Agonal Period
Definition
The final period of physiological life between loss of consciousness and cardiac arrest. Injuries inflicted in this period are legally antemortem but may show absent or attenuated vital reaction because of the compromised circulatory state.
- Defined as
- Between loss of consciousness and cardiac arrest
- Legal status of injuries in this period
- Antemortem
- Physiological effect
- Compromised circulation
- Forensic implication
- Vital reaction may be absent or attenuated
Common questions
Why would an injury inflicted while the person is still alive show no vital reaction?+
Vital reactions such as bruising and inflammatory response depend on functioning blood flow and cellular metabolism, both of which are failing during the agonal period, so an injury can be legally antemortem yet appear histologically similar to a postmortem wound.
Why does this matter in distinguishing antemortem from postmortem injury?+
An examiner who relies solely on the presence or absence of vital reaction to classify wound timing risks misclassifying a genuine antemortem agonal-period injury as postmortem, so the circumstances and other injuries must be weighed alongside histology.
Related terms
- Fibronectin
- Glycoprotein deposited in wound matrix within 12-24 hours of antemortem injury. Detectable by immunostaining; serves as an intermediate-stage vital-reaction marker when PMN...
- Histamine Vital-Reaction Marker
- Biochemical indicator released from mast cells within minutes of tissue injury. A 50% or greater histamine elevation at the wound margin versus...
- Perimortem Window
- The brief interval before and immediately after cardiac arrest in which injuries may be inflicted during life but produce absent or minimal...
- PMN (Polymorphonuclear Neutrophil) Infiltration
- The first histological cellular marker of antemortem vital reaction. Begins emigrating from wound-margin venules within 1-2 hours of injury; histologically visible at...
- Vital Reaction
- The suite of physiological responses to tissue injury that require a functioning cardiovascular and cellular metabolism to occur: haemorrhage, neutrophil infiltration, vasoactive...