For more than 100 years since their initial description, gastric mucosal petechial hemorrhages have been discovered at autopsy in cases where environmental hypothermia was determined to be the cause of death. Although these lesions are frequently seen in deaths caused by environmental hypothermia, they can also be seen in cases where hypothermia is not implicated; however, this has been seldom described. We present a series of autopsy cases where hypothermia has been conclusively ruled out as a cause of death, in which Wischnewsky lesions are found. In all of these cases, diabetic ketoacidosis (DKA) was determined to be the proximate cause of death, as confirmed through clinical history, laboratory analysis, and absence of other anatomic or toxicological findings. We provide a mechanism of Wischnewsky lesion formation and how that mechanism relates to both hypothermia and ketoacidosis. Our data show that gastric mucosal petechial hemorrhages are not specific for hypothermia-related deaths, and are likely indicative of a state in which hypothermia and DKA have a common underlying pathophysiology, most likely a coagulopathy. Our data also illustrate that in autopsy cases where Wischnewsky lesions are found, DKA should be seriously considered as the underlying cause of death, particularly in the absence of indications of environmental hypothermia.