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

2. 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

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

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

5. 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).

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

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

8. 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.

9. 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 )

10. General signs of asphyxia

11. General signs of asphyxia

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

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

14. 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

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

16. 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

17. 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

18. 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

19. 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

20. Diagnosis (post mortem) external signs Signs of immersion

21. Diagnosis (post mortem) external signs

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

23. Highly suggestive signs

24. Diagnosis (post mortem) internal signs

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

26. 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

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