Wischnewski spots and hypothermia: sensitive, specific, or serendipitous?

Abstract

Hypothermia develops when regulatory mechanisms suchas vasoconstriction and heat production fail to compensatefor heat loss to the environment and the core temperature ofthe body falls below 35 C. Severe cases may be fatal withdeath resulting from myocardial ischemia and/or hypoxia,exacerbated by electrolyte abnormalities and elevated cat-echolamine levels. The mortality rate exceeds 70 % whenthe core temperature drops to 30 C, and reaches 90 % at26 C[1, 2].Causes of hypothermia include accidental exposure tolow environmental temperatures, either outdoors or inside,the latter occurring from inadequately heated houses. It hasbeen shown that hypothermic deaths may occur in areaswhere the external temperatures are not markedly lowered.Exacerbating factors include damp conditions, inadequateor wet clothing and air movement [3]. Individual suscep-tibility is increased by the ingestion of alcohol and certainprescribed or illicit drugs. In addition, low muscle mass,immobility, trauma, open injuries, and certain cardiovas-cular, neurological, endocrine and psychiatric disordersincrease the risk. An age-related susceptibility is alsofound, with children and the elderly being the most vul-nerable [1].The pathological diagnosis of hypothermia may be dif-ficult, as body temperatures at the time of death are usuallynot available at autopsy and so the circumstances of deathare of considerable importance in formulating the diagno-sis. In addition, morphological features are subtle and notwell understood. Characteristic findings that have beendescribed at autopsy include pinkish discoloration of theskin over the extensor surfaces of large joints, such as theelbows, knees and hips, acute pancreatic inflammation withfat necrosis, fatty change in cells of the heart, liver andkidneys, skeletal muscle hemorrhage, vacuolization ofrenal tubular cells, and superficial gastric lesions that havebeen called Wischnewski spots [1, 2, 4–7]. It is the latterfinding that we would like to examine in greater detail.In 1895 a Russian district medical officer, SM Wisch-newski, reported multiple superficial hemorrhagic lesionsof the gastric mucosa in 91 % of the cases of fatal hypo-thermia that he had examined. A contemporary translationof his original paper states: ‘‘On the mucous membrane ofthe stomach in humans who have died exclusively from theeffects of low temperatures, 5–100 hemorrhages areinvariably present. Their size ranges from 0.5 to 1.0 cm.They have a round to oval form. Sometimes they arepunctiform and lie about 1–2 inches apart. These hemor-rhages are raised slightly above the surface of the mucousmembrane, can be very easily scrapped (sic) away andleave behind nothing conspicuous on the gastric mucosa.’’[8] (Fig. 1). They have also been documented in ectopi-cally situated gastric mucosa [9].Although Wischnewski described raised hemorrhagicareas that could be easily removed from the mucosa, theywere subsequently considered to be ulcers or erosions[3, 10, 11]. In an immunohistochemical study by Tsokoset al. however it was proposed that the lesions resultedfrom the action of gastric acid on hemoglobin in areas ofinterstitial mucosal hemorrhage, and not from ulceration[7]. A photomicrograph in a chapter by Madea et al. [2](Fig. 1.4B) clearly demonstrates protrusion of one of thespots above the surface of the surrounding mucosa, and notulceration. Conversely, Hirvonen and Elfving reportedthat the erosions extended ‘‘halfway through the mucosa’’and that hemorrhage was ‘‘not always present’’ [12].