Asphyxia and Asphyxial Death Overview

Asphyxia and Asphyxial Death

• Asphyxia is the interference with respiration, resulting in a lack of tissue oxygenation.
• It involves a disruption in the respiratory process, impacting oxygen intake and tissue oxygenation.
• The respiratory process involves the path of oxygen from the atmosphere, through the respiratory system (RS), heart, and blood to the tissues.

Learning Objectives

• Students should learn the definition, classifications, pathogenesis, and clinical picture of asphyxia.
• Students should be able to diagnose asphyxia early to provide timely emergency treatment.
• Students should understand the different types of violent asphyxia, drowning (mechanism, death, post-mortem appearance, and medico-legal significance).

Asphyxia - Definition

• Asphyxia is the interference with the mechanics or function of respiration.
• This results in the lack of oxygenation of tissues.
• This is represented by the interruption or stoppage of oxygen receiving, use, and transport mechanism.

Respiration Process

• Oxygen intake involves the respiratory system (RS), specifically the center, muscles, and tract.
• Oxygen is then circulated to the heart.
• The heart helps to circulate oxygen throughout the body through the blood stream.
• Tissues utilize circulated oxygen.

Causes of Asphyxia

• Cellular-level oxygenation defects, like poisoning.
• Mechanical obstruction by neck compression (e.g., hanging, strangulation).
• Mechanical restriction in openings for respiration (e.g., smothering).
• Interference with respiratory movements (e.g., traumatic "crush" asphyxia).

Stages of Asphyxia

• Dyspnea, difficulty breathing
• Convulsions
• Apnea
• Final stage

Pathophysiology of Asphyxia

• Increased carbon dioxide (PCO2) and decreased oxygen (PO2).
• Reduction in respiratory centers (RC) and ventilation muscles (VMC).
• Reduced hemoglobin saturation, causing cyanosis.
• Central paralysis and subsequent death.

Diagnosis of Asphyxia

• Detailed history and circumstantial evidence.
• Complete autopsy.
• Toxicological analysis.

General Signs of Asphyxia (External)

• Swollen, cyanosed face.
• Prominent eyeballs and petechiae (small red spots) in conjunctiva.
• Swollen or bitten tongue.
• Froth around the nose and mouth.
• Deep cyanosis (bluish discoloration) of lips, ears, and fingernails.

General Signs of Asphyxia (Internal)

• Hypoxia (low oxygen) leading to pressure increase in pulmonary blood vessels.
• Right-sided heart failure.
• Pulmonary edema (fluid in lungs).
• Froth in airways.
• Over-inflated lungs.
• Right ventricular dilation.

Classical Signs of Asphyxia

• (External)*
• Petechial hemorrhage, froth, and dark hypostasis (bluish discoloration).
• Swollen face, cyanosis, and relaxed sphincters.
• (Internal)*
• Dark blood and fluid filling the right side of the heart, petechial hemorrhage.
• Congested viscera and air passages, spots, and cyanosis.

Violent Asphyxia Deaths

• Violent asphyxia encompasses various methods: hanging, strangulation, throttling, smothering, choking, and traumatic asphyxia.

Drowning

• Death due to submersion of the mouth and nostrils under water.
• Complete body submersion isn't always necessary.

Types of Drowning

• (Wet)*
• Typical drowning, involving aspiration of fluids.
• Hypoxic death results from the disruption of normal oxygen-intake.
• Evidence of drowning is visible and identifiable.
• (Dry)*
• Atypical drowning with no aspirated fluid in lower respiratory tract.
• Laryngospasm (sudden spasm of the larynx) can occur from stimulation by immersion fluids.
• Drowning signs are either absent or minimal.

Types of Drowning (cont'd)

• *(Primary)**.
• Drowning that occurs quickly after submersion.
• Treatment and resuscitation attempts will frequently fail.
• (Secondary)*
• Drowning occurring hours or even days after submersion.
• Successful initial treatment attempts may fail later.
• Secondary drowning can result from a combination of factors, like severe lung infections, metabolic acidosis, pneumonia, and pulmonary edema.

Diagnosis of Drowning (Signs of Immersion)

• Cold, pale skin, except for a hypostasis area (where the body's heavy part is pressed to the ground).
• Granular and puckered skin (goose skin).
• Wrinkled and sodden skin.
• Peeling skin, like gloves and stockings.

Diagnosis of Drowning (Highly Suggestive Signs)

• Cadaveric spasm (sudden muscle contraction).
• Froth in the mouth, nose, or throat; usually fine, odorless, and white.
• Froth increases with chest compression.
• Mixture of air, resulting from forcible attempts at respiration.

Diagnosis of Drowning (Sure Signs)

• *(Air Passages)**.
• Filled with froth in the lungs.
• Congestion caused by petechial hemorrhage.
• Contains sand, mud, and aquatic weeds that permeated the respiratory bronchioles.
• *(Lung)**.
• Voluminous and filling the thoracic cavity and surrounding the bare heart area.
• Emphysema aquosum.
• Lateral surfaces show rib marks.

Diatom Test

• Diatoms (unicellular microorganisms with silica-based shells) can penetrate alveolar walls and spread to organs (especially the brain) during live drowning.
• The test's reliability is questionable and often yields false positives or negatives.

Diagnosis (Post Mortem) External Signs

• Peeling skin lesions.
• Dark, stained skin, indicative of staining from immersion.
• Froth, especially putrefactive froth.

Diagnosis (Post Mortem) Internal Signs

• Sure signs of drowning in the body.

Medico-Legal Issues in Drowning Deaths

• Determining if death was due to drowning.
• Determining the manner of drowning (e.g., suicide, homicide, accident).
• Establishing the duration of submersion.
• Identifying any contributing factors (e.g., drugs).

Suicidal, Homicidal, or Accidental Drowning

• Determining the cause of drowning: suicide, homicide, or accident.
• Factors relevant include history, circumstantial evidence, struggle signs, body trauma, and laboratory tests (drug detection).

This quiz covers the definition and classification of asphyxia, focusing on its impact on respiration and tissue oxygenation. Students will learn the pathogenesis and clinical picture associated with asphyxia, as well as methods for diagnosis and emergency treatment. Additionally, the quiz explores types of violent asphyxia and their medico-legal significance.