous. The complete contraction triad was identified in 48 of the 54 hypothermia fatalities, a prevalence of 88.9 percent, but in only 2 of the 170 controls, or 1.2 percent. This translates into a sensitivity of 88.9 percent and a specificity of 98.8 percent, with a positive predictive value of 96.0 percent, a negative predictive value of 96.6 percent, and an overall diagnostic accuracy of 96.4 percent. The statistical association between splenic contraction and fatal hypothermia was extraordinarily strong, with an odds ratio of 672.0 and a 95 percent confidence interval stretching from 131.4 to 3437.2, far beyond the threshold of statistical significance. Histological examination of the spleen in every hypothermia case confirmed the macroscopic impression of red-pulp anemization, revealing a depletion of erythrocytes within the red pulp and empty vascular lumina consistent with the wholesale mobilization of the splenic blood store.

Perhaps the most intriguing result concerns how splenic contraction relates to the established markers of hypothermia. Among the classical findings, only Wischnewsky spots showed a statistically significant association with splenic contraction. No significant relationships emerged with cold erythema, the inner knee sign, hemorrhages within core skeletal muscles, or fatty degeneration of renal tubular epithelial cells. In practical terms, this means that splenic contraction does not simply ride along with the other tissue changes of cold death. Among contraction-positive fatalities, cold erythema was absent in more than a quarter of cases, and roughly a third lacked either muscle hemorrhages or renal fatty degeneration; in six cases, both of those deeper findings were missing entirely. Splenic contraction, in other words, appears to carry independent diagnostic information rather than redundant confirmation of what other signs already show.

This independence points toward a compelling pathophysiological interpretation. Hemorrhagic and degenerative lesions such as muscle hemorrhages and renal tubular fatty change generally require prolonged survival and sustained exposure to critical cold before they develop. Splenic contraction, by contrast, reflects an immediate physiological adaptation: acute sympathetic activation, circulatory centralization shunting blood toward vital organs, and the rapid expulsion of the splenic erythrocyte reservoir into the systemic circulation. The authors therefore propose that a contracted spleen may represent one of the earliest morphofunctional responses to lethal cold stress, visible at autopsy even when the slower-developing hemorrhagic and degenerative manifestations have not yet had time to appear. Supporting this view, the mean splenic weight in contraction-positive hypothermia cases was just 76.1 grams, compared with 132.5 grams in contraction-negative hypothermia cases and 175.4 grams in controls, and the difference could not be explained by age differences between the groups.

The scientific groundwork for this conclusion was laid decades ago, though it was largely forgotten. In 1944, the German researcher Wendt demonstrated experimentally in rabbits that whole-body cooling reduced spleen volume by up to one third, with the most pronounced contraction occurring at core temperatures of 24 to 26 degrees Celsius, and that the organ regained its normal size after rewarming. Subsequent animal studies by Varman and Bernshtein corroborated the spleen’s reservoir role under hypothermic conditions, showing decreases in splenic weight and volume accompanied by rising circulating hemoglobin concentrations. Isolated human case reports followed, including Horn’s account of a 49-year-old sailor who died of cold exposure after falling overboard, and retrospective series by Gillner and Waltz and by Schneider and Klug that noted contracted spleens in a minority of hypothermia deaths. Two doctoral dissertations touched on the finding, but neither provided the prospective, controlled evidence needed to establish its diagnostic value, and major forensic textbooks continued to relegate splenic contraction to quotation marks and question marks—or to omit it entirely.

The practical implications for forensic practice are considerable. Hypothermia deaths are frequently misinterpreted at first glance, particularly when the scene suggests sudden natural death, acute intoxication, or even violence. Cold erythema and ecchymosis-like discolorations on the limbs can mimic traumatic injuries, occasionally raising suspicion of assault. In such ambiguous situations, the conditions that mimic hypothermia typically produce a congested, blood-filled spleen, whereas a contracted, pale, wrinkled spleen points decisively in the opposite direction. Because the contracted spleen is readily visible the moment the abdominal cavity is opened—sometimes alongside reverse Wischnewsky spots visible through the gastric wall—its early recognition can redirect the differential diagnosis toward hypothermia and prompt targeted dissection of the back and core musculature, inspection of the knee joints, and supplementary histological and toxicological analyses. The authors also suggest that the finding could support minimally invasive postmortem approaches, such as laparoscopic inspection of body cavities combined with postmortem imaging, where early visual cues carry exceptional value.

Modern imaging may soon extend this diagnostic reach even further. Preliminary work with postmortem computed tomography has reported elevated splenic radiodensity in hypothermia deaths, consistent with a denser, more compact parenchyma produced by contraction, and the present study’s exploratory imaging data showed compatible tendencies, though the small number of cases precluded statistical analysis and will be reported separately. The researchers are careful to emphasize the limits of their work: the study was conducted at a single institution, the macroscopic assessment was not blinded, interobserver agreement was not formally measured, and histological examination of the spleen was performed only in the hypothermia group. Splenic contraction is not pathognomonic and must never be interpreted in isolation. Nevertheless, with nearly nine out of ten hypothermia deaths showing the triad and fewer than two percent of controls doing so, the evidence strongly supports adding routine splenic assessment to the forensic autopsy protocol—transforming an organ long dismissed as morphologically unremarkable into a quiet but eloquent witness to death by cold.

Subject of Research: Validation of reactive splenic contraction as a diagnostic autopsy sign of fatal hypothermia

Article Title: Spleen contraction verified as a supportive autopsy sign of fatal hypothermia

Article References: Zátopková, L., Kučerová, Š. P., Kovařík, D., Pažinová, J., Pitková, R., Bačinová, P., Janík, M., & Hejna, P. (2026). Spleen contraction verified as a supportive autopsy sign of fatal hypothermia. International Journal of Legal Medicine. https://doi.org/10.1007/s00414-026-03984-x

Image Credits: AI Generated

DOI: 10.1007/s00414-026-03984-x

Keywords: hypothermia, forensic pathology, spleen, splenic contraction, autopsy, Wischnewsky spots, cold erythema, postmortem diagnosis, forensic medicine, blood reservoir, postmortem imaging, legal medicine