Complications, Embolism & Forensic Differentials

Complications of Wounds

A. Shock

Complications of Wounds

A- SHOCK:

1. Neurogenic or primary shock
2. Hematogenic shock or secondary shock
3. Hemorrhagic or oligaemic

B- Embolism:

1. Air embolism
2. Fat embolism
3. Thromboembolism

C- Infection.

D- Crush syndrome.

1. Neurogenic or Primary Shock:

Definition: It is a reflex neurovascular disturbance which follows immediately after an injury.

Differences between Parasympathetic and Sympathetic Shock:

Criteria	Parasympathetic Shock	Sympathetic Shock
Mechanism	Parasympathetic (vagal) stimulation → inhibition of the heart & circulation	Sympathetic stimulation → stimulation of the heart & circulation
Causes	1- Severe emotions 2- Rise of pressure in carotid sinuses. 3- Stimulation of trigger areas (ear, larynx, pericardium, epigastrium, testis, cervix and urethra) as in: - Application of pressure on the neck - Unexpected blows to trigger areas - Foreign bodies in the air passages. - Cervical dilatation as criminal abortion or dilatation and curettage. - Immersion in icy water	1- Severe pain. 2- Severe fright.
Clinical picture	- Pallor - Bradycardia - Sudden hypotension - Sweating - Nausea - Vertigo	- Anxiety - Tachycardia - Hypertension - Sweating - Tremors - Abdominal discomfort - Dilatation of pupil.
Cause of death	Usually death doesn’t occur because; ventricles escape the shock state as they don’t have vagal innervation. If ventricular escape does not occur → rapid death from acute circulatory failure.	Ventricular fibrillation particularly if the patient suffers from cardiac disease.

3. Hemorrhagic (Oligaemic Shock)

Factors Affecting the Gravity of Hemorrhage:

a- Amount of blood lost:
The loss of 2 liters (one third of the total blood volume) is dangerous to life.

b- Rate of hemorrhage:
Rapid loss of blood is more serious because no time is allowed for compensation $\to$ shock

c- Site of hemorrhage:
Internal hemorrhage is more serious than external due to pressure over the organs:

• 1/2 liter of blood in the pleural or peritoneal cavities is fatal.
• 1/4 liter of blood in the pericardial sac is fatal.
• 100 ccs in extradural space is fatal.
• Few ccs in the brain substance is fatal.

d- General condition of the patient:
Healthy adults can tolerate hemorrhage more than children and old people.

e- Sex: Females tolerate hemorrhage than males.

Types of Hemorrhage:

1- Primary hemorrhage: It is directly due to the wound, it is either internal or external.

2- Secondary hemorrhage:

• It is due to sepsis of the wound → dissolve the blood clot by the lytic enzymes of the organisms → patent blood vessels → bleeding
• It occurs after a time of wound infliction (days, weeks; commonly at 10-16 days)

3-Reactionary hemorrhage:

• There is minimal bleeding at the time of injury due to associated shock state.
• After about 10 hours, the person starts to bleed again (due to rise of blood pressure after recovery from the shock stage) → dislodgement of the blood clot that has been formed to close the cut vessel.

Clinical picture same as hematogenic shock

B. Embolism

1. Thromboembolism:

Causes: Prolonged recumbency in bed.

Mechanism of death Prolonged recumbency in bed → deep vein thrombosis → detached → pulmonary embolism after about 10 days of the injury or may be earlier (2-3 days).

2. Fat Embolism:

Causes:

• Fracture of a long bone with torn vein. - Trauma to a fatty area.
• Burns in a fatty area

Mechanism of death: Acute heart failure is due to obstruction of the right side of the heart and pulmonary artery with fat.

3. Air Embolism:

a- Venous air embolism b- Arterial air embolism

Air Embolism and Infection

Differences between Venous and Arterial Air Embolism

	Venous air embolism	Arterial air embolism
Causes	- Cut throat (cut jugular vein $\to$ suction of air due to the negativity of intrathoracic pressure) - I.V. infusion. - Tubal insufflation. - Criminal abortion.	- During artificial pneumothorax, if the needle is passed in a pulmonary vein. - Stab transfixing wound connecting a bronchus with a pulmonary vein.
Fatal amount	100-200 ccs	few ccs
Mechanism of death	Air fills right side of the heart and pulmonary arteries $\to$ obstruction of pulmonary circulation $\to$ acute heart failure.	Occlusion of coronary and cerebral arteries by air.

N.B.

• To save a case of venous air embolism, put the patient in left lateral position, so the level of pulmonary artery will be lower than right ventricle $\to$ air will be absorbed from the heart gradually.
• In case of arterial air embolism put the patient in left lateral position with head down.

C- Infection

Contused and lacerated wounds are the most liable to severe infection particularly, tetanus and gangrene due to devitalized tissue of wound

C- Crush Syndrome

• severe crushing of muscles ⇒ liberation of myoglobin ⇒ blocking of renal tubules ⇒ acute renal failure

Forensic Medicine: Differences between Homicidal, Suicidal, Ante-mortem, and Postmortem Injuries

Overview of Key Differences

The distinction between homicidal and suicidal injuries, as well as between ante-mortem and postmortem wounds, is crucial in forensic medicine. These distinctions help in the investigation of deaths and in determining the cause and manner of death.

Differences between Homicidal and Suicidal Injuries

Key Factors

The following table highlights the main differences between homicidal and suicidal injuries:

Category	Homicidal	Suicidal
1. Circumstantial Evidence	- History of threatening by an enemy, quarrel, or vengeance	- History of financial trouble, recent failure, a previous attempt of suicide, or psychological disturbance
2. Scene of the Crime	- Anywhere - Signs of struggle at the scene in the form of disarranged furniture. No suicide note. - Trace evidences (blood stains, finger prints, hair) are related to the assailant	- Usually indoors, the door locked from inside. - No signs of struggle, a suicide note may be present. - Related to the victim
3. Examination of the Victim a. Sex b. Age c. Clothes d. Cadaveric Spasm e. Signs of Resistance	- May be male or female. - Any age. - Tears of clothes or loss of buttons may be found. - On hair, fiber, or clothes of the assailant - Present	- Usually male. - After puberty. - No tear of clothes or loss of buttons. - Grasping the weapon - Absent
3. Examination of the Wound a. Site b. Number c. Direction	- Any site - Multiple - Any direction	- Within reach of the victim’s hand and against a vital organ. - One fatal wound - Special direction according to the type of the injury
4. Examination of the Weapon a. Present or Absent at the Scene b. Type c. Presence of Finger Print and Blood Stain	- Usually not present - Sharp or heavy blunt - May be present and related to the assailant.	- Present beside the body of the victim or clenched in his hand. - Available and less painful such as sharp weapons. - Related to the victim
5. Examination of the Suspected Assailant a. For Signs of Struggle b. His Blood Grouping and Finger Prints	- Present and coincide with the date of the crime - Coincided with that present at the scene of crime, or on suspected instrument.	- Absent - Not coincided with that present at the scene of crime (because it related to the victim)

Differences between Ante-mortem and Postmortem Wounds

Key Factors

The distinction between ante-mortem and postmortem wounds is vital for understanding the timing and nature of injuries.

Category	Ante-mortem Wound	Postmortem Wound
1. Hemorrhage	- Usually severe. - Arterial spurting. - Blood clots at the base	- Usually slight. - Oozing of venous blood. - No blood clots
2. Edges of Wound	- Gaping between edges. - The edges are everted	- No gapping. - No eversion
3. Vital Reactions (Redness-Swelling-Healing-Sepsis)	Present	Absent
4. Microscopically (Cellular Infiltration)	Present	Absent
5. Serotonin & Histamine	- Increase the serotonin and histamine content in the wound.	- No increase in both.