One possible scenario that may explain this situation is that the patient was in hypothermia, which went unrecognized, and the patient died later on.

Hypothermia in adults is defined as core temperature below 35°C. Hypothermia can be mild (core temperature 32 to 35°C), moderate (core temperature 28 to 32°C) and severe (core temperature below 28ºC).

The clinical staging scheme described by the International Commission for Mountain Emergency Medicine describes Stage 1 hypothermia as mild hypothermia with normal mental status with shivering, moderate or stage 2 hypothermia as impaired mental status, shivering may be or may not be present. In stage 3 hypothermia (severe; core temperature 24 to 28°C), the person is unconscious. Stage 4 hypothermia (severe; core temperature 13.7 to 24°C) is apparent death but resuscitation may be possible. While,stage 5 hypothermia is death due to irreversible hypothermia and it is not possible to resuscitate the person.

Cooling decreases tissue metabolism and inhibits neural activity. In mild hypothermia, shivering due to skin cooling generates heat and increases metabolism, ventilation, and cardiac output. As the body temperature falls, the cold slows down metabolism. Once the core temperature reaches 32°C, metabolism, ventilation, and cardiac output begin to decline and shivering becomes less effective in retaining heat until it finally stops as core body temperature continues to decline. For each 1°C fall in body temperature, the body metabolism slows by around 6%; at 28°C, the basal metabolic rate is about half of normal.

Neurologic function begins declining even above a core temperature of 35°C. Patients often lose consciousness; vital signs may be absent. Presence of muscle rigidity without shivering can be mistaken for rigor mortis. The absence of shivering and presence of stupor, skin flushing, muscle rigidity, hypoventilation, and circulatory failure means very cold patients often appear dead rather than hypothermic. But in this stage of severe hypothermia (core temperature <28°C or 82°F), a suspended metabolism may protect against hypoxia.

Stage 4 hypothermia must be excluded, which is the stage where it is still possible to revive the patient. Failure to recognize the condition of hypothermia may be the reason why severely hypothermic patients are sometimes pronounced dead. It may be possible to successfully revive a person if recognized in time. No patient therefore should be declared dead without measuring rectal temperature.

The cadaveric signs are algor mortis (cooling of the body after death), rigor mortis (rigidity, which begins within 2 hours of death and lasts for about 24 hours), liver mortis (lividity or pooling of blood in the dependent parts of the body; it is most evident after 2 hours of death and becomes fixed within 4-6 hours), cadaveric spasm and putrefaction. These postmortem changes begin soon after death and progress along a timeline but factors like ambient temperature may affect their development. 

So, could this be a case of erroneous or misinterpretation of postmortem findings?

Dr KK Aggarwal

Padma Shri Awardee Vice President CMAAO Group Editor-in-chief IJCP Publications

President Heart Care Foundation of India

Immediate Past National President IMA