Asphyxia Drowing Lesson 2 General signs of Asphyxia

Asphyxia & Drowing Lesson 2 General signs of Asphyxia Dr Nadir Ali Rana

PATHALOGY OF ASPHYXIA 1) Non-specific (general) pathological changes. 2) Specific pathological changes.

General pathological changes: § § § These are the histological changes in tissues associated with decreased oxygen level. These indicate the asphyxial mode of death Nervous tissue & small blood vessels i. e. venules & capillaries are extremely sensitive to O 2 lack. Reduced oxygen supply can lead to following changes:

ØCyanosis. Congestion. ØGeneralized edema (Lungs, Brain). ØPetechial Hemorrhages (Tardieu spots). ØFluidity of blood. Changes are more prominent if the agonal period is prolonged.

1. CYANOSIS • The word “cyanosis” is derived from Greek meaning “dark blue”. • It is the colour imparted to the tissues by the presence of an excess of deoxygenated blood. • Development of cyanosis requires minimum concentration of 5 g/100 ml of reduced Hb. • It is easily visible in the skin & in mucus membrane.

CYANOSIS

CYANOSIS

CYANOSIS

CYANOSIS

CONGESTION

2. CONGESTION Reduction in oxygen tension produces dilatation and stasis of capillaries & venules which results in engorgement (pooling) of blood in these vessels. This engorgement of blood vessels particularly of venous side is called congestion.

2. CONGESTION (Cont. ) Reduced oxygenation of the tissues Capillary dilatation Stasis and pooling of blood Reduced venous return to heart Reduced pulmonary blood flow Deficient oxygenation

Congestion

Congestion

3. GENERALIZED EDEMA Reduced oxygenation of the tissues Capillary dilatation Stasis and pooling of blood Increase intravascular pressure (Continued on next page)

3. GENERALIZED EDEMA Hypoxia + Intravascular pressure Enlargement of pores between the endothelial cells Increase vascular permeability Transudation of plasma into the tissue spaces Generalized Edema

3. GENERALIZED EDEMA It may be responsible for congestive facial swelling, bulging of the tongue, brain and lung edema. It is more prominent if the agonal period is prolonged.

4. PETECHIAE (Tardieu Spots) If all the factors, as already mentioned, are maintained, the capillary walls rupture causing blood leaks of small size out of these vessels, known as petechial heamorrhages In the tissues, they are found as rounded, dark red, well defined and of pinhead size spots. which are also known as “Tardieu Spots” after the name of French police surgeon who described them in 1866.

4. PETECHIAE (Tardieu Spots) • They are generally found in those parts where capillaries are least supported, e. g. face, conjunctivae, epiglottis, serous surfaces of heart and lungs. • They are more pronounced / marked in those areas where intracapillary pressure rises rapidly e. g. above the level of constriction of neck, and chest in traumatic asphyxia.

Subconjuctival Petechiae

Subconjuctival Petechiae

Petechiae on the Face

Petechiae on Eyelids

Petechiae on Mucous Membrane

5. FLUIDITY OF BLOOD • Frequently seen in asphyxial deaths. • It is result of fibrinolytic activity of the enzyme fibrinolysin. • It is so non-specific that no longer regarded as asphyxial sign.