Asphyxia and Asphyxial Death Overview

Asphyxia and Asphyxial Death

• Asphyxia is the interference with the mechanism or function of respiration, leading to a lack of tissue oxygenation.
• The respiration process involves oxygen from the atmosphere reaching the tissues via the respiratory system, heart, and blood.
• Causes of asphyxia include defective cellular oxygenation (poisoning), mechanical obstruction (neck compression, strangulation, or closure of respiratory orifices, or interference with respiratory movements), and other causes.
• Stages of asphyxia typically progress through dyspnea, convulsions, and ultimately apnea.
• Pathophysiology involves increasing carbon dioxide and decreasing oxygen, reduced hemoglobin (cyanosis), center paralysis in the brain, and eventually death.
• Diagnosis of asphyxia includes a history review, circumstantial evidence, complete autopsy, and toxicology tests.
• External signs of asphyxia include a swollen or cyanosed face, prominent eyeballs, swollen and potentially bitten tongue, froth around the mouth and nostrils, and cyanosed lips, ears, and fingernails.
• Internal signs of asphyxia include hypoxia, elevated pulmonary blood pressure, right-sided heart failure, pulmonary edema, froth in the air passages, and enlarged lungs with right ventricular dilation.
• Classical external signs of asphyxia include petechial hemorrhaging, froth, blue/dark hypostasis, swollen face, cyanosis, relaxed sphincters, and blood, dark fluid filling right side of the heart with petechial hemorrhage.
• Atypical drowning involves fluid not entering the lower respiratory tract, often due to laryngospasm. Drowning can be primary (occurring within minutes of submersion), or secondary (occurring half-hour to several weeks after submersion).
• Signs of immersion may include cold, pale skin (except in areas of hypostasis), granular/puckered skin, wrinkled/sodden skin, and peeling of epidermis (glove/stocking distribution).
• Highly suggestive signs of drowning include cadaveric spasm (on vegetation), fine, odorless, white or rarely blood-stained froth, and increased frothing during chest compression due to mixing of air, mucus, and water.
• Sure signs of drowning include frothy lungs, and signs of congestion with petechial hemorrhaging, sand, mud, and aquatic weeds in the respiratory bronchioles, voluminous/fluid-filled lungs, and rib impressions in the lateral surfaces.
• The Diatom test is unreliable in diagnosing drowning due to numerous false positives.
• Diagnosis (post-mortem) may assess external signs (e.g., peeling, or frothy discharge from an open wound) and internal signs (e.g., lungs containing water, froth or sand).
• Medico-legal investigations determine if death was due to drowning, the manner of drowning, and the duration of immersion.
• Suspected drowning cases analyze if death was suicidal, homicidal, or accidental, considering history, circumstantial evidence, struggle signs, and trauma.

Drowning

• Drowning is a death due to submersion in water. Complete submersion isn't always necessary.
• Types include wet drowning (hypoxic death, evident signs) and dry drowning (fluid not aspirated, laryngospasm).
• Primary drowning occurs within minutes of submersion. Secondary drowning occurs within half an hour to several weeks.
• Diagnosing drowning involves assessing immersion signs like skin changes and signs of frothing. Internal signs include filled lungs, sand, mud or aquatic weeds.
• Diatom test is unreliable.