Forensic medicine

Timing of rigor mortis

Firstly in small muscle groups

(around the eyes and mouth, the jaw and the fingers)

From Head to the legs

In the face 1-4 hs

In the limbs 3-6 hs after death

strength of rigor increasing to a maximum by approximately 18 hours after death

Will remain for up to approximately 50 hours after death

Hypostasis

Aka : livor mortis / postmortem lividity / suggillation

settling of the blood in the lower (dependent) portion

of the body, causing a purplish red discoloration of

the skin

Appear 20m-3h after death

Maximum lividity occurs within 6–12 hours

Hypostasis

The color of hypostasis is variable and may extend from:

pink to dark pink to deep purple

in some congestive hypoxic states, to blue.

in pressure areas such as the shoulder blades, buttock & calvesdiscoloration will be pale.

Some indicators : Cherry-pink: CO poisoning

Dark red: cyanide poisoning

Bronze: Clostridium perfringes infection.

Hypostasis

Hypostasis is not always seen

it may be absent in :

the young, the old

anemic

death from severe blood

loss.

It may be masked :

by dark skin colors

by jaundice

by some dermatological

conditions.

Sites of hypostasis

Depends on the position of the body before death: Supine:

shoulders, buttocks

heels pressing against surface give white color (pale).

Vertical (hanging): distally in legs & feet.

Drowning: غرق chest, upper chest, and upper limbs.

Face-down death: as in epilepsy, drunken victims

whitening around nose & lips.

Hypostasis may also occur in viscera: Heart: mistaken for MI

Lungs: mistaken for pneumonia

Intestine: mistaken for hemorrhagic infarction

Hypostasis vs. Bruises

(Ecchymosis)

Hypostasis Bruises

Dependant areas Any where

Well defined edges Ill defined edges

Blood is retained in

intact capillaries

Blood escapes

through ruptured

capillaries

Superficial Deep into skin

Same level on surface Raised

Pale over pressure

areas

Red

Incision: blood flows

from the cut vessel

(washable)

Incision: blood

coagulates in

tissue

No swelling May be with

swellingWith a bruise,

blood will not flow

from the cut

1.Putrefaction

Start immediately after death at the

cellular level

Become visible by naked eye at

about 3-4 days

Its onset depend on several factors

mainly: temperature and humidity

Two phenomena for putrefaction:

1.autolysis:by digestive enzymes

that released from the

cells

2.bacterial action: most of them

come from the bowel and

clostridium welchii predominates

Start as an area of green discoloration

of the Rt iliac fossa of the ant.

Abdominal wall

The gut bacteria find their way out the

bowel lumen to the abdominal cavity

and the blood vessels

As the bacteria spread through the

blood vessels they decompose

hemoglobin

When present in the superficial vessels

results in linear branching patterns of

variable discoloration of the skin called

“marbling”.

Prostate and uterus are relatively

resistant to putrefaction

Estimating the time of death1.Body temperature :

the best and the most commonly

used

Rectally using long, low-reading

thermometer

2.Rigor mortis

3.Hypostasis:

complete after 6 hrs

4.Biochemical investigation of the CSF:

requires the determination of the

amino acid content & lactic

acid & non-protein nitrogen

content of the CSF.

5.Eye pressure:

eye balls become softer, and less

fluid pressure in the first 3 hrs

6.Gastric emptying:

depend on type of meal and

emotional status.

7.The entomology of dead:

Studying insects & their maggots

which infest the dead body for

estimating the probable time of death.

Different types of insects infest the

dead body at different stages after

death occurs.

Disease of the heart :

Δ Coronary artery disease1-Coronary atherosclerosis:

-The most common cause of sudden death .

-Mostly affects :

* Left Anterior Descending Artery (LADA)

*Right Coronary Artery (RCA)

*Left Common Carotid Artery (LCCA)

Complications of coronary Atherosclerosis :

1-rupture of ulcer atheromatous plaque .

2-sub-intimal hemorrhage .

3-Thrombosis most common

4-aneurysm

5-Ischemia

6-Infarction

7-Peripheral Vascular Diseases

Δ Coronary artery disease ,Cont:

2- Myocardial Infarction :

- Myocardial infarction occurs when there is severe stenosis - 75%

or more of the lumen of a major branch - or complete occlusion

of a coronary artery . but death can be attributed to coronary

artery disease (CAD) with less stenosis if other signs of chronic

myocardial ischemia are apparent (left ventricular

hypertrophy [LVH], fibrosis, previous infarct).

Complications of MI :

1-Rupture of myocardial infarct :

The area of the myocardial infarct is weakest between 3 days

and 1 week after the clinical onset of the infarct and it is

at this time that the weakened area of myocardium may

rupture, leading to sudden death from :

*haemopericardium

*cardiac tamponade

2-Cardiac Aneurysm :

- One week post MI .

- may form at sites of infarction; they may calcify

and they may rupture.

Δ Cardiomyopathies :

HCM (hypertrophic cardiomyopathy):

-inherited (AD)or sporadic

-leading cause of sudden cardiac death in young athletes

-decreased compliance and death due to diastolic dysfunction.

-sudden death may be the first manifistation. RCM (restrictive cardiomyopathy ):

-causes . -enlarged atria and small thin ventricles . –death also due to diastoloic dysfunction

Functional abnormalities

Pathologically, there are no ‘naked eye’ or microscopic

abnormalities in the heart as the defects are at a

molecular level.

Long QT syndrome (LQTS).

short QT syndrome (SQTS).

Brugada syndrome ( It is the major cause of

sudden unexplained syndrom (SUDS) in young men)

Dissecting aortic aneurysm

(90% occur in the ascending aorta either just distal to the aortic valve or the left subclavian artery) Dissecting aneurysms are principally found in individuals with hypertension, but may also be seen in younger individuals with connective tissue defects, such as Marfan syndrome

Rupture of berry aneurysm

Any rise in the blood pressure will cause rupture of the apex

of the aneurysm/ one of the most common causes of

death inyoung to middle-aged adults, if coronary

disease is excluded.

Asthmatic patients

Pulmonary embolism

massive hemopt

ysis

Pneumonia

Respiratory causes :

1-Asthmatic patients : may die suddenly and unexpectedly, without necessarily being in status asthmaticus or even in an acute asthmatic attack.

May be due to Hypoxia and respiratory acidosis. autopsy little or nothing is found, except confirmation of the chronic asthmatic state.2-Pulmonary embolism (most common cause of death in pregnancy) :

In almost every case, the source of the emboli is in the leg veins and pelvic veins. After any tissue trauma, or even surgical operation, especially where immobility or bed rest occurs, deep vein thrombosis develops.3-massive hemoptysis from cavitating pulmonary tuberculosis or from a malignant tumor4-pneumonia

Fatal abdominal

catastrophes

Esophageal varices

Perforation of a peptic

ulcer

GI

Causes

Mesenteric

thrombosis and

infarction ,

Strangulated

intestine

: It is often difficult to identify

the varices at autopsy, as they have

collapsed

Genitourinary system

If a woman in child-bearing age is found unexpectedly death,

complications of pregnancy must be considered like :

Induced abortions

Amniotic fluid emblosim

Ruptured Uterus

ruptured ectopic gestation.

Autopsy-negative causes of

death

Every cause of death we’ve mentioned so far will have

A positive finding manifested during autopsy , now what if

there were NO PSTIVE FINDINGS ?

Then we will probably be left with what we call

Endocrinopathies ( DKA , thyrotoxicosis ..).

Electrolyte abnormalities.

Other:malignant syndrome,Cardiac

dysrhythmia,anaphylaxis

Autopsy-negative causes of death

A-External examination

Signs of malnutrition or dehydration .

Supraclavicular congestion in sudden cardiac

death.

fingernail clubbing in chronic heart disease.

Splinter hemorrhage in infective endocarditis.

Signs of trauma, such as manual strangulation or

low-voltage electrocution.

B-General internal examination

Organs should be examined in situ before manipulation

fluid within any body cavity should be measured (volume) and described (serous, serosanguineous, purulent, chylous, frank blood)

The lungs should be examined for evidence of hyperinflation (asthma, emphysema aquosum)

Evisceration should be performed, or directly observed, by the pathologist

Evaluations for tension pneumothorax should be done before the thoracic cavity is entered

Internal examination of body systems most often implicated in sudden death ( CVS , RS ,CNS , GIS)

Sudden infant death syndrome(SIDS)

Crib death, syndrome in which healthy infants(1 month to a year) die from unknown causes (usually during sleep).

Most deaths due to SIDS occur between 2 and 4 months of age, and incidence increases during cold weather.

More boys than girls fall victim to SIDS..

What are the risk factors for SIDS ?

Smoking, drinking, or drug use during pregnancy.

Poor prenatal care.

Poor prenatal nutrition.

Prematurity or low birth-weight.

No breast feeding.

Mothers younger than 20.

Smoke exposure following birth.

Overheating from excessive sleepwear and bedding.

Stomach sleeping.

Lethal Dose ( LD50 ) : the dose at which 50% of which who

took the dose will die

SPECTRUM OF ALCOHOL USE / ABUSE

Social drinker - drinks occasionally (not frequent)

Heavy drinker - drinks regularly and heavily (Men >7

units/day, Women >5 units/day).

Binge drinker - drinks irregularly and heavily.

Alcohol Absorption

*completed 1-3 hrs

20 % Stomach

80% Upper Small

Intestine

Increase Absorption

• Empty Stomach

• Gasterectomy

• 10 – 20% concentration is the optimum

Decrease Absorption

• Food in Stomach

• Higher Concentration of Alcohol

Physical clues are blood-shot eyes, dilated pupils,

rapid bounding pulse, physical inco-ordination and

nystagmus (jerking eye movements) on lateral gaze

More about alcohol effect

Skin =vasodilation and hypothermia

Respiratory=aspiration pnemonia

Blood=anemia and leukopenia

GIT=liver cirrhosis, pancreatitis, gastritis, peptic Ulcer, portal varices

Reproductive:

=Irregular period ,breast & genital atrophy

=loss of libido ,decrease sperm count, testicular atrophy

Pregnancy=spontaneous abortion ,fetal alcoholic syndrome ,delayed mental and motor development in child lactating from alcoholic mom,

CAUSES OF DEATH IN CHRONIC ALCOHOLICS

1. Trauma. The largest group (26%).

Fire deaths were the most common. Drunken falls were frequently followed by fatal head injury. Murder, Road traffic accidents (pedestrians),Drowning, Accidental poisonings.

2. Incidental Natural Disease (25%). Ischemic heart disease, cerebral hemorrhage, chronic obstructive airways disease and malignancy.

3. Alcohol Related Disease (22%). Bronchopneumonia and lobar pneumonia are the commonest. Cirrhosis of the liver due to ruptured varices or hepatic failure. Many of these deaths occur in hospital and are excluded from forensic practice. Alcoholic cardiomyopathy and pancreatitis are other rarely reported causes of death.

4. Acute Intoxication (24%).

Possible mechanisms of death from simple intoxication:

1. Simple depression of the respiratory centre in lower brain stem by alcohol itself.

2. Inhalation of vomit due to coma.

3. Postural asphyxia (obstruction of the upper airway by the swallowed tongue during coma.

5.'Obscure' cause of Death is noted in a variable proportion of cases, up to 10%.

Asphyxial Conditions

Phases of Asphyxia

1- Forced respiration: Due to Stimulation of respiratory center

Clinical Picture: Dyspnea.

2- Stage of convulsions:

It is due to cerebral irritation

Clinical Picture: Convulsions, cyanosis, Hypertension, loss of consciousness, constricted pupil.

• 3- Paralysis: Clinical Picture:loss of consciousness, flaccid muscles & lost reflexes, deep cyanosis, dilated pupils, irregular breathing.

Death occur after 5 minutes

Classical Signs of Asphyxia

Petechial hemorrhages in the skin of the face and in

the lining of the eyelids.

In the viscera, they are called Tardieu spots.

Congestion & edema of the face.

Cyanosis (blue discoloration) of the skin of the face.

Right heart congestion and abnormal fluidity of the blood.

Petechial Hemorrhages

Tardieu Spots

Survivors of Asphyxial Episodes suffer

from:

Pain and tenderness around the neck.

Damage to the larynx and hyoid bone.

Dried saliva around the mouth.

Cyanosis, congestion, edema and petechiae of the

structures above the level of compression.

Hemorrhage from the mouth, nose and ears.

Incontinence of feces and urine.

Strangulation

Manual Strangulation

Throttling.

The application of

pressure to the neck

using the hands.

Seen usually in

Homicides.

Bruises and abrasions

in the front of the neck

and lower jaw.

Ligature strangulation

May be homicidal, suicidal or accidental.

Involves the application of pressure to the neck by an item capable of constricting the neck, such as a scarf, neck-tie, stocking or telephone cable…etc.

Ligature mark.

Hanging

Suspension of the body by the neck.

Ligature mark (V shaped) with discontinuity at

suspension point.

discontinuity at suspension point

Compressional and Positional

Asphyxia

Pressure on the trunk (chest and/or abdomen) can result in an inability to breathe effectively and result in death.

Traumatic, and crush asphyxia.

Persons with impaired neurological function are more susceptible.

Smothering

The physical occlusion of the nose and mouth resulting inasphyxia.

May leave no ‘asphyxial signs’ in survivors or thedeceased.

If the individuals are unable to struggle, owing to extremesof age or intoxication, for example, they may have noevidence of injury, including around the mouth or nose.

Occasionally, examination will reveal intraoral injury(including bruising or laceration of the insides of the lips orbruising of the gums in an edentulous individual) and softtissue dissection of the face may reveal subcutaneousbruising around the mouth and nose.

Smothering

Autoerotic Asphyxia Autoerotic asphyxia is the term used to describe

those fatalities occurring during some form of

solitary sexual activity.

Sexual asphyxia, sex hanging, asphyxiophilia,

Kotzwarrism, autoasphyxiophilia and

hypoxyphilia.

The recurrent feature tends to be the use of a

device, appliance or restraint that causes neck

compression, leading to cerebral hypoxia, with the aim of heightening the sexual response.