Cherry-Red Livor Mortis
Definition
Bright pink-red post-mortem lividity produced by the spectral absorption shift of carboxyhaemoglobin; also seen in cyanide poisoning and hypothermia. Distinguished from natural blue-purple lividity by co-oximetry measurement.
- Cause
- Carboxyhaemoglobin absorption shift
- Also seen in
- Cyanide poisoning, hypothermia
- Colour
- Bright pink-red, vs normal blue-purple
- Confirmation
- Co-oximetry measurement
Common questions
Why does hypothermia also produce a cherry-red type of lividity?+
Cold impairs tissue oxygen extraction and skin metabolism in a way that keeps haemoglobin more oxygenated in the peripheral vessels, producing a similarly bright red-pink discolouration even without carbon monoxide or cyanide being present.
Is cherry-red lividity a reliable field diagnosis of carbon monoxide poisoning?+
It is a useful visual cue that should prompt suspicion, but because cyanide and hypothermia can mimic it, the colour alone is not diagnostic and must be confirmed by co-oximetry or toxicology before it is reported as a cause of death.
Related terms
- Bitter-Almond Odour
- The characteristic smell of hydrogen cyanide, detectable at autopsy in approximately 40% of people (a genetically determined anosmia to HCN). Present in...
- Carboxyhaemoglobin (COHb)
- The compound formed when carbon monoxide binds to haemoglobin at the oxygen-binding site, with an affinity 200-250 times greater than oxygen. Produces...
- Co-Oximetry
- Spectrophotometric analysis of blood that simultaneously quantifies oxyhaemoglobin, deoxyhaemoglobin, carboxyhaemoglobin, methaemoglobin, sulphhaemoglobin, and total haemoglobin by their distinct absorption wavelengths. The primary...
- Cytochrome C Oxidase (Complex IV)
- The terminal electron acceptor in the mitochondrial respiratory chain, inhibited by both cyanide and hydrogen sulphide. Inhibition prevents oxidative phosphorylation and ATP...
- GC-FID
- Gas chromatography with flame ionisation detection. The standard analytical method for quantifying cyanide and methanol in blood and tissue specimens. Provides both...
- Knockdown Pattern (H2S)
- The scene distribution of multiple H2S victims clustered at the entrance or access point of a confined space, as first responders and...
- Sulphhaemoglobin (SHb)
- A modified haemoglobin species in which one or more pyrrole rings is sulphonated by reaction with hydrogen sulphide. Produces green-brown blood and...