Asphyxia I Dr. Asmaa Fady Ph D., MSC, M.B, B.Ch

Learning objectives: By the end of the lecture, the student should Know Definition, Classifications, pathogenesis & clinical picture of asphyxia. Diagnosis of asphyxia as early as possible in order to give the emergency treatment in time. Types of violent asphyxia. Drowning (mechanism of infliction, mechanism of death, postmortem appearance and medico-legal importance) اسم ورقم المقرر – Course Name and No. 6/1/2019

Asphyxia- Definition: Interference with mechanism or function of respiration (lack of tissue oxygenation) Failure of tissues to receive mechanism function utilize

RS (center, muscles & tract) Respiration process Oxygen in atmosphere RS (center, muscles & tract) heart blood tissues

Causes of asphyxia Defective oxygenation at cellular level as in CO & CN poisoning. Mechanical obstruction by neck compression (Hanging, Strangulation (manual, ligature). Mechanical obstruction by closure of external respiratory orifices: (Smothering). Mechanical obstruction by interference with respiratory movements (Traumatic "Crush" asphyxia).

Stages of asphyxia ( 4- 5 min.) dyspnea Convulsions Apnea Final stage Study them from PDF.

Pathophysiology of asphyxia PCO2 & PO2 RC & VMC Reduced Hb (cyanosis) Brain Motor areas (convulsions) Center paralysis Death

Diagnosis (Classical asphyxia signs) History Circumstantial evidences Complete autopsy Toxicology General signs of asphyxia: External signs: -Swollen, cyanosed face -Prominent eye balls with conjunctival petechiae -Swollen, sometimes bitten tongue -Froth oozes from mouth nostrils. -Deeply cyanosed lips, ears and finger nails. Internal signs: Hypoxia → increase in pulmonary blood pressure → right heart failure → pulmonary edema, froth at air passages, over distended lungs and right ventricular dilatation.

General (classical) signs of asphyxia internal B(blood dark & fluid, filling Rt side of heart, peticheal hge ) C( congested viscera & air passages, spots, cyanosis) external B (peticheal hge, bloody froth, blue dark hypostasis) C( swollen face, cyanosis, sphincters are relaxed )

General signs of asphyxia

General signs of asphyxia

Violent asphyxia deaths Neck violence Hanging strangulation throttling drowning suffocation smothering chocking Traumatic asphyxia

Death due to submersion of mouth & or nostrils under water Drowning Death due to submersion of mouth & or nostrils under water

Types of drowning Wet "Typical" drowning→ aspiration of the drowning fluids → hypoxic death "cause of death“ (signs of drowning are evident) Dry "atypical" drowning:- Fluid was not aspirated into the lower respiratory tract. Causes of death in such condition: Laryngospasm: as a result of sudden entry of fluid into the nose and upper airways. (signs of drowning are absent or minimal) اسم ورقم المقرر – Course Name and No. 6/1/2019

Atypical drowning (usual drowning signs are absent laryngospasm Blow to trigger area Fear Cold water

Types of drowning Primary drowning: Occurs within minutes of submersion No treatment or resuscitation has made Secondary drowning: Occurs within half an hour to several weeks of submersion Death occur after trial of treatment or resuscitation Combination of causes: usually severe lung infection, Metabolic acidosis, pneumonia, pulmonary edema. اسم ورقم المقرر – Course Name and No. 6/1/2019

Diagnosis of drowning Signs of immersion "not sure": *Found in any body immersed in water whatever breaths or not at the time of immersion: *Skin appears as: Cold, pale except in area of hypostasis Granular & puckered i.e. goose skin (cutis anserine) Wrinkled, pleached & sodden (Washerwoman skin) Peeling of epidermis: gloves & stockings

Diagnosis of drowning Highly suggestive signs of drowning: Cadaveric spasm: on weeds, mud, sand, …etc Froth Fine, odorless, white or rarely blood stained Increase with chest compression Results from mixing of air, mucus and water during forcible attempts at respiration

Diagnosis of drowning Sure Characteristic signs: Air passages: Full of froth. Congested with petechial hge. Contain sand, mud and aquatic weeds till bronchioles. Lung: Voluminous, filling the thoracic cavity and covering the bare area of the heart. It was called “emphysema aquosum). Lateral surfaces are marked with rib impressions (one of the most valuable +ve signs) Diatom test +ve: When a live person is drowned in water containing diatoms (unicellular microscopic algae, with a silicaceous exoskeleton), diatoms can penetrate the alveolar walls and be carried by circulating blood to distant organs such as brain and bone marrow. 6/1/2019

Diagnosis (post mortem) external signs Signs of immersion

Diagnosis (post mortem) external signs

Diagnosis (post mortem) external signs D.D from putrefactive froth

Highly suggestive signs

Diagnosis (post mortem) internal signs

MLI of Drowning Whether death was due to drowning?? Manner of drowning??? Duration of immersion???

If the case is drowning, is it suicidal, homicidal or accidental? This question is very difficult to be answered but many points may be of help:- Suicidal: * Common * History & circumstantial evidences * Previous trials for suicide * No signs of struggle or body trauma Accidental: * The commonest * History & circumstantial evidences * No signs of struggle * May be signs of body trauma Homicidal: Less evident than suicidal & accidental cases History & circumstantial evidences Signs of struggle and/or body trauma Laboratory detection of certain drugs in the blood of the victim?! اسم ورقم المقرر – Course Name and No. 6/1/2019

اسم ورقم المقرر – Course Name and No. 6/1/2019