Postmortem changes in bruises and consequences of organ contusions
THE CONTEXT
Bruise appearance can change after death, and deep contusions can cause severe functional injury despite limited external evidence.
Postmortem extension and detection
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Putrefaction gases can push extravasated blood along tissue spaces, exaggerating the apparent extent of antemortem bruising.
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Haemolysis of extravasated red cells and diffusion of pigment can also extend a bruise after death. The postmortem interval must therefore be considered when assessing its extent.
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Ultraviolet examination of the whole body can sometimes reveal otherwise undetectable bruising.
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At autopsy, drainage of blood from surrounding vessels can make contusions more prominent. Deep contusions also become clearer because of postmortem autolytic changes.
Haemorrhage caused by procedures or handling
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Surgical removal of corneas for transplantation can cause eyelid haemorrhage resembling antemortem trauma.
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Removal of vitreous soon after death can cause scleral haemorrhage.
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In fat persons, lifting the body can tear small skin veins and cause haemorrhages in areas of lividity on the arms or shoulders, without trauma elsewhere.
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Blood within contusions does not drain with blood in surrounding vessels, allowing deep bruises to stand out against pale areas at autopsy.
Deep tissue and organ injury
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All organs can be contused.
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Brain contusion can initiate swelling and accumulation of acidic metabolic by-products, leading to further swelling, impaired function, confusion, coma and death.
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Even very small contusions in vital centres controlling respiration or blood pressure can be fatal.
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A small heart contusion can seriously disturb rhythm or stop cardiac action. Large contusions may prevent adequate cardiac emptying and cause heart failure.
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Contusions of other organs may cause rupture and slow or rapid bleeding into a body cavity, potentially causing death.